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rfc:rfc6002

Internet Engineering Task Force (IETF) L. Berger Request for Comments: 6002 LabN Updates: 3471, 3473, 3945, 4202, 4203, 5307 D. Fedyk Category: Standards Track Alcatel-Lucent ISSN: 2070-1721 October 2010

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

Abstract

 This document describes two technology-independent extensions to
 Generalized Multi-Protocol Label Switching (GMPLS).  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 a Label Switched Path
 (LSP).

Status of This Memo

 This is an Internet Standards Track document.
 This document is a product of the Internet Engineering Task Force
 (IETF).  It represents the consensus of the IETF community.  It has
 received public review and has been approved for publication by the
 Internet Engineering Steering Group (IESG).  Further information on
 Internet Standards is available in Section 2 of RFC 5741.
 Information about the current status of this document, any errata,
 and how to provide feedback on it may be obtained at
 http://www.rfc-editor.org/info/rfc6002.

Berger & Fedyk Standards Track [Page 1] RFC 6002 GMPLS DCSC Channel Extensions October 2010

Copyright Notice

 Copyright (c) 2010 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
 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.

Table of Contents

 1. Introduction ....................................................2
    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 ...............4
    3.2. Generalized Channel_Set LABEL Object .......................4
    3.3. Other Label-Related Objects ................................7
    3.4. Compatibility ..............................................7
 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 .......................8
 5. Security Considerations .........................................9
 6. References ......................................................9
    6.1. Normative References .......................................9
    6.2. Informative References ....................................10
 Acknowledgments ...................................................10

1. Introduction

 This document describes two technology-independent extensions to
 Generalized Multi-Protocol Label Switching (GMPLS).  Both of these
 extensions were initially defined in the context of Ethernet
 services, see [RFC6004] and [RFC6005], 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 (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

Berger & Fedyk Standards Track [Page 2] RFC 6002 GMPLS DCSC Channel Extensions October 2010

 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 a GMPLS Label Switched
 Path (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.  Parallel
 definitions for these switching types are also made in [RFC4202],
 [RFC4203], and [RFC5307].
 One type of switching that is not well represented in this current
 set is switching that occurs 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
 within a fiber port.
 This document defines a new switching type called Data Channel
 Switching Capable (DCSC).  Port switching seems a more intuitive
 name, but this naming collides with PSC so is not 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., Wavelength Division Multiplexing
 (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 include concatenated TDM and line-
 encoded interfaces.  Framed interfaces may also be included when they
 support switching on an interface granularity, for example Ethernet
 terminated at the physical (port) level and all traffic received on a
 port is switched to a physical port at the LSP egress.
 DCSC is represented in GMPLS, see [RFC3471] and [RFC4202], using the
 value 125.  The DCSC value is carried in routing protocols in the
 Interface Switching Capability Descriptor defined in [RFC4202], and
 used in OSPF [RFC4203] and IS-IS [RFC5307].  These documents are not
 otherwise modified by this document.

Berger & Fedyk Standards Track [Page 3] RFC 6002 GMPLS DCSC Channel Extensions October 2010

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

2.1. Compatibility

 Transit and egress nodes that do not support the DCSC Switching Type
 when receiving 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, receiving such a PathErr
 messages, 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.

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 a C-Type of 5.

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 LABEL_SET object in that the full set
 may be represented in a single object rather than the multiple

Berger & Fedyk Standards Track [Page 4] RFC 6002 GMPLS DCSC Channel Extensions October 2010

 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 = 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
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |                   Channel_Set Subobject 1                     |
    |                              ...                              |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    :                               :                               :
    :                               :                               :
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |                   Channel_Set Subobject N                     |
    |                              ...                              |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 The Channel_Set Subobject 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               |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Berger & Fedyk Standards Track [Page 5] RFC 6002 GMPLS DCSC Channel Extensions October 2010

 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 subobject.
    When the number of subchannels required exceeds the limit of the
    field, i.e., 1024, multiple Channel_Set Subobjects MUST be used.
    Note that the size of the subobject may result in a Path message
    being larger than a single unfragmented IP packet.  See Section
    4.4 of [RFC6004] 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 Subobject and only one
    Channel_Set Subobject may be present.  The zero (0) value MUST NOT
    be used in both the LABEL and UPSTREAM_LABEL objects of the same
    LSP.  Note that unacceptable label values continue to be handled
    according to [RFC3209] and [RFC3473], i.e., they result in PathErr
    or ResvErr messages with a "Routing problem/Unacceptable label
    value" indication.  For example, in the case where a Resv message
    containing a zero (0) in both the LABEL and UPSTREAM_LABEL objects
    is received, the node would generate a ResvErr message.
 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
    Subobject 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 Subobject not being 32-bit aligned.

