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Versions: 00 01 02 03                                                   
Network work group                                           Fatai Zhang
Internet Draft                                                 Young Lee
Intended status: Standards Track                             Jianrui Han
                                                                  Huawei
                                                            G. Bernstein
                                                       Grotto Networking
                                                               Yunbin Xu
                                                                    CATR
Expires: September 4, 2010                                 March 5, 2010




            OSPF Extensions in Support of Routing and Wavelength
      Assignment (RWA) in Wavelength Switched Optical Networks (WSONs)



              draft-zhang-ccamp-rwa-wson-routing-ospf-03.txt


Status of this Memo

   This Internet-Draft is submitted to IETF in full conformance with
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   This Internet-Draft will expire on September 4, 2010.



Abstract






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   This document describes OSPF routing protocols extensions to support
   Routing and Wavelength Assignment (RWA) in Wavelength Switched
   Optical Networks (WSON) under the control of Generalized MPLS (GMPLS).

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......................................... 2
   2. Node Information..................................... 3
      2.1. Connectivity Matrix..............................4
   3. Link Information..................................... 4
      3.1. Port Label Restrictions .........................5
      3.2. Available Labels.................................5
      3.3. Shared Backup Labels.............................6
   4. Routing Procedures....................................6
   5. Security Considerations...............................7
   6. IANA Considerations...................................7
      6.1. Node Information.................................7
      6.2. Link Information.................................7
   7. References............................................7
   8. Authors' Addresses....................................9
   Acknowledgment ..........................................11



1. Introduction

   [WSON-Frame] provides a framework for applying GMPLS [RFC3945] and
   the Path Computation Element (PCE) architecture [RFC4655] to the
   control of WSONs to address the RWA problem. [WSON-Info] describes an
   information model that specifies the information needed at various
   points in a WSON in order to compute paths and establish Label
   Switched Paths (LSPs). Based on the information model of [WSON-Info],
   [GEN-Encode] and [RWA-Encode] provide efficient protocol-independent
   encodings of the information needed by the RWA process in a WSON.
   Such encodings can be used to extend GMPLS signaling and routing
   protocols.

   This document provides RWA OSPF extensions based on [GEN-Encode]
   which provides encodings of the information needed by the routing and
   label assignment process in technologies such as WSON but that are


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   potentially applicable to a wider range of technologies. Additional
   RWA OSPF extensions based on [RWA-Encode] which provides encodings of
   the information specific to WSON technologies such as signal
   compatibility and wavelength resource encodings are addressed in the
   other document [WSON-COM-OSPF].

   This document defines extensions to the OSPF routing protocol to
   enhance the Traffic Engineering (TE) properties of GMPLS TE which are
   defined in [RFC3630], [RFC4202], and [RFC4203]. The enhancements to
   the Traffic Engineering (TE) properties of GMPLS TE links can be
   announced in OSPF TE LSAs. The TE LSA, which is an opaque LSA with
   area flooding scope [RFC3630], has only one top-level
   Type/Length/Value (TLV) triplet and has one or more nested sub-TLVs
   for extensibility. The top-level TLV can take one of three values (1)
   Router Address [RFC3630], (2) Link [RFC3630], (3) Node Attribute
   [OSPF-Node].  In this document, we enhance the sub-TLVs for the Link
   TLV and Node Attribute TLV in support of RWA in WSON under the
   control of GMPLS.

   The detail encoding of OSPF extensions is not redefined in this
   document. [GEN-Encode] provides encoding detail.

   No consideration of optical impairment routing related information is
   included in this document.

2. Node Information

   According to [WSON-Info] and [GEN-Encode], the node information about
   WSON nodes includes Node ID, connectivity matrix. Except for the Node
   ID which should comply with Routing Address described in [RFC3630],
   the other pieces of information are defined in this document.

   [OSPF-Node] defines a new top TLV named the Node Attribute TLV which
   carries attributes related to a router/node. This Node Attribute TLV
   contains one or more sub-TLVs.

