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Versions: 00 01 02 03 04 RFC 6002

Internet Draft                                         Lou Berger (LabN)
Updates: 3471, 3473, 3945, 4202                       Don Fedyk (Nortel)
Category: Standards Track
Expiration Date: August 25, 2009

                                                       February 25, 2009

   Generalized MPLS (GMPLS) Data Channel Switching Capable (DCSC) and
                      Channel Set Label Extensions

             draft-ietf-ccamp-gmpls-dcsc-channel-ext-01.txt

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   publication of this document. Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.

Abstract

   This document describes two technology-independent extensions to
   Generalized Multi-Protocol Label Switching.  The first extension
   defines the new switching type Data Channel Switching Capable.  Data
   Channel Switching Capable interfaces are able to support switching of
   the whole digital channel presented on single channel interfaces.
   The second extension defines a new type of generalized label and
   updates related objects.  The new label is called the Generalized
   Channel_Set Label and allows more than one data plane label to be
   controlled as part of an LSP.


Table of Contents

    1      Introduction  ...........................................   3
    1.1    Conventions used in this document  ......................   3
    2      Data Channel Switching  .................................   3
    2.1    Compatibility  ..........................................   4
    3      Generalized Channel_Set Label Related Formats  ..........   4
    3.1    Generalized Channel_Set LABEL_REQUEST Object  ...........   5
    3.2    Generalized Channel_Set LABEL Object  ...................   5
    3.3    Other Label related Objects  ............................   7
    3.4    Compatibility  ..........................................   8
    4      IANA Considerations  ....................................   8
    4.1    Data Channel Switching Type  ............................   8
    4.2    Generalized Channel_Set LABEL_REQUEST Object  ...........   8
    4.3    Generalized Channel_Set LABEL Object  ...................   9
    5      Security Considerations  ................................   9
    6      References  .............................................   9
    6.1    Normative References  ...................................   9
    6.2    Informative References  .................................  10
    7      Acknowledgments  ........................................  11
    8      Author's Addresses  .....................................  11















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1. Introduction

   This document describes two technology independent extensions to
   Generalized Multi-Protocol Label Switching (GMPLS).  Both of these
   extensions were initially defined to in the context of Ethernet
   services, see [GMPLS-ESVCS] and [GMPLS-MEF-UNI], but are generic in
   nature and may be useful to any switching technology controlled via
   GMPLS.

   The first extension defines a new switching type, which is called
   Data Channel Switching Capable, or DCSC.  DCSC interfaces are able to
   support switching of the whole digital channel presented on single
   channel interfaces.  The second extension defines a new type of
   generalized label and updates related objects.  The new label is
   called the Generalized Channel_Set Label and allows more than one
   data plane label to be controlled as part of an LSP.


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. Data Channel Switching

   Current GMPLS switching types are defined in [RFC3945] and [RFC3471]
   and support switching at the packet (PSC), frame (L2SC), time-slot
   (TDM), frequency (LSC) and fiber (FSC) granularities.  One type of
   switching that is not well represented in this current set is
   switching that occurs of the when all data received on an ingress
   port is switched through a network to an egress port.  While there
   are similarities between this level of switching and the "opaque
   single wavelength" case described in Section 3.5 of [RFC4202], such
   port-to-port switching is not limited to the optical switching
   technology implied by the LSC type. FSC is also similar, but it is
   restricted to fiber ports and also supports multiple data channels
   with in the fiber port.

   This document defines the new switching type called Data Channel
   Switching Capable (DCSC). (Port switching seems a more intuitive
   name, but it collides with PSC so isn't used.)  DCSC interfaces are
   able to support switching of the whole digital channel presented on
   single channel interfaces.  Interfaces that inherently support
   multiple channels, e.g., WDM and channelized TDM interfaces, are
   specifically excluded from this type. Any interface that can be
   represented as a single digital channel are included.  Examples



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   include concatenated TDM and line encoded interfaces.  Framed
   interfaces may also be included when they support switching on an
   interface granularity.

   DCSC is represented in GMPLS, see [RFC3471] and [RFC4202], using the
   value TBA (by IANA).

   Port labels, as defined in [RFC3471], SHOULD be used for LSPs
   signaled using the DCSC Switching Type.  The DCSC Switching Type may
   be used with wither the in the Generalized Label Request object,
   [RFC3473], or the Generalized Channel_Set LABEL_REQUEST Object
   defined below.


2.1. Compatibility

   Transit and egress nodes that do not support the DCSC Switching Type
   which received a Path message with a Label Request containing the
   DCSC Switching Type will behave in the same way nodes generally
   handle the case of an unsupported Switching Type.  Specifically, per
   [RFC3473], such nodes are required to generate a PathErr message,
   with a "Routing problem/Unsupported Encoding" indication.

   Ingress nodes initiating a Path message containing a Label Request
   containing the DCSC Switching Type should receive such PathErr
   messages, and can then notify the requesting application user as
   appropriate.