Berger & Fedyk Standards Track [Page 6] RFC 6002 GMPLS DCSC Channel Extensions October 2010

    The Padding field MUST be included when the number of bits
    represented in all the Subchannel fields included in a Generalized
    Channel_Set Subobject result in the Subobject not being 32-bit
    aligned.  When present, the Padding field MUST have a length that
    results in the Subobject 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.
    Note that the overall length of a Channel_Set Subobject is
    determined based on the value of the Num Subchannels field
    together with the size of each Subchannel field as well as any
    required padding.  The size of the Subchannel field is uniquely
    identified by the Label Type field.

3.3. Other Label-Related Objects

 The previous section introduced a new LABEL object.  As such the
 formats of the other label-related objects and subobjects are also
 impacted.  Processing of these objects and subobjects is not modified
 and remains per their respective specifications.  The other label
 related objects and subobjects are defined in [RFC3473] and include:
  1. SUGGESTED_LABEL object
  2. LABEL_SET object
  3. ACCEPTABLE_LABEL_SET object
  4. UPSTREAM_LABEL object
  5. RECOVERY_LABEL object
  6. Label ERO subobject
  7. Label RRO subobject
 The label-related objects and subobjects each contain a Label field,
 all of which may carry any label type.  As any label type may be
 carried, the introduction of a new label type means that the new
 label type may be carried in the Label field of each of the label-
 related objects and subobjects.  No new definition needs to specified
 as their original specification is label-type agnostic.

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 such a
 node receives the Path message, per [RFC3209], it will send a PathErr
 with the error code "Unknown object C_Type".

Berger & Fedyk Standards Track [Page 7] RFC 6002 GMPLS DCSC Channel Extensions October 2010

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

4. IANA Considerations

 IANA has assigned new values for namespaces defined in this document
 and summarized in this section.  The registries are available from
 http://www.iana.org.

4.1. Data Channel Switching Type

 IANA has made the following assignment in the "Switching Types"
 section of the "GMPLS Signaling Parameters" registry.
    Value   Type                                   Reference
    -----   ------------------------------------   ---------
      125   Data Channel Switching Capable (DCSC)  [RFC6002]
 The assigned value is reflected in IANAGmplsSwitchingTypeTC of the
 IANA-GMPLS-TC-MIB available from http://www.iana.org.

4.2. Generalized Channel_Set LABEL_REQUEST Object

 IANA has made the following assignment in the "Class Names, Class
 Numbers, and Class Types" section of the "RSVP PARAMETERS" registry.
 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                  [RFC6002]

4.3. Generalized Channel_Set LABEL Object

 IANA has made the following assignment in the "Class Names, Class
 Numbers, and Class Types" section of the "RSVP PARAMETERS" registry.
 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                  [RFC6002]

Berger & Fedyk Standards Track [Page 8] RFC 6002 GMPLS DCSC Channel Extensions October 2010

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 [RFC5920].

6. References

6.1. Normative References

 [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
            Requirement Levels", BCP 14, RFC 2119, March 1997.
 [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., Ed., "Generalized Multi-Protocol Label
            Switching (GMPLS) Signaling Functional Description", RFC
            3471, January 2003.
 [RFC3473]  Berger, L., Ed., "Generalized Multi-Protocol Label
            Switching (GMPLS) Signaling Resource ReserVation Protocol-
            Traffic Engineering (RSVP-TE) Extensions", RFC 3473,
            January 2003.
 [RFC3945]  Mannie, E., Ed., "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.
 [RFC4203]  Kompella, K., Ed., and Y. Rekhter, Ed., "OSPF Extensions
            in Support of Generalized Multi-Protocol Label Switching
            (GMPLS)", RFC 4203, October 2005.
 [RFC5307]  Kompella, K., Ed., and Y. Rekhter, Ed., "IS-IS Extensions
            in Support of Generalized Multi-Protocol Label Switching
            (GMPLS)", RFC 5307, October 2008.

Berger & Fedyk Standards Track [Page 9] RFC 6002 GMPLS DCSC Channel Extensions October 2010

6.2. Informative References

 [RFC4606]  Mannie, E. and D. Papadimitriou, "Generalized Multi-
            Protocol Label Switching (GMPLS) Extensions for
            Synchronous Optical Network (SONET) and Synchronous
            Digital Hierarchy (SDH) Control", RFC 4606, August 2006.
 [RFC5920]  Fang, L., Ed., "Security Framework for MPLS and GMPLS
            Networks", RFC 5920, July 2010.
 [RFC6004]  Berger, L. and D. Fedyk, "Generalized MPLS (GMPLS) Support
            for Metro Ethernet Forum and G.8011 Ethernet Service
            Switching", RFC 6004, October 2010.
 [RFC6005]  Berger, L. and D. Fedyk, "Generalized MPLS (GMPLS) Support
            for Metro Ethernet Forum and G.8011 User Network Interface
            (UNI)", RFC 6005, October 2010.

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.

Authors' Addresses

 Lou Berger
 LabN Consulting, L.L.C.
 Phone: +1-301-468-9228
 EMail: lberger@labn.net
 Don Fedyk
 Alcatel-Lucent
 Groton, MA, 01450
 Phone: +1-978-467-5645
 EMail: donald.fedyk@alcatel-lucent.com

Berger & Fedyk Standards Track [Page 10]

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