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Draft about The Constraint Information Overview on WDM Switch Optical Network




Dear All,

With this document we would like to share with you the overview of WDM switch network constraints information, In addition we declared the the mechnism of link connectivity verification on WDM switch network.

This is a new draft, welcome everyone to discuss and contrbiute your special suggestion. We are appreciating any of your contribution.


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Network Working Group                                     Zhihong Kang 
                                                           Zhenyu Wang 
                                                              Feng Gao 
Internet Draft                                                     ZTE 
Intended status:                                          July 7, 2008 
Expires: Jan 2009 
 
                                      
      Link Connectivity and Common Constraint Information Extension to 
                  GMPLS for WDM Switched Optical Networks 
                  draft-kang-ccamp-WDM-switch-info-00.txt 


Status of this Memo 

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Copyright Notice 

   Copyright (C) The IETF Trust (0000). 

Abstract 

   This document provides the mechanism of link connectivity 
   verification and the constraint information extension to route for 
   static light path computation and selection in WDM network. 

 
 
 
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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 
        . 

Table of Contents 

    
   1. Introduction................................................2 
   2. Terminology.................................................4 
   3. Link Verification...........................................4 
   4. Constraint Information......................................5 
      4.1. WDM Link...............................................5 
      4.2. WDM Link Constraint....................................5 
      4.3. OCH Constraint.........................................6 
      4.4. Tunable Laser..........................................6 
   5. Information Model..........................................6 
      5.1. Link Information......................................6 
      5.2. Lambda Group ID.......................................7 
      5.3. Wavelength Label......................................9 
   6. Application to OSPF GMPLS extensions........................9 
      6.1. Link Sub-TLVs.........................................9 
         6.1.1. Maximum of optical channels sub-TLV...............9 
         6.1.2. Link Constraint sub-TLV..........................9 
         6.1.3. Wavelength Availability,Switch Capability Sub-TLV15 
         6.1.4. Reachable OTU Sub-TLV...........................16 
   7. Security Considerations....................................17 
   8. IANA Considerations........................................18 
   9. Acknowledgments............................................18               
   10. Acknowledgments..........................................18 
   11. References................................................18 
      11.1. Normative References.................................18 
      11.2. Informative References...............................18 
   Author's Addresses............................................19 
   Intellectual Property Statement...............................19 
   Disclaimer of Validity........................................20 
    
1. Introduction 

   This document provides foundational information model Appling ASON to 
   WDM network, we called the series of function aggregation for ASON 
   applied to WDM "WASON" (WDM Automatic Switch Optical Network). This 
   likewise includes automatic discovery, route, and signaling. But the 
   current standard RFC cannot completely support WASON implementation, 
   it is well-know that RWA is the key problem in WASON. There are 
 
 
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   certain constraints in the light path computation and selection 
   process, this is the root of RWA problem. This document provides the 
   constraint character abstracting to information model for combined 
   RWA. 

   At the same time, the mechanism of automatic discovery for WASON have 
   not definitely been defined, In SDH, J0 trace correlation or test 
   message sent in band over DCC provide the mechanism of link 
   connectivity verification. In WDM network, we recommend that OSC 
   channel (which is defined in G.709) could be the mechanism of link 
   connectivity verification between adjacent nodes. 

   In DWDM network, there are certain specific constraints which are 
   different from other circuit switched network such as Time Division 
   Multiplexing (TDM). The most obvious constraint is that the 
   wavelength must be consistent in the light path, which is called 
   "wavelength continuity" constraint. Even though there are certain 
   "wavelength switch" capabilities by O-E-O way, but which cannot 
   support full switch because of the electronic matrix capability 
   limitation. At the same time between two TE links in one node may not 
   be connected to carry traffic, which depend on the inner light path 
   between these two links is whether connected through the fiber., 
   especially for multi directional ROADM equipments, and the client 
   traffic also need to know the inner optical path to the TE link. All 
   of these constraints need to face and figure out. This document start 
   form the combined RWA way to describe information model extend to 
   route application, this is considered that the restoration time in 
   optical network have relatively strict restriction, hopefully static 
   path computation and selection could be satisfied to end-to-to 
   restoration time. The link and wavelength channel constraints need to 
   be described as the explicable information flooded in the network. 
   The link constraints information mainly consists of two parts, one is 
   the connectivity with other links, the other is the arrival 
   information to the tributary side (Add and Drop port in ROADM, called 
   OTU). 

