draft-ietf-softwire-map-t-01.txt   draft-ietf-softwire-map-t-02.txt 
Network Working Group X. Li Network Working Group X. Li
Internet-Draft C. Bao Internet-Draft C. Bao
Intended status: Experimental CERNET Center/Tsinghua Intended status: Experimental CERNET Center/Tsinghua
Expires: August 22, 2013 University Expires: January 3, 2014 University
W. Dec W. Dec, Ed.
O. Troan O. Troan
Cisco Systems Cisco Systems
S. Matsushima S. Matsushima
SoftBank Telecom SoftBank Telecom
T. Murakami T. Murakami
IP Infusion IP Infusion
February 18, 2013 July 2, 2013
Mapping of Address and Port using Translation (MAP-T) Mapping of Address and Port using Translation (MAP-T)
draft-ietf-softwire-map-t-01 draft-ietf-softwire-map-t-02
Abstract Abstract
This document specifies the "Mapping of Address and Port" double This document specifies the "Mapping of Address and Port" double
stateless NAT64 translation based solution (MAP-T) for providing stateless NAT64 translation based solution (MAP-T) for providing
shared or uniquely addressed IPv4 device connectivity to and across shared or uniquely addressed IPv4 device connectivity to and across
an IPv6 domain. an IPv6 domain.
Status of this Memo Status of this Memo
skipping to change at page 1, line 41 skipping to change at page 1, line 41
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 http://datatracker.ietf.org/drafts/current/. Drafts is at http://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 August 22, 2013. This Internet-Draft will expire on January 3, 2014.
Copyright Notice Copyright Notice
Copyright (c) 2013 IETF Trust and the persons identified as the Copyright (c) 2013 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
(http://trustee.ietf.org/license-info) in effect on the date of (http://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
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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. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
2. Conventions . . . . . . . . . . . . . . . . . . . . . . . . . 4 2. Conventions . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
4. Architecture . . . . . . . . . . . . . . . . . . . . . . . . . 6 4. Architecture . . . . . . . . . . . . . . . . . . . . . . . . . 6
5. Mapping Rules . . . . . . . . . . . . . . . . . . . . . . . . 8 5. Mapping Rules . . . . . . . . . . . . . . . . . . . . . . . . 8
5.1. Port mapping algorithm . . . . . . . . . . . . . . . . . . 10 5.1. Port mapping algorithm . . . . . . . . . . . . . . . . . . 9
5.2. Basic mapping rule (BMR) . . . . . . . . . . . . . . . . . 11 5.2. Basic mapping rule (BMR) . . . . . . . . . . . . . . . . . 10
5.3. Forwarding mapping rule (FMR) . . . . . . . . . . . . . . 14 5.3. Forwarding mapping rule (FMR) . . . . . . . . . . . . . . 13
5.4. Default mapping rule (DMR) . . . . . . . . . . . . . . . . 14 5.4. Default mapping rule (DMR) . . . . . . . . . . . . . . . . 14
5.5. The IPv6 Interface Identifier . . . . . . . . . . . . . . 15 5.5. The IPv6 Interface Identifier . . . . . . . . . . . . . . 15
6. Configuration and Packet Forwarding . . . . . . . . . . . . . 15 6. MAP-T Configuration . . . . . . . . . . . . . . . . . . . . . 15
6.1. IPv4 to IPv6 at the CE . . . . . . . . . . . . . . . . . . 15 6.1. MAP CE . . . . . . . . . . . . . . . . . . . . . . . . . . 16
6.2. IPv6 to IPv4 at the CE . . . . . . . . . . . . . . . . . . 16 6.2. MAP BR . . . . . . . . . . . . . . . . . . . . . . . . . . 16
6.3. IPv6 to IPv4 at the BR . . . . . . . . . . . . . . . . . . 16 7. MAP-T Packet Forwarding . . . . . . . . . . . . . . . . . . . 17
6.4. IPv4 to IPv6 at the BR . . . . . . . . . . . . . . . . . . 17 7.1. IPv4 to IPv6 at the CE . . . . . . . . . . . . . . . . . . 17
7. ICMP Handling . . . . . . . . . . . . . . . . . . . . . . . . 17 7.2. IPv6 to IPv4 at the CE . . . . . . . . . . . . . . . . . . 17
8. Fragmentation and Path MTU Discovery . . . . . . . . . . . . . 18 7.3. IPv6 to IPv4 at the BR . . . . . . . . . . . . . . . . . . 18
8.1. Fragmentation in the MAP domain . . . . . . . . . . . . . 18 7.4. IPv4 to IPv6 at the BR . . . . . . . . . . . . . . . . . . 18
8.2. Receiving IPv4 Fragments on the MAP domain borders . . . . 18 8. ICMP Handling . . . . . . . . . . . . . . . . . . . . . . . . 19
8.3. Sending IPv4 fragments to the outside . . . . . . . . . . 19 9. Fragmentation and Path MTU Discovery . . . . . . . . . . . . . 19
9. Usage Considerations . . . . . . . . . . . . . . . . . . . . . 19 9.1. Fragmentation in the MAP domain . . . . . . . . . . . . . 20
9.1. Address Independence . . . . . . . . . . . . . . . . . . . 19 9.2. Receiving IPv4 Fragments on the MAP domain borders . . . . 20
9.2. Mesh vs Hub and spoke mode . . . . . . . . . . . . . . . . 19 9.3. Sending IPv4 fragments to the outside . . . . . . . . . . 20
9.3. Communication with IPv6 servers in the MAP-T domain . . . 19 10. Usage Considerations . . . . . . . . . . . . . . . . . . . . . 20
9.4. Backwards compatibility . . . . . . . . . . . . . . . . . 20 10.1. EA-bit length set to 0 . . . . . . . . . . . . . . . . . . 21
10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 20 10.2. Mesh and Hub and spoke modes . . . . . . . . . . . . . . . 21
11. Security Considerations . . . . . . . . . . . . . . . . . . . 20 10.3. Communication with IPv6 servers in the MAP-T domain . . . 21
12. Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 21 10.4. Compatibility with other NAT64 solutions . . . . . . . . . 21
13. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 22 11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 22
14. References . . . . . . . . . . . . . . . . . . . . . . . . . . 23 12. Security Considerations . . . . . . . . . . . . . . . . . . . 22
14.1. Normative References . . . . . . . . . . . . . . . . . . . 23 13. Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 23
14.2. Informative References . . . . . . . . . . . . . . . . . . 23 14. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 23
Appendix A. Examples of MAP-T translation . . . . . . . . . . . . 25 15. References . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Appendix B. Port mapping algorithm . . . . . . . . . . . . . . . 29 15.1. Normative References . . . . . . . . . . . . . . . . . . . 23
B.1. Bit Representation of the Algorithm . . . . . . . . . . . 30 15.2. Informative References . . . . . . . . . . . . . . . . . . 24
B.2. GMA examples . . . . . . . . . . . . . . . . . . . . . . . 31 Appendix A. Examples of MAP-T translation . . . . . . . . . . . . 26
B.3. GMA Excluded Ports . . . . . . . . . . . . . . . . . . . . 31 Appendix B. Port mapping algorithm . . . . . . . . . . . . . . . 30
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 30
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 32
1. Introduction 1. Introduction
Experiences from initial IPv6 deployments indicate that transitioning Experiences from initial IPv6-only deployments indicate that
a network providers' domain fully to IPv6 requires not only the successful transitions to IPv6 can happen while allowing for
continued support of legacy IPv4 users connected to the boundary of continued support of legacy IPv4 users connected at the boundaries of
that domain, allowing IPv4 address sharing, but also the need for that IPv6 domain. This requires the ability to support shared IPv4
carrying out IPv6-only operational practices in that domain [, also address use, while using IPv6 transport and operational practices in
for traffic from IPv4 users. The use of an double NAT64 translation the domain in a manner that ultimately minimizes to the operator any
based solutions is an optimal way to address these requirements, differences between IPv6 and IPv4 users connected to that domain.
particularly in combination with stateless translation techniques The use of an double NAT64 translation based solutions, which
that seek to minimize challenges outlined in transform IPv4 to IPv6 traffic at domain boundaries, is an optimal
[I-D.ietf-softwire-stateless-4v6-motivation]. way to address these requirements, especially in combination with
stateless translation techniques that seek to minimize operational
challenges outlined in [I-D.ietf-softwire-stateless-4v6-motivation].
The Mapping of Address and Port - Translation (MAP-T) solution The Mapping of Address and Port - Translation (MAP-T) solution
defined in this document is such a solution, that builds on existing specified in this document is such a double NAT64 based solution,
stateless NAT64 techniques specified in [RFC6145], along with a that builds on existing stateless NAT64 techniques specified in
stateless algorithmic address & transport layer port mapping scheme [RFC6145], along with a stateless algorithmic address & transport
to allow the sharing of IPv4 addresses across an IPv6 network. The layer port mapping scheme, to allow the sharing of IPv4 addresses
MAP-T solution is closely related to MAP-E [I-D.ietf-softwire-map], across an IPv6 network. The MAP-T solution is closely related to
with both utilizing the same address and port mapping method, but MAP-E [I-D.ietf-softwire-map], with both utilizing the same address
differing in their choice of IPv6 domain transport, i.e. Translation and port mapping method, but differing in their choice of IPv6 domain
[RFC6145] and encapsulation [RFC2473]. The translation mode is transport, i.e. Translation [RFC6145] for MAP-T and encapsulation
required for environments where the IP encapsulation overhead or IPv6 [RFC2473] for MAP-E. The translation mode is deemed particularly
traffic interaction & processing (eg use of IPv6 only servers) useful for environments where the encapsulation overhead, or IPv6
requirements, or both, make the use of the encapsulation solution not oriented practices (e.g. use of IPv6 only servers, or IPv6 traffic
attractive. classification) requirements, or both of these factors, contribute to
an encapsulation solution being not attractive. These scenarios are
presented in [I-D.maglione-softwire-map-t-scenarios]
A companion draft defines the DHCPv6 options for provisioning of MAP A companion document, applicable to both MAP-T and MAP-E, defines the
[I-D.mdt-softwire-map-dhcp-option], applicable to both MAP-T and DHCPv6 options for MAP provisioning
MAP-E. [I-D.mdt-softwire-map-dhcp-option].
2. Conventions 2. Conventions
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119]. document are to be interpreted as described in RFC 2119 [RFC2119].
3. Terminology 3. Terminology
MAP domain: One or more MAP CEs and BRs connected to the MAP domain: One or more MAP CEs and BRs connected to the
same IPv6 network. A service provider may same IPv6 network sharing a common MAP Rule
deploy a single MAP domain, or may utilize set. A service provider may deploy a single
multiple MAP domains. MAP domain, or may utilize multiple MAP
domains.
MAP Rule: A set of parameters describing the mapping MAP Rule: A set of parameters describing the mapping
between an IPv4 prefix, IPv4 address or between an IPv4 prefix, IPv4 address or
shared IPv4 address and an IPv6 prefix or shared IPv4 address and an IPv6 prefix or
address. Each MAP domain uses a different address. Each MAP domain uses a different
mapping rule set. mapping rule set.
MAP node: A device that implements MAP. MAP node: A device that implements MAP.
MAP Border Relay (BR): A MAP enabled router managed by the service MAP Border Relay (BR): A MAP enabled router managed by the service
skipping to change at page 5, line 43 skipping to change at page 5, line 48
Port-set ID (PSID): Algorithmically identifies a set of ports Port-set ID (PSID): Algorithmically identifies a set of ports
exclusively assigned to the CE. exclusively assigned to the CE.
Shared IPv4 address: An IPv4 address that is shared among multiple Shared IPv4 address: An IPv4 address that is shared among multiple
CEs. Only ports that belong to the assigned CEs. Only ports that belong to the assigned
port-set can be used for communication. Also port-set can be used for communication. Also
known as a Port-Restricted IPv4 address. known as a Port-Restricted IPv4 address.
End-user IPv6 prefix: The IPv6 prefix assigned to an End-user CE by End-user IPv6 prefix: The IPv6 prefix assigned to an End-user CE by
other means than MAP itself. E.g. other means than MAP itself. E.g.
Provisioned using DHCPv6 PD [RFC3633] or Provisioned using DHCPv6 PD [RFC3633],
configured manually. It is unique for each assigned via SLAAC [RFC4862], or configured
CE. manually. It is unique for each CE.
