One document matched: draft-lee-pce-wson-routing-wavelength-00.txt


Network Working Group                                          Y. Lee 
Internet Draft                                                 Huawei 
Intended status: Standard Track                            G. Bernstein  
Expires: May 2008                                    Grotto Networking 
                                                      October 29, 2007 
 
                                      
    Path Computation Element Communication Protocol (PCEP) Requirements 
       and Extensions for the Support of Wavelength Switched Optical 
                                 Networks  
               draft-lee-pce-wson-routing-wavelength-00.txt 


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Copyright Notice 

   Copyright (C) The IETF Trust (2007). 

Abstract 

 
 
 
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   This memo provides application-specific PCEP requirements and 
   protocol enhancements for the support of Wavelength Switched Optical 
   Networks (WSON).  Lightpath provisioning in WSONs requires a routing 
   and wavelength assignment (RWA) process.  Different computational 
   architectures for the RWA process are given and the PCEP extensions 
   needed to support these architectures are defined. 

    

    

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. Terminology.................................................3 
   2. Introduction................................................4 
   3. Background: RWA Computation Architectures....................4 
   4. PCECP Requirements..........................................5 
      4.1. RWA Computation Options.................................6 
      4.2. Timeliness Characteristics of lightpath.................7 
      4.3. Duration of lightpath...................................7 
      4.4. Optimization Degree.....................................8 
      4.5. Wavelength Selection Preference.........................8 
      4.6. Wavelength Assignment and Wavelength Set Information.....9 
      4.7. Lightpath Route Parameters..............................9 
   5. Protocol extensions for support of WSON Routing and Wavelength 
   Assignment (RWA)...............................................9 
      5.1. RWA Computation Options.................................9 
      5.2. Lightpath Route Parameter TLV..........................11 
      5.3. Wavelength Selection Preferences.......................12 
      5.4. Wavelength Suggestion/Restriction TLV..................14 
      5.5. Error Indicator........................................14 
      5.6. NO-PATH Indicator......................................14 
   6. Manageability Considerations................................15 
      6.1. Control of Function and Policy.........................15 
      6.2. Information and Data Models, e.g. MIB module...........16 
      6.3. Liveness Detection and Monitoring......................16 
      6.4. Verifying Correct Operation............................16 
      6.5. Requirements on Other Protocols and Functional Components16 
      6.6. Impact on Network Operation............................16 
   7. Security Considerations.....................................17 
 
 
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   8. IANA Considerations........................................17 
   9. Acknowledgments............................................17 
   10. References................................................17 
      10.1. Normative References..................................17 
      10.2. Informative References................................18 
   Author's Addresses............................................18 
   Intellectual Property Statement................................19 
   Disclaimer of Validity........................................19 
    
1. Terminology 

   The terminology explained herein complies with [RFC4655]. 

   PCC: Path Computation Client: Any client application requesting a 
   path computation to be performed by a Path Computation Element. 

   PCE: Path Computation Element: An entity (component, application or 
   network node) that is capable of computing a network path or route 
   based on a network graph and applying computational constraints. 

   TED: Traffic Engineering Database which contains the topology and 
   resource information of the domain.  The TED may be fed by IGP 
   extensions or potentially by other means. 

   PCECP: The PCE Communication Protocol: PCECP is the generic abstract 
   idea of a protocol that is used to communicate path computation 
   requests a PCC to a PCE, and to return computed paths from the PCE to 
   the PCC.  The PCECP can also be used between cooperating PCEs. 

   PCEP: The PCE communication Protocol: PCEP is the actual protocol 
   that implements the PCECP idea. 

   RWA: Routing and Wavelength Assignment 

   WSON: Wavelength Switched Optical Networks: WDM based optical 
   networks in which switching is performed selectively based on the 
   center wavelength of an optical signal. 

   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]. 

   These terms are also used in the parts of this document that specify 
   requirements for clarity of specification of those requirements. 

    

 
 
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2. 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 PCCs.  A PCC is 
   shown to be any network component that makes such a request and may 
   be for instance an Optical Switching Element with a WDM network.  The 
   PCE, itself, can be located anywhere within the network, and may be 
   within an optical switching element, an NMS or Operational Support 
   System (OSS), or may be an independent network server. 

   The PCECP 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 the PCECP.  Additional application-
   specific requirements for PCECP are deferred to separate documents. 

