draft-ietf-netconf-notification-capabilities-04.txt   draft-ietf-netconf-notification-capabilities-05.txt 
NETCONF B. Lengyel NETCONF B. Lengyel
Internet-Draft Ericsson Internet-Draft Ericsson
Intended status: Standards Track A. Clemm Intended status: Standards Track A. Clemm
Expires: March 7, 2020 Futurewei Expires: April 25, 2020 Futurewei
B. Claise B. Claise
Cisco Systems, Inc. Cisco Systems, Inc.
September 4, 2019 October 23, 2019
Yang-Push Notification Capabilities YANG-Push Notification Capabilities
draft-ietf-netconf-notification-capabilities-04 draft-ietf-netconf-notification-capabilities-05
Abstract Abstract
This document proposes a YANG module that allows a server to specify This document proposes a YANG module that allows a publisher to
server capabilities related to "Subscription to YANG Datastores" specify capabilities related to "Subscription to YANG Datastores"
(Yang-Push). It proposes to use YANG Instance Data to document this (YANG-Push). It proposes to use YANG Instance Data to document this
information and make it already available at implementation time, but information and make it already available at implementation-time, but
also allow it to be reported at run-time. also allow it to be reported at run-time.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/. Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on March 7, 2020. This Internet-Draft will expire on April 25, 2020.
Copyright Notice Copyright Notice
Copyright (c) 2019 IETF Trust and the persons identified as the Copyright (c) 2019 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info) in effect on the date of (https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Notification Capability Model . . . . . . . . . . . . . . . . 4 3. Notification Capability Model . . . . . . . . . . . . . . . . 5
3.1. Tree Diagram . . . . . . . . . . . . . . . . . . . . . . 5 3.1. Tree Diagram . . . . . . . . . . . . . . . . . . . . . . 6
3.2. YANG Module . . . . . . . . . . . . . . . . . . . . . . . 6 3.2. YANG Module . . . . . . . . . . . . . . . . . . . . . . . 6
4. Security Considerations . . . . . . . . . . . . . . . . . . . 12 4. Security Considerations . . . . . . . . . . . . . . . . . . . 12
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12
5.1. The IETF XML Registry . . . . . . . . . . . . . . . . . . 12 5.1. The IETF XML Registry . . . . . . . . . . . . . . . . . . 13
5.2. The YANG Module Names Registry . . . . . . . . . . . . . 12 5.2. The YANG Module Names Registry . . . . . . . . . . . . . 13
6. Open Issues . . . . . . . . . . . . . . . . . . . . . . . . . 12 6. References . . . . . . . . . . . . . . . . . . . . . . . . . 13
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 13 6.1. Normative References . . . . . . . . . . . . . . . . . . 13
7.1. Normative References . . . . . . . . . . . . . . . . . . 13 6.2. Informative References . . . . . . . . . . . . . . . . . 14
7.2. Informative References . . . . . . . . . . . . . . . . . 13
Appendix A. Instance data examples . . . . . . . . . . . . . . . 14 Appendix A. Instance data examples . . . . . . . . . . . . . . . 14
Appendix B. Changes between revisions . . . . . . . . . . . . . 17 Appendix B. Changes between revisions . . . . . . . . . . . . . 17
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 18 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 18
1. Terminology 1. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP "OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here. capitals, as shown here.
The terms Yang-Push, On-change subscription and Periodic subscription The terms YANG-Push, On-change subscription and Periodic subscription
are used as defined in [I-D.ietf-netconf-yang-push] are used as defined in [RFC8641]
On-change Notification Capability: The capability of the server to The terms Subscriber, Publisher and Receiver are used as defined in
support On-change subscriptions. [RFC8639]
On-change Notification Capability: The capability of the publisher to
send on-change notifications for a specific datastore or a specific
data node.
The term Server is used as defined in [RFC8342] The term Server is used as defined in [RFC8342]
Implementation-time information: Information about the server's Implementation-time information: Information about the publisher's
behavior that is made available during the implementation of the behavior that is made available during the implementation of the
server, available from a source other then a running server. publisher, available from a source other then a running server
implementing the publisher.
Run-time information: Information about the server's behavior that is Run-time information: Information about the publisher's behavior that
available from the running server via management protocols such as is available from the running server (implementing the publisher) via
NETCONF [RFC6241] or RESTCONF [RFC8040]. management protocols such as NETCONF [RFC6241] or RESTCONF [RFC8040].
2. Introduction 2. Introduction
As defined in [I-D.ietf-netconf-yang-push] a server may allow clients As defined in [RFC8641] a publisher may allow subscribers to
to subscribe to updates from a datastore and subsequently push such subscribe to updates from a datastore and subsequently push such
update notifications to the client. Notifications may be sent update notifications to the receiver. Notifications may be sent
periodically or on-change (more or less immediately after each periodically or on-change (more or less immediately after each
change). change).
A server supporting YANG-Push has a number of capabilities defined in A publisher supporting YANG-Push has a number of capabilities defined
[I-D.ietf-netconf-yang-push] that are often determined during the in [RFC8641] that are often determined during the implementation of
implementation of the server. These include: the publisher. These include:
o Supported (reporting) periods for periodic subscriptions o Supported (reporting) periods for periodic subscriptions
o Maximum number of objects that can be sent in an update o Maximum number of objects that can be sent in an update
o The set of datastores or data nodes for which periodic
notification is supported
If the optional on-change feature is supported, additionally: If the optional on-change feature is supported, additionally:
o Supported dampening periods for on-change subscriptions o Supported dampening periods for on-change subscriptions
o The set of data nodes for which on-change notification is o The set of datastores or data nodes for which on-change
supported notification is supported
Servers MAY have limitations in how many update notifications and how Publishers MAY have limitations in how many update notifications and
many datastore node updates they can send out in a certain time- how many datastore node updates they can send out in a certain time-
period. period.