   Per [GEN-Encode], we have identified the following new Sub-TLVs to
   the Node Attribute TLV. Detail description for each newly defined
   Sub-TLV is provided in subsequent sections:

      Sub-TLV Type    Length       Name

         TBD          variable    Connectivity Matrix

   In WSON networks, generally the sub-TLVs above is optional, which
   depends on the control plane implementations. Usually, Connectivity
   Matrix sub-TLV may appear in the LSAs because WSON switches are


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   asymmetric at present. It is assumed that the switches are symmetric
   switching, if there is no Connectivity Matrix sub-TLV in the LSAs.

2.1. Connectivity Matrix

   It is necessary to identify which ingress ports and wavelengths can
   be connected to (the same wavelength on) a specific egress port,
   because the switching devices in a WSON are highly asymmetric.

   The Connectivity Matrix is used to identify these restrictions, which
   can represent either the potential connectivity matrix for asymmetric
   switches (e.g. ROADMs and such) or fixed connectivity for an
   asymmetric device such as a multiplexer as defined in [WSON-Info].

   The Connectivity Matrix is a sub-TLV (the type is TBD by IANA) of the
   Node Attribute TLV. The length is the length of value field in octets.
   The meaning and format of this sub-TLV are defined in Section 5.3 of
   [GEN-Encode]. One sub-TLV contains one matrix. The Connectivity
   Matrix sub-TLV may occur more than once to contain multi-matrices
   within the Node Attribute TLV.

3. Link Information

   The most common link sub-TLVs nested to link top-level TLV are
   already defined in [RFC3630], [RFC4203]. For example, Link ID,
   Administrative Group, Interface Switching Capability Descriptor
   (ISCD), Link Protection Type, Shared Risk Link Group Information
   (SRLG), and Traffic Engineering Metric are among the typical link
   sub-TLVs.

   For WSONs, per [WSON-Info] and [GEN-Encode], we add the following
   additional link sub-TLVs to the link-TLV in this document.

      Sub-TLV Type    Length       Name

         TBD          variable    Port Label Restrictions

         TBD          variable    Available Labels

         TBD          variable    Shared Backup Labels

   In WSON networks, generally all the sub-TLVs above are optional,
   which depends on the control plane implementations. It is default no
   restrictions on wavelength, so Port Label Restrictions sub-TLV may
   not appear in the LSAs. In order to be able to compute RWA, Available


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   Labels sub-TLV may appear in the LSAs. Without available wavelength
   information, path computation need guess what lambdas may be
   available (high blocking probability or distributed wavelength
   assignment may be used). Shared Backup Labels sub-TLV SHOULD not
   appear in the LSAs, if there is no wavelength backup functionality in
   the WSON networks.

3.1. Port Label Restrictions

   Port Label Restrictions describes the wavelength restrictions that
   the link and various optical devices such as OXCs, ROADMs, and
   waveband multiplexers may impose on a port in WSON. These
   restrictions represent what wavelength may or may not be used on a
   link and are relatively static. The detailed information about Port
   label restrictions is described in [WSON-Info].

   The Port Label Restrictions is a sub-TLV (the type is TBD by IANA) of
   the Link TLV. The length is the length of value field in octets. The
   meaning and format of this sub-TLV are defined in Section 5.4 of
   [GEN-Encode]. The Port Label Restrictions sub-TLV may occur more than
   once to specify a complex port constraint within the link TLV.

3.2. Available Labels

   Available Labels indicates the wavelengths available for use on a
   link as described in [GEN-Encode] in WSON. The Available Labels is a
   sub-TLV (the type is TBD by IANA) of the Link TLV. The length is the
   length of value field in octets. The meaning and format of this sub-
   TLV are defined in Section 5.1 of [GEN-Encode]. The Available Labels
   sub-TLV may occur at most once within the link TLV.