   This document provides a set of application-specific PCECP 
   requirements and protocol enhancements for support of path 
   computation in Wavelength Switched Optical Network (WSON).  WSON 
   refers to Wavelength Division Mulitiplexing (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.  In order to provision a light path, both routing and 
   wavelength assignment (RWA) are required. 

    

3. Background: RWA Computation Architectures 

   The WSON framework [WSON Frame] document defines the following RWA 
   computation architectures.  

   o Combined RWA --- Both routing and wavelength assignment are 
      performed at a single computational entity.  This choice assumes 
      that computational entity has sufficient WSON network link/nodal 
      and topology information to be able to compute RWA. 

   o Separate Routing and WA --- Separate entities perform routing and 
      wavelength assignment.  The path obtained from the routing 
      computational entity must be furnished to the entity performing 
      wavelength assignment. 

   o Routing with Distributed WA --- Routing is performed at a 
      computational entity while wavelength assignment is performed in a 
      distributed fashion across the nodes along the path. 

 
 
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   For the Combined RWA architecture, there are two possible computing 
   entities: (i) the NE is the computational entity -- in this case, 
   there is no separate PCE as the NE assumes PCE function; (ii) a 
   separate PCE is the computational entity.  This document is only 
   concerned with case (ii). In this case, the PCE should perform both 
   routing (R) and wavelength assignment (WA) upon request of the PCC. 

   For the Separate Routing and Wavelength architecture, there can be 
   two variations: 

 
   o A separate PCE will perform only wavelength assignment (WA) while 
      the NE performs the route calculation based on its local knowledge. 
      In this case, the NE should furnish the route list to the PCE so 
      that the PCE would be able to assign wavelength to the route. 

   o One PCE performs the routing (R) function while another PCE 
      performs the Wavelength Assignment (WA) function in a tandem 
      fashion.  The fact that two PCEs are involved (one for Routing and 
      one for Wavelength Assignment (WA)) could be invisible to the 
      original PCC. 

 
   For the Routing with Distributed WA architecture, the PCE is only 
   responsible for routing (i.e., path computation), not for exact 
   wavelength assignment. The exact assignment of wavelength would be 
   performed at the NEs along the path in a distributed fashion. However, 
   the PCE may choose to limit the wavelengths that can be used (i.e., 
   suggesting the wavelength set to the NEs)  

    

4. PCECP Requirements 

   This section provides the PCECP requirements to support WSON routing 
   and wavelength assignment (RWA) application.  The requirements 
   specified in this section are detailed requirements based on high-
   level specification in the WSON Framework draft [WSON FRAME].  The 
   requirements specified here should be regarded as application-
   specific requirements and are justifiable based on the extensibility 
   clause found in section 6.1.14 of [RFC4657]: 

   The PCECP MUST support the requirements specified in the application-
   specific requirements documents.  The PCECP MUST also allow 
   extensions as more PCE applications will be introduced in the future. 

 
 
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   The PCEP SHOULD support the following capabilities either via 
   creation of new objects and/or modification of existing object where 
   applicable. 

    

    4.1. RWA Computation Options 

   The following RWA computation options should be conveyed in the PC 
   Request:  

   o The request is for Wavelength Assignment (WA) only.  This case may 
      arise when the NE is capable of route calculation at the node 
      level (e.g., via an IGP-TE) but with no wavelength information      
      available at the node level, or when two PCEs work in tandem with 
      one performing the routing (R) function and another wavelength 
      assignment (WA).  In either case, the calculated route list at one 
      computing entity should be supplied in the request message to the 
      other computing entity where WA is applied. 

   o The request is for both Routing and Wavelength Assignment (R+WA). 
      This case may arise when the NE is not capable of both route 
      calculation and wavelength assignment at the node level or a more 
      optimal RWA is desired.  

   o The request is for Routing (R) only.  This case may arise when the 
      NE is not capable of route calculation at the node level while 
      wavelength assignment is done at the node level in a distributed 
      fashion. 

   o The request is for Routing (R) with the suggested/restricted 
      wavelength set. This is a variation from the Routing only option. 
      With this option, the PCE computes the route and the candidate 
      wavelengths associated with the route. In this case, the exact 
      wavelength assignment is to be performed at the NE level.  

 
   The corresponding PC Reply message should include the following 
   information: 

   o An indicator that conveys the original request was for (i) WA only; 
      (ii) R+WA; (iii) R only; (iv) R with the suggested/restricted 
      wavelength set 




 
 
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   o The route list and the recommended wavelength(s) to be used for 
      the route. The encoding of this requirement can be fulfilled with 
      the ERO object and ERO Label subobject within the ERO as defined 
      in [RFC3471]. See section 4.6 for details of wavelength label 
      assignment.  

   o In the case of failure to find a proper route or wavelength 
      assigned to the route, proper reasons for the failure should be 
      conveyed: (i) route not found; (ii) wavelength not found (i.e., 
      wavelength blocking); (iii) both route and wavelength not found. 

