Internet DRAFT - draft-wang-ccamp-gmpls-sson-rsvpte

draft-wang-ccamp-gmpls-sson-rsvpte






Network Working Group                                         Qilei Wang
Internet-Draft                                                  Xihua Fu
Intended status: Standards Track                         ZTE Corporation
Expires: April 25, 2013                                     Oct 22, 2012


   RSVP-TE Extensions for GMPLS control of Spectrum Switched Optical
                            Networks (SSONs)
               draft-wang-ccamp-gmpls-sson-rsvpte-02.txt

Abstract

   A new architecture of optical transport networks which is addressed
   in the newest version of G.872 is being developed in ITU-T SG15.
   Compared with previous G.872 technology, this new technology allows
   the switch of large chunk of contiguous spectrum which may be wider
   than the spectrum occupied by a single optical channel signal.

   Since current control plane technology isn't able to control this
   kind of application, this document describes the signaling extension
   to support the control of this kind of new spectrum utilization and
   implementation way.  This document also addresses the interworking
   between WSON optical channel and SSON (Spectrum Switched Optical
   Network) optical channel.

Status of this Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
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   This Internet-Draft will expire on April 25, 2013.

Copyright Notice

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

   This document is subject to BCP 78 and the IETF Trust's Legal



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   Provisions Relating to IETF Documents
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Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
     1.1.  Conventions used in this document  . . . . . . . . . . . .  4
   2.  Terminology  . . . . . . . . . . . . . . . . . . . . . . . . .  4
   3.  Requirements and Modeling of SSON  . . . . . . . . . . . . . .  5
     3.1.  Hierarchy between Optical Channel and Media Channel  . . .  5
     3.2.  Switching Type . . . . . . . . . . . . . . . . . . . . . .  6
     3.3.  Media Channel  . . . . . . . . . . . . . . . . . . . . . .  6
       3.3.1.  Label Format . . . . . . . . . . . . . . . . . . . . .  6
       3.3.2.  Traffic Parameters . . . . . . . . . . . . . . . . . .  6
       3.3.3.  Grid Attributes of Forwarding Adjacency  . . . . . . .  7
     3.4.  Optical Channel  . . . . . . . . . . . . . . . . . . . . .  7
       3.4.1.  Overview of Flexible Grid and Fixed Grid . . . . . . .  7
       3.4.2.  Interwork between WSON OCh signal and SSON OCh
               signal . . . . . . . . . . . . . . . . . . . . . . . .  7
   4.  Signaling Protocol Extensions to Support Control of Media
       Layer  . . . . . . . . . . . . . . . . . . . . . . . . . . . .  8
     4.1.  Switching Type . . . . . . . . . . . . . . . . . . . . . .  9
     4.2.  Label Format Extensions of Media Channel Layer . . . . . .  9
     4.3.  Traffic Parameters of Media Channel Layer  . . . . . . . . 10
   5.  Signaling Procedures . . . . . . . . . . . . . . . . . . . . . 10
     5.1.  RSVP-TE Signaling Procedures to Support the Setup of
           Frequency Slot Channel . . . . . . . . . . . . . . . . . . 10
       5.1.1.  Centralized Spectrum Assignment  . . . . . . . . . . . 10
       5.1.2.  Distributed Spectrum Assignment  . . . . . . . . . . . 10
     5.2.  Interwork between WSON signal and SSON signal  . . . . . . 11
   6.  Security Considerations  . . . . . . . . . . . . . . . . . . . 13
   7.  References . . . . . . . . . . . . . . . . . . . . . . . . . . 13
     7.1.  Normative References . . . . . . . . . . . . . . . . . . . 13
     7.2.  Informative References . . . . . . . . . . . . . . . . . . 13
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 14









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1.  Introduction

   In the newest version of G.872, a new kind of spectrum utilization
   and implementation way is introduced to current optical network.  A
   new kind of entity called media channel which is similar to LSP is
   introduced.  According to the description in [G.872v16], the media
   channel is a topological construct that represents both the path
   through the media and the resource (frequency slot) that it occupies.
   A media channel is bounded by ports on media elements.  A media
   channel may be dimensioned to carry more than one OCh-P signal.  That
   is to say, a chunk of contiguous spectrum which can be occupied by a
   group of optical channels can be forwarded via wide-band filters as a
   whole without filtering and switching everything down to the
   individual OCh (Optical Channel) level in long-haul systems.
   Compared with narrowband, wideband filters and switching has many
   advantages, for example, building OCh Signals for management
   convenience, maximizing the reach and traversing more nodes.

