IS-IS for IP Internets                                    P. Sarkar, Ed.
Internet-Draft                                                H. Gredler
Intended status: Standards Track                                S. Hegde
Expires: August 18, 2014                                    H. Raghuveer
                                                  Juniper Networks, Inc.
                                                            S. Litkowski
                                                             B. Decraene
                                                                  Orange
                                                       February 14, 2014


                Advertising Per-node Admin Tags in IS-IS
                  draft-psarkar-isis-node-admin-tag-01

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
   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 August 18, 2014.




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




















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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

   For the purpose of advertising per-node administrative tags within
   IS-IS, a new sub-TLV to the IS-IS Router Capability TLV-242 that is
   defined in [RFC4971] 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].

   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 sub-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 sub-TLV defined will be carried inside the IS-IS Router
   Capability TLV-242 (defined in [RFC4971]) 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 sub-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 sub-TLV

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




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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     |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |                   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.


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

   The 'Per-node Admin Tag' sub-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 sub-TLV does not provide
   sufficient space.  As such occurence of the 'Per-node Admin Tag' sub-
   TLV does not cancel previous 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



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   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 Router Capability sub-TLVs.
   IS-IS Administrative Tags will require one new type code for the sub-
   TLV defined in this document.


7.  Acknowledgments


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",



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              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.

   [RFC4971]  Vasseur, JP., Shen, N., and R. Aggarwal, "Intermediate
              System to Intermediate System (IS-IS) Extensions for
              Advertising Router Information", RFC 4971, July 2007.

   [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


   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







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   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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