Publishers might not support periodic subscriptions to all
datastores.
In some cases, a publisher supporting on-change notifications will In some cases, a publisher supporting on-change notifications will
not be able to push updates for some object types on-change. Reasons not be able to push updates for some object types on-change. Reasons
for this might be that the value of the datastore node changes for this might be that the value of the datastore node changes
frequently (e.g. in-octets counter), that small object changes are frequently (e.g. in-octets counter), that small object changes are
frequent and meaningless (e.g., a temperature gauge changing 0.1 frequent and irrelevant to the receiver (e.g., a temperature gauge
degrees), or that the implementation is not capable of on-change changing 0.1 degrees within a predetermined and acceptable range), or
notification for a particular object. In those cases, it will be that the implementation is not capable of on-change notification for
important for client applications to have a way to identify for which a particular object. In those cases, it will be important for
objects on-change notifications are supported and for which ones not. subscriber applications to have a way to identify which objects on-
change notifications are supported and for which ones not.
Faced with the reality that support for on-change notification does Faced with the reality that support for on-change notification does
not mean that such notifications will be sent for any specific data not mean that such notifications will be sent for any specific data
node, client/management applications can not rely on the on-change node, subscriber/management applications can not rely on the on-
functionality unless the client has some means to identify for which change functionality unless the subscriber has some means to identify
objects on-change notifications are supported. YANG models are meant which objects on-change notifications are supported. YANG models are
to be used as an interface contract. Without identification of the meant to be used as an interface contract. Without identification of
data nodes actually supporting on-change, this contract would be the data nodes actually supporting on-change, this contract would be
incomplete. incomplete.
This document proposes a YANG module that allows a client to discover This document proposes a YANG module that allows a subscriber to
YANG-Push related capabilities both at implementation-time and run- discover YANG-Push related capabilities both at implementation-time
time. and run-time.
Implementation time information is needed by Network Management Implementation-time information is needed by Network Management
System (NMS) implementers. During NMS implementation for any System (NMS) implementers. A NMS implementation that wants to
functionality that depends on the notifications the information about support notifications, needs the information about on-change
on change notification capability is needed. If the information is notification capability. If the information is not documented in a
not available early in some document, but only as instance data from way available to the NMS designer, but only as instance data from the
the network node once it is deployed, the NMS implementation will be network node once it is deployed, the NMS implementation will be
delayed, because it has to wait for the network node to be ready. In delayed, because it has to wait for the network node to be ready. In
addition, the assumption that all NMS implementers will have a addition, the assumption that all NMS implementers will have a
correctly configured network node available to retrieve data from, is correctly configured network node available to retrieve data from is
an expensive proposition and may not always hold. (An NMS may need an expensive proposition and may not always hold. (An NMS may need
to be able to handle many dozens of network node types.) Often a to be able to handle many dozens of network node types.) Often a
fully functional NMS is a requirement for introducing a new network fully functional NMS is a requirement for introducing a new network
node type into a network, so delaying NMS readiness effectively also node type into a network, so delaying NMS readiness effectively also
delays the time at which a new network node type can be introduced delays the time at which a new network node type can be introduced
into the network. into the network.
Implementation time information is needed by system integrators. Implementation-time information is needed by system integrators.
When introducing a network node type into their network, operators When introducing a network node type into their network, operators
often need to integrate the node type into their own management often need to integrate the node type into their own management
system. The NMS may have management functions that depend on on- system. The NMS may have management functions that depend on on-
change notifications. The network operator needs to plan his change notifications. The network operator needs to plan his
management practices and NMS implementation before he even decides to management practices and NMS implementation before he even decides to
buy the specific network node type. Moreover the decision to buy the buy the specific network node type. Moreover the decision to buy the
node type sometimes depends on these management possibilities. node type sometimes depends on these management possibilities.
Run-time information is needed: Run-time information is needed:
o for any "purely model driven" client, e.g. a NETCONF-browser. As o for any "purely model driven" application, e.g. a NETCONF-browser.
long as it has a valid model to read the capability information, Such applications depend on reading models, capabilities in run-
it does not care which data nodes send notification, it will just time to support all the publisher's available functionality.
handle what is available.
o in case the capability might change during run-time e.g. due to o in case the capability might change during run-time e.g. due to
licensing, HW constraints etc. licensing, HW constraints etc.
o to check that early, implementation time capability information o to check that capability information provided early, already in
about the capabilities is indeed what the server implements (is implementation-time is indeed what the publisher implements (is
the supplied documentation correct?) the supplied documentation correct?)
3. Notification Capability Model 3. Notification Capability Model
It is a goal to provide Yang-Push notification capability information It is a goal to provide YANG-Push notification capability information
in a format that is: in a format that is:
o vendor independent o vendor independent
o formal o machine readable
o identical for implementation-time and run-time o identical for implementation-time and run-time
The YANG module ietf-notification-capabilities is defined to provide The YANG module ietf-notification-capabilities is defined to provide
the information. It contains: the information. It contains:
a set of capabilities related to the amount of notifications the o a set of capabilities related to the throughput of notification
server can send out data the publisher can send out
specification of which data nodes support on-change notifications. o specification of which data nodes support on-change notifications.
Capability values can be specified on server level, datastore Capability values can be specified on publisher level, datastore
level or on specific data nodes (and their contained sub-tree) of level or on specific data nodes (and their contained sub-tree) of a
a specific datastore. Capability values on a smaller, more specific datastore. Capability values on a smaller, more specific
specific part of the server's data always override more generic part of the publisher's data always override more generic values.
values.
