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Versions: (draft-lee-ccamp-wson-signal-compatibility-ospf) 00 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 RFC 7688

Network Working Group                                            Y. Lee
Internet Draft                                                   Huawei
Intended status: Standards Track                           G. Bernstein
Expires: August 2013                                  Grotto Networking





                                                       February 6, 2013

    GMPLS OSPF Enhancement for Signal and Network Element Compatibility
                 for Wavelength Switched Optical Networks


          draft-ietf-ccamp-wson-signal-compatibility-ospf-11.txt


Status of this Memo

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Copyright Notice

   Copyright (c) 2012 IETF Trust and the persons identified as the
   document authors.  All rights reserved.






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   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (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
   document must include Simplified BSD License text as described in
   Section 4.e of the Trust Legal Provisions and are provided without
   warranty as described in the Simplified BSD License.

Abstract

   This document provides GMPLS OSPF routing enhancements to support
   signal compatibility constraints associated with WSON network
   elements. These routing enhancements are required in common optical
   or hybrid electro-optical networks where not all of the optical
   signals in the network are compatible with all network elements
   participating in the network.

   This compatibility constraint model is applicable to common optical
   or hybrid electro optical systems such as OEO switches,
   regenerators, and wavelength converters since such systems can be
   limited to processing only certain types of WSON signals.

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 [RFC2119].

Table of Contents


   1. Introduction...................................................3
      1.1. Revision History..........................................3
   2. The Optical Node Property TLV..................................4
      2.1. Sub-TLV Details...........................................5
         2.1.1. Resource Pool Accessibility..........................6
         2.1.2. Resource Block Wavelength Constraints................6
         2.1.3. Resource Pool State..................................6
         2.1.4. Block Shared Access Wavelength Availability..........6
   3. ISCD format extensions.........................................7
      3.1. Switch Capability Specific Information....................7
   4. WSON Specific Scalability and Timeliness.......................8
   5. Security Considerations........................................9



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   6. IANA Considerations............................................9
   7. References....................................................11
      7.1. Normative References.....................................11
      7.2. Informative References...................................11
   8. Authors and Contributors......................................12
   Authors' Addresses...............................................12
   Intellectual Property Statement..................................13
   Disclaimer of Validity...........................................13

1. Introduction

   The documents [RFC6163, WSON-Info, WSON-Encode] explain how to
   extend the wavelength switched optical network (WSON) control plane
   to allow both multiple WSON signal types and common hybrid electro
   optical systems as well hybrid systems containing optical switching
   and electro-optical resources. In WSON, not all of the optical
   signals in the network are compatible with all network elements
   participating in the network. Therefore, signal compatibility is an
   important constraint in path computation in a WSON.

   This document provides GMPLS OSPF routing enhancements to support
   signal compatibility constraints associated with general WSON
   network elements. These routing enhancements are required in common
   optical or hybrid electro-optical networks where not all of the
   optical signals in the network are compatible with all network
   elements participating in the network.

   This compatibility constraint model is applicable to common optical
   or hybrid electro optical systems such as OEO switches,
   regenerators, and wavelength converters since such systems can be
   limited to processing only certain types of WSON signals.

   1.1. Revision History

   From 00 to 01: The details of the encodings for compatibility moved
   from this document to [WSON-Encode].

   From 01 to 02: Editorial changes.

   From 02 to 03: Add a new Top Level Node TLV, Optical Node Property
   TLV to carry WSON specific node information.

   From 03 to 04: Add a new sub-TLV, Block Shared Access Wavelength
   Availability TLV to be consistent with [WSON-Encode] and editorial
   changes.



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   From 04 to 05: Add a new section that discusses OSPF scalability and
   timeliness and editorial changes.

   From 05 to 06: Change the title of the draft to "GMPLS OSPF
   Enhancement" from "OSPF Enhancement" to make sure the changes apply
   to the GMPLS OSPF rather than the base OSPF. Add specific OSPF
   procedures on how sub-TLVs are packaged per [RFC3630] and editorial
   changes.

   From 06 to 07: Add clarifying texts on how to sub-divide the Optical
   Node TLV in case it exceeds the IP MTU fragmentation limit. Delete
   Section 3.2. to avoid multiple rules so as to avoid confusion.

   From 07 to 08: Clean some old texts in Section 3. Align with [WSON-
   Encode] on the modulation and FEC type.

   From 08 to 09: Added ISCD extensions for available labels and shared
   backup labels.

   From 09 to 10: Revised for OIC changes consistent with encoding
   document.

   From 10 to 11: Editorial clean-up only.

2. The Optical Node Property TLV

   [RFC3630] defines OSPF TE LSA using an opaque LSA. This document
   adds a new top level TLV for use in the OSPF TE LSA: the Optical
   Node Property TLV. The Optical Node property TLV describes a single
   node. It is constructed of a set of sub-TLVs. There are no ordering
   requirements for the sub-TLVs. Only one Optical Node TLV shall be
   advertised in each LSA.

