DHC Working Group                                                 Y. Cui
Internet-Draft                                                   H. Wang
Intended status: Standards Track                                  L. Sun
Expires: April 18, September 22, 2016                          Tsinghua University
                                                                T. Lemon
                                                                 Nominum
                                                               I. Farrer
                                                                S. Zoric
                                                     Deutsche Telekom AG
                                                        October 16, 2015
                                                          March 21, 2016

                YANG Data Model for DHCPv6 Configuration
                     draft-ietf-dhc-dhcpv6-yang-00
                     draft-ietf-dhc-dhcpv6-yang-01

Abstract

   There has no unified method to configure DHCPv6 server ,relay and
   client itself, always pre-configured manually by operators.

   IETF netmod WG has developed a general data model for NETCONF
   protocol, YANG data model [RFC6020].

   This document defines describes a YANG data model [RFC6020] for the
   configuration and management of DHCPv6 server, DHCPv6 relay and DHCPv6 client.  With
   this model, the operators can configure servers, relays and manage the devices by
   using NETCONF. clients.

Requirements Language

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in [RFC2119].

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at http://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on April 18, September 22, 2016.

Copyright Notice

   Copyright (c) 2015 2016 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Objectives  . . . . . . . . . . . . . . . . . . . . . . . . .   3
     2.1.  DHCPv6 server . . . . . . . . . . . . . . . . . . . . . .   4
     2.2.  DHCPv6 relay  . . . . . . . . . . . . . . . . . . . . . .   4
     2.3.  DHCPv6 client . . . . . . . . . . . . . . . . . . . . . .   4
   3.  DHCPv6 Tree Diagrams  . . . . . . . . . . . . . . . . . . . .   4
     3.1.   3
     2.1.  DHCPv6 Server Tree Diagrams . . . . . . . . . . . . . . .   4
     3.2.   3
     2.2.  DHCPv6 Relay Tree Diagrams  . . . . . . . . . . . . . . .  12
     3.3.
     2.3.  DHCPv6 Client Tree Diagrams . . . . . . . . . . . . . . .  14
     3.4.  15
     2.4.  Notifications Mechanism for DHCPv6  . . . . . . . . . . .  19
   4.  20
   3.  DHCPv6 YANG Model . . . . . . . . . . . . . . . . . . . . . .  21
   5.  22
   4.  Security Considerations (TBD) . . . . . . . . . . . . . . . .  80
   6.  86
   5.  IANA Considerations (TBD) . . . . . . . . . . . . . . . . . .  80
   7.  87
   6.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  80
   8.  87
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  81
     8.1.  87
     7.1.  Normative References  . . . . . . . . . . . . . . . . . .  81
     8.2.  87
     7.2.  Informative References  . . . . . . . . . . . . . . . . .  81  87
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  83  89

1.  Introduction

   DHCPv6 [RFC3315] is widely used for supplying configuration and other
   relevant parameters to clients in IPv6 networks.  This document
   defines a DHCPv6 YANG data model model, containing sub-modules for the
   configuration and management of DHCPv6 server, DHCPv6 relay servers, relays and DHCPv6 client.  With
   this model, clients.
   A single YANG model covering all of these elements provides an
   operator with a common interface for the operators can configure and manage management of the devices by
   using NETCONF.

   Model include three sub-modules:

   o  DHCPv6 server

   o  DHCPv6 relay

   o  DHCPv6 client

   For DHCPv6 client configuration, it is worth noting that as entire
   DHCPv6
   itself a device configuration protocol, deployment in their network.

   Since the intention of this
   document is not to replace client configuration publication of the original DHCPv6 options specification, there
   have been a large number of addional documents that update the
   protocol's operation, add new functions and define new options.  The
   YANG model described in this document incorporates all relevent
   changes.  A full list of the documents which have been considedered
   in the development of this model is included in Appendix A.

   IF - Commment - Does anyone have this list?
   It is worth noting that as DHCPv6 is itself a device configuration
   protocol, it is not the intention of this document to replace the
   configuration of DHCPv6 options and parameters over using the DHCPv6
   protocol with the configuration of DHCPv6 options and parameters over using NETCONF/YANG.
   The DHCPv6 client model is intended for the configuration of the
   DHCPv6 client function and also for obtaining read-only state data
   from the client which has been learnt via the normal DHCPv6 message
   flow.  This gives an operator a better method for managing DHCPv6
   clients and simplifies troubleshooting.

1.1.  Terminology

   The reader should be familiar with the terms defined in DHCPv6
   [RFC3315] and other relevant documents.

   The DHCPv6 tree diagrams provide a concise representation of a YANG
   module to help readers the reader understand the module structure.  The
   meaning
   if of the symbols in these diagrams is are as follows:

   o  Brackets "[" and "]" enclose list keys.

   o  Braces "{" and "}" enclose feature content.

   o  Parentheses "(" and ")" enclose choice and case nodes, and case
      nodes are also marked with a colon (":").

   o  Symbols after data node names: "?" means an optional node, and "*"
      denotes a list and leaf-list.

   o  Abbreviations before data node names: "rw" means configuration
      data (read-write), and "ro" means state data (read-only).

2.  Objectives

   This document defines a YANG data model that can be used to configure
   and manage DHCPv6 server, DHCPv6 relay and DHCPv6 client.

2.1.  DHCPv6 server

   DHCPv6 server parameters.

2.2.  DHCPv6 relay

   DHCPv6 relay parameters.

2.3.  DHCPv6 client

   DHCPv6 client parameters.

3.  DHCPv6 Tree Diagrams

3.1.

2.1.  DHCPv6 Server Tree Diagrams

+--rw dhcpv6
   +--rw server
      +--rw serv-attributes
      |  +--rw name                            string
      |  +--rw duid                            duidtype
      |  +--rw enable                          boolean
      |  +--rw interfaces-config*              string
      |  +--rw ipv6-address?                   inet:ipv6-address
      |  +--rw description?                    string
      |  +--rw pd-function                     boolean
      |  +--rw stateless-service               boolean
      |  +--rw rapid-commit                    boolean
      |  +--rw vendor-info
      |     +--rw ent-num                      uint32
      |     +--rw data*                        string
      +--rw option-sets
      |  +--rw option-set* [option-set-id]
      |     +--rw option-set-id                uint8                -> /dhcpv6/server/option-sets/option-set
      |     +--rw new-or-standard-option* [option-code]
      |     |  +--rw option-code               uint16
      |     |  +--rw option-name               string
      |     |  +--rw option-description        string
      |     |  +--rw option-reference?         string
      |     |  +--rw option-value              string
      |     +--rw user-class-value?            string
      |     +--rw enterprise-number?           uint32
      |     +--rw store-client-link-layer?     boolean
      |     +--rw preference-option
      |     |  +--rw enable                    boolean
      |     |  +--rw preference-value          uint8
      |     +--rw sip-server-option
      |     |  +--rw enable                    boolean
      |     |  +--rw sip-server* [sip-serv-id]
      |     |     +--rw sip-serv-id            uint8
      |     |     +--rw sip-serv-domain-name   string
      |     |     +--rw sip-serv-addr          inet:ipv6-address
      |     +--rw dns-config-option
      |     |  +--rw enable                    boolean
      |     |  +--rw dns-server* [dns-serv-id]
      |     |  |  +--rw dns-serv-id            uint8
      |     |  |  +--rw dns-serv-addr          inet:ipv6-address
      |     |  +--rw domain-search-list        string
      |     +--rw nis-config-option
      |     |  +--rw enable                    boolean
      |     |  +--rw nis-server* [nis-serv-id]
      |     |     +--rw nis-serv-id            uint8
      |     |     +--rw nis-serv-addr          inet:ipv6-address
      |     +--rw nis-plus-config-option
      |     |  +--rw enable                    boolean
      |     |  +--rw nis-plus-server* [nis-plus-serv-id]
      |     |     +--rw nis-plus-serv-id       uint8
      |     |     +--rw nis-plus-serv-addr     inet:ipv6-address
      |     +--rw info-refresh-time-option
      |     |  +--rw enable                    boolean
      |     |  +--rw info-refresh-time         yang:timeticks
      |     +--rw cli-fqdn-option
      |     |  +--rw enable                    boolean
      |     |  +--rw server-initiate-update    boolean
      |     |  +--rw client-initiate-update    boolean
      |     |  +--rw modify-name-from-cli      boolean
      |     +--rw timezone-option
      |     |  +--rw enable                    boolean
      |     |  +--rw tz-posix                  string
      |     |  +--rw tz-database               string
      |     +--rw ntp-server-option
      |     |  +--rw enable                    boolean
      |     |  +--rw ntp-server* [ntp-serv-id]
      |     |     +--rw ntp-serv-id            uint8
      |     |     +--rw ntp-serv-addr          inet:ipv6-address
      |     |     +--rw ntp-serv-mul-addr      inet:ipv6-address
      |     |     +--rw ntp-serv-fqdn          string
      |     +--rw sntp-server-option
      |     |  +--rw enable                    boolean
      |     |  +--rw sntp-server* [sntp-serv-id]
      |     |     +--rw sntp-serv-id           uint8
      |     |     +--rw sntp-serv-addr         inet:ipv6-address
      |     +--rw network-boot-option
      |     |  +--rw enable                    boolean
      |     |  +--rw boot-file* [boot-file-id]
      |     |     +--rw boot-file-id           uint8
      |     |     +--rw suitable-arch-type*    uint16
      |     |     +--rw suitable-net-if*       uint32
      |     |     +--rw boot-file-url          string
      |     |     +--rw boot-file-paras* [para-id]
      |     |        +--rw para-id             uint8
      |     |        +--rw parameter           string
      |     +--rw dslite-option
      |     |  +--rw enable                    boolean
      |     |  +--rw dslite-aftr-name          string
      |     +--rw kerberos-option
      |     |  +--rw enable                    boolean
      |     |  +--rw default-realm-name        string
      |     |  +--rw kdc-info* [kdc-id]
      |     |     +--rw kdc-id                 uint8
      |     |     +--rw priority               uint16
      |     |     +--rw weight                 uint16
      |     |     +--rw transport-type         uint8
      |     |     +--rw port-number            uint16
      |     |     +--rw kdc-ipv6-addr          inet:ipv6-address
      |     |     +--rw realm-name             string
      |     +--rw addr-selection-option
      |     |  +--rw enable                    boolean
      |     |  +--rw a-bit-set                 boolean
      |     |  +--rw p-bit-set                 boolean
      |     |  +--rw policy-table* [policy-id]
      |     |     +--rw policy-id              uint8
      |     |     +--rw label                  uint8
      |     |     +--rw precedence             uint8
      |     |     +--rw prefix-len             uint8
      |     |     +--rw prefix                 inet:ipv6-prefix
      |     +--rw sol-max-rt-option
      |     |  +--rw enable                    boolean
      |     |  +--rw sol-max-rt-value          yang:timeticks
      |     +--rw inf-max-rt-option
      |     |  +--rw enable                    boolean
      |     |  +--rw inf-max-rt-value          yang:timeticks
      |     +--rw pcp-server-option
      |     |  +--rw enable                    boolean
      |     |  +--rw pcp-server* [pcp-serv-id]
      |     |     +--rw pcp-serv-id            uint8
      |     |     +--rw pcp-serv-addr*         inet:ipv6-address
      |     +--rw s46-rule-option
      |     |  +--rw enable                    boolean
      |     |  +--rw s46-rule* [rule-id]
      |     |     +--rw rule-id                uint8
      |     |     +--rw rule-type              enumeration
      |     |     +--rw ea-len                 uint8
      |     |     +--rw prefix4-len            uint8
      |     |     +--rw ipv4-prefix            inet:ipv4-prefix
      |     |     +--rw prefix6-len            uint8
      |     |     +--rw ipv6-prefix            inet:ipv6-prefix
      |     |     +--rw port-parameter
      |     |        +--rw offset              uint8
      |     |        +--rw psid-len            uint8
      |     |        +--rw psid                uint16
      |     +--rw s46-br-option
      |     |  +--rw enable                    boolean
      |     |  +--rw br* [br-id]
      |     |      +--rw br-id                 uint8
      |     |      +--rw br-ipv6-addr          inet:ipv6-address
      |     +--rw s46-dmr-option
      |     |  +--rw enable                    boolean
      |     |  +--rw dmr* [dmr-id]
      |     |      +--rw dmr-id                uint8
      |     |      +--rw dmr-prefix6-len        uint8       inet:ipv6-address
      |     |      +--rw dmr-ipv6-prefix       inet:ipv6-prefix
      |     +--rw s46-v4-v6-binding-option operator-option-ipv6-address
      |     |  +--rw enable                    boolean
      |        +--rw ce* [ce-id]     |  +--rw ce-id                  uint8 operator-ipv6-addr* [operator-ipv6-addr-id]
      |           +--rw ipv4-addr              inet:ipv4-address     |      +--rw bind-prefix6-len operator-ipv6-addr-id uint8
      |           +--rw bind-ipv6-prefix       inet:ipv6-prefix     |      +--rw port-parameter operator-ipv6-addr    inet:ipv6-address
                  |     +--rw offset              uint8 operator-option-single-flag
      |              +--rw psid-len            uint8     |  +--rw psid                uint16
           +--rw network-ranges enable                    boolean
      |  +--rw option-set [option-set-id]     |  +--rw network-range* [network-range-id] flag* [flag-id]
      |     |      +--rw network-range-id flag-id               uint8
      |     |      +--rw network-description          string flag-value            boolean
      |     +--rw network-prefix               inet:ipv6-prefix operator-option-ipv6-prefix
      |     |  +--rw inherit-option-set enable                    boolean
      |     +--rw option-set [option-set-id]     |  +--rw address-pools operator-ipv6-prefix* [operator-ipv6-prefix-id]
      |     |     +--rw address-pool* [pool-id]
           | operator-ipv6-prefix-id   uint8
      |     |     +--rw pool-id operator-ipv6-prefix6-len uint8
      |     |  |     +--rw pool-prefix operator-ipv6-prefix      inet:ipv6-prefix
            |     +--rw operator-option-int32
      |     |  +--rw start-address          inet:ipv6-address
           | enable                    boolean
      |     |  +--rw end-address            inet:ipv6-address
           | int32val* [int32val-id]
      |     |     +--rw renew-time             yang:timeticks int32val-id            uint8
      |     |     +--rw int32val                           uint32
      |     +--rw rebind-time            yang:timeticks operator-option-int16
      |     |  +--rw enable                    boolean
      |     |  +--rw preferred-lifetime     yang:timeticks int16val* [int16val-id]
      |     |     +--rw int16val-id            uint8
      |     |     +--rw valid-lifetime         yang:timeticks int16val                           uint16
      |     +--rw operator-option-int8
      |     |  +--ro total-ipv6-count       uint64  +--rw enable                    boolean
      |     |  +--rw int8* [int8val-id]
      |  +--ro used-ipv6-count        uint64     |     +--rw int8val-id             uint8
      |     |     +--rw utilization-ratio      threshold int8val                      uint8
      |     +--rw operator-option-uri
      |     |  +--rw inherit-option-set enable                    boolean
      |     |  |  +--rw option-set [option-set-id]
           | uri* [uri-id]
      |     |     +--rw reserved-addresses uri-id                 uint8
      |     |     +--rw uri                              string
      |     +--rw static-binding* [cli-id] operator-option-textstring
      |     |  +--rw enable                    boolean
      |     |  +--rw cli-id           uint32 textstring* [textstring-id]
      |     |     +--rw textstring-id          uint8
      |     |     +--rw duid             duidtype
           | textstring                       string
      |     +--rw operator-option-var-data
      |     |  +--rw reserv-addr*     inet:ipv6-address
           | enable                    boolean
      |     |  +--rw other-reserv-addr*  inet:ipv6-address var-data* [var-data-id]
      |     |     +--rw var-data-id            uint8
      |     |     +--rw var-data               binary
      |     +--rw operator-option-dns-wire
      |     |  +--rw enable                    boolean
      |     |  +--rw operator-option-dns-wire* [operator-option-dns-wire-id]
      |     |     +--rw operator-option-dns-wire-id  uint8
      |     |     +--rw operator-option-dns-wire     string
      |     +--rw s46-v4-v6-binding-option
      |        +--rw enable                    boolean
      |        +--rw ce* [ce-id]
      |           +--rw ce-id                  uint8
      |           +--rw ipv4-addr              inet:ipv4-address
      |           +--rw bind-prefix6-len       uint8
      |           +--rw bind-ipv6-prefix       inet:ipv6-prefix
      |           +--rw port-parameter
      |              +--rw offset              uint8
      |              +--rw psid-len            uint8
      |              +--rw psid                uint16
      +--rw network-ranges
      |  +--rw option-set [option-set-id]
      |  +--rw network-range* [network-range-id]
      |     +--rw network-range-id             uint8
      |     +--rw network-description          string
      |     +--rw network-prefix               inet:ipv6-prefix
      |     +--rw inherit-option-set           boolean
      |     +--rw option-set [option-set-id]
      |     +--rw address-pools
      |     |  +--rw address-pool* [pool-id]
      |     |  |  +--rw pool-id                uint8
      |     |  |  +--rw pool-prefix            inet:ipv6-prefix
      |     |  |  +--rw start-address          inet:ipv6-address
      |     |  |  +--rw end-address            inet:ipv6-address
      |     |  |  +--rw renew-time             yang:timeticks
      |     |  |  +--rw rebind-time            yang:timeticks
      |     |  |  +--rw preferred-lifetime     yang:timeticks
      |     |  |  +--rw valid-lifetime         yang:timeticks
      |     |  |  +--ro total-ipv6-count       uint64
      |     |  |  +--ro used-ipv6-count        uint64
      |     |  |  +--rw utilization-ratio      threshold
      |     |  |  +--rw inherit-option-set     boolean
      |     |  |  +--rw option-set [option-set-id]
      |     |  |  +--rw reserved-addresses
      |     |  |     +--rw static-binding* [cli-id]
      |     |  |     |  +--rw cli-id           uint32
      |     |  |     |  +--rw duid             duidtype
      |     |  |     |  +--rw reserv-addr*     inet:ipv6-address
      |     |  |     +--rw other-reserv-addr*  inet:ipv6-address
      |     |  +--ro binding-info* [cli-id]
      |     |     +--ro cli-id                 uint32
      |     |     +--ro duid                   duidtype
      |     |     +--ro cli-ia* [iaid]
      |     |        +--ro ia-type             string
      |     |        +--ro iaid                uint32
      |     |        +--ro cli-addr*           inet:ipv6-address
      |     |        +--ro pool-id?            uint8
      |     +--rw prefix-pools
      |     |  +--rw prefix-pool* [pool-id]
      |     |  |  +--rw pool-id                uint8
      |     |  |  +--rw prefix                 inet:ipv6-prefix
      |     |  |  +--rw prefix-length          uint8
      |     |  |  +--rw renew-time             yang:timeticks
      |     |  |  +--rw rebind-time            yang:timeticks
      |     |  |  +--rw preferred-lifetime     yang:timeticks
      |     |  |  +--rw valid-lifetime         yang:timeticks
      |     |  |  +--rw utilization-ratio      threshold
      |     |  |  +--rw inherit-option-set     boolean
      |     |  |  +--rw option-set [option-set-id]
      |     |  |  +--rw reserved-prefixes
      |     |  |     +--rw static-binding* [cli-id]
      |     |  |     |  +--rw cli-id           uint32
      |     |  |     |  +--rw duid             duidtype
      |     |  |     |  +--rw reserv-prefix-len  uint8
      |     |  |     |  +--rw reserv-prefix    inet:ipv6-prefix
      |     |  |     +--rw exclude-prefix-len  uint8
      |     |  |     +--rw exclude-prefix      inet:ipv6-prefix
      |     |  |     +--rw other-reserv-prefix*  [reserv-id]
      |     |  |        +--rw reserv-id        uint8
      |     |  |        +--rw prefix-len       uint8
      |     |  |        +--rw prefix           inet:ipv6-prefix
      |     |  +--ro binding-info* [cli-id]
      |     |     +--ro cli-id                 uint32
      |     |     +--ro duid                   duidtype
      |     |     +--ro cli-iapd* [iaid]
      |     |        +--ro iaid                uint32
      |     |        +--ro cli-prefix*         uint32
      |     |        +--ro cli-prefix-len*     uint8
      |     |        +--ro pool-id?            uint8
      |     +--rw hosts
      |        +--rw host* [cli-id]
      |           +--rw cli-id                 uint32
      |           +--rw duid                   duidtype
      |           +--rw inherit-option-set     boolean
      |           +--rw option-set [option-set-id]
      |           +--rw nis-domain-name?       string
      |           +--rw nis-plus-domain-name?  string
      +--rw relay-opaque-paras
      |  +--rw relays* [relay-name]
      |     +--rw relay-name                   string
      |     +--rw interface-info* [if-name]
      |     |  +--rw if-name                   string
      |     |  +--rw interface-id              string
      |     +--rw subscribers* [subscriber]
      |     |  +--rw subscriber                uint8
      |     |  +--rw subscriber-id             string
      |     +--rw remote-host* [ent-num]
      |        +--rw ent-num                   uint32
      |        +--rw remote-id                 string
      +--rw rsoo-enabled-options
      |  +--rw rsoo-enabled-option* [option-code]
      |     +--rw option-code                  uint16
      |     +--rw description                  string
      +--ro packet-stats
         +--ro solicit-count                   uint32
         +--ro request-count                   uint32
         +--ro renew-count                     uint32
         +--ro rebind-count                    uint32
         +--ro decline-count                   uint32
         +--ro release-count                   uint32
         +--ro info-req-count                  uint32
         +--ro advertise-count                 uint32
         +--ro confirm-count                   uint32
         +--ro reply-count                     uint32
         +--ro reconfigure-count               uint32
         +--ro relay-forward-count             uint32
         +--ro relay-reply-count               uint32