   Following is the description taken from [G.872v16], "below the OCh,
   the entities that provide for configuration of the media channels are
   described separately from the entities that provide management of the
   collections of the OCh-P signals that traverse the media".  According
   to the description, we can conclude that the containment relationship
   exists between media channels and OCh signals, and the containment
   relationship should be announced to the source and end nodes of the
   media channels.  Intermediate nodes are unnecessary to know the
   containment relationship because the media channel can be switched as
   a whole without filtering and switching everything down to individual
   OCh level.

   Two kinds of entities which are spectrum configuration entity and
   signal management entity should be provide by nodes creating media
   channels from the perspective of control plane.

   Note: Optical channels switched in a media channel may have different
   spectrum bandwidth.

   From the perspective of management plane and control plane,
   containment relationship indicates that hierarchy exists between the
   media channel and optical channel.  GMPLS protocol are needed to
   extent to help manage this kind of spectrum utilization and
   implementation way.  This document first describes the coexistence of
   media channel and optical channel, then the layer model base on the
   hierarchy between optical channels (OCh) and media channel from
   management plane or control plane perspective and defines signaling
   protocol extension to support the control of media channel.  As the
   flexible grid framework document describes both the media channel and
   optical channel, this document also give a detail description about



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   the interworking between WSON optical channel and SSON (Spectrum
   Switched Optical Network) optical channel.

1.1.  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 [RFC2119].


2.  Terminology

   o  Frequency slot: As defined by Q6 in clause 3.1.2 of G.694.1, a
      frequency slot is a frequency range which is allocated to a slot
      and unavailable to other slots within a flexible grid.  A
      frequency slot is defined by its nominal central frequency and its
      slot width.  Detailed description can be found in the framework
      document.

   o  Media channel: as defined in [G.872v16], media channel is used to
      indicate a media association that represents both the topology
      (i.e., the path through the media) and the resource (frequency
      slot) that it occupies.  A media channel is bounded by ports on
      media elements and can span any combination of network elements
      and fibers.

   o  Effective frequency slot: The effective frequency slot of a media
      channel is that part of the frequency slots of the filters along
      the media channel that is common to all of the filters' frequency
      slots.  It is described by its nominal central frequency and its
      slot width.

   o  Nominal central frequency (of a frequency slot) - as used by Q6/
      SG15 in G.694.1.  This parameter is associated with a grid
      position on the fixed grid and a slot in the flexible grid.

   o  Network media channel: The end-to-end channel allocated to
      transport a single OCh payload signal is called a network media
      channel and supports a single OCh payload network connection.

   o  SSON: Spectrum-Switched Optical Network.  This concept and
      definition is introduced from the framework document.  An optical
      network in which a data plane connection is switched based on an
      optical spectrum frequency slot of a variable slot width, rather
      than based on a fixed grid and fixed slot width.






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3.  Requirements and Modeling of SSON

3.1.  Hierarchy between Optical Channel and Media Channel

   Spectrum may be allocated in larger and contiguous piece than
   spectrum occupied by a single optical channel which is called
   Frequency Slot.  The frequency slot is described by its nominal
   central frequency and its slot width [ITU-T G.694.1].  The media
   Channel is a topological construct that represents both the path
   through the media and the resource (frequency slot) that it occupies.
   A media channel is bounded by ports on media elements and can span
   any combination of network elements and fibers, while the frequency
   slot is a local concept, while the media channel has an end-to-end
   meaning.  A media channel may be dimensioned to carry more than one
   OCh P signal.  Network media channel is a specific type of media
   channel which can only be used to transport a single OCh signal and
   support a single OCh connection.

