Network Working Group                                              X. Xu
Internet-Draft                                                    Huawei
Intended status: Standards Track                                 S. Kini
Expires: June 18, 2014                                          Ericsson
                                                            S. Sivabalan
                                                             C. Filsfils
                                                                   Cisco
                                                       December 18, 2013


             Signaling Entropy Label Capability Using IS-IS
                       draft-xu-isis-mpls-elc-00

Abstract

   Multi Protocol Label Switching (MPLS) has defined a mechanism to load
   balance traffic flows using Entropy Labels (EL).  An ingress LSR
   cannot insert ELs for packets going into a given tunnel unless an
   egress LSR has indicated via signaling that it can process ELs on
   that tunnel.  This draft defines a mechanism to signal that
   capability using IS-IS.  This mechanism is useful when the label
   advertisement is also done via IS-IS.

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
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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 June 18, 2014.

Copyright Notice

   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



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   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
     1.1.  Requirements Language . . . . . . . . . . . . . . . . . .   2
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   2
   3.  Advertising ELC using IS-IS . . . . . . . . . . . . . . . . .   2
   4.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   3
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   3
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .   3
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   3
     7.1.  Normative References  . . . . . . . . . . . . . . . . . .   3
     7.2.  Informative References  . . . . . . . . . . . . . . . . .   3
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   4

.  Introduction

   Multi Protocol Label Switching (MPLS) has defined a method in
   [RFC6790] to load balance traffic flows using Entropy Labels (EL).
   An ingress LSR cannot insert ELs for packets going into a given
   tunnel unless an egress LSR has indicated via signaling that it can
   process ELs on that tunnel.  [RFC6790] defines the signaling of this
   capability (a.k.a Entropy Label Capability - ELC) via signaling
   protocols.  Recently, mechanisms are being defined to signal labels
   via link state Interior Gateway Protocols (IGP) such as IS-IS
   [I-D.previdi-isis-segment-routing-extensions].  In such scenario the
   signaling mechanisms defined in [RFC6790] are inadequate.  This draft
   defines a mechanism to signal the ELC using IS-IS.  This mechanism is
   useful when the label advertisement is also done via IS-IS.

1.1.  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].

.  Terminology

   This memo makes use of the terms defined in [RFC6790] and [RFC4971].

.  Advertising ELC using IS-IS




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   The IS-IS Router CAPABILITY TLV defined in [RFC4971] is used by IS-IS
   routers to announce their capabilities.  A new sub-TLV of this TLV,
   called ELC sub-TLV is defined to advertise the capability of the
   router to process the ELs.  It is formatted as described in [RFC5305]
   with a Type code to be assigned by IANA and a Length of zero.  The
   scope of the advertisement depends on the application but it is
   recommended that it SHOULD be domain-wide.

.  Acknowledgements

   The authors would like to thank Yimin Shen and George Swallow for
   their comments.

.  IANA Considerations

   This memo includes a request to IANA to allocate a sub-TLV type
   within the IS-IS Router Capability TLV.

.  Security Considerations

   This document does not introduce any new security considerations.

.  References

7.1.  Normative References

   [I-D.previdi-isis-segment-routing-extensions]
              Previdi, S., Filsfils, C., Bashandy, A., Gredler, H., and
              S. Litkowski, "IS-IS Extensions for Segment Routing",
              draft-previdi-isis-segment-routing-extensions-04 (work in
              progress), October 2013.

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

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

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

   [RFC6790]  Kompella, K., Drake, J., Amante, S., Henderickx, W., and
              L. Yong, "The Use of Entropy Labels in MPLS Forwarding",
              RFC 6790, November 2012.

7.2.  Informative References




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   [I-D.filsfils-rtgwg-segment-routing]
              Filsfils, C., Previdi, S., Bashandy, A., Decraene, B.,
              Litkowski, S., Horneffer, M., Milojevic, I., Shakir, R.,
              Ytti, S., Henderickx, W., Tantsura, J., and E. Crabbe,
              "Segment Routing Architecture", draft-filsfils-rtgwg-
              segment-routing-01 (work in progress), October 2013.

Authors' Addresses

   Xiaohu Xu
   Huawei

   Email: xuxiaohu@huawei.com


   Sriganesh Kini
   Ericsson

   Email: sriganesh.kini@ericsson.com


   Siva Sivabalan
   Cisco

   Email: msiva@cisco.com


   Clarence Filsfils
   Cisco

   Email: cfilsfil@cisco.com




















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