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Versions: 00 01 02 03 04 05 06                                          
     CCAMP Working Group                                       Zafar Ali
     Internet Draft                                       George Swallow
     Intended status: Standard Track                   Clarence Filsfils
     Expires: September 04, 2012                             Ori Gerstel
                                                           Cisco Systems
                                                          March 05, 2012
     
     
                         Include Routes - Extension to
          Resource ReserVation Protocol-Traffic Engineering (RSVP-TE)
                  draft-ali-ccamp-rsvp-te-include-route-00.txt
     
     Status of this Memo
     
     
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     This Internet-Draft will expire on September 04, 2012.
     
     Copyright Notice
     
     
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     Internet-Draft       draft-ali-ccamp-rsvp-te-include-route-00.txt
     
     
     This document may contain material from IETF Documents or IETF
     Contributions published or made publicly available before November
     10, 2008.  The person(s) controlling the copyright in some of this
     material may not have granted the IETF Trust the right to allow
     modifications of such material outside the IETF Standards Process.
     Without obtaining an adequate license from the person(s)
     controlling the copyright in such materials, this document may not
     be modified outside the IETF Standards Process, and derivative
     works of it may not be created outside the IETF Standards Process,
     except to format it for publication as an RFC or to translate it
     into languages other than English.
     
     
     Abstract
     
     
     There are scenarios in which it is required that two or more LSPs
     or segments of LSPs follow same route in the network. This document
     specifies methods to communicate route inclusions along the loose
     hops during path setup using the Resource ReserVation Protocol-
     Traffic Engineering (RSVP-TE) protocol.
     
     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 RFC 2119
     [RFC2119].
     
     
     Table of Contents
     
     
     Copyright Notice..................................................1
     1. Introduction...................................................3
     2. RSVP-TE signaling extensions...................................4
        2.1. Explicit Inclusion Route Subobject (EIRS).................5
        2.2. EIRS Subobject Processing Role............................7
        2.3. Processing of EIRS with XRO and EXRS......................9
     3. Security Considerations........................................9
     4. IANA Considerations............................................9
     5. Acknowledgments................................................9
     6. References....................................................10
        6.1. Normative References.....................................10
        6.2. Informative References...................................11
     
     
     
     
     
     
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     1. Introduction
     
     
        The RSVP-TE specification, "RSVP-TE: Extensions to RSVP for LSP
        Tunnels" [RFC3209] and GMPLS extensions to RSVP-TE, "Generalized
        Multi-Protocol Label Switching (GMPLS) Signaling Resource
        ReserVation Protocol-Traffic Engineering (RSVP-TE) Extensions"
        [RFC3473] allow abstract nodes and resources to be explicitly
        included in a path setup. However, such inclusion may not be
        possible when a loose hop is expanded. It is obviously possible
        to divide the loose hop into multiple loose hops and construct
        an inclusion in that fashion. However, there are scenarios where
        division of a loose hop into multiple explicit loose hops is not
        possible, including but not limited to the following:
     
     
        .  When the destination is in another area, AS, or across a UNI,
          the ingress node may not have full visibility of the topology.
          In cases where the ingress node lacks sufficient topological
          knowledge around the loose hop, it is not able to divide a
          loose hop into a proper sequence of strict or a sequence of
          finer-grained loose hops.
     
     
        .  The ingress node requires that two Label Switched Paths
          (LSPs) follow the same route but has no knowledge of how a
          loose hop of a reference LSP was expanded. There are scenarios
          in which it is required that two or more LSPs follows same
          route in the network. E.g., in many deployments it is required
          that member LSPs of a bundle/ aggregated link (or Forwarding
          Adjacency (FA))) follow the same route. Possible reasons for
          two or more LSPs to follow the same end-to-end or partial
          route include, but are not limited to:
     
     
          -  Fate sharing: it is sometimes required that two or more
             LSP fail together. In the example of bundle link this would
             mean that if one component goes down, the entire bundle
             goes down.
     
     
     
     
     
     
     
     
     
     
     
     
     
     
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          -  Homogeneous Attributes: it is often required that two or
             more LSPs have the same TE metrics like latency, delay
             variation, etc. In the example of a bundle/ aggregated link
             this would meet the requirement that all component links
             (FAs) of a bundle should have same latency and delay
             variation. As noted in [OSPF-TE-METRIC] and [ISIS-TE-
             METRIC], in certain networks, such as financial information
             networks, network performance (e.g. latency and latency
             variation) is becoming critical and hence having bundles
             with component links (FAs) with homogeneous delay and delay
             variation is important.
     
