Open Shortest Path First IGP                                    S. Hegde
Internet-Draft                                              H. Raghuveer
Intended status: Standards Track                              H. Gredler
Expires: April 24, 2014                           Juniper Networks, Inc.
                                                               R. Shakir
                                                         British Telecom
                                                        October 21, 2013


            Advertising per-node administrative tags in OSPF
                   draft-hegde-ospf-node-admin-tag-00

Abstract

   This document describes an extension to OSPF protocol [RFC2328] to
   add an optional operational capability, that allows tagging and
   grouping of the nodes in an OSPF domain.  This allows
   simplification,ease of management and control over route and path
   selection based on configured policies.

   This document describes the protocol extensions to disseminate per-
   node admin-tags to the OSPFv2 and OSPFv3 protocols.

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
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at http://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   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 April 24, 2014.

Copyright Notice




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   Copyright (c) 2013 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
   (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  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Applicability . . . . . . . . . . . . . . . . . . . . . . . .   2
   3.  Administrative Tag TLV  . . . . . . . . . . . . . . . . . . .   2
   4.  TLV format  . . . . . . . . . . . . . . . . . . . . . . . . .   3
     4.1.  OSPF per-node administrative tag TLV  . . . . . . . . . .   3
     4.2.  Ordering of tags  . . . . . . . . . . . . . . . . . . . .   4
   5.  Applications  . . . . . . . . . . . . . . . . . . . . . . . .   4
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .   4
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   4
   8.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .   5
   9.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   5
     9.1.  Normative References  . . . . . . . . . . . . . . . . . .   5
     9.2.  Informative References  . . . . . . . . . . . . . . . . .   5
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   5

.  Introduction

   This document provides mechanisms to advertise per-node
   administrative tags in the OSPF router information LSA [RFC4970].  In
   certain path-selection applications like for example in traffic-
   engineering or LFA backup selection there is a need to tag the nodes
   based on their roles in the network and have policies to prefer or
   prune a certain group of nodes.

.  Applicability

   For the purpose of advertising per-node administrative tags within
   OSPF a new TLV is proposed.  Because path selection is a functional
   set which applies both to TE and non-TE applications, this new TLV is
   carried in the Router Information LSA [RFC4970]

.  Administrative Tag TLV




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   An administrative Tag is a 32-bit integer value that can be used to
   identify a group of nodes in the OSPF domain.

   The new TLV defined will be carried within an RI LSA for OSPFV2 and
   OSPFV3.  Router information LSA [RFC4970] can have link,area or AS
   level flooding scope.  Choosing the flooding scope to flood the group
   tags are defined by the policies and is a local matter.

   The TLV specifies one or more administrative tag values.  An OSPF
   node advertises the set of groups it is part of in the OSPF domain.
   (for example, all PE-nodes are configured with certain tag value, all
   P-nodes are configured with a different tag value in a domain).

.  TLV format

4.1.  OSPF per-node administrative tag TLV

   The format of the TLVs within the body of an RI LSA is the same as
   the format used by the Traffic Engineering Extensions to OSPF
   [RFC3630].

   The LSA payload consists of one or more nested Type/Length/Value
   (TLV) triplets.  The format of each TLV is:




   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                        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |           Administrative Tag #1                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |           Administrative Tag #2                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   //                                                             //
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |           Administrative Tag #N                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

              Figure 1: OSPF per-node Administrative Tag TLV


   Type : TBA

   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 tags advertised.



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   Value: A sequence of multiple 4 octets defining the administrative
   tags.

4.2.  Ordering of tags

   The semantics of the tag order are implementation-dependent.  That
   is, there is no implied meaning to the ordering of the tags that
   indicates a certain operation or set of operations that need to be
   performed based on the ordering.

   Each tag SHOULD be treated as an independent identifier that MAY be
   used in policy to perform a policy action.  Whether or not tag A
   precedes or succeeds tag B SHOULD not change the meaning of the tag
   set.

.  Applications

   Increased deployment of Loop Free Alternates (LFA) as defined in
   [RFC5286] has exposed some limitations.New draft Operation management
   of Loop Free Alternates [I-D.litkowski-rtgwg-lfa-manageability]
   proposes refinements to address those limitations.

   One of the proposed refinements is to be able to group the nodes in
   IGP domain with administrative tags and engineer the LFA based on
   configured policies.

   The mechanisms outlined in this document helps provide the capability
   to advertise group tags within OSPF protocol in order to achieve
   policy based LFA selection.

   The policies configured on each node can then make use of these tags
   to prefer or prune certain group of nodes for selecting LFAs.

.  Security Considerations

   This document does not introduce any further security issues other
   than those discussed in [RFC2328] and [RFC5340].

.  IANA Considerations

   IANA maintains the registry for the TLVs.  OSPF Administrative Tags
   will require one new type code for the TLV defined in this document.









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.  Acknowledgments

   Thanks to Bharath R and Pushpasis Sarakar for useful inputs.

.  References

9.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC2328]  Moy, J., "OSPF Version 2", STD 54, RFC 2328, April 1998.

   [RFC3630]  Katz, D., Kompella, K., and D. Yeung, "Traffic Engineering
              (TE) Extensions to OSPF Version 2", RFC 3630, September
              2003.

   [RFC4970]  Lindem, A., Shen, N., Vasseur, JP., Aggarwal, R., and S.
              Shaffer, "Extensions to OSPF for Advertising Optional
              Router Capabilities", RFC 4970, July 2007.

   [RFC5250]  Berger, L., Bryskin, I., Zinin, A., and R. Coltun, "The
              OSPF Opaque LSA Option", RFC 5250, July 2008.

   [RFC5340]  Coltun, R., Ferguson, D., Moy, J., and A. Lindem, "OSPF
              for IPv6", RFC 5340, July 2008.

9.2.  Informative References

   [I-D.litkowski-rtgwg-lfa-manageability]
              Litkowski, S., Decraene, B., Filsfils, C., and K. Raza,
              "Operational management of Loop Free Alternates", draft-
              litkowski-rtgwg-lfa-manageability-01 (work in progress),
              February 2013.

   [RFC5286]  Atlas, A. and A. Zinin, "Basic Specification for IP Fast
              Reroute: Loop-Free Alternates", RFC 5286, September 2008.

   [RFC5310]  Bhatia, M., Manral, V., Li, T., Atkinson, R., White, R.,
              and M. Fanto, "IS-IS Generic Cryptographic
              Authentication", RFC 5310, February 2009.

   [RFC5329]  Ishiguro, K., Manral, V., Davey, A., and A. Lindem,
              "Traffic Engineering Extensions to OSPF Version 3", RFC
              5329, September 2008.

Authors' Addresses




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   Shraddha Hegde
   Juniper Networks, Inc.
   Embassy Business Park
   Bangalore, KA  560093
   India

   Email: shraddha@juniper.net


   Harish Raghuveer
   Juniper Networks, Inc.
   Embassy Business Park
   Bangalore  560093
   India

   Email: hraghuveer@juniper.net


   Hannes Gredler
   Juniper Networks, Inc.
   1194 N. Mathilda Ave.
   Sunnyvale, CA  94089
   US

   Email: hannes@juniper.net


   Rob shakir
   British Telecom

   Email: rob.shakir@bt.com




















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