   Note that there are five approaches for Wavelength (Label) Set which
   is used to represent the Available Labels described in [GEN-Encode].
   Considering that the continuity of the available or unavailable
   wavelength set can be scattered for the dynamic wavelength
   availability, so it may burden the routing to reorganize the
   wavelength set information when the Inclusive (/Exclusive) List
   (/Range) approaches are used to represent Available Wavelengths
   information. Therefore, it is RECOMMENDED that only the Bitmap Set be
   used for representation Available Wavelengths information.

   The "Base Label" and "Last Label" in label set defined in [GEN-Encode]
   corresponds to base wavelength label and last wavelength label in
   WSON, the format of which is described 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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |Grid |  C.S. |      Reserved   |    n                          |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


   The detailed information related to wavelength label can be referred
   to [Lambda-Labels]

3.3. Shared Backup Labels

   Shared Backup Labels indicates the wavelengths available for shared
   backup use on a link as described in [GEN-Encode] in WSON.

   The Shared Backup Labels is a sub-TLV (the type is TBD by IANA) of
   the Link TLV. The length is the length of value field in octets. The
   meaning and format of this sub-TLV are defined in Section 5.2 of
   [GEN-Encode]. The Shared Backup Labels sub-TLV may occur at most once
   within the link TLV.

4. Routing Procedures

   All the sub-TLVs are nested to top-level TLV(s) and contained in
   Opaque LSAs. The flooding of Opaque LSAs must follow the rules
   specified in [RFC2328], [RFC2370], [RFC3630], [RFC4203] and [OSPF-
   Node].

   In the WSON networks, the node information and link information can
   be classified as two kinds: one is relatively static information such
   as Node ID, Connectivity Matrix information; the other is dynamic
   information such as Available Wavelengths information. [GEN-Encode]
   give recommendations of typical usage of previously defined sub-TLVs
   which contain relatively static information and dynamic information.
   An implementation SHOULD take measures to avoid frequent updates of
   relatively static information when the relatively static information
   is not changed. A mechanism MAY be applied such that static
   information and dynamic information are contained in separate Opaque
   LSAs to avoid unnecessary updates of static information when dynamic
   information is changed.

   Note that as with other TE information, an implementation SHOULD take
   measures to avoid rapid and frequent updates of routing information
   that could cause the routing network to become swamped. A threshold
   mechanism MAY be applied such that updates are only flooded when a
   number of changes have been made to the wavelength availability



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   information within a specific time. Such mechanisms MUST be
   configurable if they are implemented.

5. Security Considerations

   This document does not introduce any further security issues other
   than those discussed in [RFC 3630], [RFC 4203].

6. IANA Considerations

   [RFC3630] says that the top level Types in a TE LSA and Types for
   sub-TLVs for each top level Types must be assigned by Expert Review,
   and must be registered with IANA.

   IANA is requested to allocate new Types for the sub-TLVs as defined
   in Sections 2.1, 3.1, 3.2 and 3.3 as follows:

6.1. Node Information

   This document introduces the following sub-TLVs of Node Attribute TLV
   (Value TBD, see [OSPF-Node])

   Type   sub-TLV

   TBD    Connectivity Matrix

6.2. Link Information

   This document introduces the following sub-TLVs of TE Link TLV (Value
   2)

   Type   sub-TLV

   TBD    Port Label Restrictions

   TBD    Available Labels

   TBD    Shared Backup Labels

7. 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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   [RFC3630] Katz, D., Kompella, K., and Yeung, D., "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.

   [RFC3945] E. Mannie, Ed., "OGeneralized Multi-Protocol Label Switching (GMPLS)
             Architecture", RFC 3945, October 2004.

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

   [RFC2328] Moy, J., "OSPF Version 2", STD 54, RFC 2328, April 1998.

   [RFC2370] Coltun, R., "The OSPF Opaque LSA Option", RFC 2370, July
             1998.