On-change capability is not specified on a server level as On-change capability is not specified on a publisher level as
different datastores usually have different on-change different datastores usually have different on-change capabilities.
capabilities. On a datastore level on-change capability for On a datastore level on-change capability for configuration and state
configuration and state data can be specified separately. data can be specified separately.
The information SHALL be provided in two ways both following the The information SHOULD be provided in two ways both following the
ietf-notification-capabilities module: ietf-notification-capabilities module:
o For the implementation-time use-case: It SHALL be provided by the o For the implementation-time use-case: It SHALL be provided by the
implementer as YANG instance data file complying to implementer as YANG instance data file complying to
[I-D.ietf-netmod-yang-instance-file-format]. The file SHALL be [I-D.ietf-netmod-yang-instance-file-format]. The file SHALL be
available already in implementation time retrievable in a way that available already in implementation-time retrievable in a way that
does not depend on a live network node. E.g. download from does not depend on a live network node. E.g. download from
product Website. product Website.
o For the run-time use-case: It SHALL be available via NETCONF o For the run-time use-case: It MUST be available via NETCONF
[RFC6241] or RESTCONF [RFC8040] from the live server during run- [RFC6241] or RESTCONF [RFC8040] from the live server (implementing
time. Implementations which support changing these capabilities the publisher) during run-time. Implementations which support
at run-time SHOULD support on-change notifications about the changing these capabilities at run-time SHOULD support on-change
datastore-subscription-capabilities container. notifications about the publisher-subscription-capabilities
container.
3.1. Tree Diagram 3.1. Tree Diagram
The following tree diagram [RFC8340] provides an overview of the data The following tree diagram [RFC8340] provides an overview of the data
model. model.
module: ietf-notification-capabilities module: ietf-notification-capabilities
+--ro datastore-subscription-capabilities +--ro publisher-subscription-capabilities
+--ro (update-period)? +--ro (update-period)?
| +--:(minimum-update-period) | +--:(minimum-update-period)
| | +--ro minimum-update-period? uint32 | | +--ro minimum-update-period? uint32
| +--:(supported-update-period) | +--:(supported-update-period)
| +--ro supported-update-period* uint32 | +--ro supported-update-period* uint32
+--ro max-objects-per-update? uint32 +--ro max-objects-per-update? uint32
+--ro minimum-dampening-period? uint32 {yp:on-change}? +--ro minimum-dampening-period? uint32 {yp:on-change}?
+--ro on-change-supported? notification-support
| {yp:on-change}?
+--ro periodic-notifications-supported? notification-support
+--ro supported-excluded-change-type* union {yp:on-change}?
+--ro datastore-capabilities* [datastore] +--ro datastore-capabilities* [datastore]
+--ro datastore union +--ro datastore -> /yanglib:yang-library/datastore/name
+--ro (update-period)?
| +--:(minimum-update-period)
| | +--ro minimum-update-period? uint32
| +--:(supported-update-period)
| +--ro supported-update-period* uint32
+--ro max-objects-per-update? uint32
+--ro minimum-dampening-period? uint32 {yp:on-change}?
+--ro on-change-supported-for-config? boolean {yp:on-change}?
+--ro on-change-supported-for-state? boolean {yp:on-change}?
+--ro per-node-capabilities* [node-selector] +--ro per-node-capabilities* [node-selector]
+--ro node-selector nacm:node-instance-identifier +--ro node-selector nacm:node-instance-identifier
+--ro (update-period)? +--ro (update-period)?
| +--:(minimum-update-period) | +--:(minimum-update-period)
| | +--ro minimum-update-period? uint32 | | +--ro minimum-update-period? uint32
| +--:(supported-update-period) | +--:(supported-update-period)
| +--ro supported-update-period* uint32 | +--ro supported-update-period* uint32
+--ro max-objects-per-update? uint32 +--ro max-objects-per-update? uint32
+--ro minimum-dampening-period? uint32 {yp:on-change}? +--ro minimum-dampening-period? uint32
+--ro on-change-supported boolean {yp:on-change}? | {yp:on-change}?
+--ro on-change-supported? notification-support
| {yp:on-change}?
+--ro periodic-notifications-supported? notification-support
+--ro supported-excluded-change-type* union {yp:on-change}?
3.2. YANG Module 3.2. YANG Module
<CODE BEGINS> file "ietf-notification-capabilities@2019-08-13.yang" <CODE BEGINS> file "ietf-notification-capabilities@2019-10-22.yang"
module ietf-notification-capabilities {
yang-version 1.1;
namespace
"urn:ietf:params:xml:ns:yang:ietf-notification-capabilities";
prefix inc;
import ietf-netconf-acm { prefix nacm; }
import ietf-yang-push { prefix yp; }
import ietf-yang-library {
prefix yanglib;
description
"Requires revision 2019-01-04 or a revision derived from it.";
}
organization
"IETF NETCONF (Network Configuration) Working Group";
contact
"WG Web: <https://datatracker.ietf.org/wg/netconf/>
WG List: <mailto:netconf@ietf.org>
Editor: Balazs Lengyel
<mailto:balazs.lengyel@ericsson.com>";
description
"This module specifies YANG-Push related server
capabilities.
