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Extensions to OSPF for Advertising Prefix/Link Administrative Tags
draft-acee-ospf-admin-tags-00

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This is an older version of an Internet-Draft whose latest revision state is "Replaced".
Authors Acee Lindem , Peter Psenak
Last updated 2014-09-02
Replaced by draft-ietf-lsr-ospf-admin-tags
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draft-acee-ospf-admin-tags-00
Network Working Group                                     A. Lindem, Ed.
Internet-Draft                                                 P. Psenak
Intended status: Standards Track                           Cisco Systems
Expires: March 6, 2015                                 September 2, 2014

   Extensions to OSPF for Advertising Prefix/Link Administrative Tags
                   draft-acee-ospf-admin-tags-00.txt

Abstract

   It is useful for routers in an OSPFv2 or OSPFv3 routing domain to be
   able to associate tags with prefixes and links.  Previously, OSPFv2
   and OSPFv3 were relegated to a single tag for AS External and Not-So-
   Stubby-Area (NSSA) prefixes.  With the flexible encodings provided by
   OSPFv2 Prefix/Link Attribute Advertisement and OSPFv3 Extended LSAs,
   multiple administrative tags may advertised for all types of prefixes
   and links.  These administrative tags can be used for many
   applications including route redistribution policy, selective prefix
   prioritization, selective IP Fast-ReRoute (IPFRR) prefix protection,
   and many others.

   The ISIS protocol supports a similar mechanism that is described in
   RFC 5130.

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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   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on March 6, 2015.

Copyright Notice

   Copyright (c) 2014 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

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   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
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   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
     1.1.  Requirements notation  . . . . . . . . . . . . . . . . . .  3
     1.2.  Acknowledgments  . . . . . . . . . . . . . . . . . . . . .  3
   2.  Administrative Tag Sub-TLVs  . . . . . . . . . . . . . . . . .  4
     2.1.  32-Bit Administrative Tag Sub-TLV  . . . . . . . . . . . .  4
     2.2.  64-Bit Administrative Tag Sub-TLV  . . . . . . . . . . . .  5
   3.  Administrative Tag Applicability . . . . . . . . . . . . . . .  7
   4.  Protocol Operation . . . . . . . . . . . . . . . . . . . . . .  8
   5.  Security Considerations  . . . . . . . . . . . . . . . . . . .  9
   6.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 10
   7.  References . . . . . . . . . . . . . . . . . . . . . . . . . . 11
     7.1.  Normative References . . . . . . . . . . . . . . . . . . . 11
     7.2.  Informative References . . . . . . . . . . . . . . . . . . 11
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 12

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1.  Introduction

   It is useful for routers in an OSPFv2 [OSPF] or OSPFv3 [OSPF] routing
   domain to be able to associate tags with prefixes and links.
   Previously, OSPFv3 and OSPFv3 were relegated to a single tag for AS
   External and Not-So-Stubby-Area (NSSA) prefixes.  With the flexible
   encodings provided by OSPFv2 Prefix/Link Attribute Advertisement
   ([OSPFV2-PREFIX-LINK]) and OSPFv3 Extended LSA
   ([OSPFV3-EXTENDED-LSA]), multiple administrative tags may be
   advertised for all types of prefixes and links.  These administrative
   tags can be used many applications including (but not limited to):

   1.  Controlling which routes are redistributed into other protocols
       for readvertisement.

   2.  Prioritizing selected prefixes for faster convergence and
       installation in the forwarding place.

   3.  Identifying selected prefixes for Loop-Free Alternative (LFA)
       protection.

   The ISIS protocol supports a similar mechanism that is described in
   RFC 5130 [ISIS-ADMIN-TAGS].

1.1.  Requirements notation

   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-KEYWORDS].

1.2.  Acknowledgments

   The authors of RFC 5130 are acknowledged since this document draws
   upon both the ISIS specification and deployment experience.

   The RFC text was produced using Marshall Rose's xml2rfc tool.