     
        . The ingress node requires certain SLRGs to be explicitly
           "included" when the loose hop is expanded. This document
           defines inclusion use of the SRLG subobject defined in
           [RFC4874].
     
     
       When the entire route of LSPs that need to follow the same route
       is computed by the ingress node, the aforementioned requirements
       can be met by a local decision at the ingress node. However,
       there are scenarios when a route computation is not performed at
       the ingress and instead are performed by remote nodes, in which
       case there is a need for relevant affinity requirements to be
       communicated to the route expanding nodes. These include (but are
       not limited to):
     
     
       .  LSPs with loose hops in the Explicit Route Object (ERO), e.g.
          inter-domain LSPs.
     
     
       .  Generalized Multi-Protocol Label Switching (GMPLS) User-
          Network Interface (UNI) where route computation may be
          performed by the UNI-Network (server) node;
     
     
        This document addresses the above-mentioned requirements/
        scenarios and defines procedures that may be used to signal LSPs
        such that the entire LSP or segments of LSP follow the same
        route.
     
     
     2. RSVP-TE signaling extensions
     
     
        A new ERO subobject type the Explicit Inclusion Route Subobject
        (EIRS) is introduced to indicate an inclusion between a pair of
        included nodes or abstract nodes. The ERO subobject encoding and
        processing rules are similar to Explicit Exclusion Route
        Subobject (EXRS) subobject of ERO defined in [RFC4874], with the
        exception of include vs. exclude usage.
     
     
     
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     2.1. Explicit Inclusion Route Subobject (EIRS)
     
     
        The Explicit Inclusion Route Subobject (EIRS) defines abstract
        nodes or resources (such as links, SRLG, Circuit IDs (see
        [DRAFT-LSP-XRO]), unnumbered interfaces, or labels, etc.) that
        must or should be used on the path between two inclusive
        abstract nodes or resources in the explicit route. An EIRS is an
        ERO subobject that contains one or more subobjects of its own,
        called EIRS subobjects. Each EIRS may carry multiple inclusions.
        The inclusion is encoded exactly as for XRO subobjects and
        prefixed by an additional Type and Length.
     
     
        The format of the EIRS is as follows:
     
     
        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
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |L|    Type     |     Length    |           Reserved            |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                                                               |
       //                one or more EIRS subobjects                  //
       |                                                               |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     
     
           An example of EIRS for SLRG inclusion (SRLG Id 1 and SRLG Id
        2) is provided in the following. This example is referenced in
        the following description.
     
     
        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
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |L|    Type     |     Length    |           Reserved            |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |L|    Type     |     Length    |       SRLG Id 1 (4 bytes)     |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |      SRLG Id 1 (continued)      |           Reserved          |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |L|    Type     |     Length    |      SRLG Id 2(4 bytes)       |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |      SRLG Id 2 (continued)      |           Reserved          |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     
     
                 Figure 1: Example of EIRS with SRLG subobjects
     
     
     
     
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        Please note that there are two or more "L bits" in an EIRS. The
        following convention is used to reference the individual "L
        bits".
     
     
              EIRS.L: The L bit of the header of the EIRS subobject.
              E.g., EIRS.L refers to the first L bit in EIRS example in
              Figure 1.
     
     
              EIRS.SubobjectN.L: The L bit of the nth subobject of EIRS.
              E.g., EIRS.Subobject2.L refers to the third L bit in EIRS
              example in Figure 1 (i.e., the L bit to define the
              expected treatment of SRLG ID2 value).
     
     
        The fields of the EIRS subobject are defined as follows:
     
     
              EIRS.L bit: The L bit is an attribute of the EIRS
              subobject. The L bit SHOULD be set, so that the subobject
              represents a loose hop in the explicit route.
     
     
              EIRS.Type: The type of the subobject is to be defined by
              IANA (Suggested Value: 68).
     
     
              EIRS.Reserved: This field is reserved. It SHOULD be set to
              zero on transmission and MUST be ignored on receipt.
     
     
             EIRS subobjects: An EIRS subobject indicates the abstract
             node or resource to be included in the path. The format of
             an EIRS subobject is exactly the same as the format of a
             subobject in the eXclude Route Object (XRO) (See [RFC4874]
             and [DRAFT-LSP-XRO-SUB]). This is with the exception of the
             interpretation of the "EIRS.SubobjectN.L bit" of the
             subobjects, as detailed in the following.
     
