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Versions: (RFC 4205) 00 RFC 5307

Network Working Group                                   K. Kompella, Ed.
Internet Draft                                           Y. Rekhter, Ed.
Updates: 3784bis                                        Juniper Networks
Obsoletes: 4205                                            November 2006
Category: Standards Track


      Intermediate System to Intermediate System (IS-IS) Extensions
     in Support of Generalized Multi-Protocol Label Switching (GMPLS)

                    draft-ietf-isis-rfc4205bis-00.txt

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Copyright Notice

    Copyright (C) The Internet Society (2006).

Abstract

    This document specifies encoding of extensions to the IS-IS routing
    protocol in support of Generalized Multi-Protocol Label Switching
    (GMPLS).

1.  Introduction

    This document specifies extensions to the IS-IS routing protocol in
    support of carrying link state information for Generalized Multi-



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    Protocol Label Switching (GMPLS).  The set of required enhancements
    to IS-IS are outlined in [GMPLS-ROUTING].  Support for unnumbered
    interfaces assumes support for the "Point-to-Point Three-Way
    Adjacency" IS-IS Option type [ISIS-3way].

    In this section we define the enhancements to the Traffic Engineering
    (TE) properties of GMPLS TE links that can be announced in IS-IS Link
    State Protocol Data Units.

    In this document, we enhance the sub-TLVs for the extended IS
    reachability TLV (see [ISIS-TE]) in support of GMPLS.  Specifically,
    we add the following sub-TLVs:

       Sub-TLV Type        Length    Name
                  4             8    Link Local/Remote Identifiers
                 20             2    Link Protection Type
                 21      variable    Interface Switching Capability
                                     Descriptor

































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    We further add one new TLV to the TE TLVs:

           TLV Type        Length    Name
                138      variable    Shared Risk Link Group

    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].

1.1.  Link Local/Remote Identifiers

    A Link Local Interface Identifiers is a sub-TLV of the extended IS
    reachability TLV.  The type of this sub-TLV is 4, and length is eight
    octets.  The value field of this sub-TLV contains four octets of Link
    Local Identifier followed by four octets of Link Remote Identifier
    (see Section "Support for unnumbered links" of [GMPLS-ROUTING]).  If
    the Link Remote Identifier is unknown, it is set to 0.

    The following illustrates encoding of the Value field of the Link
    Local/Remote Identifiers sub-TLV.

        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
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                  Link Local Identifier                        |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                  Link Remote Identifier                       |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

    The Link Local/Remote Identifiers sub-TLV MUST NOT occur more than
    once within the extended IS reachability TLV.  If the Link
    Local/Remote Identifiers sub-TLV occurs more than once within the
    extended IS reachability TLV, the receiver SHOULD ignore all these
    sub-TLVs.

1.2.  Link Protection Type

    The Link Protection Type is a sub-TLV (of type 20) of the extended IS
    reachability TLV, with length two octets.

    The following illustrates encoding of the Value field of the Link
    Protection Type sub-TLV.

        0                   1
        0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |Protection Cap |    Reserved   |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+



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    The first octet is a bit vector describing the protection
    capabilities of the link (see Section "Link Protection Type" of
    [GMPLS-ROUTING]).  They are:

       0x01  Extra Traffic

       0x02  Unprotected

       0x04  Shared

       0x08  Dedicated 1:1

       0x10  Dedicated 1+1

       0x20  Enhanced

       0x40  Reserved

       0x80  Reserved

    The second octet SHOULD be set to zero by the sender, and SHOULD be
    ignored by the receiver.

    The Link Protection Type sub-TLV MUST NOT occur more than once within
    the extended IS reachability TLV.  If the Link Protection Type sub-
    TLV occurs more than once within the extended IS reachability TLV,
    the receiver SHOULD ignore all these sub-TLVs.

1.3.  Interface Switching Capability Descriptor

    The Interface Switching Capability Descriptor is a sub-TLV (of type
    21) of the extended IS reachability TLV.  The length is the length of
    value field in octets.  The following illustrates encoding of the
    Value field of the Interface Switching Capability Descriptor sub-TLV.

















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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
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       | Switching Cap |   Encoding    |           Reserved            |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                  Max LSP Bandwidth at priority 0              |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                  Max LSP Bandwidth at priority 1              |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                  Max LSP Bandwidth at priority 2              |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                  Max LSP Bandwidth at priority 3              |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                  Max LSP Bandwidth at priority 4              |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                  Max LSP Bandwidth at priority 5              |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                  Max LSP Bandwidth at priority 6              |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                  Max LSP Bandwidth at priority 7              |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |        Switching Capability-specific information              |
       |                  (variable)                                   |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

    The Switching Capability (Switching Cap) field contains one of the
    following values:

            1     Packet-Switch Capable-1 (PSC-1)
            2     Packet-Switch Capable-2 (PSC-2)
            3     Packet-Switch Capable-3 (PSC-3)
            4     Packet-Switch Capable-4 (PSC-4)
            51    Layer-2 Switch Capable  (L2SC)
            100   Time-Division-Multiplex Capable (TDM)
            150   Lambda-Switch Capable   (LSC)
            200   Fiber-Switch Capable    (FSC)


    The Encoding field contains one of the values specified in Section
    3.1.1 of [GMPLS-SIG].