MAP IPv6 address: The IPv6 address used to reach the MAP MAP IPv6 address: The IPv6 address used to reach the MAP
function of a CE from other CEs and from BRs. function of a CE from other CEs and from BRs.
Rule IPv6 prefix: An IPv6 prefix assigned by a Service Provider Rule IPv6 prefix: An IPv6 prefix assigned by a Service Provider
for a mapping rule. for a MAP rule.
Rule IPv4 prefix: An IPv4 prefix assigned by a Service Provider Rule IPv4 prefix: An IPv4 prefix assigned by a Service Provider
for a mapping rule. for a MAP rule.
Embedded Address (EA) bits: The IPv4 EA-bits in the IPv6 address Embedded Address (EA) bits: The IPv4 EA-bits in the IPv6 address
identify an IPv4 prefix/address (or part identify an IPv4 prefix/address (or part
thereof) or a shared IPv4 address (or part thereof) or a shared IPv4 address (or part
thereof) and a port-set identifier. thereof) and a port-set identifier.
MRT: MAP Rule table. Address and Port aware data
structure, supporting longest match lookups.
The MRT is used by the MAP forwarding
function.
4. Architecture 4. Architecture
Figure 1 depicts the overall MAP-T architecture with IPv4 users N and Figure 1 depicts the overall MAP-T architecture, which sees any
M connected by means of MAP-T CEs to an IPv6 network that is equipped number of IPv4 users (N and M used as examples), connected by means
with one or more MAP-T BR. of MAP-T CEs to an IPv6 network that is equipped with one or more
MAP-T BR. The CEs and BRs form the MAP-T Domain, by means of
configuration that they share.
Functionally the MAP-T CE and BR utilize and extend some well
established technical building blocks to allow the IPv4 users to
correspond with nodes on the Public IPv4 network, or IPv6 network as
follows:
o A regular (NAT44) NAPT [RFC2663] function on a MAP CE is extended
with support for restricting the allowable TCP/UDP ports for a
given IPv4 address. The IPv4 address and port range used are
determined by the MAP provisioning process and identical to MAP-E
[I-D.ietf-softwire-map].
o A standard stateless NAT64 function [RFC6145] is extended to allow
stateless mapping of IPv4 and transport layer port ranges to IPv6
address space. This algorithmic mapping is specified in section
5.
User N User N
Private IPv4 Private IPv4
| Network | Network
| |
O--+---------------O O--+---------------O
| | MAP-T CE | | | MAP-T CE |
| +-----+--------+ | | +-----+--------+ |
| NAPT44| MAP-T | `-. | NAPT44| MAP-T | |
| +-----+ | | -._ ,-------. .------. | +-----+ | | -._ ,-------. .------.
| +--------+ | ,-' `-. ,-' `-. | +--------+ | ,-' `-. ,-' `-.
O------------------O / \ O---------O / Public \ O------------------O / \ O---------O / Public \
/ IPv6 only \ | MAP-T |/ IPv4 \ / IPv6 only \ | MAP-T |/ IPv4 \
( Network --+ Border +- Network ) ( Network --+ Border +- Network )
\ (MAP-T Domain)/ | Relay |\ / \ / | Relay |\ /
O------------------O \ / O---------O \ / O------------------O \ / O---------O \ /
| MAP-T CE | ;". ,-' `-. ,-' | MAP-T CE | ;". ,-' `-. ,-'
| +-----+--------+ | ," `----+--' ------' | +-----+--------+ | ," `----+--' ------'
| NAPT44| MAP-T | | ," | | NAPT44| MAP-T | |, |
| +-----+ | | IPv6 Server(s) | +-----+ | | IPv6 node(s)
| | +--------+ | (w/ v4 mapped | | +--------+ | (w/ v4 mapped
O---.--------------O address) O---.--------------O address)
| |
User M User M
Private IPv4 Private IPv4
Network Network
Figure 1: Network Topology Figure 1: MAP-T Architecture
The MAP-T CE is responsible for translating a users' private IPv4
space to a shared IPv4 address that is then mapped into the IPv6
domain using stateless NAT64.
The MAP-T BR is responsible for connecting external IPv4 networks to
all devices in one or more MAP-T domains, using stateless NAT64 as
extended by the MAP-T rules in this document.
Besides the CE and BR, the MAP-T domain can contain any regular (i.e.
Not equipped with MAP-T capabilities) IPv6-only hosts or servers that
have an IPv4 mapped IPv6 address (IPv4-translatable address per
[RFC6052]) using the prefix assigned to the MAP-T domain, e.g. An
internal web server, or cache. The MAP-T architecture support
communication initiated towards such devices from both inside or
outside the MAP-T domain including from any IPv4-only hosts. An
optional (not shown) DNS64 [RFC6147] component would be required if
the said IPv6 devices are expected to themselves to initiate
communication to IPv4-only entities outside of the domain.
Functionally the MAP-T CE and BR extend well established building Each MAP-T CE is configured by means of MAP procedures with an IPv4
blocks as follows: address and port-range, and is responsible for translating between a
given users' private IPv4 space and the CE's MAP derived IPv4
address, as well as adapting traffic between IPv4 and IPv6 using
NAT64 procedures that are in accordance with the MAP Rules applicable
for a given domain. The MAP procedures can operate with CE's using a
shared IPv4 address, full IPv4 addresses or IPv4 prefixes, and place
no assumption on the IPv6 addressing, other than an IPv6 prefix of
adequate size being allocated.
o A regular (NAT44) NAPT [RFC2663] function on a MAP CE is extended The MAP-T BR is responsible for connecting one or more MAP-T domains
with support for restricting the allowable TCP/UDP ports for a to external IPv4 networks, using stateless NAT64 as extended by the
given IPv4 address. The IPv4 address and port range used are MAP rules in this document, to relay traffic between the two.
determined by the MAP provisioning process and identical to MAP-E
[I-D.ietf-softwire-map].
o A standard stateless NAT64 function [RFC6145] is extended to allow The intended role for NAT64 technology in the architecture is two
stateless mapping of IPv4 and transport layer port ranges to IPv6 fold. Firstly, it is intended to allow the IPv6 network to focus on
address space. This algorithmic mapping is specified in section IPv6 operational procedures with minimal consideration of IPv4-only
5. nodes attached to the domain. Secondly, it is intended to allow
IPv4-only nodes to correspond directly with IPv6-only nodes, provided
they have an IPv4 mapped IPv6 address belonging to the IPv6 prefix
assigned to the MAP-T domain (as per [RFC6052]).
The operation of the above functions is modelled by means of Mapping The detailed operation of the above mechanism is governed by means of
Rules covered in Section 5. Section 6 describes how the functions MAP Rules and an address+port mapping algorithm covered in Section 5.
are used in packet forwarding operations. Section 7 describes how the mechanism is used for packet forwarding
operations.
5. Mapping Rules 5. Mapping Rules
EDITORIAL NOTE: This section is effectively identical of the Mapping A MAP node is provisioned with one or more mapping rules that govern
Rules section[I-D.ietf-softwire-map], and will be re-factored & the way an IPv4 address and port are mapped between the IPv4 and IPv6
reconciled as the MAP-E draft finalizes. domains, as well specific or default forwarding behaviour. Three
specific types of mapping rules are defined:
Any MAP node needs to be provisioned with one or more mapping rules,
that form a mapping rule table.
Every MAP node MUST be provisioned with a Basic Mapping Rule (BMR).
All node's sharing a BMR are said to be part of the same MAP domain.
On a CE this rule in combination with its natively assigned IPv6
prefix, allows the CE node to determine its IPv4 address and port
range. This same BMR, when can also be used to enable direct
communication (a.k.a. mesh mode), that bypasses the BR, between CEs
in the same MAP-T domain. In practical terms this equates to the CE
having an IPv4 route entry for the IPv4 prefix assigned to that
domain, and forwarding corresponding traffic using the parameters
defined in the rule. Additional mapping rules, termed Forward
Mapping Rules (FMRs), are used to allow for multiple different IPv4
subnets to exist within the domain and optimize forwarding between
them. These are equivalent to more specific IPv4 routes.
Destination outside of a MAP domain are reached (represented) by a
Default Mapping Rule, that directs traffic to a MAP BR. i.e. Traffic
for destination IPv4 addresses that do not match using a longest
lookup to any IPv4 prefix in the Rules database, is forwarded to the
MAP BR. In MAP-T terms the CE uses stateless NAT64 to map such
traffic to the BR's IPv6 prefix. While there can be only one Default
Mapping Rule within a MAP domain, however there can be multiple BR's
operating on that rule.
In specific terms the three types of mapping rules are defined as:
1. Basic Mapping Rule (BMR) - used for configuring the CE's IPv4 1. Basic Mapping Rule (BMR) - used for determining the CE's IPv4
address and/or port set assignment as well as deriving the MAP address and/or port set, as well as determining the MAP IPv6
IPv6 address that the CE is to use. For a given IPv6 prefix address that the CE is to use. For a given end-user IPv6 prefix
there can be only one BMR. By default a BMR MUST NOT be used to there can be only one BMR. The BMR is defined out of the
create an IPv4 route entry for the Rule IPv4 prefix.The BMR is following parameters:
composed of the following parameters:
* Rule IPv6 prefix (including prefix length) * Rule IPv6 prefix (including prefix length)
* Rule IPv4 prefix (including prefix length) * Rule IPv4 prefix (including prefix length)
* Rule EA-bits length (in bits) * Rule EA-bits length (in bits)
* Optional Rule Parameters 2. Forwarding Mapping Rule - used for setting up forwarding between
CEs in the MAP domain (a.k.a. Mesh mode). Each Forwarding
2. Forwarding Mapping Rule - used for forwarding within the MAP Mapping Rule will result in an entry in the mapping rules table
domain. Each Forwarding Mapping Rule will result in an entry in for the Rule IPv4 prefix + a given port range, i.e. Specific
the mapping rules table for the Rule IPv4 prefix + any port IPv4 + port routes.The FMR consists of the following parameters,
range. The FMR consists of the following parameters (an which are shared with the BMR:
attentive reader will note that a BMR can be set as an FMR,
thereby enabling mesh-mode communication):
* Rule IPv6 prefix (including prefix length) * Rule IPv6 prefix (including prefix length)
* Rule IPv4 prefix (including prefix length) * Rule IPv4 prefix (including prefix length)
* Rule EA-bits length (in bits) * Rule EA-bits length (in bits)
* Optional Rule Port Parameters 3. Default Mapping Rule - used for mapping and forwarding to
destinations outside the MAP domain, i.e. a default route for the
3. Default Mapping Rule - used for reaching destinations outside the MAP domain leading to the MAP BR. It consists of:
MAP domain. A DMR will result in an IPv4 0.0.0.0/0 entry in the
rules table.
* IPv6 prefix of the BR * The Pv6 prefix (including length) of the
* Rule BR IPv4 address (Optional - can be used for testing a * Rule BR IPv4 address (Optional - can be used for testing a
BR's reachability) BR's reachability)
4. Optional Rule Parameters - used to represent additional By default, every MAP node belonging to a MAP domain node, MUST be
configuration settings. Currently defined parameters are: provisioned with a Basic Mapping Rule (BMR). A MAP node finds its
Basic Mapping Rule by doing a longest match between the End-user IPv6
* Offset: Specifies the numeric value for the MAP algorithm's prefix and the Rule IPv6 prefix in the Mapping Rules table. The rule
excluded port range/offset bits (A-bits). Unless explicitly is then used for IPv4 prefix, address or shared address assignment.
defined this value MUST default to 4.
A MAP node finds its Basic Mapping Rule by doing a longest match
between its assigned IPv6 prefix (e.g. via DHCPv6 PD) and the Rule
IPv6 prefix in the Mapping Rule database. The assigned IPv6 prefix,
is the prefix that the operator assigns to the CE using regular means
like DHCP-PD. It should be noted that this prefix is simply the
prefix that any device, including non MAP CEs get assigned, i.e. MAP
does not require an additional prefix to be assigned.
