Network Working Group                                            Y. Lee
Internet Draft                                                   Huawei
Intended status: Standard                                   R. Casellas
Expires: August 2011                                               CTTC





                                                      February 18, 2011


         PCEP Extension for WSON Routing and Wavelength Assignment


                     draft-lee-pce-wson-rwa-ext-00.txt


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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.  Code Components extracted from this
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Abstract

   This draft provides the Path Computation Element communication
   Protocol (PCEP) extensions for the support of Routing and Wavelength
   Assignment (RWA) in 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.

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 RFC-2119 0.

Table of Contents


   1. Introduction...................................................3
   2. WSON PCE Architectures and Requirements........................4
      2.1. Encoding of a new RWA path request........................5
         2.1.1. Wavelength Range Constraint TLV......................6
      2.2. Encoding of a RWA Path Reply..............................9
         2.2.1. Wavelength Range Constraint TLV.....................11
      2.3. Error Indicator..........................................11
      2.4. NO-PATH Indicator........................................12
   3. Manageability Considerations..................................12
      3.1. Control of Function and Policy...........................12
      3.2. Information and Data Models, e.g. MIB module.............13
      3.3. Liveness Detection and Monitoring........................13
      3.4. Verifying Correct Operation..............................13
      3.5. Requirements on Other Protocols and Functional Components13
      3.6. Impact on Network Operation..............................14
   4. Security Considerations.......................................14
   5. IANA Considerations...........................................14



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   6. Acknowledgments...............................................14
   7. References....................................................14
      7.1. Normative References.....................................14
      7.2. Informative References...................................15
   Authors' Addresses...............................................16
   Intellectual Property Statement..................................16
   Disclaimer of Validity...........................................16



       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 the PCEP extension for the support of Routing
   and Assignment (RWA) in Wavelength Switched Optical Networks (WSON)
   based on the requirements specified in [PCE-RWA].

   WSON refers to WDM based optical networks in which switching is
   performed selectively based on the wavelength of an optical signal.
   WSONs can be transparent (A transparent optical network is made up of
   optical devices that can switch but not convert from one wavelength
   to another, all within the optical domain) or translucent
   (regenerators are sparsely placed in the network).

   A LSC Label Switched Path (LSP) may span one  or several transparent
   segments, which are delimited by 3R regenerators (typically with
   electronic regenerator and wavelength conversion). Each transparent
   segment or path in WSON is referred to as an optical path. An optical
   path may span multiple fiber links and the path should be assigned
   the same wavelength for each link. In such case, the optical path is


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   said to satisfy the wavelength-continuity constraint. Note that two
   optical paths within a WSON LSP need not operate on the same
   wavelength (due to the wavelength conversion capabilities). Two
   optical paths 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
   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
   an LSC Label Switched Path (LSP) 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.

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

       2. WSON PCE Architectures and Requirements

   Figure 1 shows one typical PCE based implementation, which is
   referred to as Combined Process (R&WA). With this architecture, the
   two processes of routing and wavelength assignment are accessed via a
   single PCE. This architecture is the base architecture from which the
   requirements have been specified in [PCE-RWA] and the PCEP extensions
   that are going to be specified in this document based on this
   architecture.

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


               Figure 1 Combined Process (R&WA) architecture



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                         2.1. Encoding of a new RWA path request

   The current RP object is used to indicate routing related information
   in a new path request per [RFC5440]. Since a new RWA path request
   involves both routing and wavelength assignment, the wavelength
   assignment related information in the request SHOULD be coupled in
   the path request.

   The Wavelength Assignment (WA) object is used to indicate wavelength
   specific request in the path request.

   The format of a PCReq message after incorporating the WA object is as
   follows:

      <PCReq Message> ::= <Common Header>

                          [<svec-list>]

                          <request-list>



      Where:

         <request-list>::=<request>[<request-list>]

         <request>::= <RP>

                      <ENDPOINTS>

                      <WA>

                      [other optional objects...]

   Note: if WA object is present in the request, the WA object MUST be
   encoded after the ENDPOINTS object.