3. Generalized Channel_Set Label Related Formats

   This section defines a new type of generalized label and updates
   related objects.  This section updates the label related definitions
   of [RFC3473].  The ability to communicate more than one label as part
   of the same LSP was motivated by the support for the communication of
   one or more VLAN IDs. Simple concatenation of labels as is done in
   [RFC4606] was deemed impractical given the large number of VLAN IDs
   (up to 4096) that may need to be communicated.  The formats defined
   in this section are not technology specific and may be useful for
   other switching technologies.  The LABEL_SET object defined in
   [RFC3473] serves as the foundation for the defined formats.










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3.1. Generalized Channel_Set LABEL_REQUEST Object

   The Generalized Channel_Set LABEL_REQUEST object is used to indicate
   that the Generalized Channel_Set LABEL Object is to be used with the
   associated LSP.  The format of the Generalized Channel_Set
   LABEL_REQUEST object is the same as the Generalized LABEL_REQUEST
   object and uses of C-Type of TBA.


3.2. Generalized Channel_Set LABEL Object

   The Generalized Channel_Set LABEL Object communicates one or more
   labels, all of which can be used equivalently in the data path
   associated with a single LSP.  The format of the Generalized
   Channel_Set LABEL Object is based on the LABEL_SET object defined in
   [RFC3473].  It differs from the the LABEL_SET object in that the full
   set may be represented in a single object rather than the multiple
   objects required by the [RFC3473] LABEL_SET object.  The object MUST
   be used on LSPs that use the Generalized Channel_Set LABEL_REQUEST
   object.  The object MUST be processed per [RFC3473].  Make-before-
   break procedures, see [RFC3209], SHOULD be used when modifying the
   Channel_Set LABEL object.

   The format of the Generalized Channel_Set LABEL object is:

   o  Generalized Channel_Set LABEL object: Class = 16, C-Type = TBA (By
   IANA)

      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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                   Channel_Set Sub-Object 1                    |
      |                              ...                              |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      :                               :                               :
      :                               :                               :
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                   Channel_Set Sub-Object N                    |
      |                              ...                              |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+











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   The Channel_Set Sub-Object size is measured in bytes and MUST always
   be a multiple of 4, and at least 4, and has the following format:

      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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |    Action     |  Num Subchannels  |        Label Type         |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                          Subchannel 1                         |
      |                               +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |       ...                     |                               :
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+                               :
      :                               :                               :
      :                               :                               :
      :                               :                               :
      :                               :                               :
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                          Subchannel N                         |
      |                               +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |           ...                 |         Padding               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

      Action: 8 bits

         See [RFC3471] for definition of actions.  Range actions SHOULD
         be used when possible to minimize the size of the Channel_Set
         LABEL Object.

      Number of Subchannels: 10 bits

         Indicates the number of subchannels carried in the sub-object.
         When the number of subchannels required exceeds the limit of
         the field, i.e., 1024, multiple Channel_Set Sub-Objects MUST be
         used.  Note that the size of the sub-object may result in a
         Path message being larger than a single unfragmented IP packet.
         See section 4.4 for an example of how this case may be handled.

         A value of zero (0) has special meaning and MAY be used in
         either the LABEL or UPSTREAM_LABEL object.  A value of zero (0)
         is used in a LABEL or UPSTREAM_LABEL object to indicate that
         the subchannel(s) used in the corresponding (downstream or
         upstream) direction MUST match the subchannel(s) carried in the
         reverse directions label object. When value of zero (0) is
         used, no Subchannels are included in the Channel_Set Sub-Object
         and only one Channel_Set Sub-Object may be present.  The zero
         (0) value MUST NOT be used in both the LABEL and UPSTREAM_LABEL
         object of the same LSP.




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      Label Type: 14 bits

         See [RFC3473] for a description of this field.

      Subchannel: Variable

         See [RFC3471] for a description of this field. Note that this
         field might not be 32 bit aligned.

      Padding: Variable

         Padding is used to ensure that the length of a Channel_Set Sub-
         Object meets the multiple of 4 byte size requirement stated
         above.  The field is only required when the Subchannel field is
         not 32 bit aligned and the number of included Subchannel fields
         result in the Sub-Object not being 32 bit aligned.

         The Padding field MUST be included when the number of bits
         represented in all the Subchannel fields included in a
         Generalized Channel_Set Sub-Object result in the Sub-Object not
         being 32 bit aligned.  When present, the Padding field MUST
         have a length that results in the Sub-Object being 32 bit
         aligned.  When present, the Padding field MUST be set to a zero
         (0) value on transmission and MUST be ignored on receipt.
         These bits SHOULD be passed through unmodified by transit
         nodes.


3.3. Other Label related Objects

   The previous section introduces a new LABEL object.  As such the
   formats of the other label related objects are also impacted.
   Processing of these objects is not modified and remain per their
   respective specifications.  The other label related objects are
   defined in [RFC3473] and include:
      - SUGGESTED_LABEL object
      - LABEL_SET object
      - ACCEPTABLE_LABEL_SET object
      - UPSTREAM_LABEL object
      - RECOVERY_LABEL object











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3.4. Compatibility

   Transit and egress nodes that do not support the Generalized
   Channel_Set Label related formats will first receive a Path message
   containing Generalized Channel_Set LABEL_REQUEST object.  When a such
   a node receives the Path message, per [RFC3209], it will sends a
   PathErr with the error code "Unknown object C_Type" .