   From the perspective of control plane or management plane, hierarchy
   exists between media channel and optical channel, as media channel
   can be used to transport optical channel signals.  During the process
   of path setup, containment relationship between optical channel
   signal and media channel should be conveyed through signaling and
   announced to source node and end node in order to help group and
   detach optical channel signals from one another.  Dependency
   relationship needs to be explicitly told.

   Notes: no hierarchy exists in either media channels or optical
   channels.

   Media channels can be switched in a media Matrix.  The media channel
   matrix provides flexible connectivity for the media channels.  Media
   ports at the edge of a media channel matrix may be created and broken
   to help route media channel path.  Media channel connection will
   limit the connectivity of optical channel signals over the network
   element within the frequency slot.  Media channel matrixes are not
   mandatory to have the function of optical channel matrix as signals
   in the media channel can be switched as a whole.

   In the case where the switching granularity of the media Matrix
   allows for independent switching of each OCh, it can be decided as a
   matter of policy that a request to establish an OCh connection will,
   internal to the NE, establish a network media channel Matrix
   Connection of the same spectrum slot width, and the network media
   Matrix Connection can be released when the OCh connection is
   released.

   As more than one optical channel signal can be carried in a media



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   channel, notion of hierarchy exists between them. current optical
   transport network can be modeled into two layers and managed
   independently from the perspective of management, one is optical
   channel layer and the other is media layer.  Optical channel layer
   can be modeled as higher layer and media channel layer can be modeled
   as lower layer.  Media layer LSP created in high layer appear as a
   data link in optical channel layer.  One or more optical channel LSPs
   can be nested into media channel LSP.  That is to say, media channel
   LSP appears as a H-LSP in the higher layer optical channel LSP.

   As a kind of resource, spectrum allows for the utilization by both
   optical channel layer and media layer.  It's not necessary to setup
   media LSP first before the setup of OCh LSP.  Coexistence of OCh and
   media channel in the same link is permitted.

3.2.  Switching Type

   Switching type can be used to indicate the type of switching that
   should be performed on a particular link.  According to the modeling
   in the previous section, a new switching type should be defined to
   indicate the switching capability of media channel layer.

3.3.  Media Channel

3.3.1.  Label Format

   Section 3.3 of [RFC3471] defines waveband switching: "A waveband
   represents a set of contiguous wavelengths which can be switched
   together to a new waveband".  This is similar to the media channel
   switching, because they both switch multiple wavelengths or spectrum
   as a unit.

   But the wavelength label defined in [RFC3471] only has significance
   between neighbors, in order to control the setup and release of media
   channel with RSVP-TE signaling, a new media channel label which has
   definite information of nominal central frequency and slot width of
   the spectrum is needed.  This chunk of spectrum can be used for
   subsequent setup of optical channel path.

3.3.2.  Traffic Parameters

   In current network, like MPLS network, OTN network, signaling can be
   used to reserve bandwidth (i.e., bitrates) at each node along the
   path when set up LSPs.  The bandwidth information describes the end-
   to-end traffic characteristic of a LSP, so the signaling SHOULD be
   able to carry bandwidth information that a LSP need to occupy.

   In the process of the setup of media channel, the most critical



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   traffic characteristic of a media channel LSP is spectrum, i.e., the
   spectrum width that a LSP can occupy.  For example, if a third party
   wants to manage and operate a chunk of spectrum by itself, carrier
   could use the signaling to set up a media channel with a specific
   spectrum width to satisfy the requirement.  Carrier doesn't care how
   this spectrum can be used by the party and how many data this chunk
   of spectrum can bear.  So when we use signaling to set up a media
   channel, spectrum resource information (i.e.,spectrum width) should
   be carried in the signaling to reserve the spectrum resource along
   the path.

3.3.3.  Grid Attributes of Forwarding Adjacency

   Media matrix connection may interconnect one or more media channels,
   which in turn may carry one or more OCh signals.  In the case the
   media matrix just allow the switching of spectrum as a whole,
   internal flexible grid or fixed grid attributes are unnecessary to be
   known by the forwarding adjacency end points.