     
             EIRS.SubobjectN.L bit: For all supported subobjects of
             EIRS, the EIRS.SubobjectN.L bit has the following
             interpretation.
     
     
             -EIRS.SubobjectN.L = 0 indicates that the attribute
               specified MUST be included.
     
     
             -EIRS.SubobjectN.L = 1 indicates that the attribute
               specified SHOULD be included.
     
     
              An EIRS may include all subobjects defined in this
              document for the XRO (See [RFC4874] and [DRAFT-LSP-XRO-
              SUB]). Specifically, an EIRS may include the following
              subobjects:
     
     
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              EIRS.SubobjectN.Type = 1: IPv4 address [RFC3209].
     
              EIRS.SubobjectN.Type = 2: IPv6 address [RFC3209].
     
              EIRS.SubobjectN.Type = 3: Label [RFC6001].
     
              EIRS.SubobjectN.Type = 4: Unnumbered Interface ID
              [RFC3477].
     
              EIRS.SubobjectN.Type = 32: Autonomous system number
              [RFC3209].
     
              EIRS.SubobjectN.Type = 34: SRLG [RFC4874].
     
              EIRS.SubobjectN.Type = 35: Switching Capability (SC)
              [RFC6001].
     
              EIRS.SubobjectN.Type = TBD (suggested value 37): LSP
              [DRAFT-LSP-XRO-SUB].
     
     
              Please note that EIRS.SubobjectN.Type = 33: Explicit
              Exclusion Route subobject (EXRS) [RFC4874] is not
              supported.
     
     
     2.2. EIRS Subobject Processing Rule
     
     
        The scope of the inclusion is the previous ERO subobject that
        identifies a node or an abstract node, and the subsequent ERO
        subobject that identifies a node or an abstract node. The
        processing rules of the EIRS are the same as the processing rule
        of the EXRS, with the exception that EIRS subobjects request
        resource inclusion, whereas EXRS subobjects request resource
        exclusion.
     
     
        Multiple inclusions may be present between any pair of nodes or
        abstract nodes. An EIRS may be present when an EXRS is also
        present in the ERO and/ or an XRO is also present in the path
        message. Section 2.3 discusses details of processing of the EIRS
        with the XRO object and the EXRS subobject of ERO.
     
     
        If the processing node does not understand the EIRS subobject,
        it behaves as described in [RFC3209] when an unrecognized ERO
        subobject is encountered.  This means that this node will return
        a PathErr with error code "Routing Error" and error value "Bad
        EXPLICIT_ROUTE object" with the EXPLICIT_ROUTE object included,
        truncated (on the left) to the offending EIRS subobject.
     
     
     
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        If the EIRS.L bit is not set, the processing node SHOULD
        generate a Path Error with error code "Routing Problem" and
        error subcode "Bad EXPLICIT_ROUTE object".
     
     
        If the processing node understands the EIRS subobject and all
        the subobjects contained in the EIRS, it takes the following
        steps:
     
        .  For all subobjects contained in the EIRS such that
          EIRS.SubobjectN.L = 0, the processing node finds a path that
          MUST include the resource attribute identified by the
          EIRS.SubobjectN.
        .  For all subobjects contained in the EIRS such that
          EIRS.SubobjectN.L = 1, the processing node finds a path that
          MUST include the resource attribute identified by the
          EIRS.SubobjectN.
        .  If the processing node fails to find a route such that the
          all resources identified in the EIRS.SubobjectN for all N can
          be included in the route (depending on EIRS.SubobjectN.L bit
          setting), the node SHOULD return a PathErr with the error code
          "Routing Problem" and error value "Route Blocked by Include
          Route". The error subcode "Route Blocked by Include Route" for
          Path Error code "Routing Problem" is to be assigned by IANA
          (Suggested Value: 110).
     
        If the processing node understands the EIRS subobject but does
        not understand or support a subobject contained in the EIRS (say
        EIRS. SubobjectN), it SHOULD return a PathErr with error code
        "Routing Error" and error value "Bad EXPLICIT_ROUTE object" with
        the EXPLICIT_ROUTE object included, truncated (on the left) to
        the EIRS subobject containing the unsupported EIRS.subobjectN.
     
     
        A node MAY reject a Path message if the EIRS is too large or
        complicated for the local implementation or as governed by local
        policy.  In this case, the node SHOULD send a PathErr message
        with the error code "Routing Error" and error subcode "EIRS Too
        Complex".  An ingress node receiving this error code/subcode
        combination MAY reduce the complexity of the EIRS. The error
        subcode "EIRS Too Complex" for Path Error code "Routing Problem"
        is to be assigned by IANA (Suggested Value: 111).
     
