[Docs] [txt|pdf] [Tracker] [Email] [Diff1] [Diff2] [Nits] [IPR]

Versions: 00 01 02 03 04 05 draft-ietf-pce-wson-routing-wavelength

Network Working Group                                            Y. Lee
Internet Draft                                                   Huawei
Intended status: Standard Track
Expires: December 2009                                     G. Bernstein
                                                      Grotto Networking

                                                        Jonas Martensson
                                                                   Acreo

                                                              T. Takeda
                                                                    NTT

                                                               T. Otani
                                                                   KDDI



                                                          June 29, 2009


       PCEP Requirements for WSON Routing and Wavelength Assignment


               draft-lee-pce-wson-routing-wavelength-05.txt


Status of this Memo

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

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF), its areas, and its working groups.  Note that
   other groups may also distribute working documents as Internet-
   Drafts.

   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."

   The list of current Internet-Drafts can be accessed at
   http://www.ietf.org/ietf/1id-abstracts.txt

   The list of Internet-Draft Shadow Directories can be accessed at
   http://www.ietf.org/shadow.html

   This Internet-Draft will expire on December 29, 2009.

Copyright Notice



Lee & Bernstein       Expires December 29, 2009                [Page 1]


Internet-Draft       PCEP Extension for WSON RWA              June 2009


   Copyright (c) 2009 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 in effect on the date of
   publication of this document (http://trustee.ietf.org/license-info).
   Please review these documents carefully, as they describe your rights
   and restrictions with respect to this document.

Abstract

   This memo provides application-specific requirements for the Path
   Computation Element communication Protocol (PCEP) for the support of
   Wavelength Switched Optical Networks (WSON). Lightpath provisioning
   in WSONs requires a routing and wavelength assignment (RWA) process.
   From a path computation perspective, wavelength assignment is the
   process of determining which wavelength can be used on each hop of a
   path and forms an additional routing constraint to optical light path
   computation. Requirements related to optical impairments will be
   addressed in a separate document.



Conventions used in this document

   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 [RFC2119].

Table of Contents


   1. Introduction...................................................3
      1.1. WSON RWA Processes........................................4
   2. WSON PCE Architectures and Requirements........................5
      2.1. RWA PCC to PCE Interface..................................5
         2.1.1. A new RWA path request...............................6
         2.1.2. An RWA path re-optimization request..................6
         2.1.3. Wavelength Range Constraint..........................6
   3. Manageability Considerations...................................7
      3.1. Control of Function and Policy............................7
      3.2. Information and Data Models, e.g. MIB module..............7
      3.3. Liveness Detection and Monitoring.........................7
      3.4. Verifying Correct Operation...............................8
      3.5. Requirements on Other Protocols and Functional Components.8
      3.6. Impact on Network Operation...............................8
   4. Security Considerations........................................8


Lee & Bernstein       Expires December 29, 2009                [Page 2]


Internet-Draft       PCEP Extension for WSON RWA              June 2009


   5. IANA Considerations............................................8
   6. Acknowledgments................................................8
   7. References.....................................................9
      7.1. Normative References......................................9
      7.2. Informative References....................................9
   Authors' Addresses...............................................10
   Intellectual Property Statement..................................10
   Disclaimer of Validity...........................................11



1. Introduction

   [RFC4655] defines the PCE based Architecture and explains how a Path
   Computation Element (PCE) may compute Label Switched Paths (LSP) in
   Multiprotocol Label Switching Traffic Engineering (MPLS-TE) and
   Generalized MPLS (GMPLS) networks at the request of Path Computation
   Clients (PCCs).  A PCC is shown to be any network component that
   makes such a request and may be for instance an Optical Switching
   Element within a Wavelength Division Multiplexing (WDM) network.  The
   PCE, itself, can be located anywhere within the network, and may be
   within an optical switching element, a Network Management System
   (NMS) or Operational Support System (OSS), or may be an independent
   network server.

   The PCE communications Protocol (PCEP) is the communication protocol
   used between PCC and PCE, and may also be used between cooperating
   PCEs.  [RFC4657] sets out the common protocol requirements for PCEP.
   Additional application-specific requirements for PCEP are deferred to
   separate documents.

   This document provides a set of application-specific PCEP
   requirements for support of path computation in Wavelength Switched
   Optical Networks (WSON).  WSON refers to WDM based optical networks
   in which switching is performed selectively based on the wavelength
   of an optical signal.