   This document prefer to the combined RWA way and provide enough 
   resource information for static path computation and selection, and 
   this is also consistent with the distributed signaling way to setup 
   end-to-end connection via multiple light paths attempt. So this 
   document is the supplementary for the automatic discovery mechanism 
   in WASON, and mainly focus on all of the constraint information 
   description and efficient encodings of information used for route 
   flood. 



 
 
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2. Terminology 

   ASON: Automatic Switch Optical Network 

   DWDM: Dense Wavelength Division Multiplexing 

   WASON: WDM Automatic Switch Optical Network 

   RWA: Route and Wavelength Assignment 

   DCC: Data Communication Channel 

   OSC: Optical Supervisory Channel 

   ROADM: Reconfigurable Optical Add/Drop Multiplexer 

   O-E-O: Optical-Electronic-Optical 

   SDH: Synchronous digital hierarchy 

   SONET: Synchronous Optical Network 

   OTU: Optical Transponder Unit 

3. Link Verification 

   Link verification is used to verify the physical connectivity of the 
   data links and to exchange the Interface Ids of the data links. The 
   data links between adjacent nodes in WDM network also need the 
   transport medium to verify the connectivity and exchange the 
   interface Ids of data plane. Then synchronize the data links to form 
   TE link used for path computation and signaling. RFC4207 have 
   significantly defined the mechanisms of link connectivity applicable 
   to SDH/SONET. But for WDM system, there is no significant definition 
   for the link connectivity verification mechanism. OSC channel is as 
   the natural and specific transport channel embedded in the DWM link. 
   So this document defines the new link verification mechanism used for 
   WDM link. The following is the two mechanism definition. 

   One is that Test message is sent over OSC channel and TestStatus 
   messages sent back over the control channel. The Test Message is 
   defined in [RFC4204]. 

   The other is that the OSC channel is used to send and receive Trace 
   Message. The Test Message is not transmitted over OSC channel (i.e., 
   over the data link), but is sent over the control channel and 

 
 
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   correlated for consistency to the received Trace Message from OSC 
   channel. 

   The content of Trace Message is unique in the network. It could be 
   the combination of local interface Id and Node Id. 

   The process of link connectivity verification between adjacent WDM 
   nodes is consistent with SDH/SONET, this can be referred to [RFC4204] 
   and [RFC4207]. 

4. Constraint Information 

   WDM Link Bandwidth 

   Link Constraint Character 

   Wavelength Continuity Constraint 

   O-E-O Wavelength Switch Capability 

   Tunable Laser 

4.1. WDM Link 

   The bandwidth of WDM link should be concerned as the number of 
   wavelength, could not be counted as signal rates because the 
   wavelength cannot be restricted to carry certain rates of signal, or 
   certain frame type of signal. 

   Consider to interlayer, Wavelength channel layer is used to be server 
   layer path to carry client traffic, such as GE multiplexing. 

4.2. WDM Link Constraint 

   There are certain constraints to set up end-to-end connection even 
   though there are available bandwidths in one light path. The 
   tributary side (We called OTU) of Ingress and Egress node need to 
   know the arrival capability to the TE link. It is not that the 
   tributary side can arrive up to all of TE links, and down from all of 
   TE links. The TE links on the two sides of Transmit node may not 
   completely have the capability to connect to transmit traffic. These 
   constraints exist in DWM node as the optical signal flow must be 
   connected from the inner of node. This is very different from circuit 
   switch network which make use of integrated circuit design to get 
   electronic signals to mutual connection. If TE links on the two sides 
   of Transmit node don't get optical inner connection, the traffic 
   carried on one wavelength can not pass through the node from one side 
 
 
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   to the other side. The constraint on the WDM link challenge the 
   traditional route computation algorithm based on the available 
   bandwidth of TE link. 