                   Figure 1: DHCPv6 Data Model Structure

   Introduction of important nodes:

   o  serv-attributes: This container contains basic attributes of a
      DHCPv6 server such as DUID, server name and so on.  Some optional
      functions that can be provided by the server is also included.

   o  duid: Each server and client has only one DUID (DHCP Unique
      Identifier).  The DUID here identifies a unique DHCPv6 server for
      clients.  DUID consists of a two-octet type field and an arbitrary
      length (no more than 128 bytes) content field.

   o  pd-function: Whether the server can act as a delegating router to
      perform prefix delegation ([RFC3633]).

   o  operator-option-ipv6-address, operator-option-single-flag,
      operator-option-ipv6-prefix, operator-option-int32, operator-
      option-int16, operator-option-int8, operator-option-uri, operator-
      option-textstring, operator-option-var-data, operator-option-dns-
      wire: are generic option formats described in ([RFC7227]).

   o  stateless-service: A boolean value specifies whether the server
      support client-server exchanges involving two messages defined in
      ([RFC3315]).

   o  rapid-commit: Setting the value to '1' represents the server
      support the Solicit-Reply message exchange. '0' means the server
      will simply ignore the Rapid Commit option in Solicit message.

   o  interfaces-config: A leaf list to denote which one or more
      interfaces the server should listen on.  The default value is to
      listen on all the interfaces.  This node is also used to set a
      unicast address for the server to listen with a specific
      interface.  For example, if people want the server to listen on a
      unicast address with a specific interface, he can use the format
      like "eth1/2001:db8::1".

   o  option-sets: DHCPv6 employs various options to carry additional
      information and parameters in DHCP messages.  This container
      defines all the possible options that need to be configured at the
      server side.  The relevant RFCs that define those options include:
      [RFC3315], [RFC3319], [RFC3646], [RFC3898], [RFC4242], [RFC4704],
      [RFC4833], [RFC5908], [RFC5970], [RFC4075], [RFC6334], [RFC6784],
      [RFC7078], [RFC7083], [RFC7291], [RFC7598].

   o  option-set: A server may allow different option sets to be
      configured for different conditions (i.e. different networks,
      clients and etc).  This "option-set" list enables various sets of
      options being defined and configured in a single server.
      Different sets are distinguished by the key called "option-set-
      id".  All the possible options discussed above are defined in the
      list and each option is corresponding to a container.  Since all
      the options in the list are optional, each container in this list
      has a boolean parameter called "enable" to indicate whether this
      option (container) will be included in the current option set or
      not.  With the "new-or-standard-option" list, it is easy to extend
      the model when new options are defined.  We could also use the
      "new-or-standard-option" list to define an IETF standard option.

   o  network-ranges: This model supports a hierarchy to achieve dynamic
      configuration.  That is to say we could configure the server at
      different levels through this model.  The top level is a global
      level which is defined as the container "network-ranges".  The
      following levels are defined as sub-containers under it.  The
      "network-ranges" contains the parameters (e.g. option-sets) that
      would be allocated to all the clients served by this server.

   o  network-range: Under the "network-ranges" container, a "network-
      range" list is defined to configure the server at a network level
      which is also considered as the second level.  Different network
      are identified by the key "network-range-id".  This is because a
      server may have different configuration parameters (e.g. option
      sets) for different networks.

   o  address-pools: Under the "network-range" list, a container
      describes the DHCPv6 server's address pools for a specific network
      is defined.  This container supports the server to be configured
      at a pool level.

   o  address-pool: A DHCPv6 server can be configured with several
      address pools for a specific network.  This list defines such
      address pools which are distinguish by the key called "pool-id".

   o  binding-info: A list records a binding information for each DHCPv6
      client that has already been allocated IPv6 addresses.

   o  prefix-pools: If a server supports prefix delegation function,
      this container under the "network-range" list will be valid to
      define the delegating router's prefix pools for a specific
      network.  This container also supports the server to be configured
      at a pool level.

   o  prefix-pool: Similar to server's address pools, a delegating
      router can also be configured with multiple prefix pools specified
      by a list called "prefix-pool".

   o  binding-info: A list records a binding information for each DHCPv6
      requesting router that has already been configured IPv6 prefixes.

   o  hosts: A server may also desire to be configured at a host level
      under some circumstances.  This container include a list called
      "host" to allow the server carrying different parameters (e.g.
      option sets) for different hosts.

   o  relay-opaque-paras: This container contains some opaque values in
      Relay Agent options that need to be configured on the server side
      only for value match.  Such Relay Agent options include Interface-
      Id option, Remote-Id option and Subscriber-Id option.

   o  rsoo-enabled-options: [RFC6422] requires that the server SHOULD
      have an administrator-configurable list of RSOO-enabled options.
      This container include a list called "rsoo-enabled-option" to
      allow new RSOO-enabled options to be defined at the server side.

   o  packet-stats: A container presents the packet statistics related
      to the DHCPv6 server.

3.2.

2.2.  DHCPv6 Relay Tree Diagrams

   +--rw dhcpv6
      +-- ...
      |
      +--rw relay
         +--rw relay-attributes
         |  +--rw name                            string
         |  +--rw enable                          boolean
         |  +--rw description?                    string
         |  +--rw dest-addrs*                     inet:ipv6-address
         |  +--rw subscribers* [subscriber]
         |  |  +--rw subscriber                   uint8
         |  |  +--rw subscriber-id                string
         |  +--rw remote-host* [entNum]
         |  |  +--rw ent-num                      uint32
         |  |  +--rw remote-id                    string
         |  +--rw vendor-info
         |     +--rw ent-num                      uint32
         |     +--rw data*                        string
         +--rw relay-supplied-options-option
         |  +--rw rsoo-set* [rsoo-set-id]
         |     +--rw rsoo-set-id               uint8
         |     +--rw erp-local-domain-name-option
         |        +--rw enable                 boolean
         |        +--rw erp-for-client* [cli-id]
         |           +--rw cli-id              uint32
         |           +--rw duid                duidtype
         |           +--rw erp-name            string
         +--rw relay-if* [if-name]
         |  +--rw if-name                   string
         |  +--rw enable                    boolean
         |  +--rw ipv6-address?             ietf:ipv6-address
         |  +--rw interface-id?             string
         |  +--rw rsoo-set [rsoo-set-id]
         |  +--rw pd-route* [pd-route-id]
         |  |  +--rw pd-route-id            uint8
         |  |  +--rw requesting-router-id   uint32
         |  |  +--rw delegating-router-id   uint32
         |  |  +--rw next-router            inet:ipv6-address
         |  |  +--rw last-router            inet:ipv6-address
         |  +--rw next-entity* [dest-addr]
         |     +--rw dest-addr              inet:ipv6-address
         |     +--rw available              boolean
         |     +--rw multicast              boolean
         |     +--rw server                 boolean
         |     +--ro packet-stats
         |        +--ro cli-packet-rvd-count  uint32
         |        +--ro solicit-rvd-count     uint32
         |        +--ro request-rvd-count     uint32
         |        +--ro renew-rvd-count       uint32
         |        +--ro rebind-rvd-count      uint32
         |        +--ro decline-rvd-count     uint32
         |        +--ro release-rvd-count     uint32
         |        +--ro info-req-rvd-count    uint32
         |        +--ro relay-for-rvd-count   uint32
         |        +--ro relay-rep-rvd-count   uint32
         |        +--ro packet-to-cli-count   uint32
         |        +--ro adver-sent-count      uint32
         |        +--ro confirm-sent-count    uint32
         |        +--ro reply-sent-count      uint32
         |        +--ro reconfig-sent-count   uint32
         |        +--ro relay-for-sent-count  uint32
         |        +--ro relay-rep-sent-count  uint32
         +--ro relay-stats
            +--ro cli-packet-rvd-count            uint32
            +--ro relay-for-rvd-count             uint32
            +--ro relay-rep-rvd-count             uint32
            +--ro packet-to-cli-count             uint32
            +--ro relay-for-sent-count            uint32
            +--ro relay-rep-sent-count            uint32
            +--ro discarded-packet-count          uint32

   Introduction of important nodes:

   o  relay-attributes: A container describes some basic attributes of
      the relay agent including some relay agent specific options data
      that need to be configured previously.  Such options include
      Remote-Id option and Subscriber-Id option.

   o  dest-addrs: Each DHCPv6 relay agent may be configured with a list
      of destination addresses.  This node defines such a list of IPv6
      addresses that may include unicast addresses, multicast addresses
      or other addresses.

   o  relay-supplied-options-option: DHCPv6 relay agent could provide
      some information that would be useful to DHCPv6 client.  Since
      relay agent cannot provide options directly to the client,
      [RFC6422] defines RSOO-enabled options to propose options for the
      server to send to the client.  This container modelled models such RSOO-
      enabled options.

   o  rsoo-set: This list under the "relay-supplied-options-option"
      container is similar to the "option-set" defined in server
      feature.  It allows the relay to implement several sets of RSOO-
      enabled options for different interfaces.  The list only include
      the EAP Re-authentication Protocol (ERP) Local Domain Name DHCPv6
      Option defined in [RFC6440], since it is the only one RSOO-enabled
      options accepted by IANA so far.

   o  relay-if: A relay agent may have several interfaces, we should
      provide a way to configure and manage parameters on the interface-
      level.  A list that describes specific interfaces and their
      corresponding parameters is employed to fulfil the configfuration.
      Here we use a string called "if-name" as the key of list.

   o  pd-route: A sub-container of "relay-if" which describes the route
      for delegated prefixes into the provider edge router.

   o  next-entity: This node defines a list that is used to describe the
      next hop entity of this relay agent.  Different entities are
      distinguished by their addresses.

   o  packet-stats: A container shows packet state information of a
      specific data communication.

   o  relay-stats: The "relay-stats" container records and presents the
      overall packet statistics of the relay agent.