   The path in WSON is referred to as a lightpath.  A lightpath may span
   multiple fiber links and the path should be assigned a wavelength for
   each link.  A transparent optical network is made up of optical
   devices that can switch but not convert from one wavelength to
   another. In a transparent optical network, a lightpath operates on
   the same wavelength across all fiber links that it traverses. In such
   case, the lightpath is said to satisfy the wavelength-continuity
   constraint. Two lightpaths that share a common fiber link can not be
   assigned the same wavelength.  To do otherwise would result in both
   signals interfering with each other. Note that advanced additional


Lee & Bernstein       Expires December 29, 2009                [Page 3]


Internet-Draft       PCEP Extension for WSON RWA              June 2009


   multiplexing techniques such as polarization based multiplexing are
   not addressed in this document since the physical layer aspects are
   not currently standardized. Therefore, assigning the proper
   wavelength on a lightpath is an essential requirement in the optical
   path computation process.

   When a switching node has the ability to perform wavelength
   conversion the wavelength-continuity constraint can be relaxed, and a
   lightpath may use different wavelengths on different links along its
   route from origin to destination. It is, however, to be noted that
   wavelength converters may be limited due to their relatively high
   cost, while the number of WDM channels that can be supported in a
   fiber is also limited. As a WSON can be composed of network nodes
   that cannot perform wavelength conversion, nodes with limited
   wavelength conversion, and nodes with full wavelength conversion
   abilities, wavelength assignment is an additional routing constraint
   to be considered in all lightpath computation.

   In this document we first review the processes for routing and
   wavelength assignment (RWA) used when wavelength continuity
   constraints are present and then specify requirements for PCEP to
   support RWA.

   The remainder of this document uses terminology from [RFC4655].

1.1. WSON RWA Processes

   In [WSON-Frame] three alternative process architectures were given
   for performing routing and wavelength assignment. These are shown
   schematically in Figure 1.

     +-------------------+
     |  +-------+  +--+  |    +-------+    +--+     +-------+    +---+
     |  |Routing|  |WA|  |    |Routing|--->|WA|     |Routing|--->|DWA|
     |  +-------+  +--+  |    +-------+    +--+     +-------+    +---+
     |   Combined        |     Separate Processes   Separate Processes
     |   Processes       |                          WA performed in a
     +-------------------+                          Distributed manner
           (a)                       (b)                    (c)

                    Figure 1 RWA process alternatives.

   These alternatives have the following properties and impact on PCEP
   requirements in this document.





Lee & Bernstein       Expires December 29, 2009                [Page 4]


Internet-Draft       PCEP Extension for WSON RWA              June 2009


   1. Combined Processes (R&WA) - Here path selection and wavelength
      assignment are performed as a single process. The requirements for
      PCC-PCE interaction with such a combined RWA process PCE is
      addressed in this document.

   2. Routing separate from Wavelength Assignment (R+WA) - Here the
      routing process furnishes one or more potential paths to the
      wavelength assignment process that then performs final path
      selection and wavelength assignment.  The requirements for PCE-PCE
      interaction with one PCE implementing the routing process and
      another implementing the wavelength assignment process are not
      addressed in this document.

   3. Routing and distributed Wavelength Assignment (R+DWA) - Here a
      standard path computation (unaware of detailed wavelength
      availability) takes place, then wavelength assignment is performed
      along this path in a distributed manner via signaling (RSVP-TE).
      This alternative should be covered by existing or emerging GMPLS
      PCEP extensions and does not present new WSON specific
      requirements.



2. WSON PCE Architectures and Requirements

   In the previous section we reviewed various process architectures for
   implementing RWA. In Figure 2 we reduce these alternatives to one
   typical PCE based implementation, which is referred to as Combined
   Process (R&WA). In Figure 2 we show the two processes of routing and
   wavelength assignment accessed via a single PCE.

                          +----------------------------+
            +-----+       |     +-------+     +--+     |
            |     |       |     |Routing|     |WA|     |
            | PCC |<----->|     +-------+     +--+     |
            |     |       |                            |
            +-----+       |             PCE            |
                          +----------------------------+


               Figure 2 Combined Process (R&WA) architecture

2.1. RWA PCC to PCE Interface

   The requirements for the PCC to PCE interface of Figure 2 are
   specified in this section.