4.3. OCH Constraint 

   It is well-known that the wavelength basically need to keep 
   consistent in the light path, this is called "Wavelength continuity" 
   constraint. Even though O-E-O can add certain "wavelength switch" 
   capability to the system, but the electronic matrix in the DWM 
   equipment do not completely have the full switch capability. 

   So wavelength availability and switch capability information is 
   important to analyze the availability of light path from end to end. 

4.4. Tunable Laser 

   The tributary transmitter laser is tunable, this add certain 
   flexibility to path computation and selection process. Ingress and 
   egress node can add and drop traffic in the extent of tunable 
   wavelength from the reachable TE links. The transmitter tuning 
   information is one factor to take into account during the light path 
   computation and selection, and connection set up. 

5. Information Model 

5.1. Link Information 

   WDM link information derived from RFC3630 and RFC4203, and add new 
   sub-elements constraints to link information model: 

   (a) Maximum of optical channels (wavelength), which is the bandwidth 
   of WDM link. 

   (b) Link direction, this is used to account for the bit map position 
   in the link constraint information, this is one global unique Id 
   assigned in the node. 

   (c) Link constraint information, which represent the connectivity 
   with other links, and was indicated by the bit map, the bit position 
   represents the connectivity with one direction link. 

   (d) Wavelength availability, which represent the state of the 
   corresponding optical wavelength channel. 

   (e) Wavelength switch capability, one set of wavelength aggregation 
   could be switched via electronic matrix. The optical signals carried 
 
 
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   in the wavelength can flow to or flow out from the same electronic 
   matrix unit after optical-electronic-optical change, all of these 
   wavelengths could switch. One global unique ID named "Lambda Group 
   Id" represents one electronic matrix unit. The Lambda Group Id is the 
   identification of the aggregation of wavelengths in which the optical 
   signals flow to or flow out from the same matrix unit. 

   Lambda Group Id represent the aggregation of wavelength set, the 
   wavelengths with same Lambda Group Id can be mutually switched via O-
   E-O. The special value 0 represent the optical signal carried in the 
   wavelength only can pass via the same wavelength. 

   Wavelength switch capability can be identified by Lambda Group Id, 
   which was carried with Wavelength availability information. 

   (f) Reachable tributary (OTU) information, which describe the 
   aggregation of Reachable OTU, and for every Reachable OTU, which also 
   indicate out the available wavelength set. The information also can 
   be got via the communication between ingress and egress nodes before 
   initiate call connection setup. 

   Note: only (a) are necessary for WDM link, others are used for static 
   path computation and assemble signaling. 

5.2. Lambda Group ID 

   +------+                                                  +------+             

   |      | =+=+=+=+=+=+=+=+¦Ë1            ¦Ë5+=+=+=+=+=+=+= |      | 

   + DWDM + =+=+=+=+=+=+¦Ë2|    +------+      |¦Ë6+=+=+=+=+= + DWDM + 

   |  1   | =+=+=+=+¦Ë3|   +=+= |      | =+=+=+   |¦Ë7+=+=+= |   2  | 

   +------+        |   +=+=+=+= +MATRIX| =+=+=+=+=+   |      +------+ 

                   +=+=+=+=+=+= |   1  | =+=+=+=+=+=+=+ 

                                +------+ 

    

    

    

    
 
 
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   +------+                                                  +------+             

   |      | =+=+=+=+=+=+=+=+¦Ë1            ¦Ë3+=+=+=+=+=+=+= |      | 

   + DWDM + =+=+=+=+=+=+¦Ë3|    +------+      |¦Ë5+=+=+=+=+= + DWDM + 

   |  3   | =+=+=+=+¦Ë4|   +=+= |      | =+=+=+   |¦Ë7+=+=+= |   4  | 

   +------+        |   +=+=+=+= +MATRIX| =+=+=+=+=+   |      +------+ 

                   +=+=+=+=+=+= |   2  | =+=+=+=+=+=+=+ 

                                +------+ 

                        Figure 1 O-E-O Switch Model 

   The Lambda Group ID is identification of the aggregation of 
   Wavelength set in which the wavelengths could be mutually switched, 
   and is also the identification of O-E-O switch capability. Here don't 
   consider the asymmetric switch matrix. 

