draft-ietf-idr-bgp-ipv6-rt-constrain-01.txt   draft-ietf-idr-bgp-ipv6-rt-constrain-02.txt 
Network Working Group K. Patel Network Working Group K. Patel
Internet-Draft Cisco Systems Internet-Draft Cisco Systems
Intended status: Standards Track R. Raszuk Intended status: Standards Track R. Raszuk
Expires: May 3, 2012 NTT MCL Inc. Expires: December 14, 2012 NTT MCL Inc.
M. Djernaes M. Djernaes
Juniper Networks Juniper Networks
J. Dong J. Dong
M. Chen M. Chen
Huawei Technologies Huawei Technologies
October 31, 2011 June 12, 2012
IPv6 Extensions for Route Target Distribution IPv6 Extensions for Route Target Distribution
draft-ietf-idr-bgp-ipv6-rt-constrain-01 draft-ietf-idr-bgp-ipv6-rt-constrain-02
Abstract Abstract
The current route target distribution specification described in The current route target distribution specification described in
RFC4684 defines Route Target NLRIs of maximum length of 12 bytes. RFC4684 defines Route Target NLRIs of maximum length of 12 bytes.
The IPv6 specific Route Target extended community is defined in The IPv6 specific Route Target extended community is defined in
[RFC5701] as length of 20 bytes. Since the current specification [RFC5701] as length of 20 bytes. Since the current specification
only supports prefixes of maximum length of 12 bytes, the lack of an only supports prefixes of maximum length of 12 bytes, the lack of an
IPv6 specific Route Target reachability information may be a problem IPv6 specific Route Target reachability information may be a problem
when an operator wants to use this application in a pure IPv6 when an operator wants to use this application in a pure IPv6
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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 May 3, 2012. This Internet-Draft will expire on December 14, 2012.
Copyright Notice Copyright Notice
Copyright (c) 2011 IETF Trust and the persons identified as the Copyright (c) 2012 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
carefully, as they describe your rights and restrictions with respect carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as the Trust Legal Provisions and are provided without warranty as
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5. Security Considerations . . . . . . . . . . . . . . . . . . . . 5 5. Security Considerations . . . . . . . . . . . . . . . . . . . . 5
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 5 6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 5
7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 5 7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 5
7.1. Normative References . . . . . . . . . . . . . . . . . . . 5 7.1. Normative References . . . . . . . . . . . . . . . . . . . 5
7.2. Informative References . . . . . . . . . . . . . . . . . . 6 7.2. Informative References . . . . . . . . . . . . . . . . . . 6
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 6 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 6
1. Introduction 1. Introduction
The current constrained route distribution specification defined in The current constrained route distribution specification defined in
[RFC4684] supports prefixes with a fixed maximum length of 12 bytes. [RFC4684] supports prefixes with a maximum length of 12 bytes. The
The prefix length needs to be extended to support the IPv6 specific prefix length needs to be extended to support the IPv6 specific Route
Route Target extended community defined in [RFC5701] which is 20 Target extended community defined in [RFC5701] which is 20 bytes in
bytes in length. This document defines an extension to the current length. This document defines an extension to the current
constrained route distribution specification that allows BGP speakers constrained route distribution specification that allows BGP speakers
to distribute longer length Route Target prefixes. A new BGP to distribute longer length Route Target prefixes. A new BGP
capability known as BGP IPv6 Constrained Route Target capability is capability known as BGP IPv6 Constrained Route Target capability is
defined as part of extension that allows an exchange of longer length defined as part of extension that allows an exchange of longer length
Route Target prefixes. BGP speakers that do not exchange this Route Target prefixes. BGP speakers that do not exchange this
capability MUST use Route Target NLRIs of maximum length of 12 bytes. capability MUST use Route Target NLRIs of maximum length of 12 bytes.
In this way, the current extension would preserve the backward In this way, the current extension would preserve the backward
compatibility with [RFC4684]. compatibility with [RFC4684].
2. BGP IPv6 Constrained Route Target Capability 2. BGP IPv6 Constrained Route Target Capability
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By advertising this capability to a peer, a BGP speaker conveys to By advertising this capability to a peer, a BGP speaker conveys to
the peer that the speaker support the longer length Route Target the peer that the speaker support the longer length Route Target
prefixes and the related procedures described in this document. prefixes and the related procedures described in this document.
3. IPv6 Constrained Route Target NLRI Advertisements 3. IPv6 Constrained Route Target NLRI Advertisements
Route Target membership NLRI is advertised in BGP UPDATE messages Route Target membership NLRI is advertised in BGP UPDATE messages
using the MP_REACH_NLRI and MP_UNREACH_NLRI attributes as defined in using the MP_REACH_NLRI and MP_UNREACH_NLRI attributes as defined in
[RFC4760]. The NLRI field in the MP_REACH_NLRI and MP_UNREACH_NLRI [RFC4760]. The NLRI field in the MP_REACH_NLRI and MP_UNREACH_NLRI
is a prefix of 0 to 24 octets, encoded as defined in Section 4 of is a prefix of 0 to 24 octets, encoded as defined in Section 4 of
[RFC4760] for all the constrain route distribution. [RFC4760] for all the constrained route distribution.
This prefix is structured as follows: This prefix is structured as follows:
+-------------------------------+ +-------------------------------+
| origin as (4 octets) | | origin as (4 octets) |
+-------------------------------+ +-------------------------------+
| route target (8 or 20 octets)| | route target (8 or 20 octets)|
~ ~ ~ ~
| | | |
+-------------------------------+ +-------------------------------+
Except for the default route target, which is encoded as a zero- Except for the default route target, which is encoded as a zero-
length prefix, the minimum prefix length is 32 bits. length prefix, the minimum prefix length is 32 bits. As the
origin-AS field cannot be interpreted as a prefix.
Route targets can then be expressed as prefixes, where, for instance, Route targets can then be expressed as prefixes, where, for instance,
a prefix would encompass all route target extended communities a prefix would encompass all route target extended communities
assigned by a given Global Administrator [RFC4360] and [RFC5701]. assigned by a given Global Administrator [RFC4360] and [RFC5701].
Alternatively, route target prefixes could be aggregated however if Alternatively, route target prefixes could be aggregated however if
done so, then only the Local Administrator field of the Route Target done so, then only the Local Administrator field of the Route Target
can be aggregated. Route Target Type and the Global Administrator can be aggregated. Route Target Type and the Global Administrator
Route Target fields MUST not be aggregated. Route Target fields MUST not be aggregated.
The default route target can be used to indicate to a peer the The default route target can be used to indicate to a peer the
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