The selected BMR rule is then used for determining the IPv4 address A MAP IPv6 address is formed from the BMR Rule IPv6 prefix. This
and port range assignment as well as forming the CE's MAP IPv6 address MUST be assigned to an interface of the MAP node and is used
address within the assigned IPv6 prefix. This IPv6 address MUST be to terminate all MAP traffic being sent or received to the node.
used for sending and receiving all MAP traffic by the CE.
Port-aware IPv4 entries in the rules table are installed for all the Port-aware IPv4 entries in the Rules table are installed for all the
Forwarding Mapping Rules and an IPv4 default route for the Default Forwarding Mapping Rules and an default route to the MAP BR as per
Mapping Rule. the DMR (see section Section 5). While there can be only one Default
Mapping Rule within a MAP domain, however there can be multiple BR's
operating on that rule.
Forwarding rules are used to allow direct communication between MAP Forwarding rules are used to allow direct communication between MAP
CEs, known as mesh mode. In hub and spoke mode, there are no CEs, known as mesh mode. In hub and spoke mode, there are no
forwarding rules, all traffic MUST be forwarded directly to the BR forwarding rules, and all traffic is forwarded from the CE to the BR
using the Default Mapping Rule. by means of the DMR.
The following subsections specify the MAP algorithm and Rule The following subsections specify the MAP algorithm and its use of
processing. Rules.
5.1. Port mapping algorithm 5.1. Port mapping algorithm
The port mapping algorithm is used in domains whose rules allow IPv4 The port mapping algorithm is used in domains whose BMR allows IPv4
address sharing. address sharing.
The simplest way to represent a port range is using a notation The simplest way to represent a port range is using a notation
similar to CIDR [RFC4632]. For example the first 256 ports are similar to CIDR [RFC4632]. For example the first 256 ports are
represented as port prefix 0.0/8. The last 256 ports as 255.0/8. In represented as port prefix 0.0/8. The last 256 ports as 255.0/8. In
hexadecimal, 0x0000/8 (PSID = 0) and 0xFF00/8 (PSID = 0xFF). hexadecimal, 0x0000/8 (PSID = 0) and 0xFF00/8 (PSID = 0xFF). Using
this technique, but wishing to avoid allocating the system ports
[I-D.ietf-tsvwg-iana-ports] to a give CE, one would have to exclude
the use of one or more PSIDs (e.g., PSIDs 0 to 3 in the example just
given).
To minimise dependencies between the End-user IPv6 prefix and the As will be seen shortly, the PSID forms a portion of the End-user
resulting port set, a PSID of 0, would, in the naive representation IPv6 prefix. To minimise dependencies between the End-user IPv6
assign the system ports [I-D.ietf-tsvwg-iana-ports] to the user. prefix and the assigned port set, it is desirable to minimize the
Instead using an infix representation, and requiring that the first restrictions on the possible PSID values. This is achieved by using
bit field (A) is greater than 0, the well known ports are excluded. an infix representation of the port value. Using such a
representation, the well-known ports are excluded by restrictions on
the value of the first bit field (A) rather than the PSID.
This algorithm allocates ports to a given CE as a series of The infix algorithm allocates ports to a given CE as a series of
contiguous ranges. contiguous ranges spaced at regular intervals throughout the complete
range of possible port set values.
0 1 0 1
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6
+-------+-----------+-----------+ +-------+-----------+-----------+
Ports in | A | PSID | M | Ports in | A | PSID | M |
the CE port set | > 0 | | any value | the CE port set | > 0 | | any value |
+-------+-----------+-----------+ +-------+-----------+-----------+
|a bits | k bits | m bits | |a bits | k bits | m bits |
Figure 2: PSID Figure 2: PSID
A For a > 0, A MUST be larger than 0. This ensures that the A Selects the range of the port number. For a > 0, A MUST be larger
algorithm excludes the system ports. than 0. This ensures that the algorithm excludes the system
ports. For this value of a, the system ports, but no others, are
excluded by requiring that A be greater than 0. For smaller
values of a, A still has to be greater than 0, but this excludes
ports above 1023. For larger values of a, the minimum value of A
has to be higher to exclude all the system ports. The interval
between successive contiguous ranges assigned to the same user is
2^a.
a-bits The number of offset bits. The default Offset bits (a) are: a-bits The number of offset bits. The default Offset bits (a) are:
4. To simplify the port mapping algorithm the defaults are chosen 6. To simplify the port mapping algorithm the defaults are chosen
so that the PSID field starts on a nibble boundary and the so that the PSID field starts on a nibble boundary and the
excluded port range (0-1023) is extended to 0-4095. excluded port range (0-1023) is extended to 0-4095.
PSID The Port Set Identifier. Different Port-Set Identifiers (PSID) PSID The Port Set Identifier. Different Port-Set Identifiers (PSID)
MUST have non-overlapping port-sets. MUST have non-overlapping port-sets.
k-bits The length in bits of the PSID field. The sharing ratio is k-bits The length in bits of the PSID field. The sharing ratio is
k^2. The number of ports assigned to the user is 2^(16-k) - 2^m k^2. The number of ports assigned to the user is 2^(16-k) - 2^m
(excluded ports) (excluded ports)
M The contiguous ports. M Selects the specific port within the particular range specified by
the concatenation of A and the PSID.
m bits The size contiguous ports. The number of contiguous ports is m bits The contiguous port size, i.e. the number of contiguous ports
allocated to a given PSID. The number of contiguous ports is
given by 2^m. given by 2^m.
This algorithm allocates ports to a given CE as a series of
contiguous ranges.
5.2. Basic mapping rule (BMR) 5.2. Basic mapping rule (BMR)
The Basic Mapping Rule is mandatory, used by the CE to provision The Basic Mapping Rule is mandatory, and is used by the CE to derive
itself with an IPv4 prefix, IPv4 address or shared IPv4 address. its IPv4 prefix, IPv4 address or shared IPv4 address and associated
port-range in conjunction with the information in the end-user IPv6
prefix. Recall from Section 5 that the BMR consists of the following
parameters:
o Rule IPv6 prefix, of a length n.
o Rule IPv4 prefix, of a length r.
o Rule EA-bits of length o.
Figure 3 shows the structure of the complete MAP IPv6 address of a CE
as specified in this document, and its relation to the information
contained in the BMR and End-user IP6 prefix. A MAP CE IPv6 address
is created by concatenating the End-user IPv6 prefix with the MAP
subnet-id (if the End-user IPv6 prefix is shorter than 64 bits) and
the interface ID as specified in Section 5.5. The MAP subnet ID is
defined to be the first subnet (all bits set to zero). For End-user
IPv6 prefixes longer than 64 bits, no subnet id is used.
| n bits | o bits | s bits | 128-n-o-s bits | | n bits | o bits | s bits | 128-n-o-s bits |
+--------------------+-----------+---------+------------+----------+ +--------------------+-----------+---------+------------+----------+
| Rule IPv6 prefix | EA bits |subnet ID| interface ID | | Rule IPv6 prefix | EA bits |subnet ID| interface ID |
+--------------------+-----------+---------+-----------------------+ +--------------------+-----------+---------+-----------------------+
|<--- End-user IPv6 prefix --->| |<--- End-user IPv6 prefix --->|
Figure 3: IPv6 address format
The Rule IPv6 prefix is the part of the End-user IPv6 prefix that is
common among all CEs using the same Basic Mapping Rule within the MAP
domain. The EA bits encode the CE specific IPv4 address and port
information. The EA bits, which are unique for a given Rule IPv6
prefix, can contain a full or part of an IPv4 address and, in the
shared IPv4 address case, a Port-Set Identifier (PSID). An EA-bit
length of 0 signifies that all relevant MAP IPv4 addressing
information is passed directly in the BMR rule, and not derived from
the End-user IPv6 prefix.
The MAP IPv6 address is created by concatenating the End-user IPv6
prefix with the MAP subnet-id (if the End-user IPv6 prefix is shorter
than 64 bits) and the interface-id as specified in Section 5.5.
The MAP subnet ID is defined to be the first subnet (all bits set to Figure 3: IPv6 address format
zero). Unless configured differently, a MAP node MUST reserve the
first IPv6 prefix in an End-user IPv6 prefix for the purpose of MAP.
The MAP IPv6 is created by combining the End-User IPv6 prefix with
the all zeros subnet-id and the MAP IPv6 interface identifier.
Shared IPv4 address:
| r bits | p bits | | q bits | The MAP CE's IPv4 address + port set id are determined by
+-------------+---------------------+ +------------+ concatenating the information in the BMR, the r bits of the Rule IPv4
| Rule IPv4 | IPv4 Address suffix | |Port-Set ID | prefix, with o bits of information, termed the EA-bits, derived from
+-------------+---------------------+ +------------+ the End-user IPv6 prefix that is assigned to the CE.
| 32 bits |
Figure 4: Shared IPv4 address The n bit Rule IPv6 prefix, expressed in the BMR, is the part of the
End-user IPv6 prefix that is common among all CEs using the same
Basic Mapping Rule within the MAP domain. Similarly, the Rule IPv4
prefix of length r is the IPv4 prefix common among all CEs using the
same BMR within the MAP domain. The combination of Rule IPv4 prefix
r, with the EA bits of length o, which is unique for a given CE,
encodes the CE's IPv4 address and port set-id, if present. An EA-bit
length of 0 signifies that all relevant MAP IPv4 addressing
information is passed directly in the BMR, and not derived from the
End-user IPv6 prefix. Examples of these and other cases are given in
Appendix A.
Complete IPv4 address: For a given BMR, if o + r < 32 (length of the IPv4 address in bits),
then an IPv4 prefix is being intended for use by the BMR. This case
is shown in Figure 4.
| r bits | p bits | | r bits | p bits |
+-------------+---------------------+ +-------------+---------------------+
| Rule IPv4 | IPv4 Address suffix | | Rule IPv4 | IPv4 Address suffix |
+-------------+---------------------+ +-------------+---------------------+
| 32 bits | | < 32 bits |
Figure 5: Complete IPv4 address Figure 4: IPv4 prefix
IPv4 prefix:
If o + r is equal to 32, then a full IPv4 address is to be assigned.
The address is created by concatenating the Rule IPv4 prefix and the
EA-bits. This case is shown in Figure 5.
| r bits | p bits | | r bits | p bits |
+-------------+---------------------+ +-------------+---------------------+
| Rule IPv4 | IPv4 Address suffix | | Rule IPv4 | IPv4 Address suffix |
+-------------+---------------------+ +-------------+---------------------+
| < 32 bits | | 32 bits |
Figure 6: IPv4 prefix
The length of r MAY be zero, in which case the complete IPv4 address
or prefix is encoded in the EA bits. If only a part of the IPv4
address/prefix is encoded in the EA bits, the Rule IPv4 prefix is
provisioned to the CE by other means (e.g. a DHCPv6 option). To
create a complete IPv4 address (or prefix), the IPv4 address suffix
(p) from the EA bits, are concatenated with the Rule IPv4 prefix (r
bits).
The offset of the EA bits field in the IPv6 address is equal to the
BMR Rule IPv6 prefix length. The length of the EA bits field (o) is
given by the BMR Rule EA-bits length, and can be between 0 and 48.
The sum of the Rule IPv6 Prefix length and the Rule EA-bits length
MUST be less or equal than the End-user IPv6 prefix length.
If o + r < 32 (length of the IPv4 address in bits), then an IPv4
prefix is assigned.
If o + r is equal to 32, then a full IPv4 address is to be assigned. Figure 5: Complete IPv4 address
The address is created by concatenating the Rule IPv4 prefix and the
EA-bits.
If o + r is > 32, then a shared IPv4 address is to be assigned. The If o + r is > 32, then a shared IPv4 address is to be assigned. The
number of IPv4 address suffix bits (p) in the EA bits is given by 32 number of IPv4 address suffix bits (p) in the EA bits is given by 32
- r bits. The PSID bits are used to create a port-set. The length - r bits. The PSID bits are used to create a port-set. The length
of the PSID bit field within EA bits is: o - p. of the PSID bit field within EA bits is: q = o - p.
The length of r MAY be 32, with no part of the IPv4 address embedded | r bits | p bits | | q bits |
in the EA bits. This results in a mapping with no dependence between +-------------+---------------------+ +------------+
the IPv4 address and the IPv6 address. In addition the length of o | Rule IPv4 | IPv4 Address suffix | |Port-Set ID |
MAY be zero (no EA bits embedded in the End-User IPv6 prefix), +-------------+---------------------+ +------------+
meaning that also the PSID is provisioned using e.g. The DHCP | 32 bits |
option.
