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Network Working Group                     K. Kompella (Juniper Networks)
Internet Draft                            Y. Rekhter  (Juniper Networks)
Expiration Date: November 2002            A. Banerjee (Calient Networks)
                                          J. Drake    (Calient Networks)
                                          G. Bernstein (Ciena)
                                          D. Fedyk    (Nortel Networks)
                                          E. Mannie   (GTS Network)
                                          D. Saha     (Tellium)
                                          V. Sharma   (Metanoia, Inc.)

            IS-IS Extensions in Support of Generalized MPLS


                draft-ietf-isis-gmpls-extensions-11.txt


1. Status of this Memo

   This document is an Internet-Draft and is in full conformance with
   all provisions of Section 10 of RFC2026.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF), its areas, and its working groups.  Note that
   other groups may also distribute working documents as Internet-
   Drafts.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as ``work in progress.''

   The list of current Internet-Drafts can be accessed at
   http://www.ietf.org/ietf/1id-abstracts.txt

   The list of Internet-Draft Shadow Directories can be accessed at
   http://www.ietf.org/shadow.html.















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2. Abstract

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


3. Summary for Sub-IP Area


3.1. Summary

   This document specifies encoding of extensions to the IS-IS routing
   protocol in support of Generalized Multi-Protocol Label Switching
   (GMPLS).  The description of the extensions is specified in [GMPLS-
   ROUTING].


3.2. Where does it fit in the Picture of the Sub-IP Work

   This work fits squarely in either CCAMP or IS-IS boxes.


3.3. Why is it Targeted at this WG

   This draft is targeted at either the CCAMP or IS-IS WGs, because this
   draft specifies the extensions to the IS-IS routing protocols in
   support of GMPLS, because GMPLS is within the scope of CCAMP WG, and
   because IS-IS is within the scope of the IS-IS WG.


3.4. Justification

   The WG should consider this document as it specifies the extensions
   to the IS-IS routing protocols in support of GMPLS.


4. Specification of Requirements

   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].










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5. Introduction

   This document specifies extensions to the IS-IS routing protocol in
   support of carrying link state information for Generalized Multi-
   Protocol Label Switching (GMPLS). The set of required enhancements to
   IS-IS are outlined in [GMPLS-ROUTING].



6. IS-IS Routing Enhancements

   In this section we define the enhancements to the TE properties of
   GMPLS TE links that can be announced in IS-IS TE LSAs.

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

   We further add one new TLV to the TE LSAs.

          TLV Type      Length     Name
            138        variable    Shared Risk Link Group


6.1. 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 Idenfier (see
   Section "Support for unnumbered links" of [GMPLS-ROUTING]).  If the
   Link Remote Identifier is unknown, it is set to 0.

       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 Idenfiier                         |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                  Link Remote Idenfiier                        |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+






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6.2. Link Protection Type

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

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

   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 may occur at most once within the
   extended IS reachability TLV.


6.3. 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 format of the value field is as shown
   below:

       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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+



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      | 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, 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.

   When the Switching Capability field is PSC-1, PSC-2, PSC-3, or PSC-4,
   the Switching Capability specific information field includes Minimum



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   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 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.

   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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6.4. Shared Risk Link Group TLV

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

       7 octets of System ID and 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

   and a list of SRLG values, where each element in the list has 4
   octets. The length of this TLV is 16 + 4 * (number of SRLG values).
   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 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.

       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|
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                  Shared Risk Link Group Value                 |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                        ............                           |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                  Shared Risk Link Group Value                 |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

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


6.5. Link Identifier for Unnumbered Interfaces

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






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7. 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 TE LSAs, these
   LSAs should be originated with 0 unreserved bandwidth, Traffic
   Engineering Default metric set to MAX_PATH_METRIC, 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 TE LSAs.

   In addition in the case of a planned restart prior to restarting, the
   restarting node SHOULD originate the TE LSAs 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 advertise the actual
   unreserved bandwidth on the TE links from the neighbors to that node.

   Regular graceful restart should not be aborted if a TE LSA or TE
   topology changes. TE graceful restart need not be aborted if a TE LSA
   or TE topology changes.



8. Security Considerations

   The extensions proposed in this document does not raise any new
   security concerns.















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9. Acknowledgements

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


10. References

   [ISIS-TE] Smit, H., Li, T., "IS-IS Extensions for Traffic
   Engineering",
       draft-ietf-isis-traffic-03.txt (work in progress)

   [GMPLS-SIG] Generalized MPLS Group, "Generalized MPLS - Signaling
   Functional
       Description", draft-ietf-mpls-generalized-signaling-04.txt (work
       in progress)

   [GMPLS-ROUTING] "Routing Extensions in Support of Generalized MPLS",
       draft-many-ccamp-gmpls-routing-01.txt (work in progress)

   [ISIS-3way] "Three-Way Handshake for IS-IS Point-to-Point
   Adjacencies",
       draft-ietf-isis-3way-05.txt (work in progress)

   [ISIS-RESTART] "Restart signaling for ISIS", draft-ietf-isis-
   restart-00.txt
       (work in progress)

   [GMPLS-RSVP] "Generalized MPLS Signaling - RSVP-TE Extensions",
       draft-ietf-mpls-generalized-rsvp-te-06.txt (work in progress)

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



11. Authors' Information


Kireeti Kompella
Juniper Networks, Inc.
1194 N. Mathilda Ave
Sunnyvale, CA 94089
Email: kireeti@juniper.net







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Yakov Rekhter
Juniper Networks, Inc.
1194 N. Mathilda Ave
Sunnyvale, CA 94089
Email: yakov@juniper.net


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: (408) 972-3720
Email: jdrake@calient.net



Greg Bernstein
Ciena Corporation
10480 Ridgeview Court
Cupertino, CA 94014
Phone: (408) 366-4713
Email: greg@ciena.com



Don Fedyk
Nortel Networks Corp.
600 Technology Park Drive
Billerica, MA 01821
Phone: +1-978-288-4506
Email: dwfedyk@nortelnetworks.com












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Eric Mannie
GTS Network Services
RDI Department, Core Network Technology Group
Terhulpsesteenweg, 6A
1560 Hoeilaart, Belgium
Phone: +32-2-658.56.52
E-mail: eric.mannie@gtsgroup.com


Debanjan Saha
Tellium Optical Systems
2 Crescent Place
P.O. Box 901
Ocean Port, NJ 07757
Phone: (732) 923-4264
Email: dsaha@tellium.com


Vishal Sharma
Metanoia, Inc.
335 Elan Village Lane, Unit 203
San Jose, CA 95134-2539
Phone: +1 408-943-1794
Email: v.sharma@ieee.org


























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