3.3.

2.3.  DHCPv6 Client Tree Diagrams

   +--rw dhcpv6
      +-- ...
      |
      +--rw client
         +--rw client-if* [if-name]
            +--rw if-name                      string
            +--rw cli-id                       uint32
            +--rw duid                         duidtype
            +--rw enable                       boolean
            +--rw description?                 string
            +--rw pd-function                  boolean
            +--rw rapid-commit                 boolean
            +--rw mo-tab
            |  +--rw m-tab                     boolean
            |  +--rw o-tab                     boolean
            +--rw oro-options
            |  +--rw oro-option* [option-code]
            |     +--rw option-code            uint16
            |     +--rw description            string
            +--rw client-configured-options
            |  +--rw new-or-standard-cli-option* [option-code]
            |  |  +--rw option-code            uint16
            |  |  +--rw option-name            string
            |  |  +--rw option-description     string
            |  |  +--rw option-reference?      string
            |  |  +--rw option-value           string
            |  +--rw user-class-option
            |  |  +--rw enable                 boolean
            |  |  +--rw user-class* [user-class-id]
            |  |     +--rw user-class-id       uint8
            |  |     +--rw user-class-info     string
            |  +--rw vendor-class-option
            |  |  +--rw enable                 boolean
            |  |  +--rw ent-num                uint32
            |  |  +--rw data*                  string
            |  +--rw client-fqdn-option
            |  |  +--rw enable                 boolean
            |  |  +--rw fqdn                   string
            |  |  +--rw server-initiate-update boolean
            |  |  +--rw client-initiate-update boolean
            |  +--rw client-architecture-type-option
            |  |  +--rw enable                 boolean
            |  |  +--rw architecture-types* [type-id]
            |  |  |  +--rw type-id             uint16
            |  |  |  +--rw most-preferred      boolean
            |  +--rw client-network-interface-option
            |  |  +--rw enable                 booelan
            |  |  +--rw type                   uint8
            |  |  +--rw major                  uint8
            |  |  +--rw minor                  uint8
            |  +--rw kerberos-principal-name-option
            |  |  +--rw enable                 boolean
            |  |  +--rw principal-name         string
            |  +--rw client-link-layer-addr-option
            |     +--rw enable                 boolean
            |     +--rw link-layer-type        uint16
            |     +--rw link-layer-addr        string
            +--ro identity-associations
            |  +--ro identity-association* [iaid]
            |     +--ro iaid                   uint32
            |     +--ro ia-type                string
            |     +--ro ipv6-addr*             inet:ipv6-address
            |     +--ro ipv6-prefix*           inet:ipv6-prefix
            |     +--ro prefix-length*         uint8
            |     +--ro t1-time                yang:timeticks
            |     +--ro t2-time                yang:timeticks
            |     +--ro preferred-lifetime     yang:timeticks
            |     +--ro valid-lifetime         yang:timeticks
            +--ro if-other-paras
            |  +--ro uni-dhcpv6-serv-addr      inet:ipv6-address
            |  +--ro dns-paras
            |  |  +--ro domain-search-list     string
            |  |  +--ro dns-servers* [dns-serv-id]
            |  |     +--ro dns-serv-id         uint8
            |  |     +--ro dns-serv-addr       inet:ipv6-address
            |  +--ro sip-paras
            |  |  +--ro sip-servers* [sip-serv-id]
            |  |     +--ro sip-serv-id         uint8
            |  |     +--ro sip-serv-addr       inet:ipv6-address
            |  |     +--ro sip-serv-domain-name  string
            |  +--ro nis-paras
            |  |  +--ro nis-domain-name        string
            |  |  +--ro nis-server* [nis-serv-id]
            |  |     +--ro nis-serv-id         uint8
            |  |     +--ro nis-serv-addr       inet:ipv6-address
            |  +--ro nis-plus-paras
            |  |  +--ro nis-plus-domain-name   string
            |  |  +--ro nis-plus-server* [nis-plus-serv-id]
            |  |     +--ro nis-plus-serv-id    uint8
            |  |     +--ro nis-plus-serv-addr  inet:ipv6-address
            |  +--ro info-refresh-time         yang:timeticks
            |  +--ro time-zone-paras
            |  |  +--ro tz-posix               string
            |  |  +--ro tz-database            string
            |  +--ro cli-fqdn                  string
            |  +--ro ntp-paras
            |  |  +--ro ntp-server* [ntp-serv-id]
            |  |     +--ro ntp-serv-id         uint8
            |  |     +--ro ntp-serv-addr       inet:ipv6-address
            |  |     +--ro ntp-serv-mul-addr   inet:ipv6-address
            |  |     +--ro ntp-serv-fqdn       string
            |  +--ro sntp-paras
            |  |  +--ro sntp-server* [sntp-serv-id]
            |  |     +--ro sntp-serv-id         uint8
            |  |     +--ro sntp-serv-addr       inet:ipv6-address
            |  +--ro network-boot-paras
            |  |  +--ro boot-file* [boot-file-id]
            |  |     +--ro boot-file-id           uint8
            |  |     +--ro suitable-arch-type*    uint16
            |  |     +--ro suitable-net-if*       uint32
            |  |     +--ro boot-file-url          string
            |  |     +--ro boot-file-paras* [para-id]
            |  |        +--ro para-id             uint8
            |  |        +--ro parameter           string
            |  +--ro kerberos-paras
            |  |  +--ro default-realm-name        string
            |  |  +--ro kdc-info* [kdc-id]
            |  |     +--ro kdc-id                 uint8
            |  |     +--ro priority               uint16
            |  |     +--ro weight                 uint16
            |  |     +--ro transport-type         uint8
            |  |     +--ro port-number            uint16
            |  |     +--ro kdc-ipv6-addr          inet:ipv6-address
            |  |     +--ro realm-name             string
            |  +--ro addr-selection-paras
            |  |  +--ro automatic-row-add         boolean
            |  |  +--ro prefer-temporary-addr     boolean
            |  |  +--ro policy-table* [policy-id]
            |  |     +--ro policy-id              uint8
            |  |     +--ro label                  uint8
            |  |     +--ro precedence             uint8
            |  |     +--ro prefix-len             uint8
            |  |     +--ro prefix                 inet:ipv6-prefix
            |  +--ro sol-max-rt                   yang:timeticks
            |  +--ro inf-max-rt                   yang:timeticks
            |  +--ro pcp-paras
            |  |  +--ro pcp-server* [pcp-serv-id]
            |  |     +--ro pcp-serv-id            uint8
            |  |     +--ro pcp-serv-addr          inet:ipv6-address
            |  +--ro s46-rule-paras
            |  |  +--ro s46-rule* [rule-id]
            |  |     +--ro rule-id                uint8
            |  |     +--ro rule-type              enumeration
            |  |     +--ro ea-len                 uint8
            |  |     +--ro prefix4-len            uint8
            |  |     +--ro ipv4-prefix            inet:ipv4-prefix
            |  |     +--ro prefix6-len            uint8
            |  |     +--ro ipv6-prefix            inet:ipv6-prefix
            |  |     +--ro port-parameter
            |  |        +--ro offset              uint8
            |  |        +--ro psid-len            uint8
            |  |        +--ro psid                uint16
            |  +--ro s46-br-paras
            |  |  +--ro br* [br-id]
            |  |     +--ro br-id                  uint8
            |  |     +--ro br-ipv6-addr           inet:ipv6-address
            |  +--ro s46-dmr-paras
            |  |  +--ro dmr* [dmr-id]
            |  |     +--ro dmr-id                 uint8
            |  |     +--ro dmr-prefix6-len        uint8
            |  |     +--ro dmr-ipv6-prefix        inet:ipv6-prefix
            |  +--ro s46-v4-v6-binding-paras
            |  |  +--ro ipv4-addr                 inet:ipv6-address
            |  |  +--ro bind-prefix6-len          uint8
            |  |  +--ro port-parameter
            |  |     +--ro offset                 uint8
            |  |     +--ro psid-len               uint8
            |  |     +--ro psid                   uint16
            |  +--ro erp-local-domain-name        string
            +--ro supported-options
            |  +--ro supported-option* [option-code]
            |     +--ro option-code            uint16
            |     +--ro description            string
            +--ro packet-stats
               +--ro solicit-count             uint32
               +--ro request-count             uint32
               +--ro renew-count               uint32
               +--ro rebind-count              uint32
               +--ro decline-count             uint32
               +--ro release-count             uint32
               +--ro info-req-count            uint32
               +--ro advertise-count           uint32
               +--ro confirm-count             uint32
               +--ro reply-count               uint32
               +--ro reconfigure-count         uint32

   Introduction of important nodes:

   o  client-if: A client may have several interfaces, it is more
      reasonable to configure and manage parameters on the interface-
      level.  The list defines a specific client interface and its data.
      Different interfaces are distinguished by the "ifName" key which
      is a configurable string value.

   o  duid: Each server and client has only one DUID (DHCP Unique
      Identifier).  The DUID here will be carried in the Client ID
      option to identify a specific DHCPv6 client.  This leaf are same
      as the "duid" leaf in "dhcpv6-server" feature.

   o  pd-function: Whether the client can act as a requesting router to
      request prefixes using prefix delegation ([RFC3633]).

   o  rapid-commit: '1' indicates a client can initiate a Solicit-Reply
      message exchange by adding a Rapid Commit option in Solicit
      message. '0' means the client is not allowed to add a Rapid Commit
      option to request addresses in a two-message exchange pattern.

   o  mo-tab: The management tab label indicates the operation mode of
      the DHCPv6 client. 'm'=1 and 'o'=1 indicate the client will use
      DHCPv6 to obtain all the configuration data. 'm'=1 and 'o'=0 are a
      meaningless combination. 'm'=0 and 'o'=1 indicate the client will
      use stateless DHCPv6 to obtain configuration data apart from
      addresses/prefixes data. 'm'=0 and 'o'=0 represent the client will
      not use DHCPv6 but use SLAAC to achieve configuration.

   o  oro-options: This container provide a way to configure the list of
      options that the client will request in its ORO option.

   o  client-configured-options: Similar to the server, the client also
      need to configure some options to fulfil some desired functions.
      This container include all the potential options that need to be
      configured at the client side.  The relevant RFCs that define
      those options include: [RFC3315], [RFC4704], [RFC5970], [RFC6784],
      [RFC6939].

   o  identity-association: IA is a construct through which a server and
      a client can identify, group, and manage a set of related IPv6
      addresses.  The key of the "identity-association" list is a 4-byte
      number IAID defined in [RFC3315].

   o  if-other-paras: A client can obtain extra configuration data other
      than address and prefix information through DHCPv6 options.  This
      container describes such data the client was configured through
      DHCPv6.  The potential configuration data may include DNS server
      parameters, SIP server parameters and etc.

   o  supported-options: This state data container defines a list of
      options supported by the client for administrator to interrogate a
      client's capabilities.

   o  packet-stats: A container records all the packet status
      information of a specific interface.

3.4.

2.4.  Notifications Mechanism for DHCPv6
   +--rw dhcpv6
      +-- ...
      |
      +--n notifications
         +--n dhcpv6-server-event
         |  +--n pool-running-out
         |  |  +--ro utilization-ratio            uint16
         |  |  +--ro duid                         duidtype
         |  |  +--ro serv-name?                   string
         |  |  +--ro pool-name                    string
         |  +--n invalid-client-detected
         |     +--ro duid                         duidtype
         |     +--ro description?                 string
         +--n dhcpv6-relay-event
         |  +--n topo-changed
         |     +--ro relay-if-name                string
         |     +--ro first-hop                    boolean
         |     +--ro last-entity-addr             inet:ipv6-address
         +--n dhcpv6-client-event
            +--n ia-lease-event
            |  +--ro event-type                   enumeration
            |  +--ro duid                         duidtype
            |  +--ro iaid                         uint32
            |  +--ro serv-name?                   string
            |  +--ro description?                 string
            +--n invalid-ia-detected
            |  +--ro duid                         duidtype
            |  +--ro iaid                         uint32
            |  +--ro serv-name?                   string
            |  +--ro description?                 string
            +--n retransmission-failed
            |  +--ro duid                         duidtype
            |  +--ro description                  enumeration
            +--n failed-status-turn-up
               +--ro duid                         duidtype
               +--ro status-code                  enumeration

   Introduction of notifications:

   o  pool-running-out: raised when the address/prefix pool is going to
      run out.  A threshold for utilization ratio of the pool has been
      defined in the server feature so that it will notify the
      administrator when the utilization ratio reaches the threshold,
      and such threshold is a settable parameter.

   o  invalid-client-detected: raised when the server has found a client
      which can be regarded as a potential attacker.  Some description
      could also be included.

   o  topo-changed: raised when the topology of the relay agent is
      changed.

   o  ia-lease-event: raised when the client was allocated a new IA from
      the server or it renew/rebind/release its current IA.

   o  invalid-ia-detected: raised when the identity association of the
      client can be proved to be invalid.  Possible condition includes
      duplicated address, illegal address, etc.

   o  retransmission-failed: raised when the retransmission mechanism
      defined in [RFC3315] is failed.

   o  failed-status-turn-up: raised when the client receives a message
      includes an unsuccessful Status Code option.

4.

3.  DHCPv6 YANG Model

   This module imports typedefs from [RFC6991].