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2.  Administrative Tag Sub-TLVs

   This document creates two new Administrative Tag sub-TLVs for OSPFv2
   and two for OSPFv3.  These TLVs specify one or more 32-bit or 64-bit
   unsigned integers that may be associated with an OSPF advertised
   prefix or OSPF Link.  The precise usage of these tags is beyond the
   scope of this document.

   The format of these TLVs is the same as the format used by the
   Traffic Engineering Extensions to OSPF [TE].  The LSA payload
   consists of one or more nested Type/Length/Value (TLV) triplets.  The
   format of each TLV is:

      0                   1                   2                   3
      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |              Type             |             Length            |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                            Value...                           |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                                TLV Format

   The Length field defines the length of the value portion in octets
   (thus a TLV with no value portion would have a length of 0).  The TLV
   is padded to 4-octet alignment; padding is not included in the length
   field (so a 3-octet value would have a length of 3, but the total
   size of the TLV would be 8 octets).

2.1.  32-Bit Administrative Tag Sub-TLV

   This sub-TLV will carry one or more 32-bit unsigned integer values
   that will be used as administrative tags.

   The format of the 32-bit Administrative Tag TLV is as follows:

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       0                   1                   2                   3
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |              Type             |             Length            |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |             First 32-bit Administrative Tag                   |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                             o                                 |
                                    o
      |                             o                                 |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |             Last 32-bit Administrative Tag                    |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

      Type     A 16-bit field set to TBD. The value MAY be different
               depending upon the registry from which it is allocated.

      Length   A 16-bit field that indicates the length of the value
               portion in octets and will be a multiple of 4 octets
               dependent on the number of administrative tags
               advertised. If the sub-TLV is specified, at least one
               administrative tag must be advertised.

      Value    A variable length list of one or more administrative
               tags.

                       32-bit Administrative Tag TLV

2.2.  64-Bit Administrative Tag Sub-TLV

   This sub-TLV will carry one or more 64-bit unsigned integer values
   that will be used as administrative tags.

   The format of the 64-bit Administrative Tag TLV is as follows:

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       0                   1                   2                   3
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |              Type             |             Length            |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |             First 64-bit Administrative Tag                   |
      |                                                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                             o                                 |
                                    o
      |                             o                                 |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |             Last 64-bit Administrative Tag                    |
      |                                                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

      Type     A 16-bit field set to TBD. The value MAY be different
               depending upon the registry from which it is allocated.

      Length   A 16-bit field that indicates the length of the value
               portion in octets and will be a multiple of 8 octets
               dependent on the number of administrative tags
               advertised. If the sub-TLV is specified, at least one
               administrative tag must be advertised.

      Value    A variable length list of one or more 64-bit
               administrative tags.

                       64-bit Administrative Tag TLV

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3.  Administrative Tag Applicability

   The administrative tag TLVs specified herein will be valid as sub-
   TLVs of the following TLVs specified in [OSPFV2-PREFIX-LINK]:

   1.  Extended Prefix TLV advertised in the OSPFv2 Extended Prefix LSA

   2.  Extended Link TLV advertised in the OSPFv2 Extended Prefix LSA

   The administrative tag TLVs specified herein will be valid as sub-
   TLVs of the following TLVs specified in [OSPFV3-EXTENDED-LSA]:

   1.  Router-Link TLV advertised in the E-Router-LSA

   2.  Inter-Area-Prefix TLV advertised in the E-Inter-Area-Prefix-LSA

   3.  Intra-Area-Prefix TLV advertised in the E-Link-LSA and the
       E-Intra-Area-LSA

   4.  External-Prefix TLV advertised in the E-AS-External-LSA and the
       E-NSSA-LSA

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4.  Protocol Operation

   An OSPF router supporting this specification MUST propagate
   administrative tags when acting as an Area Border Router and
   originating summary advertisements into other areas.  Similarly, an
   OSPF router supporting this specification and acting as an ABR for a
   Not-So-Stubby Area (NSSA) MUST propagate tags when translating NSSA
   routes to AS External advertisements [NSSA].  The number of tags
   supported MAY limit the number of tags that are propagated.