   The figure showed above, the link from DWDM1 have three lambdas (¦Ë1, 
    ¦Ë2, ¦Ë3) flow to the matrix unit1, the link from DWDM1 have three 
   lambdas (¦Ë5, ¦Ë6, ¦Ë7) flow to the matrix unit1, they could be switched. 
   Likewise the link from DWDM3 have three lambdas (¦Ë1, ¦Ë3, ¦Ë4) flow to 
   the matrix unit2, the link from DWDM4 have three lambdas (¦Ë3, ¦Ë5, ¦Ë7) 
   flow to the matrix unit2, they could be switched. 

   For the lambdas (¦Ë1, ¦Ë2, ¦Ë3) of the link of DWDM1 and the lambdas (¦Ë5, 
    ¦Ë6, ¦Ë7) of the link of DWDM2, the Lambda Group ID could assign to be 
   1; 

   For the lambdas (¦Ë1, ¦Ë3, ¦Ë4) of the link of DWDM3 and the lambdas (¦Ë3, 
    ¦Ë5, ¦Ë7) of the link of DWDM4, the Lambda Group ID could assign to be 
   2; 

   So the lambda group id is the identification of wavelength switch 
   capability, and also is the identification of the aggregation of 
   Wavelength set in which the wavelengths could be mutually switched, 
   and their lambda group ids are same. 

   The special value 0 lambda group id represent the optical signal 
   carried in the wavelength only can pass via the same wavelength. Do 
   not have the capability of O-E-O. 

 
 
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5.3. Wavelength Label 

   This document makes frequent use of the lambda label format defined 
   in [Otani] shown below: 

    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   |S|    Reserved   |              n                |  

   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 

   Grid is used to indicate which ITU-T grid specification is being used. 

   C.S. = Channel spacing used in a DWDM system, i.e., with a ITU-T 
   G.694.1 grid. 

   S = Sign for the value of n, set to 1 for (-) and 0 for (+). 

   n = Used to specify the frequency as 193.1THz +/- n*(channel spacing) 
   where the + or - is chosen based on the sign (S) bit. 

6. Application to OSPF GMPLS extensions 

6.1. Link Sub-TLVs 

   As discussed in section 5.1, some sub-TLVs need to characterize for 
   WDM links. 

6.1.1. Maximum of optical channels sub-TLV 

   Maximum of optical channels sub-TLV specifies the maximum optical 
   wavelength channels that can be used on this WDM link. The value can 
   be 40, 80, 160, 192 etc. 

6.1.2. Link Constraint sub-TLV 

   There are two ways to show the link connectivity constraint with 
   other links. One is the links including list, the second is the bit 
   map to indicate the connectivity with other links. The second need to 
   assign the unique direction Id for each link. The information carried 
   in the link constraint is: 

         0                   1                   2                   3  
 
 
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          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  

         +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+  

         |Dir|   Method  |   Direction   |   Num Links   |    Reserved   |  

         +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+  

         |             Bit Map Word #1 Or Link Identifier 1              |  

         +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+  

         :                               :                               :  

         :                               :                               :  

         +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+  

         |            Bit Map Word #N Or Link Identifier N               |  

         +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 

   Dir: 2 bits 

   0 - bidirectional, Indicate the connectivity from the link to other 
   links bidirectional. 

   1 - Ingress, Indicate the connectivity to other links from the 
   ingress port of the link to the egress ports of other links. 

   2 - Egress, Indicate the connectivity from the ingress ports of other 
   links to the egress port of the link. 

   Method: 6 bits 

   0 - Bit Map 

   1 - Link Set 

   Others - Reserved to be used later. 