   The format of the Wavelength Assignment (WA) object body is as
   follows:

       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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                          Flags                           |O |E|
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                        Request-ID-number                      |


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      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                                                               |
      //                      Optional TLVs                          //
      |                                                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                     Figure 10: WA Object Body Format

      Flags (32 bits)



   The following new flags SHOULD be defined

   o  E (Explicit - 1 bit): When E bit is set to 1, this indicates that
      the label assigned by the PCE must be explicit. That is, the
      selected way to convey the allocated wavelength is by means of
      Explicit Label Control (ELC) [RFC4003] for each hop of a computed
      LSP. Otherwise, the label assigned by the PCE needs not be
      explicit (i.e., in the form of label sets). This is to allow the
      distributed WA.

   o  O (Order - 2 bit): O bit is used to indicate the wavelength policy
      constraint in regard to the order of wavelength assignment The
      following indicators should be defined:

         00 - Reserved

         01 - Random Assignment

         10 - First Fit (FF) in descending Order

         11 - First Fit (FF) in ascending Order

   Request-ID-number is same as that in the RP object.

      2.1.1. Wavelength Range Constraint TLV

   For any request that contains a wavelength assignment object, the
   requester (PCC) MUST be able to specify a restriction on the
   wavelengths to be used. This restriction is to be interpreted by the
   PCE as a constraint on the tuning ability of the origination laser
   transmitter or on any other maintenance related constraints. Note
   that if the LSP LSC spans different segments, the PCE MUST have
   mechanisms to know the tunability restrictions of the involved
   wavelength converters / regenerators.


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    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                          Format                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                     Link Identifier                           |
   |                          . . .                                |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                     Wavelength [1]                            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   //                        . . . .                              //
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                     Wavelength [N]                            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


   Format: The format of the link identifier (32 bits)

      0 -- Reserved

      1 -- Local Interface IPv4 Address

      2 -- Local Interface IPv6 Address

      4 -- Unnumbered Interface ID



   The link identifier field can be an IPv4, IPv6 or unnumbered
   interface ID and are encoded as follows:


   IPv4 prefix Subobject

    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |X|  Type = 1   |     Length    | IPv4 address (4 bytes)        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | IPv4 address (continued)      | Prefix Length |   Attribute   |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   IPv6 prefix Subobject


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    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |X|  Type = 2   |     Length    | IPv6 address (16 bytes)       |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | IPv6 address (continued)                                      |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | IPv6 address (continued)                                      |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | IPv6 address (continued)                                      |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | IPv6 address (continued)      | Prefix Length |   Attribute   |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Unnumbered Interface ID Subobject

    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |X|  Type = 4   |     Length    |    Reserved   |  Attribute    |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                        TE Router ID                           |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                        Interface ID                           |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+




   The Wavelength is defined in [Lambda-Label] as follows:

    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |Grid | C.S   |    Identifier   |              n                |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


   See [Lambda-Label] for a description of Grid, C.S, Identifier and n.





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   Note that each 32 bit Wavelength Field is designated to represent one
   wavelength restriction on the associated link identifier.

                         2.2. Encoding of a RWA Path Reply

   The ERO is used to encode the path of a TE LSP through the network.
   The ERO is carried within a given path of a PCEP response, which is
   in turn carried in a PCRep message to provide the computed TE LSP if
   the path computation was successful. The preferred way to convey the
   allocated wavelength is by means of Explicit Label Control (ELC)
   [RFC4003].

   In order to encode wavelength assignment, the Wavelength Assignment
   (WA) Object needs to be employed to be able to specify wavelength
   assignment. Since each segment of the computed optical path is
   associated with wavelength assignment, the WA Object should be
   aligned with the ERO object.

   The format of a PCEP response after incorporating the WA object is as
   follows:

   <response>::=<RP>

                [<NO-PATH>]

                [<attribute-list>]

                [<path-list>]



   <path-list>::=<path>[<path-list>]

   <path>::= <ERO><attribute-list>

   where:

       <attribute-list>::=[<LSPA>]

                          [<BANDWIDTH>]

                          [<metric-list>]

                          [<IRO>]

                          [<WA>]



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The Wavelength Assignment (WA) Object is defined as follows:

       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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                          Flags                           |O |E|
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                      Request-ID-number                        |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                                                               |
      //                      Optional TLVs                          //
      |                                                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                     Figure 11: WA Object Body Format

      Flags (32 bits)

   The following new flags SHOULD be defined

   o  E (Explicit - 1 bit): When E bit is set to 1, this indicates that
      the label assigned by the PCE is explicit in response to the
      original request. In such case, there will be only one wavelength
      assigned to the segment of the path. Otherwise, the label assigned
      by the PCE is in the form of label sets (i.e., there is a set of
      multiple wavelengths). In such case, the final assignment of
      wavelength will be done by the nodes in a distributed fashion.

   o  O (Order - 2 bit): O bit is used to indicate the wavelength policy
      constraint applied in choosing the wavelength for the segment of
      the path. This only applied when E bit is set to 1.