     
     
     
     
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     2.3. Processing of EIRS with XRO and EXRS
     
     
        A node performing ERO expansion MAY find an XRO in the Path
        message and both EIRS and EXRS subobjects in ERO. In this case,
        the processing node MUST include all resources identified in the
        EIRS and exclude all resources identified in the EXRS and XRO.
     
     
        If the constraints identified by the EIRS, EXRS and XRO conflict
        each other, the processing node SHOULD send a PathErr message
        with the    error code "Routing Error" and error subcode
        "inconsistent include/ exclude constraints". The error subcode
        "inconsistent include/ exclude constraints" for Path Error code
        "Routing Problem" is to be assigned by IANA (Suggested Value:
        112).
     
     
     3. Security Considerations
     
     
        This document does not introduce any additional security issues
        above those identified in [RFC5920], [RFC2205], [RFC3209], and
        [RFC3473] and [RFC4874].
     
     
     4. IANA Considerations
     
     
        This document adds the following new subobject of the existing
        entry for ERO (20, EXPLICIT_ROUTE):
     
     
        Value                      Description
     
        -----                      ------------
     
        TBA (suggest value: 68)    Explicit Inclusion Route Subobject
                                   (EIRS)
     
     
        These subobject may be present in the Explicit Route Object, but
        not in the Route Record Object.
     
     
     5. Acknowledgments
     
     
        Authors would like to thank Matt Hartley, Gabriele Maria
        Galimberti, Luyuan Fang and Walid Wakim for their review
        comments.
     
     
     
     
     
     
     
     
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     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.
     
        [RFC3473] Berger, L., "Generalized Multi-Protocol Label
                  Switching (GMPLS) Signaling Resource ReserVation
                  Protocol-Traffic Engineering (RSVP-TE) Extensions",
                  RFC 3473, January 2003.
     
     
        [RFC 3473] Berger, L., Ed., "Generalized Multi-Protocol Label
                  Switching (GMPLS) Signaling Resource ReserVation
                  Protocol-Traffic Engineering (RSVP-TE) Extensions",
                  RFC 3473, January 2003.
     
        [RFC4874] Lee, CY., Farrel, A., and S. De Cnodder, "Exclude
                  Routes - Extension to Resource ReserVation Protocol-
                  Traffic Engineering (RSVP-TE)", RFC 4874, April 2007.
     
        [RFC6001] Papadimitriou, D., Vigoureux, M., Shiomoto, K.,
                  Brungard, D., and JL. Le Roux, "Generalized MPLS
                  (GMPLS) Protocol Extensions for Multi-Layer and Multi-
                  Region Networks (MLN/MRN)", RFC 6001, October 2010.
     
        [RFC3477] Kompella, K. and Y. Rekhter, "Signalling Unnumbered
                  Links in Resource ReSerVation Protocol - Traffic
                  Engineering (RSVP-TE)", RFC 3477, January 2003.
     
        [DRAFT-LSP-XRO-SUB] Ali, Z., Swallow, G., Filsfils, C., et al,
                  "Resource ReserVation Protocol-Traffic Engineering
                  (RSVP-TE) LSP Route Diversity using Exclude Routes",
                  draft-ali-ccamp-xro-lsp-subobject, work in progress.
     
     
     
     
     
     
     
     
     
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     6.2. Informative References
     
     
        [RFC4208] Swallow, G., Drake, J., Ishimatsu, H., and Y. Rekhter,
                  "Generalized Multiprotocol Label Switching (GMPLS)
                  User-Network Interface (UNI): Resource ReserVation
                  Protocol-Traffic Engineering (RSVP-TE) Support for the
                  Overlay Model", RFC 4208, October 2005.
     
        [RFC2209] Braden, R. and L. Zhang, "Resource ReSerVation
                  Protocol (RSVP) -- Version 1 Message Processing
                  Rules", RFC 2209, September 1997.
     
        [RFC5920] Fang, L., Ed., "Security Framework for MPLS and GMPLS
                  Networks", RFC 5920, July 2010.
     
     
     Authors' Addresses
     
     
        Zafar Ali
        Cisco Systems, Inc.
        Email: zali@cisco.com
     
        George Swallow
        Cisco Systems, Inc.
        swallow@cisco.com
     
        Clarence Filsfils
        Cisco Systems, Inc.
        cfilsfil@cisco.com
     
        Ori Gerstel
        Cisco Systems
        ogerstel@cisco.com
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
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