<CODE BEGINS> file "ietf-dhcpv6@2015-10-16.yang"
module ietf-dhcpv6 {
    namespace "urn:ietf:params:xml:ns:yang:ietf-dhcpv6";
    prefix "dhcpv6";

    import ietf-inet-types {
        prefix inet;
        revision-date "2013-07-15";
    }
    import ietf-yang-types {
        prefix yang;
        revision-date "2013-07-15";
    }

    organization "dhc wg";
    contact "yong@csnet1.cs.tsinghua.edu.cn
            wangh13@mails.tsinghua.edu.cn
            lh.sunlinh@gmail.com
            Ted.Lemon@nominum.com
            ian.farrer@telekom.de";

    description "This model defines a YANG data model that can be
        used to configure and manage DHCPv6 server, DHCPv6 relay and
    DHCPv6 client.";

    revision 2015-10-16 {
        description "version05: Omit the feature statement. Modify
        model according to comments from Huawei. Also correct some
        grammar errors.";

        reference "I-D: draft-ietf-dhc-dhcpv6-yang-00";
    }
    revision 2015-09-25 {
        description "version04: Correct duid and grammar errors.";

        reference "I-D: draft-cui-dhc-dhcpv6-yang-04";
    }
    revision 2015-07-01 {
        description "version03: Correct grammar errors.";

        reference "I-D: draft-cui-dhc-dhcpv6-yang-03";
    }
    revision 2015-04-13 {
        description "version02: Correct grammar errors.";

        reference "I-D: draft-cui-dhc-dhcpv6-yang-02";
    }
    revision 2015-04-02 {
        description "version01: Correct grammar errors, Reuse
            groupings, Update 'dhcpv6-relay' feature, Add
                notifications.";

        reference "I-D: draft-cui-dhc-dhcpv6-yang-01";
    }
    revision 2015-03-04 {
        description "version00: Initial revision.";

        reference "I-D: draft-cui-dhc-dhcpv6-yang-00";
    }

/*
 * Typedef
 */

    typedef duidtype {
        type union {
            type uint16;
            type string {
                pattern '(([0-9a-fA-F]{2}){2,128})';
            }
        }
        description "the type defined for duid";
    }

    typedef threshold {
        type union {
            type uint16 {
                range 0..100;
            }
            type enumeration {
                enum "disabled" {
                    description "No threshold";
                }
            }
        }
        description "Threshold value in percent";
    }

/*
 * Grouping
 */

    grouping vendor-infor {
        description "vendor info";
        container vendor-info {
            description "";
            leaf ent-num {
                type uint32;
                mandatory true;
                description "enterprise number";
            }
            leaf-list data {
                type string;
                description "specific vendor info";
            }
        }
    }

    grouping portset-para {
        description "portset parameters";
        container port-parameter {
            description "port parameter";
            leaf offset {
                type uint8;
                mandatory true;
                description "offset in a port set";
            }
            leaf psid-len {
                type uint8;
                mandatory true;
                description "length of a psid";
            }
            leaf psid {
                type uint16;
                mandatory true;
                description "psid value";
            }
        }
    }

/*
 * Data Nodes
 */

    container server {
        description "dhcpv6 server portion";
        container serv-attributes {
            description "This container contains basic attributes
            of a DHCPv6 server such as DUID, server name and so
            on. Some optional functions that can be provided by
            the server is also included.";
            leaf name {
                type string;
                mandatory true;
                description "server's name";
            }
            leaf duid {
                            type duidtype;
                mandatory true;
                description "DHCP Unique Identifer";
                        }
            leaf enable {
                type boolean;
                mandatory true;
                description "whether to enable the server";
            }
            leaf ipv6-address {
                type inet:ipv6-address;
                description "server's IPv6 address";
            }
            leaf description {
                type string;
                description "description of the server";
            }
            leaf pd-function {
                type boolean;
                mandatory true;
                description "Whether the server can act as a
                delegating router to perform prefix delegation
                                ([RFC3633]).";
            }
            leaf stateless-service {
                type boolean;
                mandatory true;
                description "A boolean value specifies whether
                the server support client-server exchanges
                involving two messages defined in ([RFC3315]).";
            }
            leaf rapid-commit {
                type boolean;
                mandatory true;
                description "A boolean value specifies whether
                the server support client-server exchanges
                involving two messages defined in ([RFC3315]).";
            }
            leaf-list interfaces-config {
                type string;
                description "A leaf list to denote which one or
                more interfaces the server should listen on. The
                default value is to listen on all the interfaces.
                This node is also used to set a unicast address
                for the server to listen with a specific interface.
                For example, if people want the server to listen
                on a unicast address with a specific interface, he
                can use the format like 'eth1/2001:db8::1'.";
            }
            uses vendor-infor;
        }
        container option-sets {
            description "DHCPv6 employs various options to carry
            additional information and parameters in DHCP messages.
            This container defines all the possible options that
            need to be configured at the server side.";
            list option-set {
                key option-set-id;
                description "A server may allow different option
                sets to be configured for different conditions
                (i.e. different networks, clients and etc). This
                'option-set' list enables various sets of options
                being defined and configured in a single server.
                Different sets are distinguished by the key called
                'option-set-id'. All the possible options discussed
                above are defined in the list and each option is
                corresponding to a container.";
                leaf option-set-id {
                    type uint8; leafref; {
                    path "/dhcpv6/server/option-sets/option-set/option-set-id";
                    mandatory true;
                    description "the option-set-id key";
                    }
                }
                                list new-or-standard-option {
                    key option-code;
                    description "new or standard option";
                    leaf option-code {
                        type uint16;
                        mandatory true;
                        description "the option code key";
                    }
                    leaf option-name {
                        type string;
                        mandatory true;
                        description "the new option's name";
                    }
                    leaf option-description {
                        type string;
                        mandatory true;
                        description "description of new option";
                    }
                    leaf option-reference {
                        type string;
                        description "reference to the
                        specification";
                    }
                    leaf option-value {
                        type string;
                        mandatory true;
                        description "the new option's value";
                    }
                }
                leaf user-class-value {
                    type string;
                    description "use class option's value";
                }
                leaf enterprise-number {
                    type uint32;
                    description "enterprise number";
                }
                leaf store-client-link-layer {
                    type boolean;
                    description "whether to store client's
                    link layer address";
                }
                container preference-option {
                    description "preference option";
                    leaf enable {
                        type boolean;
                        mandatory true;
                        description "indicate whether this
                        option will be included in the
                        option set";
                    }
                    leaf preference-value {
                        type uint8;
                        mandatory true;
                        description "the value for this option";
                    }
                }
                container sip-server-option {
                    description "sip server option";
                    leaf enable {
                        type boolean;
                        mandatory true;
                        description "indicate whether this
                        option will be included in the
                        option set";
                    }
                    list sip-server {
                        key sip-serv-id;
                        description "sip server info";
                        leaf sip-serv-id {
                            type uint8;
                            mandatory true;
                            description "sip server id";
                        }
                        leaf sip-serv-domain-name {
                            type string;
                            mandatory true;
                            description "sip serevr domain
                            name";
                        }
                        leaf sip-serv-addr {
                            type inet:ipv6-address;
                            mandatory true;
                            description "sip server addr";
                        }
                    }
                }
                container dns-config-option {
                    description "dns configuration option";
                    leaf enable {
                        type boolean;
                        mandatory true;
                        description "indicate whether this
                        option will be included in the
                        option set";
                    }
                    list dns-server {
                        key dns-serv-id;
                        description "dns server info";
                        leaf dns-serv-id {
                            type uint8;
                            mandatory true;
                            description "dns server id";
                        }
                        leaf dns-serv-addr {
                            type inet:ipv6-address;
                            mandatory true;
                            description "dns server addr";
                        }
                    }
                    leaf domain-search-list {
                        type string;
                        mandatory true;
                        description "search list";
                    }
                }
                container nis-config-option {
                    description "nis configurtaion option";
                    leaf enable {
                        type boolean;
                        mandatory true;
                        description "indicate whether this
                        option will be included in the
                        option set";
                    }
                    list nis-server {
                        key nis-serv-id;
                        description "nis server info";
                        leaf nis-serv-id {
                            type uint8;
                            mandatory true;
                            description "nis server id";
                        }
                        leaf nis-serv-addr {
                            type inet:ipv6-address;
                            mandatory true;
                            description "nis server addr";
                        }
                    }
                }
                container nis-plus-config-option {
                    description "nisp configuration option";
                    leaf enable {
                        type boolean;
                        mandatory true;
                        description "indicate whether this
                        option will be included in the
                        option set";
                    }
                    list nis-plus-server {
                        key nis-plus-serv-id;
                        description "nisp server info";
                        leaf nis-plus-serv-id {
                            type uint8;
                            mandatory true;
                            description "nisp server id";
                        }
                        leaf nis-plus-serv-addr {
                            type inet:ipv6-address;
                            mandatory true;
                            description "nisp server addr";
                        }
                    }
                }
                container info-refresh-time-option {
                    description "info refresh time option";
                    leaf enable {
                        type boolean;
                        mandatory true;
                        description "indicate whether this
                        option will be included in the
                        option set";
                    }
                    leaf info-refresh-time {
                        type yang:timeticks;
                        mandatory true;
                        description "the refresh time";
                    }
                }
                container cli-fqdn-option {
                    description "client fqdn option";
                    leaf enable {
                        type boolean;
                        mandatory true;
                        description "indicate whether this
                        option will be included in the
                        option set";
                    }
                    leaf server-initiate-update {
                        type boolean;
                        mandatory true;
                        description "server initiate";
                    }
                    leaf client-initiate-update {
                        type boolean;
                        mandatory true;
                        description "client initiate";
                    }
                    leaf modify-name-from-cli {
                        type boolean;
                        mandatory true;
                        description "modify by client";
                    }
                }
                container timezone-option {
                    description "timezone option";
                    leaf enable {
                        type boolean;
                        mandatory true;
                        description "indicate whether this
                        option will be included in the
                        option set";
                    }
                    leaf tz-posix {
                        type string;
                        mandatory true;
                        description "tz posix";
                    }
                    leaf tz-database {
                        type string;
                        mandatory true;
                        description "tz database";
                    }
                }
                container ntp-server-option {
                    description "ntp server option";
                    leaf enable {
                        type boolean;
                        mandatory true;
                        description "indicate whether this
                        option will be included in the
                        option set";
                    }
                    list ntp-server {
                        key ntp-serv-id;
                        description "ntp server info";
                        leaf ntp-serv-id {
                            type uint8;
                            mandatory true;
                            description "ntp server id";
                        }
                        leaf ntp-serv-addr {
                            type inet:ipv6-address;
                            mandatory true;
                            description "ntp server addr";
                        }
                        leaf ntp-serv-mul-addr {
                            type inet:ipv6-address;
                            mandatory true;
                            description "ntp server multicast
                            addr";
                        }
                        leaf ntp-serv-fqdn {
                            type string;
                            mandatory true;
                            description "ntp server fqdn";
                        }
                    }
                }
                container sntp-server-option {
                    description "sntp server option";
                    leaf enable {
                        type boolean;
                        mandatory true;
                        description "indicate whether this
                        option will be included in the
                        option set";
                    }
                    list sntp-server {
                        key sntp-serv-id;
                        description "sntp server info";
                        leaf sntp-serv-id {
                            type uint8;
                            mandatory true;
                            description "sntp server id";
                        }
                        leaf sntp-serv-addr {
                            type inet:ipv6-address;
                            mandatory true;
                            description "sntp server addr";
                        }
                    }
                }
                container network-boot-option {
                    description "network boot option";
                    leaf enable {
                        type boolean;
                        mandatory true;
                        description "indicate whether this
                        option will be included in the
                        option set";
                    }
                    list boot-file {
                        key boot-file-id;
                        description "boot file info";
                        leaf boot-file-id {
                            type uint8;
                            mandatory true;
                            description "boot file id";
                        }
                        leaf-list suitable-arch-type {
                            type uint16;
                            description "architecture type";
                        }
                        leaf-list suitable-net-if {
                            type uint32;
                            description "network interface";
                        }
                        leaf boot-file-url {
                            type string;
                            mandatory true;
                            description "url for boot file";
                        }
                        list boot-file-paras {
                            key para-id;
                            description "boot file parameters";
                            leaf para-id {
                                type uint8;
                                mandatory true;
                                description "parameter id";
                            }
                            leaf parameter {
                                type string;
                                mandatory true;
                                description "parameter
                                value";
                            }
                        }
                    }
                }
                container dslite-option {
                    description "dslite option";
                    leaf enable {
                        type boolean;
                        mandatory true;
                        description "indicate whether this
                        option will be included in the
                        option set";
                    }
                    leaf dslite-aftr-name {
                        type string;
                        mandatory true;
                        description "aftr name";
                    }
                }
                container kerberos-option {
                    description "kerberos option";
                    leaf enable {
                        type boolean;
                        mandatory true;
                        description "indicate whether this
                        option will be included in the
                        option set";
                    }
                    leaf default-realm-name {
                        type string;
                        mandatory true;
                        description "default realm name";
                    }
                    list kdc-info {
                        key kdc-id;
                        description "kdc info";
                        leaf kdc-id {
                            type uint8;
                            mandatory true;
                            description "kdc id";
                        }
                        leaf priority {
                            type uint16;
                            mandatory true;
                            description "priority";
                        }
                        leaf weight {
                            type uint16;
                            mandatory true;
                            description "weight";
                        }
                        leaf transport-type {
                            type uint8;
                            mandatory true;
                            description "transport type";
                        }
                        leaf port-number {
                            type uint16;
                            mandatory true;
                            description "port number";
                        }
                        leaf kdc-ipv6-addr {
                            type inet:ipv6-address;
                            mandatory true;
                            description "kdc ipv6 addr";
                        }
                        leaf realm-name {
                            type string;
                            mandatory true;
                            description "realm name";
                        }
                    }
                }
                container addr-selection-option {
                    description "address selection option";
                    leaf enable {
                        type boolean;
                        mandatory true;
                        description "indicate whether this
                        option will be included in the
                        option set";
                    }
                    leaf a-bit-set {
                        type boolean;
                        mandatory true;
                        description "a bit";
                    }
                    leaf p-bit-set {
                        type boolean;
                        mandatory true;
                        description "p bit";
                    }
                    list policy-table {
                        key policy-id;
                        description "policy table";
                        leaf policy-id {
                            type uint8;
                            mandatory true;
                            description "policy id";
                        }
                        leaf label {
                            type uint8;
                            mandatory true;
                            description "label";

                        }
                        leaf precedence {
                            type uint8;
                            mandatory true;
                            description "precedence"; "precedence";
                        }
                        leaf prefix-len {
                            type uint8;
                            mandatory true;
                            description "prefix length";
                        }
                        leaf prefix {
                            type inet:ipv6-prefix;
                            mandatory true;
                            description "prefix";
                        }
                    }
                }
                container sol-max-rt-option {
                    description "sol max rt option";
                    leaf enable {
                        type boolean;
                        mandatory true;
                        description "indicate whether this
                        option will be included in the
                        option set";
                    }
                    leaf sol-max-rt-value {
                        type yang:timeticks;
                        mandatory true;
                        description "sol max rt value";
                    }
                }
                container inf-max-rt-option {
                    description "inf max rt option";
                    leaf enable {
                        type boolean;
                        mandatory true;
                        description "indicate whether this
                        option will be included in the
                        option set";
                    }
                    leaf inf-max-rt-value {
                        type yang:timeticks;
                        mandatory true;
                        description "inf max rt value";
                    }
                }
                container pcp-server-option {
                    description "pcp server option";
                    leaf enable {
                        type boolean;
                        mandatory true;
                        description "indicate whether this
                        option will be included in the
                        option set";
                    }
                    list pcp-server {
                        key pcp-serv-id;
                        description "pcp server info";
                        leaf pcp-serv-id {
                            type uint8;
                            mandatory true;
                            description "pcp server id";
                        }
                        leaf pcp-serv-addr {
                            type inet:ipv6-address;
                            mandatory true;
                            description "pcp server addr";
                        }
                    }
                }
                container s46-rule-option {
                    description "s46 rule option";
                    leaf enable {
                        type boolean;
                        mandatory true;
                        description "indicate whether this
                        option will be included in the
                        option set";
                    }
                    list s46-rule {
                        key rule-id;
                        description "s46 rule";
                        leaf rule-id {
                            type uint8;
                            mandatory true;
                            description "rule id";
                        }
                        leaf rule-type {
                            type enumeration {
                            enum "BMR" {
                                description "BMR";
                            }
                            enum "FMR" {
                                description "FMR";

