Internet DRAFT - draft-wang-idr-eag-distribution
draft-wang-idr-eag-distribution
IDR Working Group Z. Wang
Internet-Draft Q. Wu
Intended status: Standards Track Huawei
Expires: October 16, 2015 J. Tantsura
Ericsson
April 14, 2015
Distribution of MPLS-TE Extended admin Group Using BGP
draft-wang-idr-eag-distribution-02
Abstract
As MPLS-TE network grows, administrative Groups advertised as a
fixed-length 32-bit Bitmask is quite constraining. "Extended
Administrative Group" IGP TE extensions sub-TLV defined in [RFC7308]
is introduced to provide for additional administrative groups (link
colors) beyond the current limit of 32. This document describes
extensions to BGP protocol, that can be used to distribute extended
administrative groups in MPLS-TE.
Status of This Memo
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This Internet-Draft will expire on October 16, 2015.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Conventions used in this document . . . . . . . . . . . . . . 2
3. Carrying Extended Administrative Groups in BGP . . . . . . . 2
3.1. AG and EAG coexistence . . . . . . . . . . . . . . . . . 3
3.2. Desire for unadvertised EAG bits . . . . . . . . . . . . 3
4. Security Considerations . . . . . . . . . . . . . . . . . . . 4
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4
6. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 4
7. Normative References . . . . . . . . . . . . . . . . . . . . 4
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 4
1. Introduction
MPLS-TE advertises 32 administrative groups (commonly referred to as
"colors" or "link colors") using the Administrative Group sub-TLV of
the Link TLV defined in OSPFv2 (RFC3630), OSPFv3 (RFC5329) and ISIS
(RFC5305).
As MPLS-TE network grows, administrative Groups advertised as a
fixed-length 32-bit Bitmask is quite constraining. "Extended
Administrative Group" IGP TE extensions sub-TLV defined in [RFC7308]
is introduced to provide for additional administrative groups (link
colors) beyond the current limit of 32.
This document proposes new BGP Link attribute TLVs that can be
announced as attribute in the BGP-LS attribute (defined in [I.D-ietf-
idr-ls-distribution]) to distribute extended administrative groups in
MPLS-TE.
2. Conventions used in this document
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 RFC2119 [RFC2119].
3. Carrying Extended Administrative Groups in BGP
This document proposes one new BGP link attribute TLVs that can be
announced as attribute in the BGP-LS attribute (defined in [I.D-ietf-
idr-ls-distribution]) to distribute extended administrative groups.
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The extensions in this document build on the ones provided in BGP-LS
[I.D-ietf-idr-ls-distribution] and BGP-4 [RFC4271].
BGP-LS attribute defined in [I.D-ietf-idr-ls-distribution] has nested
TLVs which allow the BGP-LS attribute to be readily extended. Link
attribute TLVs defined in section 3.2.2 of [I-D.ietf-idr-ls-
distribution]are TLVs that may be encoded in the BGP-LS attribute
with a link NLRI. Each 'Link Attribute' is a Type/Length/ Value
(TLV) triplet formatted as defined in Section 3.1 of [I-D.ietf-idr-
ls-distribution].
This document proposes one new TLV as a link attribute:
Type Value
TBD1 Extended Admin Group (EAG)
The EAG TLV is used in addition to the Administrative Groups when a
node wants to advertise more than 32 colors for a link. The EAG TLV
is optional. The format and semantics of the 'value' fields in EAG
TLVs correspond to the format and semantics of value fields in IGP
extension sub-TLVs, defined in [RFC7308].
+------------+---------------------+--------------+-----------------+
| TLV Code | Description | IS-IS | Defined in: |
| Point | | TLV/Sub-TLV | |
+------------+---------------------+--------------+-----------------+
| xxxx | Extended | 22/xx | [RFC7308] |
| | Admin Group | | |
+------------+---------------------+--------------+-----------------+
Table 1: 'EAG' Link Attribute TLV
3.1. AG and EAG coexistence
Similar to section 2.3.1 of [RFC7308],if a BGP speaker advertises
both AG and EAG then AG and EAG should be dealt with in the same way
as AG and EAG carried in the Extended Administrative Group (EAG) sub-
TLV [RFC7308] for both OSPF [RFC3630] and ISIS [RFC5305].
3.2. Desire for unadvertised EAG bits
Unlike AGs, EAGs are advertised as any non-zero-length-bit Bitmask.
the EAG length may be longer for some links than for others. Similar
to section 2.3.2 of [RFC7308], if a BGP peer wants to only use links
where the specific bits of an EAG is set to 1 but the specific bits
of this EAG is not advertised, then the implementation SHOULD process
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these desire and unadvertised EAG bits in accordance with rule
defined in section 2.3.2 of [RFC7308].
4. Security Considerations
This document does not introduce security issues beyond those
discussed in [I.D-ietf-idr-ls-distribution] and [RFC4271].
5. IANA Considerations
IANA maintains the registry for the TLVs. BGP Extended Admin Group
link attribute TLV will require one new type code defined in this
document.
6. Acknowledgments
The authors gratefully acknowledge the review made by Eric Osborne.
7. Normative References
[I-D.ietf-idr-ls-distribution]
Gredler, H., "North-Bound Distribution of Link-State and
TE Information using BGP", ID draft-ietf-idr-ls-
distribution-10, January 2015.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", March 1997.
[RFC3630] Katz, D., Yeung, D., and K. Kompella, "Traffic Engineering
(TE) Extensions to OSPF Version 2", RFC 3630, September
2003.
[RFC4271] Rekhter, Y., "A Border Gateway Protocol 4 (BGP-4)", RFC
4271, January 2006.
[RFC5305] Li, T. and H. Smit, "IS-IS Extensions for Traffic
Engineering", RFC 5305, October 2008.
[RFC7308] Osborne, E., "Extended Administrative Groups in MPLS-TE",
ID RFC7308, July 2014.
Authors' Addresses
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Zitao Wang
Huawei
101 Software Avenue, Yuhua District
Nanjing, Jiangsu 210012
China
Email: wangzitao@huawei.com
Qin Wu
Huawei
101 Software Avenue, Yuhua District
Nanjing, Jiangsu 210012
China
Email: bill.wu@huawei.com
Jeff Tantsura
Ericsson
300 Holger Way
San Jose, CA 95134
US
Email: jeff.tantsura@ericsson.com
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