   The Optical Node Property TLV contains all WSON-specific node
   properties and signal compatibility constraints. The detailed
   encodings of these properties are defined in [WSON-Encode].

   The following sub-TLVs of the Optical Node Property TLV are defined:

   Value       Length      Sub-TLV Type








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   TBA         variable    Resource Block Information
   TBA         variable    Resource Pool Accessibility
   TBA         variable    Resource Block Wavelength Constraints
   TBA         variable    Resource Pool State
   TBA         variable    Block Shared Access Wavelength Availability

   The detail encodings of these sub-TLVs are found in [WSON-Encode] as
   indicated in the table below.

   Sub-TLV Type                              Section [WSON-Encode]

   Resource Block Information                      5.1
   Resource Pool Accessibility                     4.1
   Resource Block Wavelength Constraints           4.2
   Resource Pool State                             4.3
   Block Shared Access Wavelength Availability     4.4





   All sub-TLVs defined here may occur at most once in any given
   Optical Node TLV. "At most once" means that if there is sub-TLV
   related information, it should be always included. These
   restrictions need not apply to future sub-TLVs. Unrecognized sub-
   TLVs are ignored.

   2.1. Sub-TLV Details

   Among the sub-TLVs defined above, the Resource Pool State sub-TLV
   and Block Shared Access Wavelength Availability are dynamic in
   nature while the rest are static. As such, they can be separated out
   from the rest and be advertised with multiple TE LSAs per OSPF
   router, as described in [RFC3630] and [RFC5250]. Resource Block
   Information

   Resource Block Information sub-TLVs are used to convey relatively
   static information about individual resource blocks including the
   resource block properties and the number of resources in a block.

   There are five nested sub-TLVs defined in the Resource Block
   Information sub-TLV.

   Value          Length      Sub-TLV Type




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   TBA            variable    Optical Interface Class List
   TBA            variable    Input Client Signal List
   TBA            variable    Processing Capability List


   The detail encodings of these sub-TLVs are found in [WSON-Encode] as
   indicated in the table below.

   Name                             Section [WSON-Encode]

   Optical Interface Class List           5.2
   Input Client Signal List               5.3
   Processing Capability List             5.4



   2.1.1. Resource Pool Accessibility

   This sub-TLV describes the structure of the resource pool in
   relation to the switching device. In particular it indicates the
   ability of an ingress port to reach a resource block and of a
   resource block to reach a particular egress port.

   2.1.2. Resource Block Wavelength Constraints

   Resources, such as wavelength converters, etc., may have a limited
   input or output wavelength ranges. Additionally, due to the
   structure of the optical system not all wavelengths can necessarily
   reach or leave all the resources. Resource Block Wavelength
   Constraints sub-TLV describe these properties.

   2.1.3. Resource Pool State

   This sub-TLV describes the usage state of a resource that can be
   encoded as either a list of 16 bit integer values or a bit map
   indicating whether a single resource is available or in use. This
   information can be relatively dynamic, i.e., can change when a
   connection is established or torn down.

   2.1.4. Block Shared Access Wavelength Availability

   Resources blocks may be accessed via a shared fiber. If this is the
   case then wavelength availability on these shared fibers is needed
   to understand resource availability.




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3. ISCD format extensions

   The Interface Switching Capability Descriptor describes switching
   capability of an interface [RFC 4202].  This document defines a new
   Switching Capability value for WSON as follows:

      Value                       Type
      -----                       ----
      151 (TBA by IANA)           WSON-LSC capable (WSON-LSC)

   Switching Capability and Encoding values MUST be used as follows:

           Switching Capability = WSON-LSC

           Encoding Type = Lambda [as defined in RFC3471]

   When Switching Capability and Encoding fields are set to values as
   stated above, the Interface Switching Capability Descriptor MUST be
   interpreted as in RFC4203 with the optional inclusion of one or more
   Switching Capability Specific Information sub-TLVs.

   3.1. Switch Capability Specific Information

   The technology specific part of the WSON ISCD may include a variable
   number of sub-TLVs called Bandwidth sub-TLVs.  Two types of
   Bandwidth TLV are defined (TBA by IANA):

         - Type 1 - Available Labels

         - Type 2 - Shared Backup Labels

   The format of the SCSI MUST be as depicted in the following figure:

      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 = 1 (Available)   |           Length              |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                                                               |
      |                 Available Label Sub-TLV                       |
      |                                                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      ~                               ...                             ~



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      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |     Type = 2 (Shared backup)  |           Length              |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                                                               |
      |                 Shared Backup Label Sub-TLV                   |
      |                                                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


                              Figure 1: SCSI format

   Where the Available Label Sub-TLV and Shared Backup Label sub-TLV
   are defined in [Gen-Encode].

4. WSON Specific Scalability and Timeliness

   This document has defined five sub-TLVs specific to WSON. The
   examples given in [WSON-Encode] show that very large systems, in
   terms of channel count, ports, or resources, can be very efficiently
   encoded.