3.4.  Optical Channel

   [Notes: This section mainly addresses the current status of optical
   channel interconnection, including interconnection between WSON
   optical channel signal and SSON optical channel signal.]

3.4.1.  Overview of Flexible Grid and Fixed Grid

   Fixed grid signals have fixed slot width (e.g., 50GHz), while
   flexible grid signals allow different slot widths (e.g., 50GHz,
   87.5GHz).GMPLS and PCE control of fixed grid network (i.e., WSON,
   Wavelength Switched Optical Network) is close to mature in IETF
   CCAMP, while flexible grid control plane technology is still being
   developed in IETF.  This section mainly focuses on the
   interconnection between WSON optical channel signal and SSON optical
   channel signal.

3.4.2.  Interwork between WSON OCh signal and SSON OCh signal

   Some open issues are listed in the recent flexible grid framework
   document and still need to be resolved if we want to push the
   framework document forward.  Part of these issues which may have
   relation to the interwork between SSON and WSON are listed here:

   1).  If a new switching capability is needed to represent SSON
   optical channel layer?

   2).  Potential problems with having the same switching capability but
   the label format changes compared with WSON optical channel layer.



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   3).  Role of LSP encoding type?  I think the issue listed here
   intends to say if a new LSP encoding type is needed for flexible grid
   optical channel layer.

   4).  Notion of hierarchy?  There is no notion of hierarchy between
   flexible grid OCh and fixed grid OCh.

   Just from my perspective, I think SSON optical channel layer should
   use the same switching capability as WSON optical channel layer.
   Some words are given here to describe my opinion.  A LSP which has a
   bandwidth of 50GHz pass through both WSON network and SSON network.
   We assume that no OEOs exist in the LSP, so both the WSON optical
   channel path and SSON optical channel path occupy 50GHz.  From the
   perspective of data plane, there is no change of the signal and no
   multiplexing when the WSON optical channel path interconnects with
   SSON optical channel path.  From this scenario we can conclude that
   both WSON optical channel layer and SSON optical channel layer belong
   to the same layer.  No notion of hierarchy exists between them.  Base
   on these words, I think both WSON optical channel layer and SSON
   optical channel layer should use the same switching capability.

   The previous words mention the issues 1) and 4).  Another two issues
   are to be discussed in the following description in the process of
   path setup.

   Because there is no notion of hierarchy exists between WSON optical
   channel layer and SSON optical channel layer, hierarchy LSP which is
   addressed in [RFC4206] and [RFC6107] can't be applied.  But stitching
   LSP which is described in [RFC5150] can be applied in one layer.  LSP
   hierarchy allows more than one LSP to be mapped to an H-LSP, but in
   case of S-LSP, at most one LSP may be associated with an S-LSP.  This
   is similar to the scenario of interconnection between WSON OCh LSP
   and SSON OCh LSP.  Similar to an H-LSP, an S-LSP could be managed and
   advertised, although it is not required, as a TE link, either in the
   same TE domain as it was provisioned or a different one.  Path setup
   procedure of stitching LSP can be applied in the scenario of
   interconnection between WSON optical channel path and SSON optical
   channel path.


4.  Signaling Protocol Extensions to Support Control of Media Layer

   This section mainly addresses the signaling protocol extension in
   order to support the control of spectrum-switched optical network
   media layer and the facilitating of the setup of forwarding adjacency
   in G.872 optical transport network.





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4.1.  Switching Type

   A new switching type is defined here for media channel layer.



             Value        Type
             -------      -------
             XX(IANA)     Media Channel Switched Capable (MCSC)


                      Figure 1: Switching Capability

4.2.  Label Format Extensions of Media Channel Layer

   According to the description in the section 3.2, label should be able
   to describe the frequency slot characteristic in order to facilitate
   the switch of this large piece of spectrum.  Label format of flexible
   grid can be introduced here to depict the label of media channel.



      0                   1                   2                   3
      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |Grid | C.S.  |    Identifier   |              n                |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |       m                       |  Reserved                     |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                              Figure 2: label

   Grid Type: 3.  A new grid value to support flexible grid.