    

    4.2. Timeliness Characteristics of lightpath 

   The request may indicate specific timeliness lightpath 
   characteristics associated with the request: 

   o Time Critical: this type of request is useful for those lightpath 
      establishment requests used for restoration of service or other 
      high priority real time services. 

   o Soft Time Bounds: this type of request is a more typical new 
      connection request.  While expected to be responsive, there should 
      be more time to take into account network optimization. 

   o Scheduled: this type of request is useful when the requested 
      lightpath connections are not time critical (i.e., the request is 
      significantly ahead of their intended "in-service" time.  It is to 
      be noted that we will not explicitly deal with scheduled case in 
      this document but the optimization can be handled via [PCE-GCO]. 

   The reply should indicate the original timeliness characteristics of 
   the lightpath request with path computation results.  

    

    4.3. Duration of lightpath 

   The request may indicate specific lightpath duration information 
   associated with the request. This may be useful to the PCE since it 
   is not worthwhile to optimize lightpaths with relatively short 
   duration as compared to pseudo-static paths.   

    


 
 
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    4.4. Optimization Degree 

   The PC Request Message should indicate the degree of optimization 
   associated with lightpath computation. 

 
   o Concurrent Optimization: multiple lightpaths requested at one time. 

   o Lightpath(s) and backup lightpath(s) requested at one time. 

   o Sequential Optimization: single lightpath requested at a time. 

   The PC Reply Message should include the original optimization degree 
   associated with the request when replying the path computation 
   results. 

 
    4.5. Wavelength Selection Preference 

   The PC Request may indicate the Wavelength Selection Preference to 
   which a path computation request is applied. 

   The Wavelength Selection Preference to be supported at the minimum is: 

   o Random 

   o First Fit 

   o Most Used 

   o Least Loaded 

   o Don't care: default 

   Note that the objective functions to be supported for a single LSP 
   request are listed in [PCEP] and [PCE-OF] and that the objective 
   functions to be supported for a concurrent LSP request are listed in 
   [PCE-GCO] and [PCE-OF]. 

   The PC Reply should indicate which wavelength selection preference 
   has actually been applied.  

    



 
 
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    4.6. Wavelength Assignment and Wavelength Set Information 

   The PCE MUST specify the wavelength assignment and/or wavelength set 
   information in response to the wavelength assignment/wavelength set  
   Request made by the PCC in the PCReq message.  

   If the original request is either for both Routing and Wavelength 
   Assignment or for Wavelength Assignment only, the exact wavelength 
   assignment result can be conveyed to PCC using the ERO object and ERO 
   Label subobject within the ERO. Note that this is not a new 
   requirement. Current PCEP allows this mechanism which is defined as 
   the Label Set mechanism in [RFC3471]. 

   If the original request is for Routing with wavelength 
   suggested/restricted wavelength set, then the Wavelength Set 
   information must be provided to the PCC.  

    

    4.7. Lightpath Route Parameters 

   The following Lightpath Route Parameters should be indicated: 

   o Bidirectional Assignment of wavelengths for a bidirectional LSP 
      request. 

   o Possible simultaneous assignment of the same wavelength to primary 
      and backup paths. 

   The PC Reply Message should include the original lightpath route 
   parameter associated with the request when replying the path 
   computation results. 
 
 
5. Protocol extensions for support of WSON Routing and Wavelength 
   Assignment (RWA) 

    

    5.1. RWA Computation Options 

   The PCE has to include the RWA computation option in the PCReq 
   message in order to convey a particular computation option.  To 
   support such indication a new flag, the RC flag, is defined in the RP 
   (Request Parameter) Object.  The PCE also has to include the 
   Directionality of Wavelength Assignment indicator when the request is 
 
 
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   for a bidirectional TE LSP.  To support such indication a new flag, I 
   flag, is defined in the RP Object. 