                            }
                            }
                            mandatory true;
                            description "rule type";
                        }
                        leaf prefix4-len {
                            type uint8;
                            mandatory true;
                            description "ipv4 prefix length";
                        }
                        leaf ipv4-prefix {
                            type inet:ipv4-prefix;
                            mandatory true;
                            description "ipv4 prefix";
                        }
                        leaf prefix6-len {
                            type uint8;
                            mandatory true;
                            description "ipv6 prefix length";
                        }
                        leaf ipv6-prefix {
                            type inet:ipv6-prefix;
                            mandatory true;
                            description "ipv6 prefix";
                        }
                        uses portset-para;
                    }
                }
                container s46-br-option {
                    description "s46 br option";
                    leaf enable {
                        type boolean;
                        mandatory true;
                        description "indicate whether this
                        option will be included in the
                        option set";
                    }
                    list br {
                        key br-id;
                        description "br info";
                        leaf br-id {
                            type uint8;
                            mandatory true;
                            description "br id";
                        }
                        leaf br-ipv6-addr {
                            type inet:ipv6-address;
                            mandatory true;
                            description "br ipv6 addr";
                        }
                    }
                }
                    container operator-option-ipv6-address {
                    description "operator ipv6 address option";
                    leaf enable {
                        type boolean;
                        mandatory true;
                        description "indicate whether this
                        option will be included in the
                        option set";
                    }
                    list operator-ipv6-addr {
                        key operator-ipv6-addr-id;
                        description "operator ipv6 address info";
                        leaf operator-ipv6-addr-id {
                            type uint8;
                            mandatory true;
                            description "operator ipv6 address id";
                        }
                        leaf operator-ipv6-addr {
                            type inet:ipv6-address;
                            mandatory true;
                            description "operator ipv6 address id";
                        }
                    }
                }
                  container operator-option-single-flag {
                    description "operator single flag";
                    leaf enable {
                        type boolean;
                        mandatory true;
                        description "indicate whether this
                        option will be included in the
                        option set";
                    }
                    list flag {
                        key flag-id;
                        description "operator single flag info";
                        leaf flag-id {
                            type uint8;
                            mandatory true;
                            description "operator single flag id";
                        }
                        leaf flag-value{
                            type boolean;
                            mandatory true;
                            description "operator single flag value";
                        }
                    }
                }
                   container operator-option-ipv6-prefix {
                    description "operator ipv6 prefix option";
                    leaf enable {
                        type boolean;
                        mandatory true;
                        description "indicate whether this
                        option will be included in the
                        option set";
                    }
                    list operator-ipv6-prefix{
                        key operator-ipv6-prefix-id;
                        description "operator ipv6 prefix info";
                        leaf operator-ipv6-prefix-id {
                            type uint8;
                            mandatory true;
                            description "operator ipv6 prefix id";
                        }
                        leaf prefix-len { operator-ipv6-prefix6-len{
                            type uint8;
                            mandatory true;
                            description "prefix "operator ipv6 prefix length";
                            }
                       leaf prefix operator-ipv6-prefix {
                            type inet:ipv6-prefix;
                            mandatory true;
                            description "prefix"; "operator ipv6 prefix";
                        }
                    }
                }
                  container sol-max-rt-option operator-option-int32 {
                    description "sol max rt "operator integer 32 option";
                    leaf enable {
                        type boolean;
                        mandatory true;
                        description "indicate whether this
                        option will be included in the
                        option set";
                    }
                    list int32val{
                        key int32val-id;
                        description "operator integer 32 info";
                        leaf sol-max-rt-value int32val-id {
                            type yang:timeticks; uint8;
                            mandatory true;
                            description "sol max rt "operator integer 32 id";
                        }
                        leaf int32val{
                            type uint32;
                            mandatory true;
                            description "operator integer 32 value";
                            }
                    }
                }
                  container inf-max-rt-option operator-option-int16 {
                    description "inf max rt "operator integer 16 option";
                    leaf enable {
                        type boolean;
                        mandatory true;
                        description "indicate whether this
                        option will be included in the
                        option set";
                    }
                    list int16val{
                        key int16val-id;
                        description "operator integer 16 info";
                        leaf inf-max-rt-value int16val-id {
                            type yang:timeticks; uint8;
                            mandatory true;
                            description "inf max rt "operator integer 16 id";
                        }
                        leaf int16val{
                            type uint16;
                            mandatory true;
                            description "operator integer 16 value";
                            }
                    }
                }
                  container pcp-server-option operator-option-int8 {
                    description "pcp server "operator integer 8 option";
                    leaf enable {
                        type boolean;
                        mandatory true;
                        description "indicate whether this
                        option will be included in the
                        option set";
                    }
                    list pcp-server { int8val{
                        key pcp-serv-id; int32val-id;
                        description "pcp server "operator integer 8 info";
                        leaf pcp-serv-id int8val-id {
                            type uint8;
                            mandatory true;
                            description "pcp server "operator integer 8 id";
                        }
                        leaf pcp-serv-addr { int8val{
                            type inet:ipv6-address; uint8;
                            mandatory true;
                            description "pcp server addr"; "operator integer 8 value";
                            }
                    }
                }
                 container s46-rule-option operator-option-uri {
                    description "s46 rule "operator uri option";
                    leaf enable {
                        type boolean;
                        mandatory true;
                        description "indicate whether this
                        option will be included in the
                        option set";
                    }
                    list s46-rule { uri{
                        key rule-id; uri-id;
                        description "s46 rule"; "operator uri info";
                        leaf rule-id uri-id {
                            type uint8;
                            mandatory true;
                            description "rule "operator uri id";
                        }
                        leaf rule-type { uri{
                            type enumeration {
                               enum "BMR" { string;
                            mandatory true;
                            description "BMR"; "operator uri value";
                            }
                               enum "FMR" {
                                   description "FMR";
                    }
                }
             container operator-option-textstring {
                    description "operator itext string option";
                    leaf enable {
                        type boolean;
                        mandatory true;
                        description "rule type"; "indicate whether this
                        option will be included in the
                        option set";
                    }
                    list textstring{
                        key textstring-id;
                        description "operator text string info";
                        leaf prefix4-len textstring-id {
                            type uint8;
                            mandatory true;
                            description "ipv4 prefix length"; "operator text string id";
                        }
                        leaf ipv4-prefix textstring{
                            type string;
                            mandatory true;
                            description "operator text string value";
                            }
                    }
                }
             container operator-option-var-data {
                    description "operator variable length data option";
                    leaf enable {
                        type inet:ipv4-prefix; boolean;
                        mandatory true;
                        description "ipv4 prefix"; "indicate whether this
                        option will be included in the
                        option set";
                    }
                    list int32val{
                        key var-data-id;
                        description "operator ivariable length data info";
                        leaf prefix6-len var-data-id {
                            type uint8;
                            mandatory true;
                            description "ipv6 prefix length"; "operator variable length id";
                        }
                        leaf ipv6-prefix { var-data{
                            type inet:ipv6-prefix; binary;
                            mandatory true;
                            description "ipv6 prefix"; "operator variable length value";
                            }
                           uses portset-para;
                    }
                }
                   container s46-br-option operator-option-dns-wire {
                    description "s46 br "operator dns wire format domain name list option";
                    leaf enable {
                        type boolean;
                        mandatory true;
                        description "indicate whether this
                        option will be included in the
                        option set";
                    }
                    list br { operator-option-dns-wire{
                        key br-id; operator-option-dns-wire-id;
                        description "br "operator dns wire format info";
                        leaf br-id operator-option-dns-wire-id {
                            type uint8;
                            mandatory true;
                            description "br "operator dns wire format id";
                        }
                        leaf br-ipv6-addr { operator-option-dns-wire{
                            type inet:ipv6-address; binary;
                            mandatory true;
                            description "br ipv6 addr"; "operator dns wire format value";
                            }
                    }
                }
                container s46-dmr-option {
                    description "s46 dmr option";
                    leaf enable {
                        type boolean;
                        mandatory true;
                        description "indicate whether this
                        option will be included in the
                        option set";
                    }
                    list dmr {
                        key dmr-id;
                        description "dmr info";
                        leaf dmr-id {
                            type uint8;
                            mandatory true;
                            description "dmr id";
                        }
                        leaf dmr-prefix-len {
                            type uint8;
                            mandatory true;
                            description "dmr prefix length";
                        }
                        leaf dmr-ipv6-prefix {
                            type inet:ipv6-prefix;
                            mandatory true;
                            description "dmr ipv6 prefix";
                        }
                    }
                }
                container s46-v4-v6-binding-option {
                    description "s46 binding option";
                    leaf enable {
                        type boolean;
                        mandatory true;
                        description "indicate whether this
                        option will be included in the
                        option set";
                    }
                    list ce {
                        key ce-id;
                        description "ce info";
                        leaf ce-id {
                            type uint8;
                            mandatory true;
                            description "ce id";
                        }
                        leaf ipv4-addr {
                            type inet:ipv4-address;
                            mandatory true;
                            description "ce ipv4 addr";
                        }
                        leaf bind-prefix6-len {
                            type uint8;
                            mandatory true;
                            description "bind ipv6 prefix
                            length";
                        }
                        leaf bind-ipv6-prefix {
                            type inet:ipv6-prefix;
                            mandatory true;
                            description "bind ipv6 prefix";
                        }
                        uses portset-para;
                    }
                }
            }
        }
            container network-ranges {
                description "This model supports a hierarchy
                to achieve dynamic configuration. That is to
                say we could configure the server at different
                levels through this model. The top level is a
                global level which is defined as the container
                'network-ranges'. The following levels are
                defined as sub-containers under it. The
                'network-ranges' contains the parameters
                (e.g. option-sets) that would be allocated to
                all the clients served by this server.";
                leaf-list option-set {
                    type uint8;
                    description "a specific option set";
                }
                list network-range {
                    key network-range-id;
                    description "Under the 'network-ranges'
                    container, a 'network-range' list is
                    defined to configure the server at a
                    network level which is also considered
                    as the second level. Different network
                    are identified by the key 'network-range-id'.
                    This is because a server may have different
                    configuration parameters (e.g. option sets)
                    for different networks.";
                    leaf network-range-id {
                        type uint8;
                        mandatory true;
                        description "equivalent to subnet id";
                    }
                    leaf network-description {
                        type string;
                        mandatory true;
                        description "description of the subnet";
                    }
                    leaf network-prefix {
                        type inet:ipv6-prefix;
                        mandatory true;
                        description "subnet prefix";
                    }
                    leaf inherit-option-set {
                        type boolean;
                        mandatory true;
                        description "indicate whether to inherit
                        the configuration from higher level";
                    }
                    leaf-list option-set {
                        type uint8;
                        description "configured option set";
                    }
                    container address-pools {
                        description "A container describes
                        the DHCPv6 server's address pools.";
                        list address-pool {
                            key pool-id;
                            description "A DHCPv6 server can
                            be configured with several address
                            pools. This list defines such
                            address pools which are distinguish
                            by the key called 'pool-name'.";
                            leaf pool-id {
                                type uint8;
                                mandatory true;
                                description "pool id";
                            }
                            leaf pool-prefix {
                                type inet:ipv6-prefix;
                                mandatory true;
                                description "pool prefix";
                            }
                            leaf start-address {
                                type inet:ipv6-address-no-zone;
                                mandatory true;
                                description "start address";
                            }
                            leaf end-address {
                                type inet:ipv6-address-no-zone;
                                mandatory true;
                                description "end address";
                            }
                            leaf renew-time {
                                type yang:timeticks;
                                mandatory true;
                                description "renew time";
                            }
                            leaf rebind-time {
                                type yang:timeticks;
                                mandatory true;
                                description "rebind time";
                            }
                            leaf preferred-lifetime {
                                type yang:timeticks;
                                mandatory true;
                                description "preferred lifetime
                                for IA";
                            }
                            leaf valid-lifetime {
                                type yang:timeticks;
                                mandatory true;
                                description "valid liftime for IA";
                            }
                            leaf total-ipv6-count {
                                type uint64;
                                config "false";
                                mandatory true;
                                description "how many ipv6
                                addressses are in the pool";
                            }
                            leaf used-ipv6-count {
                                type uint64;
                                config "false";
                                mandatory true;
                                description "how many are
                                allocated";
                            }
                            leaf utilization-ratio {
                                type threshold;
                                mandatory true;
                                description "the utilization ratio";
                            }
                            leaf inherit-option-set {
                                type boolean;
                                mandatory true;
                                description "indicate whether to
                                inherit the configuration from
                                higher level";
                            }
                            leaf-list option-set {
                                type uint8;
                                description "configured option
                                set";
                            }
                            container reserved-addresses {
                                description "reserved addresses";
                                list static-binding {
                                    key cli-id;
                                    description "static binding of
                                    reserved addresses";
                                    leaf cli-id {
                                        type uint32;
                                        mandatory true;
                                        description "client id";
                                    }
                                    leaf duid {
                                        type duidtype;
                                        mandatory true;
                                        description "DHCP Unique
                                        Identifer";
                                    }
                                    leaf-list reserv-addr {
                                        type inet:ipv6-address;
                                        description "reserved addr";
                                    }
                                }
                                leaf-list other-reserv-addr {
                                    type inet:ipv6-address;
                                    description "other reserved
                                    addr";
                                }
                            }
                        }
                        list binding-info {
                            key cli-id;
                            config "false";
                            description "A list records a binding
                            information for each DHCPv6 client
                            that has already been allocated IPv6
                            addresses.";
                            leaf cli-id {
                                type uint32;
                                mandatory true;
                                description "client id";
                            }
                            leaf duid {
                                type duidtype;
                                mandatory true;
                                description "DHCP Unique Identifer";
                                                        }
                            list cli-ia {
                                key iaid;
                                description "client IA";
                                leaf ia-type {
                                    type string;
                                    mandatory true;
                                    description "IA type";
                                }
                                leaf iaid {
                                    type uint32;
                                    mandatory true;
                                    description "IAID";
                                }
                                leaf-list cli-addr {
                                    type inet:ipv6-address;
                                    description "client addr";
                                }
                                leaf pool-id {
                                    type uint8;
                                    mandatory true;
                                    description "pool id";
                                }
                            }
                        }
                    }
                    container prefix-pools {
                        description "If a server supports prefix
                        delegation function, this container will
                        be used to define the delegating router's
                        refix pools.";
                        list prefix-pool {
                            key pool-id;
                            description "Similar to server's
                            address pools, a delegating router
                            can also be configured with multiple
                            prefix pools specified by a list
                            called 'prefix-pool'.";
                            leaf pool-id {
                                type uint8;
                                mandatory true;
                                description "pool id";
                            }
                            leaf prefix {
                                type inet:ipv6-prefix;
                                mandatory true;
                                description "ipv6 prefix";
                            }
                            leaf prefix-length {
                                type uint8;
                                mandatory true;
                                description "prefix length";
                            }
                            leaf renew-time {
                                type yang:timeticks;
                                mandatory true;
                                description "renew time";
                            }
                            leaf rebind-time {
                                type yang:timeticks;
                                mandatory true;
                                description "rebind time";
                            }
                            leaf preferred-lifetime {
                                type yang:timeticks;
                                mandatory true;
                                description "preferred lifetime for
                                IA";
                            }
                            leaf valid-lifetime {
                                type yang:timeticks;
                                mandatory true;
                                description "valid lifetime for IA";
                            }
                            leaf utilization-ratio {
                                type threshold;
                                mandatory true;
                                description "utilization ratio";
                            }
                            leaf inherit-option-set {
                                type boolean;
                                mandatory true;
                                description "whether to inherit
                                configuration from higher level";
                            }
                            leaf-list option-set {
                                type uint8;
                                description "configured option
                                set";
                            }
                            container reserved-prefixes {
                                description "reserved prefixes";
                                list static-binding {
                                    key cli-id;
                                    description "static binding";
                                    leaf cli-id {
                                        type uint32;
                                        mandatory true;
                                        description "client id";
                                    }
                                    leaf duid {
                                        type duidtype;
                                        mandatory true;
                                        description "DHCP Unique
                                        Identifer";
                                    }
                                    leaf reserv-prefix-len {
                                        type uint8;
                                        mandatory true;
                                        description "reserved
                                        prefix length";
                                    }
                                    leaf reserv-prefix {
                                        type inet:ipv6-prefix;
                                        mandatory true;
                                        description
                                        "reserved prefix";
                                    }
                                }
                                leaf exclude-prefix-len {
                                    type uint8;
                                    mandatory true;
                                    description "exclude prefix
                                    length";
                                }
                                leaf exclude-prefix {
                                    type inet:ipv6-prefix;
                                    mandatory true;
                                    description "exclude prefix";
                                }
                                list other-reserv-prefix {
                                    key reserv-id;
                                    description
                                    "other reserved prefix";
                                    leaf reserv-id {
                                        type uint8;
                                        mandatory true;
                                        description
                                        "reserved prefix id";
                                    }
                                    leaf prefix-len {
                                        type uint8;
                                        mandatory true;
                                        description "prefix length";
                                    }
                                    leaf prefix {
                                        type inet:ipv6-prefix;
                                        mandatory true;
                                        description
                                        "reserved prefix";
                                    }
                                }
                            }
                        }
                        list binding-info {
                            key cli-id;
                            config "false";
                            description "A list records a
                            binding information for each
                            DHCPv6 client that has already
                            been allocated IPv6 addresses.";
                            leaf cli-id {
                                type uint32;
                                mandatory true;
                                description "client id";
                            }
                            leaf duid {
                                type duidtype;
                                mandatory true;
                                description "DHCP Unique
                                Identifier";
                            }
                            list cli-iapd {
                                key iaid;
                                description "client IAPD";
                                leaf iaid {
                                    type uint32;
                                    mandatory true;
                                    description "IAID";
                                }
                                leaf-list cli-prefix {
                                    type inet:ipv6-prefix;
                                    description
                                    "client ipv6 prefix";
                                }
                                leaf-list cli-prefix-len {
                                    type uint8;
                                    description
                                    "client prefix length";
                                }
                                leaf pool-id {
                                    type uint8;
                                    mandatory true;
                                    description "pool id";
                                }
                            }
                        }
                    }
                    container hosts {
                        description "hosts level";
                        list host {
                            key cli-id;
                            description "specific host";
                            leaf cli-id {
                                type uint32;
                                mandatory true;
                                description "client id";
                            }
                            leaf duid {
                                type duidtype;
                                mandatory true;
                                description "DHCP Unique
                                Identifer";
                            }
                            leaf inherit-option-set {
                                type boolean;
                                mandatory true;
                                description "whether to inherit
                                configuration
                                from higher level";
                            }
                            leaf-list option-set {
                                type uint8;
                                description "configured option set";
                            }
                            leaf nis-domain-name {
                                type string;
                                description "nis domain name";
                            }
                            leaf nis-plus-domain-name {
                                type string;
                                description "nisp domain name";
                            }
                        }
                    }
                }
            }
            container relay-opaque-paras {
                description "This container contains some
                opaque values in Relay Agent options that
                need to be configured on the server side
                only for value match. Such Relay Agent
                options include Interface-Id option,
                Remote-Id option and Subscriber-Id option.";
                list relays {
                    key relay-name;
                    description "relay agents";
                    leaf relay-name {
                        type string;
                        mandatory true;
                        description "relay agent name";
                    }
                    list interface-info {
                        key if-name;
                        description "interface info";
                        leaf if-name {
                            type string;
                            mandatory true;
                            description "interface name";
                        }
                        leaf interface-id {
                            type string;
                            mandatory true;
                            description "interface id";
                        }
                    }
                    list subscribers {
                        key subscriber;
                        description "subscribers";
                        leaf subscriber {
                            type uint8;
                            mandatory true;
                            description "subscriber";
                        }
                        leaf subscriber-id {
                            type string;
                            mandatory true;
                            description "subscriber id";
                        }
                    }
                    list remote-host {
                        key ent-num;
                        description "remote host";
                        leaf ent-num {
                            type uint32;
                            mandatory true;
                            description "enterprise number";
                        }
                        leaf remote-id {
                            type string;
                            mandatory true;
                            description "remote id";
                        }
                    }
                }
            }
            container rsoo-enabled-options {
                description "rsoo enabled options";
                list rsoo-enabled-option{
                    key option-code;
                    description "rsoo enabled option";
                    leaf option-code {
                        type uint16;
                        mandatory true;
                        description "option code";
                    }
                    leaf description {
                        type string;
                        mandatory true;
                        description "description of the option";
                    }
                }
            }
            container packet-stats {
                config "false";
                description "A container presents
                the packet statistics related to
                the DHCPv6 server.";
                leaf solicit-count {
                    type uint32;
                    mandatory true;
                    description "solicit counter";