   The meaning of C.S. and identifier is maintained from [RFC6205] and
   [draft-farrkingel-ccamp-flexigrid-lambda-label].

   Similar to the definition in
   [draft-farrkingel-ccamp-flexigrid-lambda-label], n is used to
   identify the nominal central frequency, and m (16bits) is used to
   identify slot width of the media channel.

   [Notes: here we use 16 bits to represent the "m" value, because 8
   bits maybe not enough for the setup of media channel with large chunk
   of spectrum.  This document is different from current flexible grid
   document in CCAMP because of different model way.]





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4.3.  Traffic Parameters of Media Channel Layer

   Similar to the original signaling which carry the information of
   Bandwidth (i.e., bitrates) that a LSP may reserve at each node along
   the path, signaling that is used to set up media channel SHOULD be
   able to carry the information of spectrum width.  The spectrum width
   traffic parameters can be organized as follow, and this information
   is carried in the Sender_Tspec object within a path message.


      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
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |       m                       |  Reserved                     |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                        Figure 3: traffic parameter


   m (16 bits): the spectrum width is specified by m*12.5 GHz.


5.  Signaling Procedures

5.1.  RSVP-TE Signaling Procedures to Support the Setup of Frequency
      Slot Channel

5.1.1.  Centralized Spectrum Assignment

   In this case, both of the route and the frequency slot information
   (i.e., central frequency and spectrum width) are provided by the PCE
   or ingress node.  When signaling a LSP, the assigned label
   information is carried in the ERO label sub-object which is addressed
   in [RFC3473].  When the nodes along the LSP receive the path message
   carrying the ERO and ERO label sub-object, the procedure of path
   setup is the same as the procedure which is described in [RFC3473]
   and [RFC4003].  RRO and RRO label sub-object are used to record the
   label information of the egress.

5.1.2.  Distributed Spectrum Assignment

   In this case, only the route is provided by a PCE or ingress node
   before the signaling procedure.  The available spectrum SHALL be
   collected hop by hop and the egress node SHOULD select a proper label
   for the LSP.  After the route is computed, the ingress node SHOULD
   find out the available spectrum for the LSP on the next link of the
   route.




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   Then a path message is sent to the next node along the path according
   to the route information.  The path message MUST contain a
   Sender_Tspec object to specify the spectrum width of the media
   channel.  A Label_set object SHALL be added to the path message,
   which contains the candidate available spectrum for the LSP on the
   next link.

   When an intermediate node receives the path message, it can deserve
   the spectrum width information from the Sender_Tspec object.  Then it
   SHOULD find the available spectrum for the LSP on the next link of
   the route similar to the ingress node.  The common part of the two
   available spectrum sets.  If the new set is null, the path message
   SHALL be rejected by a patherr message.  Otherwise, the Label_set
   object in the path message SHALL be updated according to the new set
   and the path message is forwarded to the next node according to the
   route.

   When an egress node receives a path message, it SHOULD select an
   available spectrum from the Label_set object based on local policy
   and determine the media channel base on the spectrum width and the
   available spectrum.  Then a Resv message is responded so that the
   nodes along the LSP can establish the optical cross-connect based on
   the Label object which is determined by the spectrum width in the
   traffic parameters and the available spectrum in the Label_set
   object.

5.2.  Interwork between WSON signal and SSON signal

   The path setup procedure of WSON OCh signal's interworking with SSON
   OCh signal is described as follows:

   Let's take the following network into consideration.


                        e2e LSP
                  +++++++++++++++++++++++++++++++++++> (LSP1-2)

                            LSP segment (flexi-LSP)
                          ====================> (LSP-AB)
                              C --- E --- G
                             /|\    |   / |\
                            / | \   |  /  | \
                  R1 ---- A \ |  \  | /   | / B --- R2
                             \|   \ |/    |/
                              D --- F --- H

             fixed grid --A-- flexi-grid    --B-- fixed grid




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           Figure 4: Interworking between WSON OCh and SSON OCh


   In this scenario, R1 and R2 are traditional WSON signal capable
   nodes, A and B are both WSON optical channel signal and SSON optical
   channel signal capable nodes, the other nodes are SSON optical
   channel capable nodes.  We assume that a 40Gbit/s LSP from R1 to R2
   needs to be set up.