   Ingress nodes initiating a Path message containing a Generalized
   Channel_Set LABEL_REQUEST object should receive such PathErr
   messages, and can then notify the requesting application user as
   appropriate.


4. IANA Considerations

   IANA is requested to administer assignment of new values for
   namespaces defined in this document and reviewed in this section.


4.1. Data Channel Switching Type

   Upon approval of this document, the IANA will make the assignment in
   the "Switching Types"  section of the "GMPLS Signaling Parameters"
   registry located at http://www.iana.org/assignments/gmpls-sig-
   parameters:

   Value   Type                                      Reference
   -----   ---------------------------               ---------
     125*   Data Channel Switching Capable (DCSC) [This document]

   (*) Suggested value.

   It should be noted that the assigned value should be reflected in
   IANAGmplsSwitchingTypeTC at
   http://www.iana.org/assignments/ianagmplstc-mib.


4.2. Generalized Channel_Set LABEL_REQUEST Object

   Upon approval of this document, the IANA will make the assignment in
   the "Class Names, Class Numbers, and Class Types" section of the
   "RSVP PARAMETERS" registry located at
   http://www.iana.org/assignments/rsvp-parameters.







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   A new class type for the existing LABEL_REQUEST Object class number
   (19) with the following definition:

      Class Types or C-Types:

        5* Generalized Channel_Set                  [This document]

   (*) Suggested value.


4.3. Generalized Channel_Set LABEL Object

   Upon approval of this document, the IANA will make the assignment in
   the "Class Names, Class Numbers, and Class Types" section of the
   "RSVP PARAMETERS" registry located at
   http://www.iana.org/assignments/rsvp-parameters.

   A new class type for the existing RSVP_LABEL Object class number (16)
   with the following definition:

      Class Types or C-Types:

        4* Generalized Channel_Set                  [This document]

   (*) Suggested value.


5. Security Considerations

   This document introduces new message object formats for use in GMPLS
   signaling [RFC3473].  It does not introduce any new signaling
   messages, nor change the relationship between LSRs that are adjacent
   in the control plane. As such, this document introduces no additional
   security considerations.  See [RFC3473] for relevant security
   considerations.  Additionally, the existing framework for MPLS and
   GMPLS security is documented in [MPLS-SEC].


6. References

6.1. Normative References

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







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   [RFC3209] Awduche, D., Berger, L., Gan, D., Li, T.,
             Srinivasan, V. and G. Swallow, "RSVP-TE: Extensions
             to RSVP for LSP Tunnels", RFC 3209, December 2001.

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

   [RFC3473] Berger, L., Editor, "Generalized Multi-Protocol Label
             Switching (GMPLS) Signaling - Resource ReserVation
             Protocol-Traffic Engineering (RSVP-TE) Extensions",
             RFC 3473, January 2003.

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

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



6.2. Informative References

   [GMPLS-ESVCS] Berger, L., Papadimitriou, P., Fedyk, D.,
                 "Generalized MPLS (GMPLS) Support For Metro Ethernet
                 Forum and G.8011 Ethernet Service Switching", Work in
                 Progress, draft-ietf-ccamp-gmpls-ether-svcs-02.txt,
                 August 2008.

   [GMPLS-MEF-UNI]  Berger, L., Papadimitriou, P., Fedyk, D.,
                    "Generalized MPLS (GMPLS) Support For Metro
                    Ethernet Forum and G.8011 User-Network Interface
                    (UNI)", Work in Progress,
                    draft-ietf-ccamp-gmpls-mef-uni-01.txt,
                    August 2008.

   [MPLS-SEC] Fang, L., et al, "Security Framework for MPLS and
              GMPLS Networks", Work in Progress,
              draft-ietf-mpls-mpls-and-gmpls-security-framework-04.txt,
              November 2008.

   [RFC4606] Mannie, E., et al "Generalized Multi-Protocol Label
             Switching (GMPLS) Extensions for Synchronous Optical
             Network (SONET) and Synchronous Digital Hierarchy (SDH)
             Control", RFC 4606, August 2006.




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7. Acknowledgments

   Dimitri Papadimitriou provided substantial textual contributions to
   this document and coauthored earlier versions of this document.

   The authors would like to thank Evelyne Roch, Stephen Shew, and
   Adrian Farrel for their valuable comments.


8. Author's Addresses

   Lou Berger
   LabN Consulting, L.L.C.
   Phone: +1-301-468-9228
   Email: lberger@labn.net

   Don Fedyk
   Nortel Networks
   600 Technology Park Drive
   Billerica, MA, 01821
   Phone: +1-978-288-3041
   Email: dwfedyk@nortel.com





























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