   An OSPF router supporting this specification MUST be able to
   advertise and interpret one 32-bit tag for prefixes and links.  An
   OSPF router supporting this specification SHOULD be able to advertise
   and interpret one 64-bit tag for prefixes and links.  An OSPF router
   supporting this specification MAY be able to advertise and propagate
   multiple 32-bit and 64-bit tags.  The maximum tags that an
   implementation supports is a local matter depending upon supported
   tag applications.

   When a single tag is advertised for AS External or NSSA LSA prefix,
   the existing tag encoding SHOULD be utilized.

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5.  Security Considerations

   This document describes both a generic mechanism for advertising
   administrative tags for OSPF prefixes and links.  The administrative
   tags are generally less critical than the topology information
   currently advertised by the base OSPF protocol.  The security
   considerations for the generic mechanism are dependent on the future
   application and, as such, should be described as additional
   capabilities are proposed for advertisement.  Security considerations
   for the base OSPF protocol are covered in [OSPF] and [OSPFV3].

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6.  IANA Considerations

   The following values should be allocated from the OSPF Extended
   Prefix TLV Sub-TLV Registry [OSPFV2-PREFIX-LINK]:

   o  TBD - 32-bit Administrative Tag TLV

   o  TBD - 64-bit Administrative Tag TLV

   The following values should be allocated from the OSPF Extended Link
   TLV Sub-TLV Registry [OSPFV2-PREFIX-LINK]:

   o  TBD - 32-bit Administrative Tag TLV

   o  TBD - 64-bit Administrative Tag TLV

   The following values should be allocated from the OSPFv3 Extended-LSA
   Sub-TLV Registry [OSPFV3-EXTENDED-LSA]:

   o  TBD - 32-bit Administrative Tag TLV

   o  TBD - 64-bit Administrative Tag TLV

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7.  References

7.1.  Normative References

   [OSPF]     Moy, J., "OSPF Version 2", STD 54, RFC 2328, April 1998.

   [OSPFV2-PREFIX-LINK]
              Psenak, P., Gredler, H., Shakir, R., Henderickx, W.,
              Tantsura, J., and A. Lindem, "OSPFv2 Prefix/Link Attribute
              Advertisement", draft-ietf-ospf-prefix-link-attr-00.txt
              (work in progress).

   [OSPFV3]   Coltun, R., Ferguson, D., Moy, J., and A. Lindem, "OSPF
              for IPv6", RFC 5340, July 2008.

   [OSPFV3-EXTENDED-LSA]
              Lindem, A., Mirtorabi, S., Roy, A., and F. Baker, "OSPFv3
              LSA Extendibility",
              draft-ietf-ospf-ospfv3-lsa-extend-02.txt (work in
              progress).

   [RFC-KEYWORDS]
              Bradner, S., "Key words for use in RFC's to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [TE]       Katz, D., Kompella, K., and D. Yeung, "Traffic Engineering
              Extensions to OSPF", RFC 3630, September 2003.

7.2.  Informative References

   [ISIS-ADMIN-TAGS]
              Previdi, S., Shand, M., and C. Martin, "A Policy Control
              Mechanism in IS-IS Using Administrative Tags", RFC 5130,
              February 2008.

   [NSSA]     Murphy, P., "The OSPF Not-So-Stubby Area (NSSA) Option",
              RFC 3101, January 2003.

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Authors' Addresses

   Acee Lindem (editor)
   Cisco Systems
   301 Midenhall Way
   Cary, NC  27513
   USA

   Email: acee@cisco.com

   Peter Psenak
   Cisco Systems
   Apollo Business Center
   Mlynske nivy 43
   Bratislava, 821 09
   Slovakia

   Email: ppsenak@cisco.com

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