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Versions: 00                                                            
Network Working Group                                      L. Ong, Ciena
Internet-Draft                                         A. Malis, Verizon
Intended status: Standards Track           R. Theillaud, Marben Products
Expires: April 18, 2011
                                                            Oct 18, 2010


   Traffic Engineering Extensions to OSPF for Generalized MPLS (GMPLS)
                    Control of SONET/SDH Networks
                  draft-ong-ccamp-gmpls-ospf-sdh-00

Status of this Memo

   This Internet-Draft is submitted to IETF in full conformance with the
   provisions of BCP 78 and BCP 79.

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   This Internet-Draft will expire on January 12, 2011.

Abstract

   This draft defines an optimization for bandwidth advertisement for
   SONET/SDH that removes the need to carry multiple copies of the ISCD
   sub-TLV and has been designed to be consistent with the work on
   Technology Agnostic OSPF Traffic Engineering Extensions for
   Generalized MPLS (GMPLS) [BA-TLV].







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   These formats are based on previous experience prototyping and
   testing control plane for ASON networks and are proposed for
   adoption as a Standards Track RFC for support of ASON routing.


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].


Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
   2.  Optimization of bandwidth advertisement for SONET/SDH. . . . .  3
     2.1.  Requirements for Multi-layer SONET/SDH Links . . . . . . .  3
     2.2.  Bandwidth Accounting Sub-TLV for SONET/SDH.  . . . . . . .  4
   3.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . .  5
   4.  Security Considerations  . . . . . . . . . . . . . . . . . . .  6
   5.  Acknowledgements . . . . . . . . . . . . . . . . . . . . . . .  6
   6. References. . . . . . . . . . . . . . . . . . . . . . . . . . .  6
     6.1. Normative References. . . . . . . . . . . . . . . . . . . .  6
     6.2. Informative References. . . . . . . . . . . . . . . . . . .  6
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . .  7
   Intellectual Property and Copyright Statements . . . . . . . . . .  7






















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1.  Introduction

   The ITU-T defines the architecture of the Automatically Switched
   Optical Network (ASON) in [G.8080].

   [RFC4258] details the routing requirements for the GMPLS suite of
   routing protocols to support the capabilities and functionality of
   ASON control planes identified in [G.7715] and in [G.7715.1].

   [RFC4652] evaluates the IETF Link State Routing Protocols against the
   requirements identified in [RFC4258]. Section 7.1 of [RFC4652]
   summarizes the capabilities to be provided by OSPFv2 [RFC2328] in
   support of ASON routing. [RFC5787] is an Experimental RFC that
   defines extensions to OSPFv2 to support these requirements.  It
   notes that the Interface Switching Capability Descriptor may
   be included for each layer of a multi-layer link [RFC4202] to meet
   ASON needs.  However, for some types SONET/SDH links there can be
   several data plane layers supported by a single link, and as a
   result a need to carry several copies of the ISCD.

   This draft defines the application of the Bandwidth Accounting
   sub-TLV defined in [BA-TLV] for SONET/SDH,
   to address the issues identified above.


2.  Optimization of bandwidth advertisement for SONET/SDH

2.1 Requirements for Multi-layer SONET/SDH Links

   [RFC4652] notes that in the ASON context, bandwidth accounting
   representations are possible, taking the form of a set of tuples
   <signal_type; number of unallocated timeslots>, and that this
   representation may also require definition of additional signal
   types (from those defined in [RFC4606]) to represent support of
   contiguously concatenated signals,
   i.e., STS-(3xN)c SPE / VC-4-Nc, N = 4, 16, 64, 256.

   It notes that the ISCD defined in [RFC4202] can be used to
   support ASON without requiring any bandwidth accounting
   change from an LSR perspective.  However, the ISCD defined
   in [RFC4202} must be advertised once per signal type
   (identified by the Minimum Reservable Bandwidth value) in
   order to provide an accurate advertisement of bandwidth
   for each signal.  For SONET/SDH links, it is common to support
   4-5 signal types (e.g., STS-1, 3c, 12c, 48c and 192c) at once,



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   and advertisement of 4-5 ISCD sub-TLVs would consume about
   200 bytes as compared to 20-30 bytes for a tuple format.

   Most of the ISCD bytes are required to advertise 8 levels of
   priority.  We believe this overhead can be reduced as (a) ASON
   specifications do not identify priority as an ASON service; and
   (b) TDM networks generally to not support preemption priority
   and do not require 8 levels of priority.


2.2.  Bandwidth Accounting Sub-TLV for SONET/SDH

   [BA-TLV] defines a Bandwidth
   Accounting Sub-TLV that can be used to carry SONET/SDH bandwidth
   availability at multiple link component signal
   types as supplementary information to the ISCD sub-TLV.

   When multiple SONET/SDH signal types are advertised, a single ISCD
   is given for the smallest bandwidth signal type and the BA sub-TLV
   is also advertised to provide compact bandwidth availability
   advertisement for all signal types.

   The type used for the sub-TLV is TBD.