   Direction: 8 bits 

   Direction is one unique Id assigned in the node, start from 1. This 
   is different from link index, and is used to account for bit position 
   in the bit map carried in other links constraint sub-TLV. 

 
 
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   Num Links: 8 bits 

   Num links tell us the number of link identifiers followed or the 
   number bits of link connectivity represented by the bit map. 

   Bit map have the same rule in the link constraint information in 
   order that RWA algorithm can analyze the connectivity of links. Each 
   bit in the bit map represents one specific link with value 1/0 
   indicating the constraint connectivity with the link. The bit 
   position represent the specific link witch is its own, the value on 
   this bit is 1. 

    A B C D E F G H I K J L M N O P Q R S       

   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+  

   | | | | | | | | | | | | | | | | | | | | :::  

   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+  

    

   The rule for bit map showed below, the link direction is used here to 
   indicate the bit position. 

    

   Position Link Direction     Meaning 

   --------------------------------------------------------------------- 

    A       1    indicate the connectivity between the link and specific link of direction Id 1 

    B       2    indicate the connectivity between the link and specific link of direction Id 2 

    C       3    indicate the connectivity between the link and specific link of direction Id 3 

    D       4    indicate the connectivity between the link and specific link of direction Id 4 

    E       5   indicate the connectivity between the link and specific link of direction Id 5 

    F       6    indicate the connectivity between the link and specific link of direction Id 6 

    G       7    indicate the connectivity between the link and specific link of direction Id 7 

    H       8    indicate the connectivity between the link and specific link of direction Id 8 
 
 
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    I        9   indicate the connectivity between the link and specific link of direction Id 9 

    :               :                                    : 

    :               :                                    : 

    :               :                                    : 

    :               :                                    : 

   --------------------------------------------------------------------- 

   For example: 

                                V^ 2 

                                || 

                                || 

                                || 

                                || 

           1               +-+-+-+-+-+-+-+                 3 

           <---------------|             | ----------------< 

           >---------------+   ROADM     + ----------------> 

                          |             | 

                          +-+-+-+-+-+-+-+ 

                                || 

                                || 

                                || 

                                || 

                                ^V 4 

                        Figure 2 Example For WDM Links 


 
 
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   There are four WDM links in the ROADM node, and the link direction 
   Ids are respectively 1, 2, 3, 4. Here ignore the detail of 
   connectivity between the links. Assume that Link 1 bidirectional 
   connect to Link 2, and Link 3 bidirectional connect to Link 4. 

   The constraint information in each link represent as follows: 

   Link of direction 1: 

    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 

    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+  

   | 0 |     1     |       1       |       1       |    Reserved   |  

   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+  

   |                Link identifier of direction 2                 |  

   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+  

   Or: 

    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 

    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+  

   | 0 |     0     |       1       |       4       |    Reserved   |  

   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+  

   |1|1|0|0|                                                       | 

   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 

   Link of direction 2: 

    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 

   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+  

 
 
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   | 0 |     1     |       2       |       1       |    Reserved   |  

   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+  

   |                Link identifier of direction 1                 |  

   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 

   Or: 

    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 

   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+  

   | 0 |     0     |       2       |       4       |    Reserved   |  

   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+  

   |1|1|0|0|                                                       | 

   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 

   Link of direction 3: 

    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 

   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+  

   | 0 |     1     |       3       |       1       |    Reserved   |  

   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+  

   |                Link identifier of direction 4                 |  

   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 

   Or: 

    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 

   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+  
 
 
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   | 0 |     0     |       3       |       4       |    Reserved   |  

   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+  

   |0|0|1|1|                                                       | 

   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 

   Link of direction 4: 

    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 

   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+  

   | 0 |     1     |       4       |       1       |    Reserved   |  

   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+  

   |                Link identifier of direction 3                 |  

   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 

   Or: 

    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 

   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+  

   | 0 |     0     |       4       |       4       |    Reserved   |  

   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+  

   |0|0|1|1|                                                       | 

   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 

6.1.3. Wavelength Availability,Switch Capability Sub-TLV 

   The information of optical wavelength channel includes the resource 
   state, and description of switch capability via O-E-O. 