    Maximum LSP Bandwidth is encoded as a list of eight 4 octet fields in
    the IEEE floating point format [IEEE], with priority 0 first and
    priority 7 last.  The units are bytes (not bits!) per second.

    The content of the Switching Capability specific information field
    depends on the value of the Switching Capability field.




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    When the Switching Capability field is PSC-1, PSC-2, PSC-3, or PSC-4,
    the Switching Capability specific information field includes Minimum
    LSP Bandwidth and Interface MTU.

        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
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                  Minimum LSP Bandwidth                        |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |           Interface MTU       |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

    The Minimum LSP Bandwidth is encoded in a 4 octets field in the IEEE
    floating point format.  The units are bytes (not bits!) per second.
    The Interface MTU is encoded as a 2 octets integer, and carries the
    MTU value in the units of bytes.

    When the Switching Capability field is L2SC, there is no Switching
    Capability specific information field present.

    When the Switching Capability field is TDM, the Switching Capability
    specific information field includes Minimum LSP Bandwidth and an
    indication whether the interface supports Standard or Arbitrary
    SONET/SDH.

        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
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                  Minimum LSP Bandwidth                        |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |   Indication  |
       +-+-+-+-+-+-+-+-+

    The Minimum LSP Bandwidth is encoded in a 4 octets field in the IEEE
    floating point format.  The units are bytes (not bits!) per second.
    The indication whether the interface supports Standard or Arbitrary
    SONET/SDH is encoded as 1 octet.  The value of this octet is 0 if the
    interface supports Standard SONET/SDH, and 1 if the interface
    supports Arbitrary SONET/SDH.

    When the Switching Capability field is LSC, there is no Switching
    Capability specific information field present.

    To support interfaces that have more than one Interface Switching
    Capability Descriptor (see Section "Interface Switching Capability
    Descriptor" of [GMPLS-ROUTING]) the Interface Switching Capability
    Descriptor sub-TLV MAY occur more than once within the extended IS
    reachability TLV.



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1.4.  Shared Risk Link Group TLV

    The SRLG TLV (of type 138) contains a data structure consisting of:

        6 octets of System ID
        1 octet of Pseudonode Number
        1 octet Flag
        4 octets of IPv4 interface address or 4 octets of a Link Local
          Identifier
        4 octets of IPv4 neighbor address or 4 octets of a Link Remote
          Identifier
        (variable) list of SRLG values, where each element in the list
          has 4 octets.

    The following illustrates encoding of the Value field of the SRLG
    TLV.

        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
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                          System ID                            |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |            System ID (cont.)  | Pseudonode num|    Flags      |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |        IPv4 interface address/Link Local Identifier           |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |        IPv4 neighbors address/Link Remote Identifier          |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                  Shared Risk Link Group Value                 |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                        ............                           |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                  Shared Risk Link Group Value                 |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

    The neighbor is identified by its System Id (6-octets), plus one
    octet to indicate the pseudonode number if the neighbor is on a LAN
    interface.

    The Least Significant Bit of the Flag octet indicates whether the
    interface is numbered (set to 1), or unnumbered (set to 0).  All
    other bits are reserved and should be set to 0.

    The length of this TLV is 16 + 4 * (number of SRLG values).

    This TLV carries the Shared Risk Link Group information (see Section
    "Shared Risk Link Group Information" of [GMPLS-ROUTING]).




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    The SRLG TLV MAY occur more than once within the IS-IS Link State
    Protocol Data Units.

1.5.  Link Identifier for Unnumbered Interfaces

    Link Identifiers are exchanged in the Extended Local Circuit ID field
    of the "Point-to-Point Three-Way Adjacency" IS-IS Option type
    [ISIS-3way].

2.  Implications on Graceful Restart

    The restarting node SHOULD follow the ISIS restart procedures
    [ISIS-RESTART], and the RSVP-TE restart procedures [GMPLS-RSVP].

    When the restarting node is going to originate its IS-IS Link State
    Protocol data units for TE links, these Link State Protocol data
    units SHOULD be originated with 0 unreserved bandwidth, Traffic
    Engineering Default metric set to 0xffffff, and if the link has LSC
    or FSC as its Switching Capability then also with 0 as Max LSP
    Bandwidth, until the node is able to determine the amount of
    unreserved resources taking into account the resources reserved by
    the already established LSPs that have been preserved across the
    restart.  Once the restarting node determines the amount of
    unreserved resources, taking into account the resources reserved by
    the already established LSPs that have been preserved across the
    restart, the node SHOULD advertise these resources in its Link State
    Protocol data units.