   Node R1 prepares signaling path message for the end-to-end path setup
   from R1 to the destination node R2.  Before R1 sends path message, R1
   should fist send a path computation request to the path computation
   element in order to compute an end-to-end path from R1 to R2.  After
   path computation, PCRep message which contains ERO and label
   information is send back to R1 from PCE.

   R1 encapsulates the path message which contains ERO to explicitly
   indicate the path and label used and RRO to record the path traversed
   and label used by node traversed.  Then R1 sends the path message to
   the next hop node A. Here we assume path computation element is
   capable of fixed grid and flexible grid path computation, and the ERO
   contain the path information (R1, A, B, R2).  When the path message
   arrives at node A, node A verifies the path message and finds
   incomplete ERO information, then send another path computation
   request message to the PCE in order to obtain the whole path
   information.  PCE sends path computation response message which
   contain ERO (A, D, F, H, B) and label information.  Here the label is
   flexible label information which is addressed in [draft-farrkingel].

   To facilitate the control of stitching LSP boundaries, we may use a
   different encoding type for flexible grid to help control.  Encoding
   type can be used to help stitching LSP boundaries control.  Stitching
   LSP boundaries control looks like FA-LSP boundaries control, but has
   many differences.

   After matching the switching type and encoding type of the interface,
   Node A blocks the signaling process and decides to set up a stitching
   LSP according to the flexible grid LSP setup procedure using another
   signaling process.  Procedure for set up stitching LSP can be found
   in RFC5150.  The stitching LSP can be seen as a TE link in the fixed
   grid network.  After the setup of stitching LSP between A and B, A
   then continues the blocking signaling procedure and sends the path
   message to the next hop B directly and finishes the end-to-end LSP.

   In this scenario of interconnection between WSON OCh and SSON OCh,
   dynamic stitching LSP setup is frequent, static stitching LSP
   configuration may not be needed here.




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6.  Security Considerations

   TBD


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.

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

7.2.  Informative References

   [G.694.1 v6]
              International Telecommunications Union, "Draft revised
              G.694.1 version 1.6".

   [G.872 v16]
              International Telecommunications Union, "Draft revised
              Recommendation ITU-T G.872".

   [flexible-grid-ospf-ext]
              Fatai Zhang, Xiaobing Zi, Ramon Casellas, O. Gonzalez de
              Dios, and D. Ceccarelli, "GMPLS OSPF-TE Extensions in
              support of Flexible-Grid in DWDM Networks",
              draft-zhang-ccamp-flexible-grid-ospf-ext-00.txt .

   [flexible-grid-requirements]
              Fatai Zhang, Xiaobing Zi, O. Gonzalez de Dios, and Ramon
              Casellas, "Requirements for GMPLS Control of Flexible
              Grids",
              draft-zhang-ccamp-flexible-grid-requirements-01.txt .

   [flexigrid-lambda-label]
              D. King, A. Farrel, Y. Li, F. Zhang, and R. Casellas,
              "Generalized Labels for the Flexi-Grid in Lambda-Switch-
              Capable (LSC) Label Switching Routers",
              draft-farrkingel-ccamp-flexigrid-lambda-label-01.txt .

   [ospf-ext-constraint-flexi-grid]
              L Wang, Y Li, "OSPF Extensions for Routing Constraint
              Encoding in Flexible-Grid Networks",
              draft-wangl-ccamp-ospf-ext-constraint-flexi-grid-00.txt .




Qilei Wang & Xihua Fu    Expires April 25, 2013                [Page 13]

Internet-Draft      Spectrum Switched Optical Network           Oct 2012


Authors' Addresses

   Qilei Wang
   ZTE Corporation

   Email: wang.qilei@zte.com.cn


   Xihua Fu
   ZTE Corporation
   ZTE Plaza, No.10, Tangyan South Road, Gaoxin District
   Xi'an
   P.R.China

   Email: fu.xihua@zte.com.cn




































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