                }
                leaf request-count {
                    type uint32;
                    mandatory true;
                    description "request counter";
                }
                leaf renew-count {
                    type uint32;
                    mandatory true;
                    description "renew counter";
                }
                leaf rebind-count {
                    type uint32;
                    mandatory true;
                    description "rebind counter";
                }
                leaf decline-count {
                    type uint32;
                    mandatory true;
                    description "decline count";
                }
                leaf release-count {
                    type uint32;
                    mandatory true;
                    description "release counter";
                }
                leaf info-req-count {
                    type uint32;
                    mandatory true;
                    description "information request
                    counter";
                }
                leaf advertise-count {
                    type uint32;
                    mandatory true;
                    description "advertise counter";
                }
                leaf confirm-count {
                    type uint32;
                    mandatory true;
                    description "confirm counter";
                }
                leaf reply-count {
                    type uint32;
                    mandatory true;
                    description "reply counter";
                }
                leaf reconfigure-count {
                    type uint32;
                    mandatory true;
                    description "reconfigure counter";
                }
                leaf relay-forward-count {
                    type uint32;
                    mandatory true;
                    description "relay forward counter";
                }
                leaf relay-reply-count {
                    type uint32;
                    mandatory true;
                    description "relay reply counter";
                }
            }
    }

    container relay {
        description "dhcpv6 relay portion";
        container relay-attributes {
            description "A container describes
            some basic attributes of the relay
            agent including some relay agent
            specific options data that need to
            be configured previously. Such options
            include Remote-Id option and
            Subscriber-Id option.";
            leaf name {
                type string;
                mandatory true;
                description "relay agent name";
            }
            leaf enable {
                type boolean;
                mandatory true;
                description "whether the relay is enabled";
            }
            leaf description {
                type string;
                description "description of the relay agent";
            }
            leaf-list dest-addrs {
                type inet:ipv6-address;
                description "Each DHCPv6 relay agent may
                be configured with a list of destination
                addresses. This node defines such a list
                of IPv6 addresses that may include
                unicast addresses, multicast addresses
                or other addresses.";
            }
            list subscribers {
                key subscriber;
                description "subscribers";
                leaf subscriber {
                    type uint8;
                    mandatory true;
                    description "subscriber";
                }
                leaf subscriber-id {
                    type string;
                    mandatory true;
                    description "subscriber id";
                }
            }
            list remote-host {
                key ent-num;
                description "remote host";
                leaf ent-num {
                    type uint32;
                    mandatory true;
                    description "enterprise number";
                }
                leaf remote-id {
                    type string;
                    mandatory true;
                    description "remote id";
                }
            }
            uses vendor-infor;
        }
            container relay-supplied-options-option {
                description "relay supplied options option";
                list rsoo-set {
                    key rsoo-set-id;
                    description "rsoo set";
                    leaf rsoo-set-id {
                        type uint8;
                        mandatory true;
                        description "rsoo set id";
                    }
                    container erp-local-domain-name-option {
                        description "erp local domain name option";
                        leaf enable {
                            type boolean;
                            mandatory true;
                            description "indicate whether
                            this option is included in the
                            rsoo set";
                        }
                        list erp-for-client {
                            key cli-id;
                            description "erp for client";
                            leaf cli-id {
                                type uint32;
                                mandatory true;
                                description "client id";
                            }
                            leaf duid {
                                type duidtype;
                                mandatory true;
                                description "DHCP Unique
                                Identifer";
                            }
                            leaf erp-name {
                                type string;
                                mandatory true;
                                description "erp name";
                            }
                        }
                    }
                }
            }
            list relay-if {
                    key if-name;
                    description "A relay agent may have several
                    interfaces, we should provide a way to configure
                    and manage parameters on the interface-level. A
                    list that describes specific interfaces and
                    their corresponding parameters is employed to
                    fulfil the configfuration. Here we use a string
                    called 'if-name; as the key of list.";
                    leaf if-name {
                        type string;
                        mandatory true;
                        description "interface name";
                    }
                    leaf enable {
                        type boolean;
                        mandatory true;
                        description
                        "whether this interface is enabled";
                    }
                    leaf ipv6-address {
                        type inet:ipv6-address;
                        description
                        "ipv6 address for this interface";
                    }
                    leaf interface-id {
                        type string;
                        description "interface id";
                    }
                    leaf-list rsoo-set {
                        type uint8;
                        description "configured rsoo set";
                    }
                    list pd-route {
                        key pd-route-id;
                        description "pd route";
                        leaf pd-route-id {
                            type uint8;
                            mandatory true;
                            description "pd route id";
                        }
                        leaf requesting-router-id {
                            type uint32;
                            mandatory true;
                            description "requesting router id";
                        }
                        leaf delegating-router-id {
                            type uint32;
                            mandatory true;
                            description "delegating router id";
                        }
                        leaf next-router {
                            type inet:ipv6-address;
                            mandatory true;
                            description "next router";
                        }
                        leaf last-router {
                            type inet:ipv6-address;
                            mandatory true;
                            description "previous router";
                        }
                    }
                    list next-entity {
                        key dest-addr;
                        description "This node defines
                        a list that is used to describe
                        the next hop entity of this
                        relay distinguished by their
                        addresses.";
                        leaf dest-addr {
                            type inet:ipv6-address;
                            mandatory true;
                            description "destination addr";
                        }
                        leaf available {
                            type boolean;
                            mandatory true;
                            description "whether the next entity
                            is available or not";
                        }
                        leaf multicast {
                            type boolean;
                            mandatory true;
                            description "whether the address is
                            multicast or not";
                        }
                        leaf server {
                            type boolean;
                            mandatory true;
                            description "whether the next entity
                            is a server";
                        }
                        container packet-stats {
                            config "false";
                            description "packet statistics";
                            leaf cli-packet-rvd-count {
                                type uint32;
                                mandatory true;
                                description "client received packet
                                counter";
                            }
                            leaf solicit-rvd-count {
                                type uint32;
                                mandatory true;
                                description
                                "solicit received counter";
                            }
                            leaf request-rvd-count {
                                type uint32;
                                mandatory true;
                                description
                                "request received counter";
                            }
                            leaf renew-rvd-count {
                                type uint32;
                                mandatory true;
                                description
                                "renew received counter";

                            }
                            leaf rebind-rvd-count {
                                type uint32;
                                mandatory true;
                                description
                                "rebind recevied counter";
                            }
                            leaf decline-rvd-count {
                                type uint32;
                                mandatory true;
                                description
                                "decline received counter";
                            }
                            leaf release-rvd-count {
                                type uint32;
                                mandatory true;
                                description
                                "release received counter";
                            }
                            leaf info-req-rvd-count {
                                type uint32;
                                mandatory true;
                                description
                                "information request counter";
                            }
                            leaf relay-for-rvd-count {
                                type uint32;
                                mandatory true;
                                description
                                "relay forward received counter";
                            }
                            leaf relay-rep-rvd-count {
                                type uint32;
                                mandatory true;
                                description
                                "relay reply received counter";
                            }
                            leaf packet-to-cli-count {
                                type uint32;
                                mandatory true;
                                description
                                "packet to client counter";
                            }
                            leaf adver-sent-count {
                                type uint32;
                                mandatory true;
                                description
                                "advertisement sent counter";

                            }
                            leaf confirm-sent-count {
                                type uint32;
                                mandatory true;
                                description
                                "confirm sent counter";
                            }
                            leaf reply-sent-count {
                                type uint32;
                                mandatory true;
                                description
                                "reply sent counter";
                            }
                            leaf reconfig-sent-count {
                                type uint32;
                                mandatory true;
                                description
                                "reconfigure sent counter";
                            }
                            leaf relay-for-sent-count {
                                type uint32;
                                mandatory true;
                                description
                                "relay forward sent counter";
                            }
                            leaf relay-rep-sent-count {
                                type uint32;
                                mandatory true;
                                description
                                "relay reply sent counter";
                            }
                        }
                    }
            }
            container relay-stats {
                config "false";
                description "relay statistics";
                leaf cli-packet-rvd-count {
                    type uint32;
                    mandatory true;
                    description "client packet received counter";
                }
                leaf relay-for-rvd-count {
                    type uint32;
                    mandatory true;
                    description "relay forward received counter";
                }
                leaf relay-rep-rvd-count {
                    type uint32;
                    mandatory true;
                    description "relay reply recevied counter";
                }
                leaf packet-to-cli-count {
                    type uint32;
                    mandatory true;
                    description "packet to client counter";
                }
                leaf relay-for-sent-count {
                    type uint32;
                    mandatory true;
                    description "relay forward sent counter";
                }
                leaf relay-rep-sent-count {
                    type uint32;
                    mandatory true;
                    description "relay reply sent counter";
                }
                leaf discarded-packet-count {
                    type uint32;
                    mandatory true;
                    description "discarded packet counter";
                }
            }
    }
    container client {
            description "dhcpv6 client portion";
            list client-if {
                key if-name;
                description "A client may have several
                interfaces, it is more reasonable to
                configure and manage parameters on
                the interface-level. The list defines
                specific client interfaces and their
                data. Different interfaces are distinguished
                by the key which is a configurable string
                value.";
                leaf if-name {
                    type string;
                    mandatory true;
                    description "interface name";
                }
                leaf cli-id {
                    type uint32;
                    mandatory true;
                    description "client id";
                }
                leaf duid {
                    type duidtype;
                    mandatory true;
                    description "DHCP Unique
                    Identifer";
                }
                leaf enable {
                    type boolean;
                    mandatory true;
                    description "whether the interface is enabled";
                }
                leaf description {
                    type string;
                    description
                    "description of the client interface";
                }
                leaf pd-function {
                    type boolean;
                    mandatory true;
                    description "Whether the client
                    can act as a requesting router
                    to request prefixes using prefix
                    delegation ([RFC3633]).";
                }
                leaf rapid-commit {
                    type boolean;
                    mandatory true;
                    description "'1' indicates a client can
                    initiate a Solicit-Reply message exchange
                    by adding a Rapid Commit option in Solicit
                    message. '0' means the client is not allowed
                    to add a Rapid Commit option to request
                    addresses in a two-message exchange
                    pattern.";
                }
                container mo-tab {
                    description "The management tab
                    label indicates the operation
                    mode of the DHCPv6 client. 'm'=1
                    and 'o'=1 indicate the client
                    will use DHCPv6 to obtain all
                    the configuration data. 'm'=1
                    and 'o'=0 are a meaningless
                    combination. 'm'=0 and 'o'=1
                    indicate the client will use
                    stateless DHCPv6 to obtain
                    configuration data apart from
                    addresses/prefixes data.