    In addition, in the case of a planned restart prior to restarting,
    the restarting node SHOULD originate the IS-IS Link State Protocol
    data units for TE links with 0 as unreserved bandwidth, and if the
    link has LSC or FSC as its Switching Capability then also with 0 as
    Max LSP Bandwidth.  This would discourage new LSP establishment
    through the restarting router.

    Neighbors of the restarting node SHOULD continue to advertise the
    actual unreserved bandwidth on the TE links from the neighbors to
    that node.













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3.  Contributors

    Ayan Banerjee
    Calient Networks
    5853 Rue Ferrari
    San Jose, CA 95138

    Phone: +1 408 972 3645
    EMail: abanerjee@calient.net

    John Drake
    Calient Networks
    5853 Rue Ferrari
    San Jose, CA 95138

    Phone: +1 408 972 3720
    EMail: jdrake@calient.net

    Greg Bernstein
    Grotto Networking

    EMail: gregb@grotto-networking.com

    Don Fedyk
    Nortel Networks Corp.
    600 Technology Park Drive
    Billerica, MA 01821

    Phone: +1 978 288 4506
    EMail: dwfedyk@nortelnetworks.com

    Eric Mannie
    Independent Consultant

    EMail: eric_mannie@hotmail.com

    Debanjan Saha
    Tellium Optical Systems
    2 Crescent Place
    P.O. Box 901
    Ocean Port, NJ 07757

    Phone: +1 732 923 4264
    EMail: dsaha@tellium.com

    Vishal Sharma

    EMail: v.sharma@ieee.org



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4.  Acknowledgements

    The authors would like to thank Jim Gibson, Suresh Katukam, Jonathan
    Lang and Quaizar Vohra for their comments on the draft.

5.  Security Considerations

    This document specifies the contents of GMPLS TE TLVs in ISIS.  As
    these TLVs are not used for SPF computation or normal routing, the
    extensions specified here have no direct effect on IP routing.
    Tampering with GMPLS TE TLVs may have an effect on the underlying
    transport (optical and/or SONET-SDH) network.  Mechanisms to secure
    ISIS Link State PDUs and/or the TE TLVs [ISIS-HMAC] can be used to
    secure the GMPLS TE TLVs as well.

6.  IANA Considerations

    This document defines the following new ISIS TLV type that needs to
    be reflected in the ISIS TLV code-point registry:

           Type        Description              IIH   LSP   SNP
           ----        ----------------------   ---   ---   ---
            138        Shared Risk Link Group    n     y     n

    This document also defines the following new sub-TLV types of top-
    level TLV 22 that need to be reflected in the ISIS sub-TLV registry
    for TLV 22:

           Type        Description                        Length
           ----        ------------------------------   --------
              4        Link Local/Remote Identifiers           8
             20        Link Protection Type                    2
             21        Interface Switching Capability   variable
                       Descriptor

References

Normative References

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

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




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

    [IEEE]          IEEE, "IEEE Standard for Binary Floating-Point
                    Arithmetic", Standard 754-1985, 1985 (ISBN
                    1-5593-7653-8).

    [ISIS-3way]     Katz, D. and R. Saluja, "Three-Way Handshake for
                    Intermediate System to Intermediate System (IS-IS)
                    Point-to-Point Adjacencies", RFC 3373, September
                    2002.

    [ISIS-RESTART]  Shand, M. and L. Ginsberg, "Restart Signaling for
                    Intermediate System to Intermediate System (IS-IS)",
                    RFC 3847, July 2004.

    [ISIS-TE]       Smit, H. and T. Li, "Intermediate System to
                    Intermediate System (IS-IS) Extensions for Traffic
                    Engineering (TE)", RFC 3784, June 2004.

    [RFC2119]       Bradner, S., "Key words for use in RFCs to Indicate
                    Requirement Levels", BCP 14, RFC 2119, March 1997.

    [ISIS-HMAC]     Li, T. and R. Atkinson, "Intermediate System to
                    Intermediate System (IS-IS) Cryptographic
                    Authentication", RFC 3567, July 2003.

Authors' Addresses

    Kireeti Kompella
    Juniper Networks, Inc.
    1194 N. Mathilda Ave
    Sunnyvale, CA 94089

    EMail: kireeti@juniper.net


    Yakov Rekhter
    Juniper Networks, Inc.
    1194 N. Mathilda Ave
    Sunnyvale, CA 94089

    EMail: yakov@juniper.net







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