 
   The RC flag and I flag are defined in the RP (Request Parameter) 
   object 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 
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
   |       Reserved    |            Flags   |I|RC|D|M|F|O|B|R| Pri | 
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
   |                        Request-ID-number                      | 
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
   |                                                               | 
   //                      Optional TLV(s)                        // 
   |                                                               | 
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
    
    
       Figure 1            RP object body format in the PCReq Message 

 
   RC bits (Routing wavelength Computation bits - 2 bits): 

   o 11: Request is for both R (Routing) and Wavelength Assignment (WA). 

   o 01: Request is for Wavelength Assignment (WA) only. 

   o 10: Request is for Routing (R) with suggested/restricted 
      Wavelength Set 

   o 00: Request is for Routing (R) only.  

   When RC bit is set to 11 in a PCReq message, the requesting PCC 
   requires the PCE to provide in the PCRep message the assigned 
   wavelength associated with the computed path.  This request is for 
   both Routing (R) and Wavelength Assignment (WA). 

   When RC bit is set to 01 in a PCReq message, the requesting PCC 
   requires the PCE only to provide wavelength assignment (WA).  In such 
   case, the PCC must provide the already computed route (as indicated 
   by the ERO and the Bandwidth Object following the RP object) to which 
   the PCE would assign the wavelengths.  Note that this option is to 
   fulfill one of the RWA computational architectures, namely, the 
   Separate Routing and WA option. 
 
 
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   When RC bit is set to 10, then the PCE is expected to provide some 
   suggestive or restrictive wavelength information associated with the 
   route.  

   When RC bit is set to either 11, 01 or 10, then additional parameters 
   associated with the requested lightpath should be provided in 
   optional lightpath Route Parameter TLV (as specified in Section 4.7) 
   within the RP object. See Section 5.2 for the encoding of Lightpath 
   Route Parameter TLV. 

   When B bit is set in the RP object in a PCReq message, this indicates 
   that the path computation request relates to a bidirectional TE LSP 
   [PCEP].  In such case, a new flag, I flag, should be defined in the 
   RP object should be defined in order to indicate that a bidirectional 
   assignment of wavelength be required for the bidirectional TE LSP. 

   I bit (dIrectionality bit - 1 bit): When set, the request is a 
   bidirectional wavelength assignment.  Otherwise, the request is a 
   unidirectional wavelength assignment. 

   The RP object in the PC Reply message should properly indicate the 
   original request for the RWA Computation (RC) bit and I bit that have 
   actually been applied by the PCE. The actual route list and 
   wavelength assignment is to be found in the ERO object and within an 
   ERO an ERO Label subobject. An ERO Label subobject can be used to 
   indicate the wavelength to be used at a particular node. Note that 
   current GMPLS signaling supports an explicit route object (ERO) and 
   within an ERO an ERO Label subobject.  

    

    5.2. Lightpath Route Parameter TLV 

   When the RC bit is set to either 11, 01 or 10 in the RP object 
   associated with PC Req message, then the following TLV should be 
   included as part of the RP object within the PC Request message.  

   The format of the Lightpath Route Parameter TLV is as follows: 

 
 





 
 
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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 
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
   |     Type      |    Length     |                               | 
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
   |         Bidirectional Assignment of wavelengths               | 
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
   |         Same wavelength to primary and backup paths           |     
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+      

    
              Type     To be defined by IANA (suggested value = ) 
              Length   Variable 
              Value    Bidirectional Assignment of wavelengths (0 or 1) 
                      Same Wavelength to primary and backup (0 or 1) 
            
 
   Figure 2    The Lightpath Route Parameter TLV in the RP object in the 
                              PC Rep Message 

    

    5.3. Wavelength Selection Preferences 

   When the RC (RWA Computation) option is associated with computing 
   wavelength assignment in the RP object of the PC Request message, 
   then the following Wavelength Selection Preference TLV may be 
   included in the RP object as an optional TLV. 

   The format of the Wavelength Selection Preference TLV is as follows: 

 
 













 
 
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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 
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
   |     Type      |    Length     |                               | 
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
   |                Wavelength Selection Preference                | 
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
   |                           TDB                                 | 
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
    
              Type     To be defined by IANA (suggested value = ) 
              Length   Variable 
              Value    Wavelength Selection Preference 
 
     Figure 3    The Wavelength Selection/Assignment Preferences TLV in 
                    the RP object in the PC Rep Message 

 
   Five wavelength selection preferences are defined in this document 
   and their identifier should be assigned by IANA (suggested value) 

   Function 
   Code            Description 
 
   1               Random 
 
   2               First Fit 
 
   3               Most Used 
 
   4               Least Loaded 
 
   5              Don't Care 
    

   The Wavelength Selection Preference TLV should also be included in 
   the RP object in the PC Reply message to indicate which wavelength 
   selection preference has actually been applied by the PCE in its 
   wavelength assignment procedure.   

