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Network Working Group                                              X. Xu
Internet-Draft                                                    Huawei
Intended status: Standards Track                                 S. Kini
Expires: March 10, 2014                                         Ericsson
                                                            S. Sivabalan
                                                             C. Filsfils
                                                                   Cisco
                                                      September 06, 2013


  Signaling Entropy Label Capability Using Interior Gateway Protocols
              draft-xu-mpls-el-capability-signaling-igp-00

Abstract

   Multi Protocol Label Switching (MPLS) has defined a mechanism to load
   balance traffic flows using Entropy Labels (EL).  An LSR inserts the
   EL Indicator and the EL label only if the LSR that pops them has the
   capability of processing them.  This draft defines a mechanism to
   signal that capability using link state Interior Gateway Protocols
   (IGP).  This mechanism is useful when the label advertisement is also
   done via that IGP.

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 March 10, 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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   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.  Abbreviations and Terminology . . . . . . . . . . . . . . . .   3
   3.  Advertising ELC using OSPF  . . . . . . . . . . . . . . . . .   3
   4.  Advertising ELC using ISIS  . . . . . . . . . . . . . . . . .   3
   5.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   3
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   3
   7.  Security Considerations . . . . . . . . . . . . . . . . . . .   3
   8.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   3
     8.1.  Normative References  . . . . . . . . . . . . . . . . . .   4
     8.2.  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 LSR inserts the EL Indicator and the EL only if the LSR that pops
   those labels has the capability of recognizing and processing them.
   [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] and ISIS
   [I-D.previdi-isis-segment-routing-extensions].  In such scenarios the
   signaling mechanisms defined in [RFC6790] are inadequate.  This draft
   defines mechanisms to signal the ELC using the link state
   advertisements (LSA) of the IGPs OSPF and ISIS.  These capabilities
   are advertised for the entire router and not just a single prefix.
   This mechanism is useful when the label advertisement is also done
   via that IGP.

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].





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2.  Abbreviations and Terminology

   This memo makes use of the terms defined in [RFC6790], [RFC4970] and
   [RFC4971].

3.  Advertising ELC using OSPF

   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 ELI and EL.  Its
   formatting follows that 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.  Advertising ELC using ISIS

   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 ELI and EL.  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.

5.  Acknowledgements

   The authors would like to thank TBD for their comments.

6.  IANA Considerations

   This memo includes requests to IANA to allocate a TLV type from the
   OSPF RI TLVs registry and a sub-TLV type within the IS-IS Router
   Capability TLV.

7.  Security Considerations

   This document does not introduce any new security considerations.

8.  References









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8.1.  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-02 (work in
              progress), July 2013.

   [I-D.psenak-ospf-segment-routing-extensions]
              Psenak, P., Previdi, S., Filsfils, C., Gredler, H., and R.
              Shakir, "OSPF Extensions for Segment Routing", draft-
              psenak-ospf-segment-routing-extensions-02 (work in
              progress), July 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.

   [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.

8.2.  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-00 (work in progress), June 2013.

Authors' Addresses

   Xiaohu Xu
   Huawei

   Email: xuxiaohu@huawei.com




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   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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