The module contains module ietf-notification-capabilities {
- capabilities related to the amount of notifications the yang-version 1.1;
server can send out. (Note that for a specific subscription namespace
the server MAY still allow only longer periods or smaller "urn:ietf:params:xml:ns:yang:ietf-notification-capabilities";
updates depending on e.g. actual load conditions.) prefix inc;
- specification of which data nodes support on-change import ietf-netconf-acm { prefix nacm; }
notifications. import ietf-yang-push { prefix yp; }
import ietf-yang-library {
prefix yanglib;
description
"Requires revision 2019-01-04 or a revision derived from it.";
}
Capability values on a organization
smaller, more specific part of the server's data always override "IETF NETCONF (Network Configuration) Working Group";
more generic values. The hierarchy of specifications from generic contact
to more specific is: "WG Web: <https://datatracker.ietf.org/wg/netconf/>
1) top level values valid for all datastores WG List: <mailto:netconf@ietf.org>
2) values for a specific datastore (including the special
'all' datastore identifier)
3) Value for a specific data node and its contained sub-tree
in one of the datastores. Such capability values are inherited
down the containment tree unless a more specific value is
provided, as described in 4)
4) A contained, smaller, more specific sub-tree in a specific
datastore (could be a single leaf)
Any capability value MAY be absent if a more generic capability Editor: Balazs Lengyel
value is already provided or if the server is not capable of <mailto:balazs.lengyel@ericsson.com>";
providing a value. description
"This module specifies YANG-Push related publisher
capabilities.
The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL', The module contains
'SHALL NOT', 'SHOULD', 'SHOULD NOT', 'RECOMMENDED', - capabilities related to the throughput of notification data the
'NOT RECOMMENDED', 'MAY', and 'OPTIONAL' in this document publisher can support. (Note that for a specific subscription
are to be interpreted as described in BCP 14 (RFC 2119) the publisher MAY still allow only longer periods or smaller
(RFC 8174) when, and only when, they appear in all updates depending on e.g. actual load conditions.)
capitals, as shown here. - specification of which data nodes support on-change or periodic
notifications.
Copyright (c) 2019 IETF Trust and the persons identified as Capability values can be specified on publisher level, datastore
authors of the code. All rights reserved. level or on specific data nodes (and their contained sub-tree) of
a specific datastore.
If a capability is specified on multiple levels, the
specification on a more specific level overrides more
generic capability specifications; thus
- a publisher level specification is overridden by any other
specification
- a datastore level specification (with a node-selector '/') is
overridden by a specification with a more specific node-selector.
- a specification for a specific datastore and node-selector
is overridden by a specification for the same datastore with
a node-slector that describes more levels of containing lists
and containers.
Redistribution and use in source and binary forms, with or If for a specific capability different values are indicated
without modification, is permitted pursuant to, and subject for different nodes in a subscription, then only values
to the license terms contained in, the Simplified BSD License acceptable for every node are guaranteed to be acceptable
set forth in Section 4.c of the IETF Trust's Legal Provisions for the subscription.
Relating to IETF Documents
(http://trustee.ietf.org/license-info).
This version of this YANG module is part of RFC XXXX; see To find a capability value for a specific node in a
the RFC itself for full legal notices."; specific datastore the user SHALL
1) consider the publisher level capabilities under the
publisher-subscription-capabilities container if such exist
2) search for a datastore-capabilities list entry for
the specific datastore
3) within that datastore entry search for a
per-node-capabilities entry that specifies the specific
capability and that has the node-selector selecting the
specific data node and that specifies the most levels of
containing containers and lists.
4) If no entries are found in the previous steps the
publisher is not capable of providing a value because
it is unknown, the capability is changing for some reason,
there is no specified limit etc. In this case the
publisher's behavior is unspecified.
revision 2019-08-13 { The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL',
description 'SHALL NOT', 'SHOULD', 'SHOULD NOT', 'RECOMMENDED',
"Initial version"; 'NOT RECOMMENDED', 'MAY', and 'OPTIONAL' in this document
reference are to be interpreted as described in BCP 14 (RFC 2119)
"RFC XXX: Yang-Push Notification Capabilities"; (RFC 8174) when, and only when, they appear in all
} capitals, as shown here.
container datastore-subscription-capabilities { Copyright (c) 2019 IETF Trust and the persons identified as
config false; authors of the code. All rights reserved.
description
"YANG-Push related server capabilities";
grouping datastore-subscription-throughput-capabilities { Redistribution and use in source and binary forms, with or
description "Capability values that affect the amount of without modification, is permitted pursuant to, and subject
notifications the server can send out."; to the license terms contained in, the Simplified BSD License
set forth in Section 4.c of the IETF Trust's Legal Provisions
Relating to IETF Documents
(http://trustee.ietf.org/license-info).
choice update-period { This version of this YANG module is part of RFC XXXX; see
description the RFC itself for full legal notices.";
"Supported update-period values.";
leaf minimum-update-period {
type uint32;
units "centiseconds";
description
"Minimum update period supported for a
periodic subscription.";
}
leaf-list supported-update-period { revision 2019-10-22 {
type uint32; description
units "centiseconds"; "Initial version";
description "Supported update period values for a reference
periodic subscription (used if only these specific "RFC XXX: YANG-Push Notification Capabilities";
values are supported)."; }
}
}
leaf max-objects-per-update { grouping subscription-capabilities {
type uint32 { description "Capabilities related to Yang-Push notifications";
range "1..max";
}
description
"Maximum number of objects that can be sent
in an update.";
}
leaf minimum-dampening-period { typedef notification-support {
if-feature yp:on-change ; type enumeration {
type uint32; enum no-notifications-supported {
units "centiseconds"; description "The publisher is not capable of sending any
description notifications for the relevant scope and subscription
"The minimum dampening period supported for on-change type." ;
subscriptions."; }
} enum notifications-for-config-changes-supported {
} description "The publisher is capable of sending
notifications for config=true nodes, but not
for config=false nodes for the relevant scope
and subscription type." ;
}
enum notifications-for-state-changes-supported {
description "The publisher is capable of sending
notifications for config=false nodes, but not
for config=true nodes for the relevant scope
and subscription type." ;
}
enum notifications-for-all-changes-supported {
description "The publisher is capable of sending
notifications for both config=false and config=true
nodes for the relevant scope and subscription type." ;
}
}
description "Type for defining whether on-change or
periodic notifications are supported for no, only config=true,
only config=false or all data nodes.";
}
uses datastore-subscription-throughput-capabilities { choice update-period {
description "Top level throughput capabilities. description "Supported update-period values.";
These values can be overridden by values provided per leaf minimum-update-period {
datastore or for individual data nodes in a datastore."; type uint32;
} units "centiseconds";
description "Indicates the minimal update period that is
supported for a periodic subscription.