   Wavelength Availability, Switch Capability Set Sub-TLV format is 
   given by: 
 
 
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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 

   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+  

   |Grid | C.S   |S|    Reserved   |        Num Wavelengths        | 

   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 

   | N1 For Start Center Frequency |Lambda Group Id|   State       | 

   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 

   |    N2                         |Lambda Group Id|   State       |  

   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 

   |                ..                                            |  

   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+  

   |Nn (Highest frequency channels)|Lambda Group Id|   State       | 

   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 

   Num Wavelengths specifies the number of wavelengths followed in the 
   sub-TLV. This is generally equal to Maximum of optical channels. 

   Lambda group Id indicates the wavelength switch capability. 

   State indicates the resource state of wavelength channel. 0 is free, 
   1 is occupied. 

6.1.4. Reachable OTU Sub-TLV 

   The reachable OTU sub-TLV format is given by: 

   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 

   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+  

   |                        Num Reachable OTUs                     | 

   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
 
 
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   |                         OTU Identifier1                       | 

   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 

   |             Num Suggested Lambda For OTU Identifier1          |  

   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 

   |    Suggested Lambda #1        |     Suggested Lambda #2       | 

   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 

   |            ...                |     Suggested Lambda #N       | 

   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 

   |                ...                                            |  

   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 

   |                         OTU IdentifierN                       | 

    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 

   |             Num Suggested Lambda For OTU IdentifierN          |  

   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 

   |    Suggested Lambda #1        |     Suggested Lambda #2       | 

   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 

   |            ...                |     Suggested Lambda #N       | 

   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 

   This sub-TLV gives out the reachable OTU information and the 
   suggested available lambdas could be dropped traffic signal from the 
   link to OTU, and can add client traffic signal from OTU to the link. 

7. Security Considerations 

   This document has no requirement for a change to the security models 
   within GMPLS and associated protocols. 



 
 
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8. IANA Considerations 

   No new values are specified in this document. 

9. Acknowledgments 

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

10. References 

10.1. Normative References 

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

   [G.694.1] ITU-T Recommendation G.694.1, "Spectral grids for WDM 
             applications: DWDM frequency grid", June, 2002.  

   [RFC3630] Katz, D., Kompella, K., and D. Yeung, "Traffic Engineering 
             (TE) Extensions to OSPF Version 2", RFC 3630, September 
             2003.  

   [RFC4202] Kompella, K., Ed., and Y. Rekhter, Ed., "Routing Extensions 
             in Support of Generalized Multi-Protocol Label Switching 
             (GMPLS)", RFC 4202, October 2005  

   [RFC4203] Kompella, K., Ed., and Y. Rekhter, Ed., "OSPF Extensions in 
             Support of Generalized Multi-Protocol Label Switching 
             (GMPLS)", RFC 4203, October 2005. 

10.2. Informative References 

   [Otani]   T. Otani, H. Guo, K. Miyazaki, D. Caviglia, "Generalized 
             Labels of Lambda-Switching Capable Label Switching Routers 
             (LSR)", work in progress: draft-otani-ccamp-gmpls-lambda-
             labels-01.txt, November 2007. 









 
 
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Author's Addresses 

   Zhihong Kang 
   ZTE Technologies Co., Ltd. 
   12F, ZTE Plaza, No.19 East HuaYuan Road, HaiDian District 
      
   Phone: +86-10-82963984 
   Email: kang.zhihong@zte.com.cn 
    
   Zhenyu Wang 
   ZTE Technologies Co., Ltd. 
   12F, ZTE Plaza, No.19 East HuaYuan Road, HaiDian District 
      
   Phone: +86-10-82963987 
   Email: wang.zhenyu1@zte.com.cn 
    
   Feng Gao 
   ZTE Technologies Co., Ltd. 
   12F, ZTE Plaza, No.19 East HuaYuan Road, HaiDian District 
      
   Phone: +86-10-82963984 
   Email: gao.feng1@zte.com.cn 

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