Figure 6: Shared IPv4 address
It should be noted that the length r MAY be zero, in which case the
complete IPv4 address or prefix is encoded in the EA bits. Similarly
the length of o MAY, in which case no part of the CE's IPv6 end-user
prefix is used to derive the CE's IPv4 address. To create a complete
IPv4 address (or prefix), the IPv4 address suffix (p) from the EA
bits, is concatenated with the Rule IPv4 prefix (r bits).
The BMR is provisioned to the CE by means (e.g. a DHCPv6 option) not
specified in this document.
See Appendix A for an example of the Basic Mapping Rule. See Appendix A for an example of the Basic Mapping Rule.
5.3. Forwarding mapping rule (FMR) 5.3. Forwarding mapping rule (FMR)
The Forwarding Mapping Rule is optional, and used in mesh mode to The Forwarding Mapping Rule is an optional rule used in mesh mode to
merit direct CE to CE connectivity. enable direct CE to CE connectivity.
On adding an FMR rule, an IPv4 route is installed in the Rules table The processing of an FMR rule results in a route entry being
for the Rule IPv4 prefix. installed in a rules table on the processing MAP device for the IPv4
Rule prefix and any associated port range. The "next hop" of such a
route is the MAP transformation defined by the rule's key elements:
o The Rule IPv6 prefix, of a length n.
o The Rule IPv4 prefix, of a length r.
o The Rule EA-bits of length o.
On forwarding an IPv4 packet, a best matching prefix look up is done On forwarding an IPv4 packet, a best matching prefix look up is done
in the Rules table and the correct FMR is chosen. in the rules table and the correct FMR is chosen. The IPv6
destination address is derived from the destination IPv4 + port in
combination with the rule's parameters as exemplified in Figure 7.
| 32 bits | | 16 bits | | 32 bits | | 16 bits |
+--------------------------+ +-------------------+ +--------------------------+ +-------------------+
| IPv4 destination address | | IPv4 dest port | | IPv4 destination address | | IPv4 dest port |
+--------------------------+ +-------------------+ +--------------------------+ +-------------------+
: : ___/ : : : ___/ :
| p bits | / q bits : | p bits | / q bits :
+----------+ +------------+ +----------+ +------------+
|IPv4 sufx| |Port-Set ID | |IPv4 sufx| |Port-Set ID |
+----------+ +------------+ +----------+ +------------+
skipping to change at page 14, line 40 skipping to change at page 14, line 29
| Rule IPv6 prefix | EA bits |subnet ID| interface ID | | Rule IPv6 prefix | EA bits |subnet ID| interface ID |
+--------------------+-----------+---------+-----------------------+ +--------------------+-----------+---------+-----------------------+
|<--- End-user IPv6 prefix --->| |<--- End-user IPv6 prefix --->|
Figure 7: Deriving of MAP IPv6 address Figure 7: Deriving of MAP IPv6 address
See Appendix A for an example of the Forwarding Mapping Rule. See Appendix A for an example of the Forwarding Mapping Rule.
5.4. Default mapping rule (DMR) 5.4. Default mapping rule (DMR)
The Default Mapping rule is used to reach all IPv4 destinations IPv4 traffic between MAP-T nodes that are all within one MAP domain
outside of the MAP-T domain. For MAP-T, the DMR is specified in is translated to IPv6, with the senders MAP IPv6 address as the IPv6
terms of the BR IPv6 prefix that MAP-T CEs will use to form IPv6 source address and the receiving MAP node's MAP IPv6 address as the
addresses out of IPv4 destination addresses. IPv6 destination address. To reach destinations outside the MAP-T
domain and/or for the case when the MAP domain is defined to be
composed out of a single CE and BR, the Default Mapping rule is used.
The DMR is specified in terms of the BR IPv6 prefix that MAP-T CEs
will use for mapping an IPv4 destination address.
Default Mapping Rule: Default Mapping Rule:
{2001:db8:0001::/Prefix-length (Rule IPv6 prefix), {2001:db8:0001::/Prefix-length (Rule IPv6 prefix),
0.0.0.0/0 (Rule IPv4 prefix)} 0.0.0.0/0 (Rule IPv4 prefix)}
Example: Default Mapping Rule Example: Default Mapping Rule
Note that the BR prefix-length is variable and can be both shorter or It is recommended that the BR prefix-length SHOULD be by default 64
longer than 64 bits, up to 96 bits. In the respective cases the IPv4 bits long, and in any case MUST NOT exceed 96 bits. The mapping of
address and the BR prefix are shifted and "bit spread" across the the IPv4 destination behind the IPv6 prefix will by default follow
fixed u-octet boundary as per [RFC6052]. All trailing bits after the the /64 rule as per [RFC6052]. Any trailing bits after the IPv4
IPv4 address are set to 0x0. address are set to 0x0.
5.5. The IPv6 Interface Identifier 5.5. The IPv6 Interface Identifier
The Interface identifier format of a MAP node is described below. The Interface identifier format of a MAP node is described below.
| 128-n-o-s bits | | 128-n-o-s bits |
| 16 bits| 32 bits | 16 bits| | 16 bits| 32 bits | 16 bits|
+--------+----------------+--------+ +--------+----------------+--------+
| 0 | IPv4 address | PSID | | 0 | IPv4 address | PSID |
+--------+----------------+--------+ +--------+----------------+--------+
Figure 8 Figure 8
In the case of an IPv4 prefix, the IPv4 address field is right-padded In the case of an IPv4 prefix, the IPv4 address field is right-padded
with zeroes up to 32 bits. The PSID field is left-padded to create a with zeros up to 32 bits. The PSID field is left-padded to create a
16 bit field. For an IPv4 prefix or a complete IPv4 address, the 16 bit field. For an IPv4 prefix or a complete IPv4 address, the
PSID field is zero. PSID field is zero.
If the End-user IPv6 prefix length is larger than 64, the most If the End-user IPv6 prefix length is larger than 64, the most
significant parts of the interface identifier is overwritten by the significant parts of the interface identifier is overwritten by the
prefix. prefix.
6. Configuration and Packet Forwarding 6. MAP-T Configuration
The mapping rules and architectural building blocks are combined at For a given MAP domain, the BR and CE MUST be configured with the
the CE and BR to enable IPv4-IPv6 communication as follows. following MAP elements. The configured values for these elements are
identical for all CEs and BRs within a given MAP domain.
The MAP-T CE and BR are set-up as described in Section 7 of o The Basic Mapping Rule and optionally the Forwarding Mapping
[I-D.ietf-softwire-map] with the only difference being that they are Rules, including the Rule IPv6 prefix, Rule IPv4 prefix, and
set-up to operate in translation mode rather than encapsulation. Length of EA bits
6.1. IPv4 to IPv6 at the CE o Hub and spoke mode or Mesh mode. (If all traffic should be sent
to the BR, or if direct CE to CE traffic should be supported).
A MAP-T CE receiving IPv4 packets SHOULD perform NAT44 function first o Use of Translation mode (MAP-T)
and create appropriate NAT44 stateful bindings. The resulting IPv4
packets MUST contain the source IPv4 address and source transport
port number assigned to the CE by means of the MAP Basic Mapping Rule
(BMR).
The IPv4 traffic is subject to a longest IPv4 address + port match o The BR's IPv6 prefix used in the DMR
MAP rule selection using the MRT, which then determines the
subsequent NAT64 operation. By default, all traffic is matched to
default mapping rule (DMR), and subject to the stateless NAT64
operation using the DMR parameters for the MAP algorithm and NAT64.
An optional mapping rule, known as a forward mapping rule (FMR), can The MAP-T CE and BR configuration is the same as for MAP-E described
be used when forwarding to destinations that correspond to a specific in Section 7 of [I-D.ietf-softwire-map] except for two differences:
IPv4+port range in the MAP-T domain i.e. Typically the IPv4 address
and port range of another MAP-T CE, aka mesh-mode. Traffic that is o Translation mode is used instead of Encapsulation
matched to such a rule is subject to the stateless NAT64 operation o Use of the BR's IPv6 prefix instead of address
6.1. MAP CE
The MAP elements are set to values that are the same across all CEs
within a MAP domain. The values may be configured in a variety of
manners, including provisioning methods such as the Broadband Forum's
"TR-69" Residential Gateway management interface, an XML-based object
retrieved after IPv6 connectivity is established, DHCPv6, or manual
configuration by an administrator. This document does not prescribe
any of these methods, but recommends that a MAP CE SHOULD implement
DHCPv6 options as per [I-D.mdt-softwire-map-dhcp-option]. Other
configuration and management methods may use the format described by
this option for consistency and convenience of implementation on CEs
that support multiple configuration methods.
The only remaining provisioning information the CE requires in order
to calculate the MAP IPv4 address and enable IPv4 connectivity is the
IPv6 prefix for the CE. The End-user IPv6 prefix is configured as
part of obtaining IPv6 Internet access, and requires no special
handling.
The MAP provisioning parameters, and hence the IPv4 service itself,
is tied to the End-user IPv6 prefix; thus, the MAP service is also
tied to this in terms of authorization, accounting, etc. The MAP
IPv4 address, prefix or shared IPv4 address and port set has the same
lifetime as its associated End-user IPv6 prefix.
A single MAP CE MAY be connected to more than one MAP domain, just as
any router may have more than one IPv4-enabled service provider
facing interface and more than one set of associated addresses
assigned by DHCPv6. Each domain a given CE operates within would
require its own set of MAP configuration elements and would generate
its own IPv4 address. The MAP DHCPv6 option is specified in
[I-D.mdt-softwire-map-dhcp-option]
6.2. MAP BR
The MAP BR MUST be configured with the same MAP elements as the MAP
CEs operating within the same domain.
For increased reliability and load balancing, the BR IPv6 prefix MAY
be shared across a given MAP domain. As MAP is stateless, any BR may
be used at any time.
Since MAP uses provider address space, no specific routes need to be
advertised externally for MAP to operate, neither in IPv6 nor IPv4
BGP. However, the BR prefix needs to be advertised in the service
provider's IGP.
7. MAP-T Packet Forwarding
The end-end packet flow in MAP-T involves an IPv4 or IPv6 packet
being forwarded across one or both of a CE and a BR, in one of two
directions in for each such case.
7.1. IPv4 to IPv6 at the CE
A MAP-T CE receiving IPv4 packets SHOULD perform NAPT NAT44 function,
and create any necessary NAT44 bindings. The NAT'ed IPv4 packet's
source address and port MUST correspond to the source IPv4 address
and source transport port number computed to belong to the CE by
means of the MAP Basic Mapping Rule (BMR).
The resulting IPv4 packet is subject to a longest IPv4 address + port
match MAP rule selection, which then determines the parameters for
the subsequent NAT64 operation. By default, all traffic is matched
to the default mapping rule (DMR), and subject to the stateless NAT64
operation using the DMR parameters for the MAP algorithm and NAT64.
Packets matching destinations covered by any (optional) forward
mapping rules (FMRs) are subject to the stateless NAT64 operation
using the FMR parameters for the MAP algorithm and stateless NAT64. using the FMR parameters for the MAP algorithm and stateless NAT64.
A MAP-T CE MUST support a default mapping rule and SHOULD support one A MAP-T CE MUST support a default mapping rule and SHOULD support one
or more forward mapping rules. or more forward mapping rules.
6.2. IPv6 to IPv4 at the CE 7.2. IPv6 to IPv4 at the CE
A MAP-T CE receiving an IPv6 packet performs its regular IPv6 A MAP-T CE receiving an IPv6 packet performs its regular IPv6
operations, whereby only packets that are addressed to the MAP-T BMR operations (filtering, pre-routing, etc). Only packets that are
addresses are forwarded to the CE's stateless NAT64 function. All addressed to the CE's MAP-T addresses, and with source addresses
other IPv6 traffic SHOULD be forwarded as per the CE's IPv6 routing matching the IPv6 map-rule prefixes of a DMR or FMR, are processed by
rules. The CE SHOULD check that MAP-T received packets' transport- the MAP-T CE. All other IPv6 traffic SHOULD be forwarded as per the
layer destination port number is in the range configured by MAP for CE's IPv6 routing rules. The CE SHOULD check that MAP-T received
the CE and the CE SHOULD drop any non conforming packet and respond packets' destination transport-layer destination port number is in
with an ICMPv6 "Address Unreachable" (Type 1, Code 3). the range allowed for by the CE's MAP BMR configuration. The CE
SHOULD drop any non conforming packet and respond with an ICMPv6
"Address Unreachable" (Type 1, Code 3). For packets whose source
address matches an FMR, the CE SHOULD perform a check of consistency
of the source against the allowed values from the source port-range.