A periodic subscription to the selected data nodes must
specify a value that is at least as large or greater than
this";
}
list datastore-capabilities { leaf-list supported-update-period {
key datastore ; type uint32;
description "Capabilities values per datastore. units "centiseconds";
For non-NMDA servers the config=false data is considered description "Supported update period values for a
as if it was part of the running datastore. periodic subscription.
A periodic subscription to the selected data nodes must
specify one of the values in the list; other values
are not supported.";
}
}
Indicates per datastore throughput capabilities. leaf max-objects-per-update {
type uint32 {
range "1..max";
}
description
"Maximum number of objects that can be sent
in an update for the selected data nodes.";
}
Indicates per datastore the data nodes for which the leaf minimum-dampening-period {
server is capable of sending on-change notifications. if-feature yp:on-change;
If a datastore implemented by the server is not specified type uint32;
in this list and there is no list element for 'all' datastores units "centiseconds";
the datastore does not support any on-change notifications. description
"The minimum dampening period supported for on-change
subscriptions for the selected data nodes.";
}
On-change notifications SHALL be sent for a config=true leaf on-change-supported {
data node if one of the following is true: if-feature yp:on-change;
- if it is a top level data-node and is not specified in the type notification-support;
per-node-capabilities list and on-change-supported-for-config description
is true; or "Specifies whether the publisher is capable of
- notifications are sent for its parent data node and it is sending on-change notifications for the selected
not specified in the per-node-capabilities list; or data store or data nodes and the subtree below them.";
- it is specified in the per-node-capabilities list and has }
an on-change-supported value true.
On-change notifications SHALL be sent for a config=false leaf periodic-notifications-supported {
data node if one of the following is true: type notification-support;
- if it is a top level data-node (a config=false data node with description
a config=true parent SHALL be treated as a top level data node) "Specifies whether the publisher is capable of
and is not specified in the per-node-capabilities list and sending periodic notifications for the selected
on-change-supported-for-state is true; or data store or data nodes and the subtree below them.";
- notifications are sent for its parent data node }
which is also config=false and it is not specified in the
per-node-capabilities list; or
- it is specified in the per-node-capabilities list and has
an on-change-supported value true";
leaf datastore { leaf-list supported-excluded-change-type {
type union { if-feature yp:on-change;
type leafref { type union {
path /yanglib:yang-library/yanglib:datastore/yanglib:name ; type enumeration {
} enum none {
type enumeration { description "None of the change types can be excluded.";
enum all ; }
} enum all {
} description
must '. != "all" or count(..) = "1" ' { "Any combination of change types can be excluded.";
error-message }
"If 'all' is present individual datastores cannot be " + }
"specified."; type yp:change-type;
} }
description "The datastore for which capabilities are defined."; description "The change types that can be excluded in
} YANG-Push subscriptions.";
}
}
uses datastore-subscription-throughput-capabilities { container publisher-subscription-capabilities {
description "Throughput capabilities for a datastore. config false;
These values will override top level values and can be description "YANG-Push related publisher capabilities.
overridden by values provided for individual data nodes Capability values specified here at the publisher level
in a datastore."; are valid for all datastores and
} are used when the capability is not specified on the
datastore level or for specific data nodes. ";
leaf on-change-supported-for-config { uses subscription-capabilities {
if-feature yp:on-change ; refine supported-excluded-change-type {
type boolean; default none;
default "true"; }
description }
"Specifies the default value for
top level config=true data nodes for the
on-change-supported capability.";
}
leaf on-change-supported-for-state { list datastore-capabilities {
if-feature yp:on-change ; key datastore;
type boolean;
default "false";
description
"Specifies the default value for
top level config=false data nodes for the
on-change-supported capability.";
}
list per-node-capabilities { description "Capabilities values per datastore.
key "node-selector"; For non-NMDA servers/publishers the config=false data is
description considered as if it was part of the running datastore.";
"A list of data nodes that have either a throughput or
on-change-notification capability specifically defined.
Should be used only when specific data nodes support leaf datastore {
capabilities that are different from capabilities type leafref {
of their parent nodes or the default for the datastore."; path /yanglib:yang-library/yanglib:datastore/yanglib:name;
}
description "The datastore for which capabilities are defined.
Only individual datastores can be specified
e.g. ds:conventional is not allowed.";
}
leaf node-selector { list per-node-capabilities {
type nacm:node-instance-identifier; key "node-selector";
description description
"Selects the data nodes for which "Each list entry specifies notification capabilities
a capability is specified."; for the selected data nodes. The same capabilities apply for
} the data nodes in the subtree below them unless another list
entry with a more specific node selector is present.";
uses datastore-subscription-throughput-capabilities { leaf node-selector {
description "Throughput capabilities for a specific data node. type nacm:node-instance-identifier;
These values will override top level or datastore description
specific values."; "Selects the data nodes for which capabilities are
} specified. The special value '/' denotes all data nodes
in the datastore.