                    'm'=0 and 'o'=0 represent the
                    client will not use DHCPv6
                    but use SLAAC to achieve
                    configuration.";
                    leaf m-tab {
                        type boolean;
                        mandatory true;
                        description "m tab";
                    }
                    leaf o-tab {
                        type boolean;
                        mandatory true;
                        description "o tab";
                    }
                }
                container oro-options {
                    description "oro options";
                    list oro-option {
                        key option-code;
                        description "oro option";
                        leaf option-code {
                            type uint16;
                            mandatory true;
                            description "option code";
                        }
                        leaf description {
                            type string;
                            mandatory true;
                            description "description of oro
                            options";
                        }
                    }
                }
                container client-configured-options {
                    description "client configured options";
                    list new-or-standard-cli-option {
                        key option-code;
                        description "new or standard client option";
                        leaf option-code {
                            type uint16;
                            mandatory true;
                            description "option code";
                        }
                        leaf option-name {
                            type string;
                            mandatory true;
                            description "option name";
                        }
                        leaf option-description {
                            type string;
                            mandatory true;
                            description "description of client
                            option";
                        }
                        leaf option-reference {
                            type string;
                            description "the reference of option";
                        }
                        leaf option-value {
                            type string;
                            mandatory true;
                            description "the option value";
                        }
                    }
                    container user-class-option {
                        description "user class option";
                        leaf enable {
                            type boolean;
                            mandatory true;
                            description "indicate whether this
                            option will be configured at the
                            client";
                        }
                        list user-class {
                            key user-class-id;
                            description "user class";
                            leaf user-class-id {
                                type uint8;
                                mandatory true;
                                description "user class id";
                            }
                            leaf user-class-info {
                                type string;
                                mandatory true;
                                description "user class info";
                            }
                        }
                    }
                    container vendor-class-option {
                        description "vendor class option";
                        leaf enable {
                            type boolean;
                            mandatory true;
                            description "indicate whether this
                            option will be configured at the
                            client";

                        }
                        leaf ent-num {
                            type uint32;
                            mandatory true;
                            description "enterprise number";
                        }
                        leaf-list data {
                            type string;
                            description "option data";
                        }
                    }
                    container client-fqdn-option {
                        description "client fqdn option";
                        leaf enable {
                            type boolean;
                            mandatory true;
                            description "indicate whether this
                            option will be configured at the
                            client";
                        }
                        leaf fqdn {
                            type string;
                            mandatory true;
                            description "fqdn";
                        }
                        leaf server-initiate-update {
                            type boolean;
                            mandatory true;
                            description "whether server initiate";
                        }
                        leaf client-initiate-update {
                            type boolean;
                            mandatory true;
                            description "whether client initiate";
                        }
                    }
                    container client-architecture-type-option {
                        description
                        "client architecture type option";
                        leaf enable {
                            type boolean;
                            mandatory true;
                            description "indicate whether this
                            option will be configured at the
                            client";
                        }
                        list architecture-types {
                            key type-id;
                            description "architecture types";
                            leaf type-id {
                                type uint16;
                                mandatory true;
                                description "type id";
                            }
                            leaf most-preferred {
                                type boolean;
                                mandatory true;
                                description "most preferred flag";
                            }
                        }
                    }
                    container client-network-interface-option {
                        description
                        "client network interface option";
                        leaf enable {
                            type boolean;
                            mandatory true;
                            description "indicate whether this
                            option will be configured at the
                            client";
                        }
                        leaf type {
                            type uint8;
                            mandatory true;
                            description "type";
                        }
                        leaf major {
                            type uint8;
                            mandatory true;
                            description "major";
                        }
                        leaf minor {
                            type uint8;
                            mandatory true;
                            description "minor";
                        }
                    }
                    container kerberos-principal-name-option {
                        description
                        "kerberos principal name option";
                        leaf enable {
                            type boolean;
                            mandatory true;
                            description "indicate whether this
                            option will be configured at the
                            client";

                        }
                        leaf principal-name {
                            type string;
                            mandatory true;
                            description "principal name";
                        }
                    }
                    container client-link-layer-addr-option {
                        description
                        "client link layer address option";
                        leaf enable {
                            type boolean;
                            mandatory true;
                            description "indicate whether this
                            option will be configured at the
                            client";
                        }
                        leaf link-layer-type {
                            type uint16;
                            mandatory true;
                            description "link layer type";
                        }
                        leaf link-layer-addr {
                            type string;
                            mandatory true;
                            description "link layer address";
                        }
                    }
                }
                container identity-associations {
                    config "false";
                    description "IA is a construct through
                    which a server and a client can identify,
                    group, and manage a set of related IPv6
                    addresses. The key of the list is a
                    4-byte number IAID defined in [RFC3315].";
                    list identity-association {
                        key iaid;
                        description "IA";
                        leaf iaid {
                            type uint32;
                            mandatory true;
                            description "IAID";
                        }
                        leaf ia-type {
                            type string;
                            mandatory true;
                            description "IA type";

                        }
                        leaf-list ipv6-addr {
                            type inet:ipv6-address;
                            description "ipv6 address";
                        }
                        leaf-list ipv6-prefix {
                            type inet:ipv6-prefix;
                            description "ipv6 prefix";
                        }
                        leaf-list prefix-length {
                            type uint8;
                            description "ipv6 prefix length";
                        }
                        leaf t1-time {
                            type yang:timeticks;
                            mandatory true;
                            description "t1 time";
                        }
                        leaf t2-time {
                            type yang:timeticks;
                            mandatory true;
                            description "t2 time";
                        }
                        leaf preferred-lifetime {
                            type yang:timeticks;
                            mandatory true;
                            description "preferred lifetime";
                        }
                        leaf valid-lifetime {
                            type yang:timeticks;
                            mandatory true;
                            description "valid lifetime";
                        }
                    }
                }
                container if-other-paras {
                    config "false";
                    description "A client can obtain
                    extra configuration data other than
                    address and prefix information through
                    DHCPv6. This container describes such
                    data the client was configured. The
                    potential configuration data may
                    include DNS server addresses, SIP
                    server domain names, etc.";
                    leaf-list uni-dhcpv6-serv-addr {
                        type inet:ipv6-address;
                        description "unicast server address";

                    }
                    container dns-paras {
                        description "dns parameters";
                        leaf domain-search-list {
                            type string;
                            mandatory true;
                            description "domain search list";
                        }
                        list dns-servers {
                            key dns-serv-id;
                            description "dns servers";
                            leaf dns-serv-id {
                                type uint8;
                                mandatory true;
                                description "dns server id";
                            }
                            leaf dns-serv-addr {
                                type inet:ipv6-address;
                                mandatory true;
                                description "dns server address";
                            }
                        }
                    }
                    container sip-paras {
                        description "sip parameters";
                        list sip-servers {
                            key sip-serv-id;
                            description "sip server info";
                            leaf sip-serv-id {
                                type uint8;
                                mandatory true;
                                description "sip server id";
                            }
                            leaf sip-serv-addr {
                                type inet:ipv6-address;
                                mandatory true;
                                description "sip server address";
                            }
                            leaf sip-serv-domain-name {
                                type string;
                                mandatory true;
                                description
                                "sip server domain name";
                            }
                        }
                    }
                    container nis-paras {
                        description "nis parameters";
                        leaf nis-domain-name {
                            type string;
                            mandatory true;
                            description "nis domain name";
                        }
                        list nis-server {
                            key nis-serv-id;
                            description "nis server";
                            leaf nis-serv-id {
                                type uint8;
                                mandatory true;
                                description "nis server id";
                            }
                            leaf nis-serv-addr {
                                type inet:ipv6-address;
                                mandatory true;
                                description "nis server address";
                            }
                        }
                    }
                    container nis-plus-paras {
                        description "nisp parameters";
                        leaf nis-plus-domain-name {
                            type string;
                            mandatory true;
                            description "nisp domian name";
                        }
                        list nis-plus-server {
                            key nis-plus-serv-id;
                            description "nisp server";
                            leaf nis-plus-serv-id {
                                type uint8;
                                mandatory true;
                                description "nisp server id";
                            }
                            leaf nis-plus-serv-addr {
                                type inet:ipv6-address;
                                mandatory true;
                                description "nisp server address";
                            }
                        }
                    }
                    leaf info-refresh-time {
                        type yang:timeticks;
                        description "info refresh time";
                    }
                    container time-zone-paras {
                        description "time zone parameters";
                        leaf tz-posix {
                            type string;
                            mandatory true;
                            description "tz posix";
                        }
                        leaf tz-database {
                            type string;
                            mandatory true;
                            description "tz database";
                        }
                    }
                    leaf cli-fqdn {
                        type string;
                        description "client fqdn";
                    }
                    container ntp-paras {
                        description "ntp parameters";
                        list ntp-server {
                            key ntp-serv-id;
                            description "ntp server";
                            leaf ntp-serv-id {
                                type uint8;
                                mandatory true;
                                description "ntp server id";
                            }
                            leaf ntp-serv-addr {
                                type inet:ipv6-address;
                                mandatory true;
                                description "ntp server address";
                            }
                            leaf ntp-serv-mul-addr {
                                type inet:ipv6-address;
                                mandatory true;
                                description "ntp server multicast
                                address";
                            }
                            leaf ntp-serv-fqdn {
                                type string;
                                mandatory true;
                                description "ntp server fqdn";
                            }
                        }
                    }
                    container sntp-paras {
                        description "sntp parameters";
                        list sntp-server {
                            key sntp-serv-id;
                            description "sntp server";
                            leaf sntp-serv-id {
                                type uint8;
                                mandatory true;
                                description "sntp server id";
                            }
                            leaf sntp-serv-addr {
                                type inet:ipv6-address;
                                mandatory true;
                                description "sntp server address";
                            }
                        }
                    }
                    container network-boot-paras {
                        description "network boot parameters";
                        list boot-file {
                            key boot-file-id;
                            description "boot file";
                            leaf boot-file-id {
                                type uint8;
                                mandatory true;
                                description "boot file id";
                            }
                            leaf-list suitable-arch-type {
                                type uint16;
                                description "architecture type";
                            }
                            leaf-list suitable-net-if {
                                type uint32;
                                description "network interface";
                            }
                            leaf boot-file-url {
                                type string;
                                mandatory true;
                                description "boot file url";
                            }
                            list boot-file-paras {
                                key para-id;
                                description "boot file parameters";
                                leaf para-id {
                                    type uint8;
                                    mandatory true;
                                    description "parameter id";
                                }
                                leaf parameter {
                                    type string;
                                    mandatory true;
                                    description "parameter value";
                                }

                            }
                        }
                    }
                    container kerberos-paras {
                        description "kerberos parameters";
                        leaf default-realm-name {
                            type string;
                            mandatory true;
                            description "default realm name";
                        }
                        list kdc-info {
                            key kdc-id;
                            description "kdc info";
                            leaf kdc-id {
                                type uint8;
                                mandatory true;
                                description "kdc id";
                            }
                            leaf priority {
                                type uint16;
                                mandatory true;
                                description "priority";
                            }
                            leaf weight {
                                type uint16;
                                mandatory true;
                                description "weight";
                            }
                            leaf transport-type {
                                type uint8;
                                mandatory true;
                                description "transport type";
                            }
                            leaf port-number {
                                type uint16;
                                mandatory true;
                                description "port number";
                            }
                            leaf kdc-ipv6-addr {
                                type inet:ipv6-address;
                                mandatory true;
                                description "kdc ipv6 address";
                            }
                            leaf realm-name {
                                type string;
                                mandatory true;
                                description "realm name";
                            }

                        }
                    }
                    container addr-selection-paras {
                        description "address selection parameters";
                        leaf automatic-row-add {
                            type boolean;
                            mandatory true;
                            description "row add";
                        }
                        leaf prefer-temporary-addr {
                            type boolean;
                            mandatory true;
                            description "prefer temporary";
                        }
                        list policy-table {
                            key policy-id;
                            description "policy table";
                            leaf policy-id {
                                type uint8;
                                mandatory true;
                                description "policy id ";
                            }
                            leaf label {
                                type uint8;
                                mandatory true;
                                description "label";
                            }
                            leaf precedence {
                                type uint8;
                                mandatory true;
                                description "precedence";
                            }
                            leaf prefix-len {
                                type uint8;
                                mandatory true;
                                description "prefix length";
                            }
                            leaf prefix {
                                type inet:ipv6-prefix;
                                mandatory true;
                                description "prefix";
                            }
                        }
                    }
                    leaf sol-max-rt {
                        type yang:timeticks;
                        mandatory true;
                        description "sol max rt";

