Advertising Per-node Admin Tags in IS-IS
draft-psarkar-isis-node-admin-tag-00

IS-IS for IP Internets                                    P. Sarkar, Ed.
Internet-Draft                                                H. Gredler
Intended status: Standards Track                                S. Hegde
Expires: April 24, 2014                                     H. Raghuveer
                                                  Juniper Networks, Inc.
                                                            S. Litkowski
                                                             B. Decraene
                                                                  Orange
                                                        October 21, 2013

                Advertising Per-node Admin Tags in IS-IS
                  draft-psarkar-isis-node-admin-tag-00

Abstract

   This document describes an extension to IS-IS protocol [ISO10589],
   [RFC1195] to add an optional operational capability, that allows
   tagging and grouping ofthe nodes in an IS-IS domain.  This allows
   simple management and easy control over route and path selection,
   based on local configured policies.

   This document describes the protocol extensions to disseminate per-
   node admin-tags in IS-IS 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
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   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on April 24, 2014.

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Copyright Notice

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   document authors.  All rights reserved.

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   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Administrative Tag TLV  . . . . . . . . . . . . . . . . . . .   2
   3.  TLV format  . . . . . . . . . . . . . . . . . . . . . . . . .   3
     3.1.  Per-node Admin Tag TLV  . . . . . . . . . . . . . . . . .   3
     3.2.  Ordering of tags  . . . . . . . . . . . . . . . . . . . .   4
   4.  Applications  . . . . . . . . . . . . . . . . . . . . . . . .   4
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .   4
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   4
   7.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .   4
   8.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   5
     8.1.  Normative References  . . . . . . . . . . . . . . . . . .   5
     8.2.  Informative References  . . . . . . . . . . . . . . . . .   5
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   5

1.  Introduction

   This document provides mechanisms to advertise per-node
   administrative tags in the IS-IS Link State PDU [RFC1195].  In
   certain path-selection applications like for example in traffic-
   engineering or LFA [RFC5286] 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.

2.  Administrative Tag TLV

   For the purpose of advertising per-node administrative tags within
   IS-IS, a new TLV is proposed.  Because path selection is a functional
   set which applies both to TE and non-TE applications the same has not
   added as a new sub-TLV in the Traffic Engingineering TLVs [RFC5305].

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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 IS-IS domain.  The new TLV specifies
   one or more administrative tag values.  An IS-IS node advertises the
   set of groups it is part of in the specific IS-IS level.  As an
   example, all PE-nodes may be configured with certain tag value,
   whereas all P-nodes are configured with a different tag value in.

   The new TLV defined will be carried as a new TLV in the Link State
   PDUs originated by the router.  Link State PDUs [ISO10589] has level-
   wise (i.e. L1 or L2) flooding scope.  Choosing the flooding scope to
   flood the group tags are defined by the policies and is a local
   matter.  Once a group tag is decided in a specific level the same
   will be inserted in the administrative tag TLV in the Link State PDU
   for the same level.  Implementations should allow configuring both a
   'global' and 'per-level' admin tag.  In the absence of a specific
   admin tag configuration for a specific level the global admin tag
   should be copied in to the LSP PDU for the same level.

3.  TLV format

3.1.  Per-node Admin Tag TLV

   The new Administrative Tag TLV, like other ISIS TLVs, is formatted as
   Type/Length/Value (TLV)triplets.  Figure 1 below shows the format of
   the new TLV.

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

    Type :  TBA

    Length: A 8-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.

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

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              Figure 1: IS-IS per-node Administrative Tag TLV

   The 'Per-node Admin Tag' TLV may be generated more than once by an
   originating router.  This MAY happen if a node carries more than 63
   per-node admin groups and a single TLV does not provide sufficient
   space.  As such occurence of the 'Per-node Admin Tag' TLV does not
   cancel previous TLV announcements, but rather is cumulative.

3.2.  Ordering of tags

   The semantics of the tag order are implementation-dependent.  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.

4.  Applications

   Increased deployment of Loop Free Alternates (LFA) [RFC5286] has
   exposed some limitations.  A recent draft on Operation management of
   Loop Free Alternates [I-D.ietf-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 alternate paths based on
   configured policies.

   The proposal in this document helps provide the capability to
   advertise group tags within IS-IS protocol and perform policy based
   LFA selection.  The policies configured on each node can then make
   use of these tags to prefer or prune LFAs via certain group of nodes.

5.  Security Considerations

   This document does not introduce any further security issues other
   than those discussed in [ISO10589] and [RFC1195].

6.  IANA Considerations

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

7.  Acknowledgments

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8.  References

8.1.  Normative References

   [ISO10589]
              , "Intermediate system to Intermediate system intra-domain
              routeing information exchange protocol for use in
              conjunction with the protocol for providing the
              connectionless-mode Network Service (ISO 8473), ISO/IEC
              10589:2002, Second Edition.", Nov 2002.

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

8.2.  Informative References

   [I-D.ietf-rtgwg-lfa-manageability]
              Litkowski, S., Decraene, B., Filsfils, C., and K. Raza,
              "Operational management of Loop Free Alternates", draft-
              ietf-rtgwg-lfa-manageability-00 (work in progress), May
              2013.

   [RFC1195]  Callon, R., "Use of OSI IS-IS for routing in TCP/IP and
              dual environments", RFC 1195, December 1990.

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

   [RFC5305]  Li, T. and H. Smit, "IS-IS Extensions for Traffic
              Engineering", RFC 5305, October 2008.

Authors' Addresses

   Pushpasis Sarkar (editor)
   Juniper Networks, Inc.
   Electra, Exora Business Park
   Bangalore, KA  560103
   India

   Email: psarkar@juniper.net

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

   Email: hannes@juniper.net

   Shraddha Hegde
   Juniper Networks, Inc.
   Electra, Exora Business Park
   Bangalore, KA  560103
   India

   Email: shraddha@juniper.net

   Harish Raghuveer
   Juniper Networks, Inc.
   Electra, Exora Business Park
   Bangalore, KA  560103
   India

   Email: hraghuveer@juniper.net

   Stephane Litkowski
   Orange

   Email: stephane.litkowski@orange.com

   Bruno Decraene
   Orange

   Email: bruno.decraene@orange.com

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