The system SHOULD order list entries according to
the tree structure of the data models to make
reading/parsing the data model more simple.";
}
leaf on-change-supported { uses subscription-capabilities;
if-feature yp:on-change ; }
type boolean; }
mandatory true; }
description }
"Specifies whether the server is capable of
sending on-change notifications for the selected
data nodes.";
}
}
}
}
}
<CODE ENDS> <CODE ENDS>
4. Security Considerations 4. Security Considerations
The YANG module specified in this document defines a schema for data The YANG module specified in this document defines a schema for data
that is designed to be accessed via network management protocols such that is designed to be accessed via network management protocols such
as NETCONF [RFC6241] or RESTCONF [RFC8040]. The lowest NETCONF layer as NETCONF [RFC6241] or RESTCONF [RFC8040]. The lowest NETCONF layer
is the secure transport layer, and the mandatory-to-implement secure is the secure transport layer, and the mandatory-to-implement secure
transport is Secure Shell (SSH) [RFC6242]. The lowest RESTCONF layer transport is Secure Shell (SSH) [RFC6242]. The lowest RESTCONF layer
is HTTPS, and the mandatory-to-implement secure transport is TLS is HTTPS, and the mandatory-to-implement secure transport is TLS
[RFC8446]. [RFC8446].
The Network Configuration Access Control Model (NACM) [RFC8341] The Network Configuration Access Control Model (NACM) [RFC8341]
provides the means to restrict access for particular NETCONF or provides the means to restrict access for particular NETCONF or
RESTCONF users to a preconfigured subset of all available NETCONF or RESTCONF users to a preconfigured subset of all available NETCONF or
RESTCONF protocol operations and content. RESTCONF protocol operations and content.
The data in this module is not security sensitive. All protocol-accessible data are read-only and cannot be modified.
The data in this module is not security sensitive. Access control
may be configured, to avoid exposing the read-only data.
5. IANA Considerations When that data is in file format, data should be protected against
modification or unauthorized access using normal file handling and
secure and mutually authenticated file transport mechanisms.
5. IANA Considerations
5.1. The IETF XML Registry 5.1. The IETF XML Registry
This document registers one URI in the IETF XML registry [RFC3688]. This document registers one URI in the IETF XML registry [RFC3688].
Following the format in [RFC3688], the following registrations are Following the format in [RFC3688], the following registrations are
requested: requested:
URI: urn:ietf:params:xml:ns:yang:ietf-notification-capabilities URI: urn:ietf:params:xml:ns:yang:ietf-notification-capabilities
Registrant Contact: The NETCONF WG of the IETF. Registrant Contact: The NETCONF WG of the IETF.
XML: N/A, the requested URI is an XML namespace. XML: N/A, the requested URI is an XML namespace.
skipping to change at page 12, line 45 skipping to change at page 13, line 25
This document registers one YANG module in the YANG Module Names This document registers one YANG module in the YANG Module Names
registry [RFC7950]. Following the format in [RFC7950], the the registry [RFC7950]. Following the format in [RFC7950], the the
following registrations are requested: following registrations are requested:
name: ietf-notification-capabilities name: ietf-notification-capabilities
namespace: urn:ietf:params:xml:ns:yang:ietf-notification-capabilities namespace: urn:ietf:params:xml:ns:yang:ietf-notification-capabilities
prefix: inc prefix: inc
reference: RFC XXXX reference: RFC XXXX
6. Open Issues 6. References
-
7. References
7.1. Normative References
[I-D.ietf-netconf-yang-push] 6.1. Normative References
Clemm, A. and E. Voit, "Subscription to YANG Datastores",
draft-ietf-netconf-yang-push-25 (work in progress), May
2019.
[I-D.ietf-netmod-yang-instance-file-format] [I-D.ietf-netmod-yang-instance-file-format]
Lengyel, B. and B. Claise, "YANG Instance Data File Lengyel, B. and B. Claise, "YANG Instance Data File
Format", draft-ietf-netmod-yang-instance-file-format-04 Format", draft-ietf-netmod-yang-instance-file-format-04
(work in progress), August 2019. (work in progress), August 2019.
[RFC6241] Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed., [RFC6241] Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed.,
and A. Bierman, Ed., "Network Configuration Protocol and A. Bierman, Ed., "Network Configuration Protocol
(NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011, (NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011,
<https://www.rfc-editor.org/info/rfc6241>. <https://www.rfc-editor.org/info/rfc6241>.
skipping to change at page 13, line 45 skipping to change at page 14, line 14
[RFC8342] Bjorklund, M., Schoenwaelder, J., Shafer, P., Watsen, K., [RFC8342] Bjorklund, M., Schoenwaelder, J., Shafer, P., Watsen, K.,
and R. Wilton, "Network Management Datastore Architecture and R. Wilton, "Network Management Datastore Architecture
(NMDA)", RFC 8342, DOI 10.17487/RFC8342, March 2018, (NMDA)", RFC 8342, DOI 10.17487/RFC8342, March 2018,
<https://www.rfc-editor.org/info/rfc8342>. <https://www.rfc-editor.org/info/rfc8342>.
[RFC8446] Rescorla, E., "The Transport Layer Security (TLS) Protocol [RFC8446] Rescorla, E., "The Transport Layer Security (TLS) Protocol
Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018, Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018,
<https://www.rfc-editor.org/info/rfc8446>. <https://www.rfc-editor.org/info/rfc8446>.
7.2. Informative References [RFC8639] Voit, E., Clemm, A., Gonzalez Prieto, A., Nilsen-Nygaard,
E., and A. Tripathy, "Subscription to YANG Notifications",
RFC 8639, DOI 10.17487/RFC8639, September 2019,
<https://www.rfc-editor.org/info/rfc8639>.
