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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 OSPF
                       draft-xu-ospf-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 OSPF.  This mechanism is useful when the label
   advertisement is also done via OSPF.

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
   to this document.  Code Components extracted from this document must
   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 OSPF  . . . . . . . . . . . . . . . . .   2
   4.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   3
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   3
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .   3
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   3
     7.1.  Normative References  . . . . . . . . . . . . . . . . . .   3
     7.2.  Informative References  . . . . . . . . . . . . . . . . .   4
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   4

1.  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 OSPF
   [I-D.psenak-ospf-segment-routing-extensions] . In such scenario the
   signaling mechanisms defined in [RFC6790] are inadequate.  This draft
   defines a mechanism to signal the ELC using OSPF.  This mechanism is
   useful when the label advertisement is also done via OSPF.

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].

2.  Terminology

   This memo makes use of the terms defined in [RFC6790] and [RFC4970].

3.  Advertising ELC using OSPF




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   The OSPF Router Information (RI) Opaque LSA defined in [RFC4970] is
   used by OSPF routers to announce their capabilities.  A new TLV
   within the body of this LSA, called ELC TLV is defined to advertise
   the capability of the router to process the ELs.  It is formatted as
   described in sec 2.1 of [RFC4970].  This TLV is applicable to both
   OSPFv2 and OSPFv3.  The Type for the ELC TLV needs to be assigned by
   IANA and it has a Length of zero.  The scope of the advertisement
   depends on the application but it is recommended that it SHOULD be
   AS-scoped.

4.  Acknowledgements

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

5.  IANA Considerations

   This memo includes a request to IANA to allocate a TLV type from the
   OSPF RI TLVs registry.

6.  Security Considerations

   This document does not introduce any new security considerations.

7.  References

7.1.  Normative References

   [I-D.psenak-ospf-segment-routing-extensions]
              Psenak, P., Previdi, S., Filsfils, C., Gredler, H.,
              Shakir, R., and W. Henderickx, "OSPF Extensions for
              Segment Routing", draft-psenak-ospf-segment-routing-
              extensions-03 (work in progress), October 2013.

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

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




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7.2.  Informative References

   [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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