Lee & Bernstein       Expires December 29, 2009                [Page 5]


Internet-Draft       PCEP Extension for WSON RWA              June 2009


      2.1.1.  A new RWA path request

   1. The PCReq Message MUST include the path computation type. This can
      be: RWA, or only routing. This requirement is needed to
      differentiate between the currently supported routing with
      distribute wavelength assignment option and combined RWA.

   2. The PCRep Message MUST include the route, and wavelengths assigned
      to the route. In the case where a valid path is not found, the
      PCRep Message MUST include why the path is not found (e.g., no
      route, wavelength not found, etc.)



      2.1.2.  An RWA path re-optimization request

   1. For a re-optimization request, the PCReq Message MUST provide the
      path to be re-optimized and include the following options:

       a. Re-optimize the path keeping the same wavelength(s)

       b. Re-optimize wavelength(s) keeping the same path

       c. Re-optimize allowing both wavelength and the path to change

   2. The corresponding PCRep Message for the re-optimized request MUST
      provide the Re-optimized path and wavelengths. In case that the
      path is not found, the PCRep Message MUST include why the path is
      not found (e.g., no route, wavelength not found, both route and
      wavelength not found, etc.)



      2.1.3.  Wavelength Range Constraint

   For any PCReq Message that is associated with a request for
   wavelength assignment the requester (PCC) MUST be able to specify a
   restriction on the wavelengths to be used.

   Note that the requestor (PCC) is NOT required to furnish any range
   restrictions. This restriction is to be interpreted by the PCE as a
   constraint on the tuning ability of the origination laser
   transmitter.






Lee & Bernstein       Expires December 29, 2009                [Page 6]


Internet-Draft       PCEP Extension for WSON RWA              June 2009


3. Manageability Considerations

   Manageability of WSON Routing and Wavelength Assignment (RWA) with
   PCE must address the following considerations:

3.1. Control of Function and Policy

   In addition to the parameters already listed in Section 8.1 of
   [PCEP], a PCEP implementation SHOULD allow configuring the following
   PCEP session parameters on a PCC:

   o  The ability to send a WSON RWA request.

   In addition to the parameters already listed in Section 8.1 of
   [PCEP], a PCEP implementation SHOULD allow configuring the following
   PCEP session parameters on a PCE:

   o  The support for WSON RWA.

   o  The maximum number of synchronized path requests associated with
      WSON RWA per request message.

   o  A set of WSON RWA specific policies (authorized sender, request
      rate limiter, etc).


   These parameters may be configured as default parameters for any PCEP
   session the PCEP speaker participates in, or may apply to a specific
   session with a given PCEP peer or a specific group of sessions with a
   specific group of PCEP peers.


3.2. Information and Data Models, e.g. MIB module

   Extensions to the PCEP MIB module defined in [PCEP-MIB] should be
   defined, so as to cover the WSON RWA information introduced in this
   document. A future revision of this document will list the
   information that should be added to the MIB module.

3.3. Liveness Detection and Monitoring

   Mechanisms defined in this document do not imply any new liveness
   detection and monitoring requirements in addition to those already
   listed in section 8.3 of [PCEP].





Lee & Bernstein       Expires December 29, 2009                [Page 7]


Internet-Draft       PCEP Extension for WSON RWA              June 2009


3.4. Verifying Correct Operation

   Mechanisms defined in this document do not imply any new verification
   requirements in addition to those already listed in section 8.4 of
   [PCEP]


3.5. Requirements on Other Protocols and Functional Components

   The PCE Discovery mechanisms ([RFC5089] and [RFC5088]) may be used to
   advertise WSON RWA path computation capabilities to PCCs.


3.6. Impact on Network Operation

   Mechanisms defined in this document do not imply any new network
   operation requirements in addition to those already listed in section
   8.6 of [PCEP].



4. Security Considerations

   This document has no requirement for a change to the security models
   within PCEP [PCEP]. However the additional information distributed in
   order to address the RWA problem represents a disclosure of network
   capabilities that an operator may wish to keep private. Consideration
   should be given to securing this information.



5. IANA Considerations

   A future revision of this document will present requests to IANA for
   codepoint allocation.



6. Acknowledgments

   The authors would like to thank Adrian Farrel for many helpful
   comments that greatly improved the contents of this draft.

   This document was prepared using 2-Word-v2.0.template.dot.





Lee & Bernstein       Expires December 29, 2009                [Page 8]


Internet-Draft       PCEP Extension for WSON RWA              June 2009


7. References

7.1. Normative References

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

   [RFC4655] Farrel, A., Vasseur, J., and J. Ash, "A Path Computation
             Element (PCE)-Based Architecture", RFC 4655, August 2006.