[RFC8641] Clemm, A. and E. Voit, "Subscription to YANG Notifications
for Datastore Updates", RFC 8641, DOI 10.17487/RFC8641,
September 2019, <https://www.rfc-editor.org/info/rfc8641>.
6.2. Informative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>. <https://www.rfc-editor.org/info/rfc2119>.
[RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688, [RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
DOI 10.17487/RFC3688, January 2004, DOI 10.17487/RFC3688, January 2004,
<https://www.rfc-editor.org/info/rfc3688>. <https://www.rfc-editor.org/info/rfc3688>.
skipping to change at page 14, line 23 skipping to change at page 14, line 48
[RFC8340] Bjorklund, M. and L. Berger, Ed., "YANG Tree Diagrams", [RFC8340] Bjorklund, M. and L. Berger, Ed., "YANG Tree Diagrams",
BCP 215, RFC 8340, DOI 10.17487/RFC8340, March 2018, BCP 215, RFC 8340, DOI 10.17487/RFC8340, March 2018,
<https://www.rfc-editor.org/info/rfc8340>. <https://www.rfc-editor.org/info/rfc8340>.
Appendix A. Instance data examples Appendix A. Instance data examples
The following example is instance-data describing the notification The following example is instance-data describing the notification
capabilities of a hypothetical "acme-switch". The switch implements capabilities of a hypothetical "acme-switch". The switch implements
the running, candidate and operational datastores. Every change can the running, candidate and operational datastores. Every change can
be reported on-change from running, nothing from candidate and all be reported on-change from running, nothing from candidate and all
config=false data from operational. config=false data from operational. Periodic subscriptions are
supported for running and operational, but not for candidate.
<?xml version="1.0" encoding="UTF-8"?> <?xml version="1.0" encoding="UTF-8"?>
<instance-data-set xmlns= <instance-data-set xmlns=
"urn:ietf:params:xml:ns:yang:ietf-yang-instance-data"> "urn:ietf:params:xml:ns:yang:ietf-yang-instance-data">
<name>acme-switch-notification-capabilities</name> <name>acme-switch-notification-capabilities</name>
<module>ietf-notification-capabilities@2019-08-13.yang</module> <module>ietf-notification-capabilities@2019-10-22.yang</module>
<!-- revision date, contact, etc. --> <!-- revision date, contact, etc. -->
<description>Notification capabilities of acme-switch. <description>Notification capabilities of acme-switch.
Acme-switch implements the running, candidate and operational Acme-switch implements the running, candidate and operational
datastores. Every change can be reported on-change from running, datastores. Every change can be reported on-change from running,
nothing from candidate and all config=false data from operational. nothing from candidate and all config=false data from operational.
</description> Periodic subscriptions are supported for running and
<content-data> operational, but not for candidate.
<datastore-subscription-capabilities> </description>
<minimum-update-period>500</minimum-update-period> <content-data>
<max-objects-per-update>2000</max-objects-per-update> <publisher-subscription-capabilities
<minimum-dampening-period>100</minimum-dampening-period> xmlns="urn:ietf:params:xml:ns:yang:ietf-notification-capabilities"
<datastore-capabilities> xmlns:ds="urn:ietf:params:xml:ns:yang:ietf-datastores">
<datastore xmlns="urn:ietf:params:xml:ns:yang:ietf-datastores"> <minimum-update-period>500</minimum-update-period>
running <max-objects-per-update>2000</max-objects-per-update>
</datastore> <minimum-dampening-period>100</minimum-dampening-period>
<!-- Neither on-change-supported-for-config nor <periodic-notifications-supported>
on-change-supported-for-state are present as the notifications-for-all-changes-supported
default values are in effect. --> </periodic-notifications-supported>
</datastore-capabilities> <datastore-capabilities>
<!-- The candidate datastore is implemented, but not present <datastore>ds:operational</datastore>
here as it does not support any on-change notifications. --> <per-node-capabilities>
<datastore-capabilities> <node-selector>/</node-selector>
<datastore xmlns="urn:ietf:params:xml:ns:yang:ietf-datastores"> <on-change-supported>
operational notifications-for-state-changes-supported
</datastore> </on-change-supported>
<on-change-supported-for-config> </per-node-capabilities>
false </datastore-capabilities>
</on-change-supported-for-config> <datastore-capabilities>
<on-change-supported-for-state> <datastore>ds:candidate</datastore>
true <per-node-capabilities>
</on-change-supported-for-state> <node-selector>/</node-selector>
</datastore-capabilities> <on-change-supported>no-notifications-supported
</datastore-subscription-capabilities> </on-change-supported>
</content-data> <periodic-notifications-supported>no-notifications-supported
</instance-data-set> </periodic-notifications-supported>
</per-node-capabilities>
</datastore-capabilities>
<datastore-capabilities>
<datastore>ds:running</datastore>
<per-node-capabilities>
<node-selector>/</node-selector>
<on-change-supported>notifications-for-all-changes-supported
</on-change-supported>
</per-node-capabilities>
</datastore-capabilities>
Figure 1: Notification Capabilities with default settings </publisher-subscription-capabilities>
</content-data>
</instance-data-set>
Figure 1: Notification Capabilities with datastore level settings
The following is the instance-data describing the notification The following is the instance-data describing the notification
capabilities of a hypothetical "acme-router". The router implements capabilities of a hypothetical "acme-router". The router implements
the running, and operational datastores. Every change can be the running, and operational datastores. Every change can be
reported on-change from running, but only config=true nodes and some reported on-change from running, but only config=true nodes and some
config=false data from operational. Interface statistics are not config=false data from operational. Interface statistics are not
reported on-change only 2 important counters. Datastore subscription reported on-change only 2 important counters. Datastore subscription
capabilities are not reported on-change as they never change on the capabilities are not reported on-change as they never change on the
acme-router during run-time. acme-router during run-time.