    

    


 
 
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    5.4. Wavelength Suggestion/Restriction TLV 

   With the Routing with Distributed Wavelength Assignment option, the 
   PC Reply should specify the wavelength set information in response to 
   the wavelength assignment/wavelength set Request made by the PCC in 
   the PCReq message if so requested by the setting of the RC bit in the 
   RP object in the PCReq message.   

   We refer to this information as wavelength restriction TLV.  

   The encoding of wavelength Suggestion/Restriction TLV is to be 
   provided in the next version.  

      
    5.5. Error Indicator 

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

   A new Error-Type (15) and subsequent error-values are defined as 
   follows: 

   Error-Type=15 and Error-Value=1: if a PCE receives a RWA computation 
   request and the PCE is not capable of RWA, the PCE MUST send a PCErr 
   message with a PCEP ERROR object (Error-Type=15) and an Error-Value 
   (Error-Value=1).  The corresponding RWA computation request MUST be 
   cancelled. 

   To indicate an error associated with policy violation, a new error 
   value "RWA not allowed" should be added to an existing error code for 
   policy violation (Error-Type=6) as defined in [PCEP]. 

   Error-Type=6; Error-Value=3: if a PCE receives a RWA computation 
   request which is not compliant with administrative privileges (i.e., 
   the PCE policy does not support RWA), the PCE sends a PCErr message 
   with a PCEP-ERROR Object (Error-Type=6) and an Error-Value (Error-
   Value=3).  The corresponding RWA computation MUST be cancelled. 

    5.6. NO-PATH Indicator  

   To communicate the reason(s) for not being able to find RWA 
   computation, the NO-PATH object can be used in the PCRep message.   

   The format of the NO-PATH object body is as follows: 


 
 
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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 
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
       |C|        Flags                |          Reserved             | 
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
       |                                                               | 
       //                      Optional TLV(s)                        // 
       |                                                               | 
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
 
 
                      Figure 4 NO-PATH object format 

 
   Flags (16 bits).  The C flag is defined in [PCEP]. 
 
   Two new bit flags are defined in the NO-PATH-VECTOR TLV carried in 
   the NO-PATH Object: 
 
   0x08: when set, the PCE indicates that no path was found. 
 
   0x10: when set, the PCE indicates that no wavelength was found 
   associated with RWA computation in the PCRep message. 

    

6. Manageability Considerations 

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

    6.1. 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: 

 
 
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   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. 

 
    6.2. 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. 

    6.3. Liveness Detection and Monitoring 

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

 
    6.4. Verifying Correct Operation 

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

 
    6.5. Requirements on Other Protocols and Functional Components 

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

 
    6.6. Impact on Network Operation 

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

 
 
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7. 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.   

    

8. IANA Considerations 

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

    

9. Acknowledgments 

    

10. References 

    10.1. Normative References 

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

   [RFC2234] Crocker, D. and Overell, P.(Editors), "Augmented BNF for 
             Syntax Specifications: ABNF", RFC 2234, Internet Mail 
             Consortium and Demon Internet Ltd., November 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", 
             draft-ietf-pce-pcep, work in progress. 



 
 
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   [PCE-OF]  Le Roux, JL., Vasseur, JP., and Y. Lee, "Objective Function 
             encoding in Path Computation Element communication and 
             discovery protocols", draft-ietf-pce-pce-of, work in 
             progress.  

   [PCE-GCO] Y. Lee, J.L. Le Roux, D. King, and E. Oki, "Path 
             Computation Element Communication Protocol (PCECP) 
             Requirements and Protocol Extensions In Support of Global 
             Concurrent Optimization", draft-ietf-pce-global-concurrent-
             optimization, work in progress.  

    

    10.2. Informative References 

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

   [ISIS-PCED] Le Roux, J. and JP. Vasseur, "IS-IS protocol extensions 
             for Path Computation Element (PCE) Discovery", draft-ietf-
             pce-disco-proto-isis, work in progress. 

   [OSPF-PCED] Le Roux, J. and JP. Vasseur, "OSPF protocol extensions 
             for Path Computation Element (PCE) Discovery", draft-ietf-
             pce-disco-proto-ospf, work in progress.  

    

 
Author's Addresses 

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





 
 
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   Greg Bernstein (ed.)  
   Grotto Networking  
   Fremont, CA, USA  
           
   Phone: (510) 573-2237  
   Email: gregb@grotto-networking.com  
    
    
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