Distribution of MPLS-TE Extended admin Group Using BGP
draft-wang-idr-eag-distribution-00

IDR Working Group                                                Z. Wang
Internet-Draft                                                     Q. Wu
Intended status: Standards Track                                  Huawei
Expires: March 24, 2015                               September 20, 2014

         Distribution of MPLS-TE Extended admin Group Using BGP
                   draft-wang-idr-eag-distribution-00

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 [I-D.ietf-
   mpls-extended-admin-group] 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.

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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.  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 [I-D.ietf-
   mpls-extended-admin-group] 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.
   The extensions in this document build on the ones provided in BGP-LS
   [I.D-ietf-idr-ls-distribution] and BGP-4 [RFC4271].

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   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 [I-D.ietf-mpls-extended- admin-group].

   +------------+---------------------+--------------+-----------------+
   |  TLV Code  | Description         |     IS-IS    | Defined in:     |
   |    Point   |                     |  TLV/Sub-TLV |                 |
   +------------+---------------------+--------------+-----------------+
   |    xxxx    | Extended            |    22/xx     |[I-D.ietf-mpls-  |
   |            | Admin Group         |              |extended-admin   |
   |            |                     |              |-group           |
   +------------+---------------------+--------------+-----------------+

                     Table 1: 'EAG' Link Attribute TLV

3.1.  AG and EAG coexistence

   Similar to section 2.3.1 of [I-D.ietf-mpls-extended- admin-group],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 [I-D.ietf-mpls-extended- admin-
   group] 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 [I-D.ietf-mpls-extended- admin-group], 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 these desire and unadvertised EAG bits

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   in accordance with rule defined in section 2.3.2 of [I.D-ietf-mpls-
   extended-admin- group].

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-03, May 2013.

   [I-D.ietf-mpls-extended-admin-group]
              Osborne, E., "Extended Administrative Groups in MPLS-TE",
              ID draft-ietf-mpls-extended-admin-group-07, May 2014.

   [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.

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

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