         01 - Random Assignment

         10 - First Fit (FF) in descending Order

         11 - First Fit (FF) in ascending Order

   The Request-ID-Number is the same as that in the WA Object in the
   Path Request message (See Section 2.1.)


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      2.2.1. Wavelength Range Constraint TLV

   This TLV is used as a part of optional TLV in the Wavelength
   Assignment (WA) Object defined in the previous section. The purpose
   of this TLV is to specify the wavelength assignment for the segment
   of the computed path. If E bit is set to 1 in the WA Object, then
   there will be only one entry for the wavelength field. If E bit is
   set to 0, then there will be multiple wavelength fields.

    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                          Format                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                     Link Identifier                           |
   |                         . . .                                 |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                     Wavelength [1]                            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   //                        . . . .                              //
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                     Wavelength [N]                            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


The meaning of each field has been defined in Section 2.1.1.


                         2.3. Error Indicator

   To indicate errors associated with the RWA request, a new Error Type
   (TDB) and subsequent error-values are defined as follows for
   inclusion in the PCEP-ERROR Object:

   A new Error-Type (TDB) and subsequent error-values are defined as
   follows:









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   o  Error-Type=TBD; Error-value=1: if a PCE receives a RWA request and
      the PCE is not capable of processing the request due to
      insufficient memory, the PCE MUST send a PCErr message with a
      PCEP-ERROR Object (Error-Type=TDB) and an Error-value(Error-
      value=1).  The PCE stops processing the request.  The
      corresponding RWA request MUST be cancelled at the PCC.

   o  Error-Type=TBD; Error-value=2: if a PCE receives a RWA request and
      the PCE is not capable of RWA computation, the PCE MUST send a
      PCErr message with a PCEP-ERROR Object (Error-Type=15) and an
      Error-value (Error-value=2). The PCE stops processing the request.
      The corresponding RWA computation MUST be cancelled at the PCC.




                         2.4. NO-PATH Indicator


   To communicate the reason(s) for not being able to find RWA for the
   path request, the NO-PATH object can be used in the PCRep message.
   The format of the NO-PATH object body is defined in [RFC5440].  The
   object may contain a NO-PATH-VECTOR TLV to provide additional
   information about why a path computation has failed.

   Two new bit flags are defined to be carried in the Flags field in the
   NO-PATH-VECTOR TLV carried in the NO-PATH Object.

   o  Bit TDB: When set, the PCE indicates no feasible route was found
      that meets all the constraints associated with RWA.

   o  Bit TDB: When set, the PCE indicates that no wavelength was
      assigned to at least one hop of the route in the response.



       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:


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   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  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 [RFC5440].


                         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
   [RFC5440]


                         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.




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                         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.



       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.

   [RFC3471] Berger, L., "Generalized Multi-Protocol Label Switching
             (GMPLS) Signaling Functional Description", RFC 3471,
             January 2003.





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   [RFC3473] Berger, L., Ed., "Generalized Multi-Protocol Label
             Switching (GMPLS) Signaling Resource ReserVation Protocol-
             Traffic Engineering (RSVP-TE) Extensions", RFC 3473,
             January 2003.

   [RFC3477] Kompella, K. and Y. Rekhter, "Signalling Unnumbered Links
             in Resource ReSerVation Protocol - Traffic Engineering
             (RSVP-TE)", RFC 3477, January 2003.

   [RFC4003] Berger, L., "GMPLS Signaling Procedure for Egress Control",
             RFC 4003, February 2005.

   [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.

   [RFC5440] Vasseur, JP., Ed. and JL. Le Roux, Ed., "Path Computation
             Element (PCE) communication Protocol", RFC 5440, March
             2009.

                         7.2. Informative References

   [WSON-Frame] Lee, Y. and Bernstein, G. (Editors), and W. Imajuku,
             "Framework for GMPLS and PCE Control of Wavelength Switched
             Optical Networks", draft-ietf-ccamp-rwa-wson-framework,
             work in progress.

   [PCE-RWA] Lee, Y., et. al., "PCEP Requirements for WSON Routing and
             Wavelength Assignment", draft-ietf-pce-wson-routing-
             wavelength, work in progress.

   [Lambda-Label] Tomohiro, O. and D. Li, "Generalized Labels for
             Lambda-Switching Capable Label Switching Routers", draft-
             ietf-ccamp-gmpls-g-694-lambda-labels, work in progress.



       8. Contributors








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Authors' Addresses

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


   Ramon Casellas (Ed.)
   CTTC

   Email: ramon.casellas@cttc.es




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Internet-Draft       PCEP Extension for WSON RWA          February 2011


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Acknowledgment

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