   [RFC4657] Ash, J. and J. Le Roux, "Path Computation Element (PCE)
             Communication Protocol Generic Requirements", RFC 4657,
             September 2006.

   [PCEP]    Vasseur, JP., Ed. and JL. Le Roux, Ed., "Path Computation
             Element (PCE) communication Protocol (PCEP) - Version 1",
             RFC 5440, March 2009.

   [PCEP-MIB] "PCE communication protocol(PCEP) Management Information
             Base", draft-ietf-pce-pcep-mib, work in progress.



7.2. Informative References

   [WSON-Frame] Bernstein, G. and Lee, Y. (Editors), and W. Imajuku, "A
             Framework for the Control and Measurement of Wavelength
             Switched Optical Networks (WSON) with Impairments
             draft-bernstein-ccamp-wson-impairments, work in progress.

   [WSON-IMP] Bernstein, G. and Lee, Y. (Editors), and D. Li, "Framework
             for GMPLS and PCE Control of Wavelength Switched Optical
             Networks", draft-bernstein-ccamp-wavelength-switched, work
             in progress.

   [RFC5088] Le Roux, JL., Ed., Vasseur, JP., Ed., Ikejiri, Y., and R.
             Zhang, "OSPF Protocol Extensions for Path Computation
             Element (PCE) Discovery", RFC 5088, January 2008.

   [RFC5089] Le Roux, JL., Ed., Vasseur, JP., Ed., Ikejiri, Y., and R.
             Zhang, "IS-IS Protocol Extensions for Path Computation
             Element (PCE) Discovery", RFC 5089, January 2008.







Lee & Bernstein       Expires December 29, 2009                [Page 9]


Internet-Draft       PCEP Extension for WSON RWA              June 2009


Authors' Addresses

   Young Lee (Ed.)
   Huawei Technologies
   1700 Alma Drive, Suite 100
   Plano, TX 75075, USA
   Phone: (972) 509-5599 (x2240)
   Email: ylee@huawei.com


   Greg M. Bernstein (ed.)
   Grotto Networking
   Fremont California, USA

   Phone: (510) 573-2237
   Email: gregb@grotto-networking.com

   Jonas Martensson
   Acreo
   Email:Jonas.Martensson@acreo.se

   Tomonori Takeda
   NTT Corporation
   3-9-11, Midori-Cho
   Musashino-Shi, Tokyo 180-8585, Japan
   Email: takeda.tomonori@lab.ntt.co.jp


   Tomohiro Otani
   KDDI R&D Laboratories, Inc.
   2-1-15 Ohara Kamifukuoka Saitama, 356-8502. Japan
   Phone:  +81-49-278-7357
   Email:  otani@kddilabs.jp

Intellectual Property Statement

   The IETF Trust takes no position regarding the validity or scope of
   any Intellectual Property Rights or other rights that might be
   claimed to pertain to the implementation or use of the technology
   described in any IETF Document or the extent to which any license
   under such rights might or might not be available; nor does it
   represent that it has made any independent effort to identify any
   such rights.

   Copies of Intellectual Property disclosures made to the IETF
   Secretariat and any assurances of licenses to be made available, or
   the result of an attempt made to obtain a general license or


Lee & Bernstein       Expires December 29, 2009               [Page 10]


Internet-Draft       PCEP Extension for WSON RWA              June 2009


   permission for the use of such proprietary rights by implementers or
   users of this specification can be obtained from the IETF on-line IPR
   repository at http://www.ietf.org/ipr

   The IETF invites any interested party to bring to its attention any
   copyrights, patents or patent applications, or other proprietary
   rights that may cover technology that may be required to implement
   any standard or specification contained in an IETF Document. Please
   address the information to the IETF at ietf-ipr@ietf.org.

Disclaimer of Validity

   All IETF Documents and the information contained therein are provided
   on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE
   REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE
   IETF TRUST AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL
   WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY
   WARRANTY THAT THE USE OF THE INFORMATION THEREIN WILL NOT INFRINGE
   ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS
   FOR A PARTICULAR PURPOSE.

Acknowledgment

   Funding for the RFC Editor function is currently provided by the
   Internet Society.
























Lee & Bernstein       Expires December 29, 2009               [Page 11]


Html markup produced by rfcmarkup 1.129c, available from https://tools.ietf.org/tools/rfcmarkup/