Internet DRAFT - draft-ietf-idr-bgp-ipv6-rt-constrain
draft-ietf-idr-bgp-ipv6-rt-constrain
Network Working Group K. Patel
Internet-Draft Arrcus, Inc.
Intended status: Standards Track R. Raszuk
Expires: October 28, 2018 Bloomberg LP
M. Djernaes
Juniper Networks
J. Dong
M. Chen
Huawei Technologies
April 26, 2018
IPv6 Extensions for Route Target Distribution
draft-ietf-idr-bgp-ipv6-rt-constrain-12
Abstract
The current route target distribution specification as described in
[RFC 4684] defines Route Target NLRIs of maximum length of 12 bytes.
The IPv6 specific Route Target extended community is defined in [RFC
5701] 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.
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].
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
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Internet-Drafts are draft documents valid for a maximum of six months
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time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
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This Internet-Draft will expire on October 28, 2018.
Copyright Notice
Copyright (c) 2018 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info) in effect on the date of
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the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. BGP IPv6 Constrained Route Target Capability . . . . . . . . 3
3. IPv6 Constrained Route Target NLRI Advertisements . . . . . . 3
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4
5. Security Considerations . . . . . . . . . . . . . . . . . . . 4
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 4
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 4
7.1. Normative References . . . . . . . . . . . . . . . . . . 4
7.2. Informative References . . . . . . . . . . . . . . . . . 5
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 5
1. Introduction
The current constrained route distribution specification defined in
[RFC4684] supports prefixes with a 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 capability 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].
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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 Considerations 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
[RFC4760] for all the constrained route distribution.
This prefix is structured as follows:
+-------------------------------+
| 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. As the origin-
AS field cannot be interpreted as a prefix.
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 [RFC4360] and [RFC5701].
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.
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4. IANA Considerations
IANA is requested to assign one new code point for "IPv6 Constrained
Route Target Capability" from the "First Come First Served" range of
BGP "Capability Codes" registry.
+-------+------------------------------------------+----------------+
| Value | Description | Reference |
+-------+------------------------------------------+----------------+
| TBA | IPv6 Constrained Route Target Capability | [this document]|
+-------+------------------------------------------+----------------+
5. Security Considerations
This extension to [RFC4684] does not change the underlying security
issues inherent in the existing BGP and [RFC4684].
6. Acknowledgements
The authors would like to thank Pedro Marques, John Scudder, Alton Lo
and Zhenqiang Li for discussions and review.
7. References
7.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC4271] Rekhter, Y., Ed., Li, T., Ed., and S. Hares, Ed., "A
Border Gateway Protocol 4 (BGP-4)", RFC 4271,
DOI 10.17487/RFC4271, January 2006,
<https://www.rfc-editor.org/info/rfc4271>.
[RFC4360] Sangli, S., Tappan, D., and Y. Rekhter, "BGP Extended
Communities Attribute", RFC 4360, DOI 10.17487/RFC4360,
February 2006, <https://www.rfc-editor.org/info/rfc4360>.
[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, DOI 10.17487/RFC4684,
November 2006, <https://www.rfc-editor.org/info/rfc4684>.
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[RFC5492] Scudder, J. and R. Chandra, "Capabilities Advertisement
with BGP-4", RFC 5492, DOI 10.17487/RFC5492, February
2009, <https://www.rfc-editor.org/info/rfc5492>.
[RFC5701] Rekhter, Y., "IPv6 Address Specific BGP Extended Community
Attribute", RFC 5701, DOI 10.17487/RFC5701, November 2009,
<https://www.rfc-editor.org/info/rfc5701>.
7.2. Informative References
[RFC4760] Bates, T., Chandra, R., Katz, D., and Y. Rekhter,
"Multiprotocol Extensions for BGP-4", RFC 4760,
DOI 10.17487/RFC4760, January 2007,
<https://www.rfc-editor.org/info/rfc4760>.
Authors' Addresses
Keyur Patel
Arrcus, Inc.
USA
Email: keyur@arrcus.com
Robert Raszuk
Bloomberg LP
731 Lexington Ave
New York City, NY 10022
USA
Email: robert@raszuk.net
Martin Djernaes
Juniper Networks
1194 N. Mathilda Avenue
Sunnyvale, CA 94089
USA
Email: mdjernaes@juniper.net
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Jie Dong
Huawei Technologies
Huawei Campus, No.156 Beiqing Rd.
Beijing 100095
China
Email: jie.dong@huawei.com
Mach(Guoyi) Chen
Huawei Technologies
Huawei Campus, No.156 Beiqing Rd.
Beijing 100095
China
Email: mach.chen@huawei.com
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