                    }
                    leaf inf-max-rt {
                        type yang:timeticks;
                        mandatory true;
                        description "inf max rt";
                    }
                    container pcp-server-paras {
                        description "pcp server parameters";
                        list pcp-server {
                            key pcp-serv-id;
                            description "pcp server";
                            leaf pcp-serv-id {
                                type uint8;
                                mandatory true;
                                description "pcp server id";
                            }
                            leaf pcp-serv-addr {
                                type inet:ipv6-address;
                                mandatory true;
                                description "pcp server address";
                            }
                        }
                    }
                    container s46-rule-paras {
                        description "s46 rule parameters";
                        list s46-rule {
                            key rule-id;
                            description "s46 rule";
                            leaf rule-id {
                                type uint8;
                                mandatory true;
                                description "rule id";
                            }
                            leaf rule-type {
                                type enumeration {
                                enum "BMR"{
                                    description "BMR";
                                }
                                enum "FMR"{
                                    description "FMR";
                                }
                                }
                                mandatory true;
                                description "rule type";
                            }
                            leaf ea-len {
                                type uint8;
                                mandatory true;
                                description "EA bits length";
                            }
                            leaf prefix4-len {
                                type uint8;
                                mandatory true;
                                description "ipv4 prefix length";
                            }
                            leaf ipv4-prefix {
                                type inet:ipv4-prefix;
                                mandatory true;
                                description "ipv4 prefix";
                            }
                            leaf prefix6-len {
                                type uint8;
                                mandatory true;
                                description "ipv6 prefix length";
                            }
                            leaf ipv6-prefix {
                                type inet:ipv6-prefix;
                                mandatory true;
                                description "ipv6 prefix";
                            }
                            uses portset-para;
                        }
                    }
                    container s46-br-paras {
                        description "s46 br parameters";
                        list br {
                            key br-id;
                            description "br";
                            leaf br-id {
                                type uint8;
                                mandatory true;
                                description "br id";
                            }
                            leaf br-ipv6-addr {
                                type inet:ipv6-address;
                                mandatory true;
                                description "br ipv6 address";
                            }
                        }
                    }
                    container s46-dmr-paras {
                        description "s46 dmr parameters";
                        list dmr {
                            key dmr-id;
                            description "dmr";
                            leaf dmr-id {
                                type uint8;
                                mandatory true;
                                description "dmr id";
                            }
                            leaf dmr-prefix-len {
                                type uint8;
                                mandatory true;
                                description "dmr prefix length";
                            }
                            leaf dmr-ipv6-prefix {
                                type inet:ipv6-prefix;
                                mandatory true;
                                description "dmr prefix";
                            }
                        }
                    }
                    container s46-v4-v6-binding-paras {
                        description "s46 v4 v6 binding parameters";
                        leaf ipv4-addr {
                            type inet:ipv4-address;
                            mandatory true;
                            description "ipv4 address";
                        }
                        leaf bind-prefix6-len {
                            type uint8;
                            mandatory true;
                            description "bind ipv6 prefix";
                        }
                        uses portset-para;
                        leaf erp-local-domain-name {
                            type string;
                            mandatory true;
                            description "erp local domain name";
                        }
                    }
                    container supported-options {
                        description "supported options";
                        list supported-option {
                            key option-code;
                            description "supported option";
                            leaf option-code {
                                type uint16;
                                mandatory true;
                                description "option code";
                            }
                            leaf description {
                                type string;
                                mandatory true;
                                description
                                "description of supported
                                option";
                            }
                        }
                    }
                }
                container packet-stats {
                    config "false";
                    description "A container records
                    all the packet status information
                    of a specific interface.";
                    leaf solicit-count {
                        type uint32;
                        mandatory true;
                        description "solicit counter";
                    }
                    leaf request-count {
                        type uint32;
                        mandatory true;
                        description "request counter";
                    }
                    leaf renew-count {
                        type uint32;
                        mandatory true;
                        description "renew counter";
                    }
                    leaf rebind-count {
                        type uint32;
                        mandatory true;
                        description "rebind counter";
                    }
                    leaf decline-count {
                        type uint32;
                        mandatory true;
                        description "decline counter";
                    }
                    leaf release-count {
                        type uint32;
                        mandatory true;
                        description "release counter";
                    }
                    leaf info-req-count {
                        type uint32;
                        mandatory true;
                        description "information request counter";
                    }
                    leaf advertise-count {
                        type uint32;
                        mandatory true;
                        description "advertise counter";
                    }
                    leaf confirm-count {
                        type uint32;
                        mandatory true;
                        description "confirm counter";
                    }
                    leaf reply-count {
                        type uint32;
                        mandatory true;
                        description "reply counter";
                    }
                    leaf reconfigure-count {
                        type uint32;
                        mandatory true;
                        description "recofigure counter";
                    }
                }
            }
    }

/*
 * Notifications
 */

    notification notifications {
        description "dhcpv6 notification module";
        container dhcpv6-server-event {
            description "dhcpv6 server event";
            container pool-running-out {
                description "raised when the
                address/prefix pool is going to
                run out.  A threshold for utilization
                ratio of the pool has been defined in
                the server feature so that it will
                notify the administrator when the
                utilization ratio reaches the threshold,
                and such threshold is a settable
                parameter";
                leaf utilization-ratio {
                    type uint16;
                    mandatory true;
                    description "utilization ratio";
                }
                leaf duid {
                    type duidtype;
                    mandatory true;
                    description "DHCP Unique
                    Identifer";
                }
                leaf serv-name {
                    type string;
                    description "server name";
                }
                leaf pool-name {
                    type string;
                    mandatory true;
                    description "pool name";
                }
            }
            container invalid-client-detected {
                description "raised when the server
                has found a client which can be
                regarded as a potential attacker. Some
                description could also be included.";
                leaf duid {
                    type duidtype;
                    mandatory true;
                    description "DHCP Unique
                    Identifer";
                }
                leaf description {
                    type string;
                    description "description of the event";
                }
            }
        }
        container dhcpv6-relay-event {
            description "dhcpv6 relay event";
            container topo-changed {
                description "raised when the topology
                of the relay agent is changed.";
                leaf relay-if-name {
                    type string;
                    mandatory true;
                    description "relay interface name";
                }
                leaf first-hop {
                    type boolean;
                    mandatory true;
                    description "first hop";
                }
                leaf last-entity-addr {
                    type inet:ipv6-address;
                    mandatory true;
                    description "last entity address";
                }
            }
        }
        container dhcpv6-client-event {
            description "dhcpv6 client event";
            container ia-lease-event {
                description "raised when the
                client was allocated a new IA from
                the server or it renew/rebind/release
                its current IA";
                leaf event-type {
                    type enumeration{
                    enum "allocation" {
                        description "allocate";
                    }
                    enum "rebind" {
                        description "rebind";
                    }
                    enum "renew" {
                        description "renew";
                    }
                    enum "release" {
                        description "release";
                    }
                    }
                    mandatory true;
                    description "event type";
                }
                leaf duid {
                    type duidtype;
                    mandatory true;
                    description "DHCP Unique
                    Identifer";
                }
                leaf iaid {
                    type uint32;
                    mandatory true;
                    description "IAID";
                }
                leaf serv-name {
                    type string;
                    description "server name";
                }
                leaf description {
                    type string;
                    description "description of event";

                }
            }
            container invalid-ia-detected {
                description "raised when the identity
                association of the client can be proved
                to be invalid.  Possible condition includes
                duplicated address, illegal address, etc.";
                leaf duid {
                    type duidtype;
                    mandatory true;
                    description "DHCP Unique
                    Identifer";
                }
                leaf cli-duid {
                    type uint32;
                    mandatory true;
                    description "duid of client";
                }
                leaf iaid {
                    type uint32;
                    mandatory true;
                    description "IAID";
                }
                leaf serv-name {
                    type string;
                    description "server name";
                }
                leaf description {
                    type string;
                    description "description of the event";
                }
            }
            container retransmission-failed {
                description "raised when the retransmission
                mechanism defined in [RFC3315] is failed.";
                leaf duid{
                    type duidtype;
                    description "DUID";
                }
                leaf description {
                    type enumeration {
                        enum "MRC failed" {
                            description "MRC failed";
                        }
                        enum "MRD failed" {
                            description "MRD failed";
                        }
                    }
                    mandatory true;
                    description "description of failure";
                }
            }
            container failed-status-turn-up {
                description "raised when the client receives
                a message includes an unsuccessful Status Code
                option.";
                leaf duid {
                    type duidtype;
                    mandatory true;
                    description "DHCP Unique
                    Identifer";
                }
                leaf status-code {
                    type enumeration {
                        enum "1" {
                            description "UnspecFail";
                        }
                        enum "2" {
                            description "NoAddrAvail";
                        }
                        enum "3" {
                            description "NoBinding";
                        }
                        enum "4" {
                            description "NotOnLink";
                        }
                        enum "5" {
                            description "UseMulticast";
                        }
                    }
                    mandatory true;
                    description "employed status code";
                }
            }
        }
    }
}
<CODE ENDS>

5.

4.  Security Considerations (TBD)

   TBD

6.

5.  IANA Considerations (TBD)

   TBD

7.

6.  Acknowledgements

   The authors would like to thank Qi Sun, Lishan Li, Sladjana Zoric,
   Tomek Mrugalski, Marcin Siodelski, Bernie Volz and Bing Liu for their
   valuable comments and contributions to this work.

8.

7.  References

8.1.

7.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <http://www.rfc-editor.org/info/rfc2119>.

   [RFC3315]  Droms, R., Ed., Bound, J., Volz, B., Lemon, T., Perkins,
              C., and M. Carney, "Dynamic Host Configuration Protocol
              for IPv6 (DHCPv6)", RFC 3315, DOI 10.17487/RFC3315, July
              2003, <http://www.rfc-editor.org/info/rfc3315>.

   [RFC3633]  Troan, O. and R. Droms, "IPv6 Prefix Options for Dynamic
              Host Configuration Protocol (DHCP) version 6", RFC 3633,
              DOI 10.17487/RFC3633, December 2003,
              <http://www.rfc-editor.org/info/rfc3633>.

   [RFC6020]  Bjorklund, M., Ed., "YANG - A Data Modeling Language for
              the Network Configuration Protocol (NETCONF)", RFC 6020,
              DOI 10.17487/RFC6020, October 2010,
              <http://www.rfc-editor.org/info/rfc6020>.

   [RFC6087]  Bierman, A., "Guidelines for Authors and Reviewers of YANG
              Data Model Documents", RFC 6087, DOI 10.17487/RFC6087,
              January 2011, <http://www.rfc-editor.org/info/rfc6087>.

   [RFC6991]  Schoenwaelder, J., Ed., "Common YANG Data Types",
              RFC 6991, DOI 10.17487/RFC6991, July 2013,
              <http://www.rfc-editor.org/info/rfc6991>.

8.2.

7.2.  Informative References

   [RFC3319]  Schulzrinne, H. and B. Volz, "Dynamic Host Configuration
              Protocol (DHCPv6) Options for Session Initiation Protocol
              (SIP) Servers", RFC 3319, DOI 10.17487/RFC3319, July 2003,
              <http://www.rfc-editor.org/info/rfc3319>.

   [RFC3646]  Droms, R., Ed., "DNS Configuration options for Dynamic
              Host Configuration Protocol for IPv6 (DHCPv6)", RFC 3646,
              DOI 10.17487/RFC3646, December 2003,
              <http://www.rfc-editor.org/info/rfc3646>.

   [RFC3898]  Kalusivalingam, V., "Network Information Service (NIS)
              Configuration Options for Dynamic Host Configuration
              Protocol for IPv6 (DHCPv6)", RFC 3898,
              DOI 10.17487/RFC3898, October 2004,
              <http://www.rfc-editor.org/info/rfc3898>.

   [RFC4075]  Kalusivalingam, V., "Simple Network Time Protocol (SNTP)
              Configuration Option for DHCPv6", RFC 4075,
              DOI 10.17487/RFC4075, May 2005,
              <http://www.rfc-editor.org/info/rfc4075>.

   [RFC4242]  Venaas, S., Chown, T., and B. Volz, "Information Refresh
              Time Option for Dynamic Host Configuration Protocol for
              IPv6 (DHCPv6)", RFC 4242, DOI 10.17487/RFC4242, November
              2005, <http://www.rfc-editor.org/info/rfc4242>.

   [RFC4704]  Volz, B., "The Dynamic Host Configuration Protocol for
              IPv6 (DHCPv6) Client Fully Qualified Domain Name (FQDN)
              Option", RFC 4704, DOI 10.17487/RFC4704, October 2006,
              <http://www.rfc-editor.org/info/rfc4704>.

   [RFC4833]  Lear, E. and P. Eggert, "Timezone Options for DHCP",
              RFC 4833, DOI 10.17487/RFC4833, April 2007,
              <http://www.rfc-editor.org/info/rfc4833>.

   [RFC5908]  Gayraud, R. and B. Lourdelet, "Network Time Protocol (NTP)
              Server Option for DHCPv6", RFC 5908, DOI 10.17487/RFC5908,
              June 2010, <http://www.rfc-editor.org/info/rfc5908>.

   [RFC5970]  Huth, T., Freimann, J., Zimmer, V., and D. Thaler, "DHCPv6
              Options for Network Boot", RFC 5970, DOI 10.17487/RFC5970,
              September 2010, <http://www.rfc-editor.org/info/rfc5970>.

   [RFC6334]  Hankins, D. and T. Mrugalski, "Dynamic Host Configuration
              Protocol for IPv6 (DHCPv6) Option for Dual-Stack Lite",
              RFC 6334, DOI 10.17487/RFC6334, August 2011,
              <http://www.rfc-editor.org/info/rfc6334>.

   [RFC6422]  Lemon, T. and Q. Wu, "Relay-Supplied DHCP Options",
              RFC 6422, DOI 10.17487/RFC6422, December 2011,
              <http://www.rfc-editor.org/info/rfc6422>.

   [RFC6440]  Zorn, G., Wu, Q., and Y. Wang, "The EAP Re-authentication
              Protocol (ERP) Local Domain Name DHCPv6 Option", RFC 6440,
              DOI 10.17487/RFC6440, December 2011,
              <http://www.rfc-editor.org/info/rfc6440>.

   [RFC6784]  Sakane, S. and M. Ishiyama, "Kerberos Options for DHCPv6",
              RFC 6784, DOI 10.17487/RFC6784, November 2012,
              <http://www.rfc-editor.org/info/rfc6784>.

   [RFC6939]  Halwasia, G., Bhandari, S., and W. Dec, "Client Link-Layer
              Address Option in DHCPv6", RFC 6939, DOI 10.17487/RFC6939,
              May 2013, <http://www.rfc-editor.org/info/rfc6939>.

   [RFC7078]  Matsumoto, A., Fujisaki, T., and T. Chown, "Distributing
              Address Selection Policy Using DHCPv6", RFC 7078,
              DOI 10.17487/RFC7078, January 2014,
              <http://www.rfc-editor.org/info/rfc7078>.

   [RFC7083]  Droms, R., "Modification to Default Values of SOL_MAX_RT
              and INF_MAX_RT", RFC 7083, DOI 10.17487/RFC7083, November
              2013, <http://www.rfc-editor.org/info/rfc7083>.

   [RFC7227]  Hankins, D., Mrugalski, T., Siodelski, M., Jiang, S., and
              S. Krishnan, "Guidelines for Creating New DHCPv6 Options",
              BCP 187, RFC 7227, DOI 10.17487/RFC7227, May 2014,
              <http://www.rfc-editor.org/info/rfc7227>.

   [RFC7291]  Boucadair, M., Penno, R., and D. Wing, "DHCP Options for
              the Port Control Protocol (PCP)", RFC 7291,
              DOI 10.17487/RFC7291, July 2014,
              <http://www.rfc-editor.org/info/rfc7291>.

   [RFC7598]  Mrugalski, T., Troan, O., Farrer, I., Perreault, S., Dec,
              W., Bao, C., Yeh, L., and X. Deng, "DHCPv6 Options for
              Configuration of Softwire Address and Port-Mapped
              Clients", RFC 7598, DOI 10.17487/RFC7598, July 2015,
              <http://www.rfc-editor.org/info/rfc7598>.

Authors' Addresses

   Yong Cui
   Tsinghua University
   Beijing  100084
   P.R.China

   Phone: +86-10-6260-3059
   Email: yong@csnet1.cs.tsinghua.edu.cn
   Hao Wang
   Tsinghua University
   Beijing  100084
   P.R.China

   Phone: +86-10-6278-5822
   Email: wangh13@mails.tsinghua.edu.cn

   Linhui Sun
   Tsinghua University
   Beijing  100084
   P.R.China

   Phone: +86-10-6278-5822
   Email: lh.sunlinh@gmail.com

   Ted Lemon
   Nominum, Inc.
   950 Charter St.
   Redwood City, CA  94043
   USA

   Email: Ted.Lemon@nominum.com

   Ian Farrer
   Deutsche Telekom AG
   CTO-ATI, Landgrabenweg 151
   Bonn, NRW  53227
   Germany

   Email: ian.farrer@telekom.de

   Sladjana Zoric
   Deutsche Telekom AG
   CTO-IPT, Landgrabenweg 151
   Bonn, NRW  53227
   Germany

   Email: sladjana.zoric@telekom.de