   There has been concern expressed that some possible systems may
   produce LSAs that exceed the IP Maximum Transmission Unit (MTU). In
   a typical node configuration, the optical node property TLV will not
   exceed the IP MTU. In a rare case where the TLV exceed the IP MTU,
   IP fragmentation/reassembly can be used, which is an acceptable
   method.

   If the size of this LSA is greater than the MTU, then these sub-TLVs
   can be packed into separate LSAs. From the point of view of path
   computation, the presence of the Resource Block Information sub-TLV
   indicates that resources exist in the system and may have signal
   compatibility or other constraints. The other four sub-TLVs indicate
   constraints on access to, and availability of those resources.

   Hence the "synchronization" procedure from a path computation point
   of view is quite simple. Until a Resource Block Information sub-TLV
   is received for a system path cannot make use of the other four sub-
   TLVs since it does not know the nature of the resources, e.g., are
   the resources wavelength converters, regenerators, or something
   else. Once this sub-TLV is received path computation can proceed
   with whatever of the additional types of sub-TLVs it may have
   received (there use is dependent upon the system type). If path
   computation proceeds with out of date or missing information from



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   these sub-TLVs then there is the possibility of either (a) path
   computation computing a path that does not exist in the network, (b)
   path computation failing to find a path through the network that
   actually exists. Both situations are currently encountered with
   GMPLS, i.e., out of date information on constraints or resource
   availability.

   Note that the connection establishment mechanism (signaling or
   management) is ultimately responsible for the establishment of the
   connection, and this implies that such mechanisms must insure signal
   compatibility.




5. Security Considerations

   This document does not introduce any further security issues other
   than those discussed in [RFC3630], [RFC4203].

6. IANA Considerations

   This document introduces a new Top Level Node TLV (Optical Node
   Property TLV) under the OSPF TE LSA defined in [RFC3630].

   Value    TLV Type

   TBA      Optical Node Property

   IANA is to allocate a new TLV Type and its Value for this Top Level
   Node TLV.

   This document also introduces the following sub-TLVs associated with
   the Optical Node Property TLV as defined in Section 2.1 as follows:

   Value       Length      Sub-TLV Type

   TBA         variable    Resource Block Information
   TBA         variable    Resource Pool Accessibility
   TBA         variable    Resource Block Wavelength Constraints
   TBA         variable    Resource Pool State
   TBA         variable    Block Shared Access Wavelength Availability






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   IANA is to allocate new sub-TLV Types and their Values for these
   sub-TLVs defined under the Optical Node Property TLV.



   There are three nested sub-TLVs defined in the Resource Block
   Information sub-TLV as follows:

   Value          Length      Sub-TLV Type

   TBA            variable    Optical Interface Class List
   TBA            variable    Input Client Signal List
   TBA            variable    Processing Capability List


   IANA is to allocate new Sub-TLV Types and their Values for these
   Sub-TLVs defined under the Resource Block Information Sub-TLV.

   Upon approval of this document, IANA will make the assignment of a
   new Switching Capability value for the existing ISCD located at http:
   //www.iana.org/assignments/ospf-traffic-eng-tlvs/ospf-traffic-eng-
   tlvs.xml:

   15     Interface Switching Capability Descriptor      [RFC4203]

   Switching capability     Description                Reference
   ----------------------  --------------------------  ----------
   151 (suggested)         WSON-LSC capable (WSON-LSC) [This.I-D]

This document defines the following sub-TLVs of the ISCD TLV:

          Value  Sub-TLV
          -----  -------------------------------------------------
          1      Available Labels
          2      Shared Backup Labels












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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.

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

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

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



   [WSON-Encode]  G. Bernstein, Y. Lee, D. Li, W. Imajuku, "Routing and
             Wavelength Assignment Information Encoding for Wavelength
             Switched Optical Networks", draft-ietf-ccamp-rwa-wson-
             encode, work in progress.

   [Gen-Encode] G. Bernstein, Y. Lee, D. Li, W. Imajuku, "General
             Network Element Constraint Encoding for GMPLS Controlled
             Networks", draft-ietf-ccamp-general-constraint-encode,
             work in progress.

   7.2. Informative References

   [WSON-Info] Y. Lee, G. Bernstein, D. Li, W. Imajuku, "Routing and
             Wavelength Assignment Information Model for Wavelength
             Switched Optical Networks", draft-ietf-ccamp-rwa-info,
             work in progress.

   [RFC6250] T. Otani, Ed., D. Li, Ed., "Generalized Labels for G.694
             Lambda-Switching Capable Label Switching Routers", RFC
             6250, March 2011.






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   [RFC6163] Y. Lee, G. Bernstein,  W. Imajuku, "Framework for GMPLS
             and PCE Control of Wavelength Switched Optical Networks",
             RFC 6163, April 2011.

   [RFC5250] Berger, L., et al., "The OSPF Opauqe LSA option", RFC
             5250, July 2008.













8. Authors and Contributors




Authors' Addresses

   Young Lee (ed.)
   Huawei Technologies
   1700 Alma Drive, Suite 100
   Plano, TX 75075
   USA

   Phone: (972) 509-5599 (x2240)
   Email: ylee@huawei.com


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

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






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










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