<?xml version="1.0" encoding="UTF-8"?> <?xml version="1.0" encoding="UTF-8"?>
<instance-data-set xmlns= <instance-data-set xmlns=
"urn:ietf:params:xml:ns:yang:ietf-yang-instance-data"> "urn:ietf:params:xml:ns:yang:ietf-yang-instance-data">
<name>acme-router-notification-capabilities</name> <name>acme-router-notification-capabilities</name>
<module>ietf-notification-capabilities@2019-08-13.yang</module> <module>ietf-notification-capabilities@2019-10-22.yang</module>
<!-- revision date, contact, etc. --> <!-- revision date, contact, etc. -->
<description>Defines the notification capabilities of an acme-router. <description>Defines the notification capabilities of an acme-router.
The router only has running, and operational datastores. The router only has running, and operational datastores.
Every change can be reported on-change from running, but Every change can be reported on-change from running, but
only config=true nodes and some config=false data from operational. only config=true nodes and some config=false data from operational.
Statistics are not reported on-change only 2 important counters, Statistics are not reported on-change only 2 important counters,
for these a smaller dampening period is possible. for these a smaller dampening period is possible.
</description> </description>
<content-data> <content-data>
<datastore-subscription-capabilities <publisher-subscription-capabilities
xmlns="urn:ietf:params:xml:ns:yang:ietf-notification-capabilities"> xmlns="urn:ietf:params:xml:ns:yang:ietf-notification-capabilities"
xmlns:ds="urn:ietf:params:xml:ns:yang:ietf-datastores">
<minimum-update-period>500</minimum-update-period> <minimum-update-period>500</minimum-update-period>
<max-objects-per-update>2000</max-objects-per-update> <max-objects-per-update>2000</max-objects-per-update>
<minimum-dampening-period>100</minimum-dampening-period> <minimum-dampening-period>100</minimum-dampening-period>
<periodic-notifications-supported>
notifications-for-all-changes-supported
</periodic-notifications-supported>
<on-change-supported>
notifications-for-all-changes-supported
</on-change-supported>
<supported-excluded-change-type>
all
</supported-excluded-change-type>
<datastore-capabilities> <datastore-capabilities>
<datastore xmlns="urn:ietf:params:xml:ns:yang:ietf-datastores"> <datastore xmlns="urn:ietf:params:xml:ns:yang:ietf-datastores">
running ds:operational
</datastore>
</datastore-capabilities>
<datastore-capabilities>
<datastore xmlns="urn:ietf:params:xml:ns:yang:ietf-datastores">
operational
</datastore> </datastore>
<on-change-supported-for-state>
true
</on-change-supported-for-state>
<per-node-capabilities> <per-node-capabilities>
<node-selector> <node-selector>
/inc:datastore-subscription-capabilities</node-selector> /if:interfaces/if:interface/if:statistics</node-selector>
<on-change-supported>false</on-change-supported> <on-change-supported>
</per-node-capabilities> no-notifications-supported
<per-node-capabilities> </on-change-supported>
<node-selector>
/if:interfaces/if:interface/if:statistics</node-selector>
<on-change-supported>false</on-change-supported>
</per-node-capabilities> </per-node-capabilities>
<per-node-capabilities> <per-node-capabilities>
<node-selector> <node-selector>
/if:interfaces/if:interface/if:statistics/if:in-octets /if:interfaces/if:interface/if:statistics/if:in-octets
</node-selector> </node-selector>
<minimum-dampening-period>10</minimum-dampening-period> <minimum-dampening-period>10</minimum-dampening-period>
<on-change-supported>true</on-change-supported> <on-change-supported>
notifications-for-all-changes-supported
</on-change-supported>
</per-node-capabilities> </per-node-capabilities>
<per-node-capabilities> <per-node-capabilities>
<node-selector> <node-selector>
/if:interfaces/if:interface/if:statistics/if:out-octets /if:interfaces/if:interface/if:statistics/if:out-octets
</node-selector> </node-selector>
<on-change-supported>true</on-change-supported>
<minimum-dampening-period>10</minimum-dampening-period> <minimum-dampening-period>10</minimum-dampening-period>
<on-change-supported>
notifications-for-all-changes-supported
</on-change-supported>
</per-node-capabilities> </per-node-capabilities>
</datastore-capabilities> </datastore-capabilities>
</datastore-subscription-capabilities> </publisher-subscription-capabilities>
</content-data> </content-data>
</instance-data-set> </instance-data-set>
Figure 2: Notification Capabilities with data node specific settings Figure 2: Notification Capabilities with data node specific settings
Appendix B. Changes between revisions Appendix B. Changes between revisions
v04 - v05
o Added new capabilities periodic-notifications-supported and
supported-excluded-change-type.
o Restructured YANG module to make the node-selector's usage similar
to how NACM uses it: "/" means the whole datastore.
o Small corrections, spelling, rewording
o Replaced the term server with the term publisher except in cases
where we speak about datastores and functionality based on get,
getconfig operations. In this latter case it is really the server
functionality that is discussed
v03 - v04 v03 - v04
o Clarified recommended support for on-change notifications about o Clarified recommended support for on-change notifications about
the datastore-subscription-capabilities. the datastore-subscription-capabilities.
v02 - v03 v02 - v03
o Allow throughput related capabilities to be defined on top, o Allow throughput related capabilities to be defined on top,
datastore or data node level. Described that specific capability datastore or data node level. Described that specific capability
values always override generic ones. values always override generic ones.
 End of changes. 93 change blocks. 
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