If the packets' source port number is found to be outside the range
allowed, the CE MUST drop the packet and SHOULD respond with an
ICMPv6 "Destination Unreachable, Source address failed ingress/egress
policy" (Type 1, Code 5).
The CE's stateless NAT64 function MUST derive the IPv4 source and For each MAP-T processed packet, the CE's NAT64 function MUST derive
destination addresses as per Section 5 of this document and MUST the IPv4 source and destination addresses. The IPv4 destination
replace the IPv6 header with an IPv4 header in accordance with address is derived by extracting relevant information from the IPv6
[RFC6145]. The resulting IPv4 packet is then forwarded to the CE's destination and the information stored in the BMR as per Section 5.2
NAPT function, when this is enabled, where the destination IPv4 of this document. The IPv4 source address is formed by classifying
address and port number MUST be mapped to their original value, the packet's source as matching a DMR or FMR rule prefix, and then
before being forwarded according to the CE's regular IPv4 rules. using that NAT64 rule-set, as per Section 5.4 or Section 5.3
When the NAPT function is not enabled, the traffic from the stateless respectively.
NAT64 function is directly forwarded according to the CE's IPv4
rules.
6.3. IPv6 to IPv4 at the BR The resulting IPv4 packet is then forwarded to the CE's NAPT NAT44
function, where the destination IPv4 address and port number MUST be
mapped to their original value, before being forwarded according to
the CE's regular IPv4 rules. When the NAPT function is not enabled,
the traffic from the stateless NAT64 function is directly forwarded
according to the CE's IPv4 rules.
A MAP-T BR receiving IPv6 packets MUST select a best matching MAP 7.3. IPv6 to IPv4 at the BR
rule based on a longest address match of the packets' source address
against the BR's configured MAP BMR prefix(es), as well as a match of
the packet destination address against the configured FMR prefix(es).
The selected MAP rule allows the BR to determine the CE's range from
the port-set-id contained in the source IPv6 address. The BR MUST
perform a validation of the consistency of the source against the
allowed values from the identified port-range port. If the packets
source port number is found to be outside the range allowed for this
CE-index and the BMR, the BR MUST drop the packet and respond with an
ICMPv6 "Destination Unreachable, Source address failed ingress/egress
policy" (Type 1, Code 5).
The BR MUST derive the source and destination IPv4 addresses as per A MAP-T BR receiving IPv6 packets MUST select a matching MAP rule
Section 5 of this document and translate the IPv6 to IPv4 headers based on a longest address match of the packets' source address
following [RFC6145]. The resulting IPv4 packets are then passed to against the BR's configured MAP Rules. In combination with the port-
regular IPv4 forwarding by the BR. set-id contained in the packet's source IPv6 address, the selected
MAP rule allows the BR to verify that the CE is using its allowed
address and port range. Thus, the BR MUST perform a validation of
the consistency of the source against the allowed values from the
identified port-range. If the packets' source port number is found
to be outside the range allowed, the BR MUST drop the packet and
respond with an ICMPv6 "Destination Unreachable, Source address
failed ingress/egress policy" (Type 1, Code 5).
6.4. IPv4 to IPv6 at the BR When constructing the IPv4 packet, the BR MUST derive the source and
destination IPv4 addresses as per Section 5 of this document and
translate the IPv6 to IPv4 headers as per [RFC6145]. The resulting
IPv4 packets are then passed to regular IPv4 forwarding.
A MAP-T BR receiving IPv4 packets uses a longest match IPv4 + port 7.4. IPv4 to IPv6 at the BR
lookup to select the target MAP-T domain and rule. The BR MUST then
derive the IPv6 source and destination addresses from the IPv4 source A MAP-T BR receiving IPv4 packets uses a longest match IPv4 +
and destination address and port as per Section 5 of this document. transport layer port lookup to identify the target MAP-T domain and
Following this, the BR MUST translate the IPv4 to IPv6 headers rule. The MAP-T BR MUST then compute the IPv6 destination addresses
following [RFC6145]. The resulting IPv6 packets are then passed to from the IPv4 destination address and port as per Section 5.2 of this
document. The MAP-T BR MUST also compute the IPv6 source addresses
from the IPv4 source address as per Section 5.4 (i.e. It needs to
form an IPv6 mapped IPv4 address using the BR's DMR prefix).
Throughout the generic IPv4 to IPv6 header procedures following
[RFC6145] apply. The resulting IPv6 packets are then passed to
regular IPv6 forwarding. regular IPv6 forwarding.
Note that the operation of a BR when forwarding to MAP-T domains that Note that the operation of a BR when forwarding to MAP-T domains that
do not utilize IPv4 address sharing, is the same as stateless IPv4/ are defined without IPv4 address sharing is the same as stateless
IPv6 translation. NAT64 IPv4/IPv6 translation.
7. ICMP Handling 8. ICMP Handling
ICMP messages need to be supported in MAP-T domain and also across ICMP messages supported in the MAP-T domain needs to take into
it, taking into consideration also the NAPT component and best consideration also the NAPT component and best current practice
current practice documented in [RFC5508] along with some additional documented in [RFC5508] along with some additional specific
specific considerations. considerations.
MAP-T CEs and BRs MUST follow ICMP/ICMPv6 translation as per MAP-T CEs and BRs MUST follow ICMP/ICMPv6 translation as per
[RFC6145], with the following extension to cover the address sharing/ [RFC6145], with the following extension to cover the address sharing/
port-range feature. port-range feature.
Unlike TCP and UDP, which each provide two port fields to represent Unlike TCP and UDP, which provide two transport protocol port fields
both source and destination, the ICMP/ICMPv6 [RFC0792], [RFC4443] to represent both source and destination, the ICMP/ICMPv6 [RFC0792],
Query message header has only one ID field which needs to be used to [RFC4443] Query message header has only one ID field which needs to
identify a sending IPv4 host. be used to identify a sending IPv4 host.
When receiving IPv4 ICMP messages, the MAP-T CE SHOULD rewrite the ID When receiving IPv4 ICMP messages, the MAP-T CE MUST rewrite the ID
field to a port value derived from the Port-set-id. A BR MUST field to a port value derived from the Port-set-id. A BR MUST
translate the resulting ICMPv6 packets back to ICMP preserving the ID translate the resulting ICMPv6 packets back to ICMP preserving the ID
field on its way to an IPv4 destination. field on its way to an IPv4 destination.
In the return path, when MAP-T BR receives an ICMP packet containing In the return path, when MAP-T BR receives an ICMP packet containing
an ID field which is bound for a shared address in the MAP-T domain, an ID field which is bound for a shared address in the MAP-T domain,
the MAP-T BR SHOULD use the ID value as a substitute for the the MAP-T BR SHOULD use the ID value as a substitute for the
destination port in determining the IPv6 destination address. In all destination port in determining the IPv6 destination address. In all
other cases, the MAP-T BR MUST derive the destination IPv6 address by other cases, the MAP-T BR MUST derive the destination IPv6 address by
simply mapping the destination IPv4 address without additional port simply mapping the destination IPv4 address without additional port
skipping to change at page 18, line 23 skipping to change at page 19, line 48
If a MAP BR receives an ICMP error message on its IPv4 interface, the If a MAP BR receives an ICMP error message on its IPv4 interface, the
MAP BR should translate the ICMP message to an appropriate ICMPv6 MAP BR should translate the ICMP message to an appropriate ICMPv6
message, as per [RFC6145] and forward it to the intended MAP CE with message, as per [RFC6145] and forward it to the intended MAP CE with
the following considerations. If IPv4 address is not shared, the MAP the following considerations. If IPv4 address is not shared, the MAP
BR generates a CE IPv6 address from the IPv4 destination address in BR generates a CE IPv6 address from the IPv4 destination address in
the ICMP error message and encapsulates the ICMP message in IPv6. If the ICMP error message and encapsulates the ICMP message in IPv6. If
the IPv4 address is shared, the MAP BR derives an original IPv4 the IPv4 address is shared, the MAP BR derives an original IPv4
packet from the ICMP payload and generates a CE IPv6 address from the packet from the ICMP payload and generates a CE IPv6 address from the
source address and the source port in the original IPv4 packet. source address and the source port in the original IPv4 packet.
8. Fragmentation and Path MTU Discovery 9. Fragmentation and Path MTU Discovery
Due to the different sizes of the IPv4 and IPv6 header, handling the Due to the different sizes of the IPv4 and IPv6 header, handling the
maximum packet size is relevant for the operation of any system maximum packet size is relevant for the operation of any system
connecting the two address families. There are three mechanisms to connecting the two address families. There are three mechanisms to
handle this issue: Path MTU discovery (PMTUD), fragmentation, and handle this issue: Path MTU discovery (PMTUD), fragmentation, and
transport-layer negotiation such as the TCP Maximum Segment Size transport-layer negotiation such as the TCP Maximum Segment Size
(MSS) option [RFC0897]. MAP uses all three mechanisms to deal with (MSS) option [RFC0897]. MAP uses all three mechanisms to deal with
different cases. different cases.
8.1. Fragmentation in the MAP domain 9.1. Fragmentation in the MAP domain
Translating an IPv4 packet to carry it across the MAP domain will Translating an IPv4 packet to carry it across the MAP domain will
increase its size by 20 bytes respectively. It is strongly increase its size by 20 bytes respectively. It is strongly
recommended that the MTU in the MAP domain is well managed and that recommended that the MTU in the MAP domain is well managed and that
the IPv6 MTU on the CE WAN side interface is set so that no the IPv6 MTU on the CE WAN side interface is set so that no
fragmentation occurs within the boundary of the MAP domain. fragmentation occurs within the boundary of the MAP domain.
Fragmentation in MAP-T domain is to be handled as described in Fragmentation in MAP-T domain is to be handled as described in
section 4 and 5 of [RFC6145]. section 4 and 5 of [RFC6145].
8.2. Receiving IPv4 Fragments on the MAP domain borders 9.2. Receiving IPv4 Fragments on the MAP domain borders
Forwarding of an IPv4 packet received from the outside of the MAP Forwarding of an IPv4 packet received from the outside of the MAP
domain requires the IPv4 destination address and the transport domain requires the IPv4 destination address and the transport
protocol destination port. The transport protocol information is protocol destination port. The transport protocol information is
only available in the first fragment received. As described in only available in the first fragment received. As described in
section 5.3.3 of [RFC6346] a MAP node receiving an IPv4 fragmented section 5.3.3 of [RFC6346] a MAP node receiving an IPv4 fragmented
packet from outside has to reassemble the packet before sending the packet from outside has to reassemble the packet before sending the
packet onto the MAP link. If the first packet received contains the packet onto the MAP link. If the first packet received contains the
transport protocol information, it is possible to optimize this transport protocol information, it is possible to optimize this
behavior by using a cache and forwarding the fragments unchanged. A behavior by using a cache and forwarding the fragments unchanged. A
description of this algorithm is outside the scope of this document. description of this algorithm is outside the scope of this document.
8.3. Sending IPv4 fragments to the outside 9.3. Sending IPv4 fragments to the outside
If two IPv4 host behind two different MAP CE's with the same IPv4 If two IPv4 host behind two different MAP CE's with the same IPv4
address sends fragments to an IPv4 destination host outside the address sends fragments to an IPv4 destination host outside the
domain. Those hosts may use the same IPv4 fragmentation identifier, domain. Those hosts may use the same IPv4 fragmentation identifier,
resulting in incorrect reassembly of the fragments at the destination resulting in incorrect reassembly of the fragments at the destination
host. Given that the IPv4 fragmentation identifier is a 16 bit host. Given that the IPv4 fragmentation identifier is a 16 bit
field, it could be used similarly to port ranges. A MAP CE SHOULD field, it could be used similarly to port ranges. A MAP CE SHOULD
rewrite the IPv4 fragmentation identifier to be within its allocated rewrite the IPv4 fragmentation identifier to be within its allocated
port set. port set.
