L3VPN Working Group K. Patel
Internet-Draft R. Raszuk
Intended status: Standards Track Cisco Systems
Expires: September 10, 2011 M. Djernaes
Juniper Networks
J. Dong
M. Chen
Huawei Technologies Co., Ltd.
March 9, 2011
IPv6 AF Extensions for Route Target Distribution
draft-keyur-bgp-af-specific-rt-constrain-01.txt
Abstract
The current route target distribution specification described in
RFC4684 defines Route Target NLRIs of maxiumum length of 12 bytes.
The IPv6 specific Route Target extended community is defined in
RFC5701 as length of 20 bytes. Since the current specification only
supports prefixes of maximum length of 12 bytes, the lack of an IPv6
specific Route Target reachability information may be a problem when
an operator wants to use this application in a pure IPv6 environment.
This document defines an extension that allows BGP to exchange longer
length IPv6 Route Target prefixes.
Status of this Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on September 10, 2011.
Copyright Notice
Copyright (c) 2011 IETF Trust and the persons identified as the
document authors. All rights reserved.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.1. Requirements Language . . . . . . . . . . . . . . . . . . . 4
2. BGP IPV6 Constrained Route Target Capability . . . . . . . . . 4
3. IPV6 Constrained Route Target NLRI Advertisements . . . . . . . 4
4. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 5
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 5
6. Security Considerations . . . . . . . . . . . . . . . . . . . . 5
7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 6
7.1. Normative References . . . . . . . . . . . . . . . . . . . 6
7.2. Informative References . . . . . . . . . . . . . . . . . . 6
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 6
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1. Introduction
The current constrained route distribution specification defined in
[RFC4684] supports prefixes with a fixed maximum length of 12 bytes.
The prefix length needs to be extended to support the IPv6 specific
Route Target extended community defined in [RFC5701] which is 20
bytes in length.
This document defines an extension to the current constrained route
distribution specification that allows BGP speakers to distribute
longer length Route Target prefixes. A new BGP capability known as
BGP IPv6 Constrained Route Target capabiltiy is defined as part of
extension that allows an exchange of longer length Route Target
prefixes. BGP speakers that do not exchange this capability MUST use
Route Target NLRIs of maximum length of 12 bytes. In this way, the
current extension would preserve the backward compatibility with
[RFC4684].
1.1. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].
2. BGP IPV6 Constrained Route Target Capability
The "BGP IPV6 Constrained Route Target Capability" is a new BGP
capability [RFC5492]. The Capability code for this capability is
specified in the IANA Considersations section of this document. The
Capability length field of this capability is zero.
By advertising this capability to a peer, a BGP speaker conveys to
the peer that the speaker support the longer length Route Target
prefixes and the related procedures described in this document.
3. IPV6 Constrained Route Target NLRI Advertisements
Route Target membership NLRI is advertised in BGP UPDATE messages
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
is a prefix of 0 to 24 octets, encoded as defined in Section 4 of [5]
for all the constrain route distribution.
This prefix is structured as follows:
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+-------------------------------+
| origin as (4 octets) |
+-------------------------------+
| route target (8 or 20 octets)|
~ ~
| |
+-------------------------------+
Except for the default route target, which is encoded as a zero-
length prefix, the minimum prefix length is 32 bits.
Route targets can then be expressed as prefixes, where, for instance,
a prefix would encompass all route target extended communities
assigned by a given Global Administrator [6]. Alternatively, route
target prefixes could be aggregated however if done so, then only the
Local Administrator field of the Route Target can be aggregated.
Route Target Type and the Global Administrator Route Target fields
MUST not be aggregated.
The default route target can be used to indicate to a peer the
willingness to receive all VPN route advertisements such as, for
instance, the case of a route reflector speaking to one of its PE
router clients.
4. Acknowledgements
The authors would like to thank Pedro Marques, John Scudder, Alton Lo
and Zhengqiang Li for discussions and review.
5. IANA Considerations
This document defined the IPV6 Constrained Route Target Capability
for BGP. The Capability code needs to be assigned by the IANA.
6. Security Considerations
This extension to [RFC4684] does not change the underlying security
issues inherent in the existing BGP and [RFC4684].
7. References
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7.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC4271] Rekhter, Y., Li, T., and S. Hares, "A Border Gateway
Protocol 4 (BGP-4)", RFC 4271, January 2006.
[RFC4684] Marques, P., Bonica, R., Fang, L., Martini, L., Raszuk,
R., Patel, K., and J. Guichard, "Constrained Route
Distribution for Border Gateway Protocol/MultiProtocol
Label Switching (BGP/MPLS) Internet Protocol (IP) Virtual
Private Networks (VPNs)", RFC 4684, November 2006.
[RFC5492] Scudder, J. and R. Chandra, "Capabilities Advertisement
with BGP-4", RFC 5492, February 2009.
[RFC5701] Rekhter, Y., "IPv6 Address Specific BGP Extended Community
Attribute", RFC 5701, November 2009.
7.2. Informative References
[RFC4760] Bates, T., Chandra, R., Katz, D., and Y. Rekhter,
"Multiprotocol Extensions for BGP-4", RFC 4760,
January 2007.
Authors' Addresses
Keyur Patel
Cisco Systems
170 W. Tasman Drive
San Jose, CA 95134
USA
Email: keyupate@cisco.com
Robert Raszuk
Cisco Systems
170 W. Tasman Drive
San Jose, CA 95134
USA
Email: raszuk@cisco.com
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Martine Djernaes
Juniper Networks
1194 N. Mathilda Avenue
Sunnyvale, CA 94089
USA
Email: mdjernaes@juniper.net
Jie Dong
Huawei Technologies Co., Ltd.
KuiKe Building, No.9 Xinxi Rd.
Hai-Dian District, Beijing 100085
P.R. China
Email: dongjie_dj@huawei.com
Mach(Guoyi) Chen
Huawei Technologies Co., Ltd.
KuiKe Building, No.9 Xinxi Rd.
Hai-Dian District, Beijing 100085
P.R. China
Email: mach@huawei.com
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