   [BA-TLV] defines this format:

       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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      | Switching Cap |   Encoding    |           Reserved            |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      | Service Type  | M |  T.S. Flags   |     Reserved        |Prior|
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                           Bandwidth                           |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      | Service Type  | M |  T.S. Flags   |     Reserved        |Prior|
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                           Bandwidth                           |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      | Service Type  | M |  T.S. Flags   |     Reserved        |Prior|
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                           Bandwidth                           |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      ~                             ...                               ~
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      | Service Type  | M |  T.S. Flags   |     Reserved        |Prior|
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                           Bandwidth                           |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


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   For SONET/SDH networks, the Switching Capability field and the
   Encoding field MUST take the following values: Switching
   Capability (8 bits)=100 (TDM).  Encoding (8 bits)=5 (Sonet/SDH).

   If no priority is supported, just the 0 priority MUST be advertised.

   Service Type (8 bits) takes values as below for
   SONET/SDH Signal Type:

   Value  Type (Elementary Signal)
   -----  ------------------------
    TBD   STS-1 SPE / VC-3
    TBD   STS-3c SPE / VC-4
    TBD   STS-12c SPE/VC-4-4c
    TBD   STS-48c SPE/VC-4-16c
    TBD   STS-192c SPE/VC-4-64c

   Bandwidth (32 bits) is used to specify the number of identical
   unallocated timeslots per Service
   Type and per TE Link.  As such, the initial value(s) of this TLV
   indicates the total capacity in terms of number of timeslots per TE
   link.  The service type included in the BW sub-TLV is specific to
   the layer link being reported and is not derived from some other
   signal type (e.g.  STS-48c is not announced as 16 x STS-3c).

   For instance on an OC-192/STM-64 interface the bandwidth for
   service type STS-3c SPE/VC-4 may be initially equal to 64, and
   the bandwidth for service type STS-48c SPE/VC-4-16c may be equal to
   4 depending on the interface capabilities.  Once one timeslot is
   occupied by being allocated for a connection at the same or a larger
   service type or being blocked due to the allocation of part of
   the timeslot for a connection at a smaller service type, the
   bandwidth is decreased by the number of timeslots
   this connection implies.


3.  IANA Considerations

   IANA will allocate codepoints for the Service Type of the
   Bandwidth Availability sub-TLV for SONET/SDH from the
   standard range.  Five Service Type values are requested.






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4.  Security Considerations

   This document defines an optimization for SONET/SDH link bandwidth
   advertisement consistent with the requirements in [RFC4258] and
   [RFC4652].  No additional security issues are identified.

5.  Acknowledgements

   The authors would like to thank the following OIF members for their
   comments and support for this document:

      Richard Graveman (Department of Defense)
      Hans-Martin Foisel (Deutsche Telekom)
      Thierry Marcot (France Telecom)
      Evelyne Roch (Nortel Networks)
      Jonathan Sadler (Tellabs)
      Yoshiaki Sone (NTT Corporation)
      Takehiro Tsuritani (KDDI R&D Laboratories)


6.  References

6.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.
   [RFC2328]  Moy, J., "OSPF Version 2", RFC 2328,April 1998.
   [RFC3630]  Katz, D., Kompella, K., and D. Yeung, "Traffic Engineering
              (TE) Extensions to OSPF Version 2", RFC 3630,
              September 2003.
   [RFC4202]  Kompella, K. and Y. Rekhter, "Routing Extensions in
              Support of Generalized Multi-Protocol Label Switching
              (GMPLS)", RFC 4202,February 2005.
   [BA-TLV]   D. Ceccarelli, et al, " Technology Agnostic OSPF Traffic
              Engineering Extensions  for Generalized MPLS (GMPLS)",
              draft-bccdg-ccamp-gmpls-ospf-agnostic-00.txt, Oct 2010.

6.2.  Informative References

   [RFC5787] Papadimitriou, D., "OSPFv2 Routing Protocol Extensions
              for ASON Routing," RFC 5787, March 2010.
   [RFC4258]  Brungard, D., "Requirements for Generalized Multi-Protocol
              Label Switching (GMPLS) Routing for the Automatically
              Switched Optical Network (ASON)", RFC 4258, November 2005.
   [RFC4652]  Papadimitriou, D., L.Ong, Sadler, J., Shew, S., and D.
              Ward, "Evaluation of Existing Routing Protocols against
              Automatic Switched Optical Network (ASON) Routing
              Requirements", RFC 4652, February 2006.

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Authors' Addresses

   Lyndon Ong
   Ciena
   P.O.Box 308
   Cupertino  CA 95015
   USA

   Phone: +1 408 962 4929
   Email: lyong@ciena.com

   Andrew Malis
   Verizon
   117 West St.
   Waltham, MA 02451
   USA

   Email: andrew.g.malis@verizon.com
   Phone: +1 781 466 2362

   Remi Theillaud
   Marben Products
   176 rue Jean Jaures
   Puteaux  92800
   France

   Email: remi.theillaud@marben-products.com


Copyright Notice

   Copyright (c) 2010 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
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   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with
   respect to this document.






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