   [OSPF-Node] R. Aggarwal and K. Kompella, "Advertising a Router's
               Local Addresses in OSPF TE Extensions", draft-ietf-ospf-
               te-node-addr, work in progress.

   [Lambda-Labels] T. Otani, H. Guo, K. Miyazaki, D. Caviglia, "
                    Generalized Labels for Lambda-Switching Capable
                    Label Switching Routers", work in progress: draft-
                    ietf-ccamp-gmpls-g-694-lambda-labels-05.txt,
                    December 2009.

   [WSON-Frame] Y. Lee, G. Bernstein,  W. Imajuku, "Framework for GMPLS
                and PCE Control of Wavelength Switched Optical Networks
                (WSON)", work in progress: draft-ietf-ccamp-rwa-WSON-
                Framework-05.txt, February 2010.

   [WSON-Info] Y. Lee, G. Bernstein, D. Li, W. Imajuku, "Routing and
               Wavelength Assignment Information Model for Wavelength
               Switched Optical Networks", work in progress: draft-ietf-
               ccamp-rwa-info-07.txt, February 2010.






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   [RWA-Encode]G. Bernstein, Y. Lee, D. Li, W. Imajuku, "Routing and
                Wavelength Assignment Information Encoding for
                Wavelength Switched Optical Networks", work in progress:
                draft-ietf-ccamp-rwa-wson-encode-04.txt, February 2010.

   [GEN-Encode] G. Bernstein, Y. Lee, D. Li, W. Imajuku, " General
                Network Element Constraint Encoding for GMPLS
                Controlled Networks", work in progress: draft-ietf-
                ccamp-general-constraint-encode-01.txt, March 2010.

   [WSON-COM-OSPF] Y. Lee, G. Bernstein, "OSPF Enhancement for Signal
                and Network Element Compatibility for Wavelength
                Switched Optical Networks", work in progress: draft-
                ietf-ccamp-wson-signal-compatibility-ospf-00.txt,
                December 8, 2009.



8. Authors' Addresses

   Fatai Zhang
   Huawei Technologies
   F3-5-B R&D Center, Huawei Base
   Bantian, Longgang District
   Shenzhen 518129 P.R.China

   Phone: +86-755-28972912
   Email: zhangfatai@huawei.com

   Young Lee
   Huawei Technologies
   1700 Alma Drive, Suite 100
   Plano, TX 75075
   USA

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


   Jianrui Han
   Huawei Technologies Co., Ltd.
   F3-5-B R&D Center, Huawei Base
   Bantian, Longgang District


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   Shenzhen 518129 P.R.China

   Phone: +86-755-28972913
   Email: hanjianrui@huawei.com


   Greg Bernstein
   Grotto Networking
   Fremont CA, USA

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


   Yunbin Xu
   China Academy of Telecommunication Research of MII
   11 Yue Tan Nan Jie Beijing, P.R.China
   Phone: +86-10-68094134
   Email: xuyunbin@mail.ritt.com.cn


   Guoying Zhang
   China Academy of Telecommunication Research of MII
   11 Yue Tan Nan Jie Beijing, P.R.China
   Phone: +86-10-68094272
   Email: zhangguoying@mail.ritt.com.cn


   Dan Li
   Huawei Technologies Co., Ltd.
   F3-5-B R&D Center, Huawei Base
   Bantian, Longgang District
   Shenzhen 518129 P.R.China

   Phone: +86-755-28973237
   Email: danli@huawei.com


   Ming Chen
   European Research Center
   Huawei Technologies


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   Riesstr. 25, 80992 Munchen, Germany

   Phone: 0049-89158834072
   Email: minc@huawei.com


   Yabin Ye
   European Research Center
   Huawei Technologies
   Riesstr. 25, 80992 Munchen, Germany

   Phone: 0049-89158834074
   Email: yabin.ye@huawei.com


Acknowledgment

   We thank Ming Chen and Yabin Ye from DICONNET Project who provided
   valuable information for this document.


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