9. Usage Considerations 10. Usage Considerations
10.1. EA-bit length set to 0
9.1. Address Independence
The MAP solution supports use and configuration of domains in so The MAP solution supports use and configuration of domains with a BMR
called 1:1 mode (meaning 1 mapping rule set per CE), which allows having an EA-bit length is set to 0. This results in independence
complete independence between the IPv6 prefix assigned to the CE and between the end-user IPv6 prefix assigned to the CE and the IPv4
the IPv4 address and/or port-range it uses. This is achieved in all address and/or port-range used by MAP.
cases when the EA-bit length is set to 0.
The constraint imposed is that each such MAP domain be composed of The constraint imposed is that each such MAP domain be composed of
just 1 MAP CE which has a predetermined IPv6 prefix, i.e. The BR just 1 MAP CE which has a predetermined IPv6 prefix, i.e. The BR
would be configured with a rule-set per CPE, where the FMR would would be configured with a rule-set per CPE, where the FMR would
uniquely describe the IPv6 prefix of a given CE. Each CE would have uniquely describe the IPv6 prefix of a given CE. Each CE would have
a distinct BMR, that would fully describe that CE's IPv4 address, and a distinct BMR, that would fully describe that CE's IPv4 address, and
PSID if any. PSID if any.
9.2. Mesh vs Hub and spoke mode 10.2. Mesh and Hub and spoke modes
The hub and spoke mode of communication, whereby all traffic sent by The hub and spoke mode of communication, whereby all traffic sent by
a MAP-T CE is forwarded via a BR, and the mesh mode, whereby a CE is a MAP-T CE is forwarded via a BR, and the mesh mode, whereby a CE is
directly able to forward traffic to another CE in the same MAP-T directly able to forward traffic to another CE in the same MAP-T
domain, are governed by the activation of a Basic Mapping Rule as a domain, are governed by the activation of a Basic Mapping Rule as a
Forward Mapping Rule. By default, a MAP CE will interpret its BMR Forward Mapping Rule, and/or the configuration of additional FMRs.
only to setup its IPv4 parameters and IPv6 MAP address and not as an By default, a MAP CE will interpret its BMR only to configure its
FMR. IPv4 parameters and IPv6 MAP address. The enable mesh-mode in a
domain, an FMR containing the equivalent information of the domain's
BMR needs to be created and used to configure the CEs.
9.3. Communication with IPv6 servers in the MAP-T domain 10.3. Communication with IPv6 servers in the MAP-T domain
MAP-T allows communication between both IPv4-only and any IPv6 By default, MAP-T allows communication between both IPv4-only and any
enabled end hosts, with native IPv6-only servers which are using IPv6 enabled devices, as well as with native IPv6-only servers
IPv4-mapped IPv6 address based on DMR in the MAP-T domain. In this provided that the servers are configured with an IPv4-mapped IPv6
mode, the IPv6-only servers SHOULD have both A and AAAA records in address using the DMR IPv6 prefix in the MAP-T domain. Such IPv6
DNS [RFC6219]. DNS64 [RFC6147] become required only when IPv6 servers (e.g. an HTTP server, or a web content cache device) are thus
servers in the MAP-T domain are expected themselves to initiate able to serve both IPv6 users as well as IPv4-only users users alike
communication to external IPv4-only hosts. utilizing IPv6. Any such IPv6-only servers SHOULD have both A and
AAAA records in DNS [RFC6219]. DNS64 [RFC6147] become required only
when IPv6 servers in the MAP-T domain are expected themselves to
initiate communication to external IPv4-only hosts.
9.4. Backwards compatibility 10.4. Compatibility with other NAT64 solutions
A MAP-T CE, in all configuration modes, is by default compatible with A MAP-T CE, is by default compatible with [RFC6146] stateful NAT64
regular [RFC6146] stateful NAT64 devices that are configured to use/ devices that are placed to use/advertise the BR prefix. This in
advertise BR prefixes. This allows the use of MAP-T CEs in effect allows the use of MAP-T CEs in environments that need to
environments that require statistical multiplexing of IPv4 addresses perform statistical multiplexing of IPv4 addresses, while utilizing
while being able to compromise on the stateful nature. Furthermore, stateful NAT64 devices, and can take the role of a CLAT as defined in
a MAP-T CE configured to operate without address sharing (no PSID) is [RFC6877].
compatible with any stateless NAT64 [RFC6146] devices positioned as
BRs.
10. IANA Considerations Furthermore, a MAP-T CE configured to operate without address sharing
(no PSID) is compatible with any stateless NAT64 devices positioned
as BRs.
11. IANA Considerations
This specification does not require any IANA actions. This specification does not require any IANA actions.
11. Security Considerations 12. Security Considerations
Spoofing attacks: With consistency checks between IPv4 and IPv6 Spoofing attacks: With consistency checks between IPv4 and IPv6
sources that are performed on IPv4/IPv6 packets received by MAP sources that are performed on IPv4/IPv6 packets received by MAP
nodes, MAP does not introduce any new opportunity for spoofing nodes, MAP does not introduce any new opportunity for spoofing
attacks that would not already exist in IPv6. attacks that would not already exist in IPv6.
Denial-of-service attacks: In MAP domains where IPv4 addresses are Denial-of-service attacks: In MAP domains where IPv4 addresses are
shared, the fact that IPv4 datagram reassembly may be necessary shared, the fact that IPv4 datagram reassembly may be necessary
introduces an opportunity for DOS attacks. This is inherent to introduces an opportunity for DOS attacks. This is inherent to
address sharing, and is common with other address sharing address sharing, and is common with other address sharing
skipping to change at page 21, line 22 skipping to change at page 23, line 5
port range restrictions. To minimize this type of attacks when port range restrictions. To minimize this type of attacks when
using a restricted port set, the MAP CE's NAT44 filtering behavior using a restricted port set, the MAP CE's NAT44 filtering behavior
SHOULD be "Address-Dependent Filtering". Furthermore, the MAP CEs SHOULD be "Address-Dependent Filtering". Furthermore, the MAP CEs
SHOULD use a DNS transport proxy function to handle DNS traffic, SHOULD use a DNS transport proxy function to handle DNS traffic,
and source such traffic from IPv6 interfaces not assigned to and source such traffic from IPv6 interfaces not assigned to
MAP-T. Practicalities of these methods are discussed in Section MAP-T. Practicalities of these methods are discussed in Section
5.9 of [I-D.dec-stateless-4v6]. 5.9 of [I-D.dec-stateless-4v6].
[RFC6269] outlines general issues with IPv4 address sharing. [RFC6269] outlines general issues with IPv4 address sharing.
12. Contributors 13. Contributors
Mohamed Boucadair, Gang Chen, Maoke Chen, Wojciech Dec, Xiaohong
Deng, Jouni Korhonen, Tomasz Mrugalski, Jacni Qin, Chunfa Sun, Qiong
Sun, Leaf Yeh.
The following are the authors who provided a major contribution to
this document:
Chongfeng Xie (China Telecom)
Room 708, No.118, Xizhimennei Street Beijing 100035 CN
Phone: +86-10-58552116
Email: xiechf@ctbri.com.cn
Qiong Sun (China Telecom)
Room 708, No.118, Xizhimennei Street Beijing 100035 CN
Phone: +86-10-58552936
Email: sunqiong@ctbri.com.cn
Rajiv Asati (Cisco Systems)
7025-6 Kit Creek Road Research Triangle Park NC 27709 USA
Email: rajiva@cisco.com
Gang Chen (China Mobile)
53A,Xibianmennei Ave. Beijing 100053 P.R.China
Email: chengang@chinamobile.com
Wentao Shang (CERNET Center/Tsinghua University)
Room 225, Main Building, Tsinghua University Beijing 100084 CN The following individuals authored major contribution to this
document:
Email: wentaoshang@gmail.com Chongfeng Xie (China Telecom) Room 708, No.118, Xizhimennei Street
Beijing 100035 CN Phone: +86-10-58552116 Email: xiechf@ctbri.com.cn
Guoliang Han (CERNET Center/Tsinghua University) Qiong Sun (China Telecom) Room 708, No.118, Xizhimennei Street
Beijing 100035 CN Phone: +86-10-58552936 Email: sunqiong@ctbri.com.cn
Room 225, Main Building, Tsinghua University Beijing 100084 CN Rajiv Asati (Cisco Systems) 7025-6 Kit Creek Road Research Triangle
Park NC 27709 USA Email: rajiva@cisco.com
Email: bupthgl@gmail.com Gang Chen (China Mobile) 53A,Xibianmennei Ave. Beijing 100053
P.R.China Email: chengang@chinamobile.com
Yu Zhai CERNET Center/Tsinghua University Wentao Shang (CERNET Center/Tsinghua University) Room 225, Main
Building, Tsinghua University Beijing 100084 CN Email:
wentaoshang@gmail.com
Room 225, Main Building, Tsinghua University Beijing 100084 CN Guoliang Han (CERNET Center/Tsinghua University) Room 225, Main
Building, Tsinghua University Beijing 100084 CN Email:
bupthgl@gmail.com
Email: jacky.zhai@gmail.com Yu Zhai CERNET Center/Tsinghua University Room 225, Main Building,
Tsinghua University Beijing 100084 CN Email: jacky.zhai@gmail.com
13. Acknowledgements 14. Acknowledgements
This document is based on the ideas of many. In particular Remi This document is based on the ideas of many. In particular Remi
Despres, who has tirelessly worked on generalized mechanisms for Despres, who has tirelessly worked on generalized mechanisms for
stateless address mapping. stateless address mapping.
The authors would like to thank Guillaume Gottard, Dan Wing, Jan The authors would like to thank Mohamed Boucadair, Guillaume Gottard,
Zorz, Necj Scoberne, Tina Tsou for their thorough review and Dan Wing, Jan Zorz, Necj Scoberne, Tina Tsou, , Gang Chen, Maoke
comments. Chen, Xiaohong Deng, Jouni Korhonen, Tomasz Mrugalski, Jacni Qin,
Chunfa Sun, Qiong Sun, and Leaf Yeh for their review and comments.
14. References 15. References
14.1. Normative References 15.1. Normative 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, March 1997. Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC6052] Bao, C., Huitema, C., Bagnulo, M., Boucadair, M., and X. [RFC6052] Bao, C., Huitema, C., Bagnulo, M., Boucadair, M., and X.
Li, "IPv6 Addressing of IPv4/IPv6 Translators", RFC 6052, Li, "IPv6 Addressing of IPv4/IPv6 Translators", RFC 6052,
October 2010. October 2010.
[RFC6145] Li, X., Bao, C., and F. Baker, "IP/ICMP Translation [RFC6145] Li, X., Bao, C., and F. Baker, "IP/ICMP Translation
Algorithm", RFC 6145, April 2011. Algorithm", RFC 6145, April 2011.
[RFC6346] Bush, R., "The Address plus Port (A+P) Approach to the [RFC6346] Bush, R., "The Address plus Port (A+P) Approach to the
IPv4 Address Shortage", RFC 6346, August 2011. IPv4 Address Shortage", RFC 6346, August 2011.
14.2. Informative References 15.2. Informative References
[I-D.dec-stateless-4v6] [I-D.dec-stateless-4v6]
Dec, W., Asati, R., and H. Deng, "Stateless 4Via6 Address Dec, W., Asati, R., and H. Deng, "Stateless 4Via6 Address
Sharing", draft-dec-stateless-4v6-04 (work in progress), Sharing", draft-dec-stateless-4v6-04 (work in progress),
October 2011. October 2011.
[I-D.ietf-softwire-map] [I-D.ietf-softwire-map]
Troan, O., Dec, W., Li, X., Bao, C., Matsushima, S., and Troan, O., Dec, W., Li, X., Bao, C., Matsushima, S.,
T. Murakami, "Mapping of Address and Port with Murakami, T., and T. Taylor, "Mapping of Address and Port
Encapsulation (MAP)", draft-ietf-softwire-map-04 (work in with Encapsulation (MAP)", draft-ietf-softwire-map-07
progress), February 2013. (work in progress), May 2013.
[I-D.ietf-softwire-stateless-4v6-motivation] [I-D.ietf-softwire-stateless-4v6-motivation]
Boucadair, M., Matsushima, S., Lee, Y., Bonness, O., Boucadair, M., Matsushima, S., Lee, Y., Bonness, O.,
Borges, I., and G. Chen, "Motivations for Carrier-side Borges, I., and G. Chen, "Motivations for Carrier-side
Stateless IPv4 over IPv6 Migration Solutions", Stateless IPv4 over IPv6 Migration Solutions",
draft-ietf-softwire-stateless-4v6-motivation-05 (work in draft-ietf-softwire-stateless-4v6-motivation-05 (work in
progress), November 2012. progress), November 2012.
[I-D.ietf-tsvwg-iana-ports] [I-D.ietf-tsvwg-iana-ports]
Cotton, M., Eggert, L., Touch, J., Westerlund, M., and S. Cotton, M., Eggert, L., Touch, J., Westerlund, M., and S.
Cheshire, "Internet Assigned Numbers Authority (IANA) Cheshire, "Internet Assigned Numbers Authority (IANA)
Procedures for the Management of the Service Name and Procedures for the Management of the Service Name and
Transport Protocol Port Number Registry", Transport Protocol Port Number Registry",
draft-ietf-tsvwg-iana-ports-10 (work in progress), draft-ietf-tsvwg-iana-ports-10 (work in progress),
February 2011. February 2011.
[I-D.maglione-softwire-map-t-scenarios]
Maglione, R., Dec, W., Kuarsingh, V., and E. Mallette,
"Use cases for MAP-T",
draft-maglione-softwire-map-t-scenarios-02 (work in
progress), June 2013.
[I-D.mdt-softwire-map-dhcp-option] [I-D.mdt-softwire-map-dhcp-option]
Mrugalski, T., Troan, O., Bao, C., and W. Dec, "DHCPv6 Mrugalski, T., Troan, O., Bao, C., and W. Dec, "DHCPv6
Options for Mapping of Address and Port", Options for Mapping of Address and Port",
draft-mdt-softwire-map-dhcp-option-03 (work in progress), draft-mdt-softwire-map-dhcp-option-03 (work in progress),
July 2012. July 2012.
[I-D.xli-behave-divi] [I-D.xli-behave-divi]
Shang, W., Li, X., Zhai, Y., and C. Bao, "dIVI: Dual- Bao, C., Li, X., Zhai, Y., and W. Shang, "dIVI: Dual-
Stateless IPv4/IPv6 Translation", draft-xli-behave-divi-04 Stateless IPv4/IPv6 Translation", draft-xli-behave-divi-05
(work in progress), October 2011. (work in progress), June 2013.
[RFC0792] Postel, J., "Internet Control Message Protocol", STD 5, [RFC0792] Postel, J., "Internet Control Message Protocol", STD 5,
RFC 792, September 1981. RFC 792, September 1981.
[RFC0897] Postel, J., "Domain name system implementation schedule", [RFC0897] Postel, J., "Domain name system implementation schedule",
RFC 897, February 1984. RFC 897, February 1984.
[RFC2473] Conta, A. and S. Deering, "Generic Packet Tunneling in [RFC2473] Conta, A. and S. Deering, "Generic Packet Tunneling in
IPv6 Specification", RFC 2473, December 1998. IPv6 Specification", RFC 2473, December 1998.
skipping to change at page 24, line 45 skipping to change at page 25, line 40
December 2003. December 2003.
[RFC4443] Conta, A., Deering, S., and M. Gupta, "Internet Control [RFC4443] Conta, A., Deering, S., and M. Gupta, "Internet Control
Message Protocol (ICMPv6) for the Internet Protocol Message Protocol (ICMPv6) for the Internet Protocol
Version 6 (IPv6) Specification", RFC 4443, March 2006. Version 6 (IPv6) Specification", RFC 4443, March 2006.
[RFC4632] Fuller, V. and T. Li, "Classless Inter-domain Routing [RFC4632] Fuller, V. and T. Li, "Classless Inter-domain Routing
(CIDR): The Internet Address Assignment and Aggregation (CIDR): The Internet Address Assignment and Aggregation
Plan", BCP 122, RFC 4632, August 2006. Plan", BCP 122, RFC 4632, August 2006.
[RFC4862] Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless
Address Autoconfiguration", RFC 4862, September 2007.
[RFC4953] Touch, J., "Defending TCP Against Spoofing Attacks", [RFC4953] Touch, J., "Defending TCP Against Spoofing Attacks",
RFC 4953, July 2007. RFC 4953, July 2007.
[RFC5508] Srisuresh, P., Ford, B., Sivakumar, S., and S. Guha, "NAT [RFC5508] Srisuresh, P., Ford, B., Sivakumar, S., and S. Guha, "NAT
Behavioral Requirements for ICMP", BCP 148, RFC 5508, Behavioral Requirements for ICMP", BCP 148, RFC 5508,
April 2009. April 2009.
[RFC5961] Ramaiah, A., Stewart, R., and M. Dalal, "Improving TCP's [RFC5961] Ramaiah, A., Stewart, R., and M. Dalal, "Improving TCP's
Robustness to Blind In-Window Attacks", RFC 5961, Robustness to Blind In-Window Attacks", RFC 5961,
August 2010. August 2010.
[RFC6056] Larsen, M. and F. Gont, "Recommendations for Transport- [RFC6056] Larsen, M. and F. Gont, "Recommendations for Transport-
Protocol Port Randomization", BCP 156, RFC 6056, Protocol Port Randomization", BCP 156, RFC 6056,
January 2011. January 2011.
[RFC6146] Bagnulo, M., Matthews, P., and I. van Beijnum, "Stateful
NAT64: Network Address and Protocol Translation from IPv6
Clients to IPv4 Servers", RFC 6146, April 2011.
[RFC6147] Bagnulo, M., Sullivan, A., Matthews, P., and I. van [RFC6147] Bagnulo, M., Sullivan, A., Matthews, P., and I. van
Beijnum, "DNS64: DNS Extensions for Network Address Beijnum, "DNS64: DNS Extensions for Network Address
Translation from IPv6 Clients to IPv4 Servers", RFC 6147, Translation from IPv6 Clients to IPv4 Servers", RFC 6147,
April 2011. April 2011.
[RFC6219] Li, X., Bao, C., Chen, M., Zhang, H., and J. Wu, "The [RFC6219] Li, X., Bao, C., Chen, M., Zhang, H., and J. Wu, "The
China Education and Research Network (CERNET) IVI China Education and Research Network (CERNET) IVI
Translation Design and Deployment for the IPv4/IPv6 Translation Design and Deployment for the IPv4/IPv6
Coexistence and Transition", RFC 6219, May 2011. Coexistence and Transition", RFC 6219, May 2011.
[RFC6269] Ford, M., Boucadair, M., Durand, A., Levis, P., and P. [RFC6269] Ford, M., Boucadair, M., Durand, A., Levis, P., and P.
Roberts, "Issues with IP Address Sharing", RFC 6269, Roberts, "Issues with IP Address Sharing", RFC 6269,
June 2011. June 2011.
[RFC6324] Nakibly, G. and F. Templin, "Routing Loop Attack Using [RFC6324] Nakibly, G. and F. Templin, "Routing Loop Attack Using
IPv6 Automatic Tunnels: Problem Statement and Proposed IPv6 Automatic Tunnels: Problem Statement and Proposed
Mitigations", RFC 6324, August 2011. Mitigations", RFC 6324, August 2011.
[RFC6877] Mawatari, M., Kawashima, M., and C. Byrne, "464XLAT:
Combination of Stateful and Stateless Translation",
RFC 6877, April 2013.
Appendix A. Examples of MAP-T translation Appendix A. Examples of MAP-T translation
Example 1 - BMR: Example 1 - Basic Mapping Rule:
Given the MAP domain information and an IPv6 address of Given the following MAP domain information and IPv6 end-user
an endpoint: prefix assigned to a MAP CE:
IPv6 prefix assigned to the end user: 2001:db8:0012:3400::/56 IPv6 prefix assigned to the end-user: 2001:db8:0012:3400::/56
Basic Mapping Rule: {2001:db8:0000::/40 (Rule IPv6 prefix), Basic Mapping Rule: {2001:db8:0000::/40 (Rule IPv6 prefix),
192.0.2.0/24 (Rule IPv4 prefix), 16 (Rule EA-bits length)} 192.0.2.0/24 (Rule IPv4 prefix), 16 (Rule EA-bits length)}
PSID length: (16 - (32 - 24) = 8. (Sharing ratio of 256) PSID length: (16 - (32 - 24) = 8. (Sharing ratio of 256)
PSID offset: 4 PSID offset: 6 (default)
A MAP node (CE or BR) can via the BMR, or equivalent FMR, A MAP node (CE or BR) can via the BMR, or equivalent FMR,
determine the IPv4 address and port-set as shown below: determine the IPv4 address and port-set as shown below:
EA bits offset: 40 EA bits offset: 40
IPv4 suffix bits (p) Length of IPv4 address (32) - IPv4 prefix IPv4 suffix bits (p) Length of IPv4 address (32) - IPv4 prefix
length (24) = 8 length (24) = 8
IPv4 address 192.0.2.18 (0xc0000212) IPv4 address 192.0.2.18 (0xc0000212)
PSID start: 40 + p = 40 + 8 = 48 PSID start: 40 + p = 40 + 8 = 48
PSID length: o - p = (56 - 40) - 8 = 8 PSID length (q): o - p = (End-user prefix len -
rule IPv6 prefix len) - p = (56 - 40) - 8 = 8
PSID: 0x34 PSID: 0x34
Port-set-1: 4928, 4929, 4930, 4931, 4932, 4933, 4934, 4935, 4936, Available ports (63 ranges) : 1232-1235, 2256-2259, ...... ,
4937, 4938, 4939, 4940, 4941, 4942, 4943 63696-63699, 64720-64723
Port-set-2: 9024, 9025, 9026, 9027, 9028, 9029, 9030, 9031, 9032,
9033, 9034, 9035, 9036, 9037, 9038, 9039
... ...
Port-set-15 62272, 62273, 62274, 62275, 62276, 62277, 62278,
62279, 62280, 62281, 62282, 62283, 62284, 62285, 62286, 62287
The BMR information allows a MAP CE also to determine (complete) The BMR information allows a MAP CE to determine (complete)
its IPv6 address within the indicated IPv6 prefix. its IPv6 address within the indicated end-user IPv6 prefix.
IPv6 address of MAP-T CE: 2001:db8:0012:3400:00c0:0002:1200:3400 IPv6 address of MAP CE: 2001:db8:0012:3400:0000:c000:0212:0034
Example 2: Example 2 - BR:
Another example can be made of a hypothetical MAP-T BR, Another example can be made of a hypothetical MAP-T BR,
configured with the following FMR when receiving a packet configured with the following FMR when receiving a packet
with the following characteristics: with the following characteristics:
IPv4 source address: 1.2.3.4 (0x01020304) IPv4 source address: 1.2.3.4 (0x01020304)
IPv4 source port: 80 TCP source port: 80
IPv4 destination address: 192.0.2.18 (0xc0000212) IPv4 destination address: 192.0.2.18 (0xc0000212)
IPv4 destination port: 9030 TCP destination port: 1232
Configured Forwarding Mapping Rule: {2001:db8:0000::/40 Configured Forwarding Mapping Rule: {2001:db8::/40
(Rule IPv6 prefix), 192.0.2.0/24 (Rule IPv4 prefix), (Rule IPv6 prefix), 192.0.2.0/24 (Rule IPv4 prefix),
16 (Rule EA-bits length)} 16 (Rule EA-bits length)}
MAP-T BR Prefix 2001:db8:ffff::/64 MAP-T BR Prefix (DMR) 2001:db8:ffff::/64
The above information allows the BR to derive as follows The above information allows the BR to derive as follows
the mapped destination IPv6 address for the corresponding the mapped destination IPv6 address for the corresponding
MAP-T CE, and also the mapped source IPv6 address for MAP-T CE, and also the source IPv6 address for
the IPv4 source. the mapped IPv4 source address.
IPv4 suffix bits (p) 32 - 24 = 8 (18 (0x12)) IPv4 suffix bits (p) 32 - 24 = 8 (18 (0x12))
PSID length: 8 PSID length: 8
PSID: 0x34 (9030 (0x2346)) PSID: 0x34 (1232)
The resulting IPv6 packet will have the following key fields: The resulting IPv6 packet will have the following header fields:
IPv6 source address 2001:db8:ffff:0:0001:0203:0400:: IPv6 source address 2001:db8:ffff:0:0001:0203:0400::
IPv6 destination address: 2001:db8:0012:3400:00c0:0002:1200:3400 IPv6 destination address: 2001:db8:0012:3400:0000:c000:0212:0034
IPv6 source Port: 80 TCP source Port: 80
IPv6 destination Port: 9030 TCP destination Port: 1232
Example 3- FMR: Example 3- FMR:
An IPv4 host behind the MAP-T CE (addressed as per the previous An IPv4 host behind a MAP-T CE (configured as per the previous
examples) corresponding with IPv4 host 1.2.3.4 will have its examples) corresponding with an IPv4 host 1.2.3.4 will have its
packets converted into IPv6 using the DMR configured on the MAP-T packets converted into IPv6 using the DMR configured on the MAP-T
CE as follows: CE as follows:
Default Mapping Rule used by MAP-T CE: {2001:db8:ffff::/64 Default Mapping Rule used by MAP-T CE: {2001:db8:ffff::/64
(Rule IPv6 prefix), 0.0.0.0/0 (Rule IPv4 prefix), null (BR IPv4 (Rule IPv6 prefix), 0.0.0.0/0 (Rule IPv4 prefix), null (BR IPv4
address)} address)}
IPv4 source address (post NAT44 if present) 192.0.2.18 IPv4 source address (post NAT44 if present) 192.0.2.18
IPv4 destination address: 1.2.3.4 IPv4 destination address: 1.2.3.4
IPv4 source port (post NAT44 if present): 9030 IPv4 source port (post NAT44 if present): 1232
IPv4 destination port: 80 IPv4 destination port: 80
IPv6 source address of MAP-T CE: IPv6 source address of MAP-T CE:
2001:db8:0012:3400:00c0:0002:1200:3400 2001:db8:0012:3400:0000:c000:0212:0034
IPv6 destination address: 2001:db8:ffff:0:0001:0203:0400:: IPv6 destination address: 2001:db8:ffff:0:0001:0203:0400::
Example 4 - 1:1 Rule with no address sharing Example 4 - Rule with no embedded address bits and no address sharing
IPv6 prefix assigned to the end user: 2001:db8:0012:3400::/56 End-user IPv6 prefix: 2001:db8:0012:3400::/56
Basic Mapping Rule: {2001:db8:0012:3400::/56 (Rule IPv6 prefix), Basic Mapping Rule: {2001:db8:0012:3400::/56 (Rule IPv6 prefix),
192.0.2.1/32 (Rule IPv4 prefix), 0 (Rule EA-bits length)} 192.0.2.1/32 (Rule IPv4 prefix), 0 (Rule EA-bits length)}
PSID length: 0 (Sharing ratio is 1) PSID length: 0 (Sharing ratio is 1)
PSID offset: n/a PSID offset: n/a
A MAP node (CE or BR) can via the BMR or equivalent FMR, determine A MAP node can via the BMR or equivalent FMR, determine
the IPv4 address and port-set as shown below: the IPv4 address and port-set as shown below:
EA bits offset: 0 EA bits offset: 0
IPv4 suffix bits (p) Length of IPv4 address (32) - IPv4 prefix IPv4 suffix bits (p) Length of IPv4 address - IPv4 prefix
length (32) = 0 length = 32 - 32 = 0
IPv4 address 192.0.2.1 (0xc0000201) IPv4 address 192.0.2.1 (0xc0000201)
PSID start: 0 PSID start: 0
PSID length: 0 PSID length: 0
PSID: null PSID: null
The BMR information allows a MAP CE also to determine (complete) The BMR information allows a MAP CE also to determine (complete)
its full IPv6 address by combining the IPv6 prefix with the MAP its full IPv6 address by combining the IPv6 prefix with the MAP
interface identifier (that embeds the IPv4 address). interface identifier (that embeds the IPv4 address).
IPv6 address of MAP CE: 2001:db8:0012:3400:00c0:0002:0100:0000 IPv6 address of MAP CE: 2001:db8:0012:3400:0000:c000:0201:0000
Example 5 - 1:1 Rule with address sharing (sharing ratio 256) Example 5 - Rule with no embedded address bits and address sharing
(sharing ratio 256)
IPv6 prefix assigned to the end user: 2001:db8:0012:3400::/56 End-user IPv6 prefix: 2001:db8:0012:3400::/56
Basic Mapping Rule: {2001:db8:0012:3400::/56 (Rule IPv6 prefix), Basic Mapping Rule: {2001:db8:0012:3400::/56 (Rule IPv6 prefix),
192.0.2.1/32 (Rule IPv4 prefix), 0 (Rule EA-bits length)} 192.0.2.1/32 (Rule IPv4 prefix), 0 (Rule EA-bits length)}
PSID length: (16 - (32 - 24) = 8. (Sharing ratio of 256) PSID length: (16 - (32 - 24)) = 8. (Provisioned with DHCPv6.
PSID offset: 4 Sharing ratio of 256.).
PSID offset: 6 (default)
PSID: 0x20 (Provisioned with DHCPv6)
A MAP node (CE or BR) can via the BMR or equivalent FMR determine A MAP node can via the BMR determine the IPv4 address and port-set
the IPv4 address and port-set as shown below: as shown below:
EA bits offset: 0 EA bits offset: 0
IPv4 suffix bits (p) Length of IPv4 address (32) - IPv4 prefix IPv4 suffix bits (p): Length of IPv4 address - IPv4 prefix
length (32) = 0 length = 32 -32 = 0
IPv4 address 192.0.2.1 (0xc0000201) IPv4 address 192.0.2.1 (0xc0000201)
PSID start: 0 PSID start: 0
PSID length: 8 PSID length: 8
PSID: 0x34 PSID: 0x20
Port-set-1: 4928, 4929, 4930, 4931, 4932, 4933, 4934, 4935, 4936, Available ports (63 ranges) : 1536-1551, 2560-2575, ...... ,
4937, 4938, 4939, 4940, 4941, 4942, 4943 64000-64015, 65024-65039
Port-set-2: 9024, 9025, 9026, 9027, 9028, 9029, 9030, 9031, 9032,
9033, 9034, 9035, 9036, 9037, 9038, 9039
... ...
Port-set-15 62272, 62273, 62274, 62275, 62276, 62277, 62278,
62279, 62280, 62281, 62282, 62283, 62284, 62285, 62286, 62287
The BMR information allows a MAP CE also to determine (complete) The BMR information allows a MAP CE also to determine (complete)
its full IPv6 address by combining the IPv6 prefix with the MAP its full IPv6 address by combining the IPv6 prefix with the MAP
interface identifier (that embeds the IPv4 address and PSID). interface identifier (that embeds the IPv4 address and PSID).
IPv6 address of MAP CE: 2001:db8:0012:3400:00c0:0002:1200:3400 IPv6 address of MAP CE: 2001:db8:0012:3400:0000:c000:0212:0034
Note that the IPv4 address and PSID is not derived from the IPv6 Note that the IPv4 address and PSID is not derived from the IPv6
prefix assigned to the CE. prefix assigned to the CE, but provisioned separately using for
example MAP options in DHCPv6.
Appendix B. Port mapping algorithm Appendix B. Port mapping algorithm
The Generalized Modulus Algorithm (GMA) used in MAP domains can also The driving principles and the mathematical expression of the mapping
be expressed mathematically. Each CE in such a domain has an IPv4 algorithm used by MAP can be found in Appendix B of
address and a unique Port-Set Identifier (PSID), that is derived by [I-D.ietf-softwire-map]
means of the BMR. For a given IPv4 address, the algorithm allows
each PSID to be processed to reveal a set of unique non-overlapping
ports, or alternatively for any given port to derive the PSID it
corresponds to. Two extreme cases supported by algorithm are: (1)
the port numbers are not contiguous for each PSID, but uniformly
distributed across the port range (0-65535); (2) the port numbers are
contiguous in a single range for each PSID.
For a given sharing ratio (R) and the maximum number of contiguous
ports (M), the GMA algorithm is defined as:
1. The port (P) of a given PSID (K) is composed of:
P = R * M * j + M * K + i
Where:
* PSID: K = 0 to R - 1
* Port range index: j = (4096 / M) / R to ((65536 / M) / R) - 1,
if the port numbers (0 - 4095) are excluded.
* Contiguous Port index: i = 0 to M - 1
2. The PSID (K) of a given port number (P) is determined by:
K = (floor(P/M)) % R
Where:
* % is the modulus operator
* floor(arg) is a function that returns the largest integer not
greater than arg.
B.1. Bit Representation of the Algorithm
Given a sharing ratio (R=2^k), the maximum number of contiguous ports
(M=2^m), for any PSID (K) and available ports (P) can be represented
as:
0 8 15
+---------------+----------+------+-------------------+
| Port (P) |
----------------+-----------------+-------------------+
| j | PSID (K) | M (i) |
+---------------+----------+------+-------------------+
|<----a bits--->|<-----k bits---->|<------m bits----->|
Figure 9: Bit representation
Where j and i are the same indexes defined in the port mapping
algorithm.
For any port number, the PSID can be obtained by a bit mask
operation.
For a > 0, j MUST be larger than 0. This ensures that the algorithm
excludes the system ports ([I-D.ietf-tsvwg-iana-ports]). For a = 0,
j MAY be 0 to allow for the provisioning of the system ports.
B.2. GMA examples
For example, for R = 1024, PSID offset: a = 4 and PSID length: k = 10
bits
Port-set-1 Port-set-2
PSID=0 | 4096, 4097, 4098, 4099, | 8192, 8193, 8194, 8195, | ...
PSID=1 | 4100, 4101, 4102, 4103, | 8196, 8197, 8198, 8199, | ...
PSID=2 | 4104, 4105, 4106, 4107, | 8200, 8201, 8202, 8203, | ...
PSID=3 | 4108, 4109, 4110, 4111, | 8204, 8205, 8206, 8207, | ...
...
PSID=1023| 8188, 8189, 8190, 8191, | 12284, 12285, 12286, 12287,| ...
Example 1: with offset = 4 (a = 4)
For example, for R = 64, a = 0 (PSID offset = 0 and PSID length = 6
bits):
Port-set
PSID=0 | [ 0 - 1023]
PSID=1 | [1024 - 2047]
PSID=2 | [2048 - 3071]
PSID=3 | [3072 - 4095]
...
PSID=63 | [64512 - 65535]
Example 2: with offset = 0 (a = 0)
B.3. GMA Excluded Ports
By default the GMA ensures that a number of "well known" ports are
excluded from use by the algorithm. This number is determined by the
number of offset bits (a), in the figure above. This value can be
optionally provisioned via the "Rule Port Mapping Parameters" in the
Basic Mapping Rule. In the absence of such provisioning, the
defaults are:
o Excluded ports : 0-4095
o Offset bits (a) : 4
For (a) offset bits, the range of excluded ports is 0 to 2 ^ (16-a) -
1.
Authors' Addresses Authors' Addresses
Xing Li Xing Li
CERNET Center/Tsinghua University CERNET Center/Tsinghua University
Room 225, Main Building, Tsinghua University Room 225, Main Building, Tsinghua University
Beijing 100084 Beijing 100084
CN CN
Email: xing@cernet.edu.cn Email: xing@cernet.edu.cn
Congxiao Bao Congxiao Bao
CERNET Center/Tsinghua University CERNET Center/Tsinghua University
Room 225, Main Building, Tsinghua University Room 225, Main Building, Tsinghua University
Beijing 100084 Beijing 100084
CN CN
Email: congxiao@cernet.edu.cn Email: congxiao@cernet.edu.cn
Wojciech Dec Wojciech Dec (editor)
Cisco Systems Cisco Systems
Haarlerbergpark Haarlerbergweg 13-19 Haarlerbergpark Haarlerbergweg 13-19
Amsterdam, NOORD-HOLLAND 1101 CH Amsterdam, NOORD-HOLLAND 1101 CH
Netherlands Netherlands
Phone: Phone:
Email: wdec@cisco.com Email: wdec@cisco.com
Ole Troan Ole Troan
Cisco Systems Cisco Systems
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