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Versions: (draft-ali-mpls-rsvp-te-no-php-oob-mapping) 00 01 02 03 04 05 06 07 08 09 RFC 6511

   MPLS Working Group                                            Z. Ali
                                                             G. Swallow
   Internet Draft                                   Cisco Systems, Inc.
                                                             R. Aggarwal
                                                        Juniper Networks
   Intended status: Standard Track                     October 26, 2009
   Expires: April 25, 2010
  
  
  
           Non PHP Behavior and out-of-band mapping for RSVP-TE LSPs
               draft-ietf-mpls-rsvp-te-no-php-oob-mapping-03.txt
  
  
   Status of this Memo
  
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  Internet-Draft     draft-ietf-mpls-rsvp-te-no-php-oob-mapping-03.txt
  
  
   Abstract
  
      There are many deployment scenarios which require Egress LSR to
      receive binding of the RSVP-TE LSP to an application, and payload
      identification, using some "out-of-band" (OOB) mechanism. This
      document proposes protocol mechanisms to address this
      requirement. The procedures described in this document are
      equally applicable for point-to-point (P2P) and point-to-
      multipoint (P2MP) LSPs.
  
   Conventions used in this document
  
      In examples, "C:" and "S:" indicate lines sent by the client and
      server respectively.
  
      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 0.
  
   Table of Contents
  
  
      1. Introduction...............................................2
      2. RSVP-TE signaling extensions...............................3
         2.1. Signaling non-PHP behavior............................3
         2.2. Signaling OOB Mapping Indication......................4
         2.3. Relationship between OOB and non-PHP flags............6
         2.4. Egress Procedure for label binding....................6
      3. Security Considerations....................................6
      4. IANA Considerations........................................6
         4.1. Attribute Flags for LSP_ATTRIBUTES object.............6
      5. Acknowledgments............................................7
      6. References.................................................7
         6.1. Normative References..................................7
         6.2. Informative References................................8
      Copyright Notice..............................................8
      Legal.........................................................9
  
   1. Introduction
  
      When RSVP-TE is used for applications like MVPN [MVPN] and VPLS
      [VPLS], an Egress LSR receives the binding of the RSVP-TE LSP to
      an application, and payload identification, using an "out-of-
      band" (OOB) mechanism (e.g., using BGP). In such cases, the
      Egress LSR cannot make correct forwarding decision until such OOB
      mapping information is received. Furthermore, in order to apply
  
  
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      the binding information, the Egress LSR needs to identify the
      incoming LSP. Therefore, non Penultimate Hop Popping (non-PHP)
      behavior is required at the Egress LSR to apply OOB mapping.
  
      There are other applications that require non-PHP behavior. When
      RSVP-TE P2MP LSPs are used to carry IP multicast traffic non-PHP
      behavior enables a leaf LSR to identify the P2MP TE LSP, on which
      traffic is received. Hence the egress LSR can determine whether
      traffic is received on the expected P2MP LSP and discard traffic
      that is not received on the expected P2MP LSP. Non-PHP behavior
      is also required to determine the context of upstream assigned
      labels when the context is a MPLS LSP. Non-PHP behavior may also
      be required for MPLS-TP LSPs [MPLS-TP-Framework].
  
      This document defines two new flags in the Attributes Flags TLV
      of the LSP_ATTRIBUTES object defined in [RFC5420]: one flag for
      communication of non-PHP behavior, and one flag to indicate that
      the binding of the LSP to an application and payload identifier
      (payload-Id) needs to be learned via an out-of-band mapping
      mechanism.
  
      The procedures described in this document are equally applicable
      for P2P and P2MP LSPs. Specification of the OOB communication
      mechanism(s) is beyond the scope of this document.
  
   2. RSVP-TE signaling extensions
  
      This section describes the signaling extensions required to
      address the above-mentioned requirements.
  
   2.1. Signaling non-PHP behavior
  
      In order to request non-PHP behavior for RSVP-TE LSP, this
      document defines a new flag in the Attributes Flags TLV of the
      LSP_ATTRIBUTES object defined in [RFC5420]:
  
      Bit Number 6 (TBD): non-PHP behavior desired flag.
  
      In order to indicate to the Ingress LSR that the Egress LSR
      recognizes the "non-PHP behavior desired flag", the following new
      bit is defined in the Flags field of the Record Route object
      (RRO) Attributes subobject:
  
      Bit Number 6 (TBD): Non-PHP behavior acknowledgement flag.
  
  
  
  
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      An Ingress LSR sets the non-PHP behavior desired flag to signal
      the egress LSRs SHOULD assign non-NULL label for the LSP being
      signaled.  This flag MUST NOT be modified by any other LSRs in
      the network. LSRs other than the Egress LSRs SHOULD ignore this
      flag.
  
      If an egress LSR receiving the Path message, supports the
      LSP_ATTRIBUTES object and the Attributes Flags TLV, and also
      recognizes the "non-PHP behavior desired flag", it MUST allocate
      a non-NULL local label. The egress LSR MUST also set the "Non-PHP
      behavior acknowledgement flag" in the Flags field of the RRO
      Attribute subobject.
  
      If the egress LSR supports the LSP_ATTRIBUTES object but does not
      recognize the Attributes Flags TLV, or supports the TLV as well
      but does not recognize this particular flag, then it SHOULD
      simply ignore the above request.
  
      An ingress LSR requesting non-PHP behavior MAY examine "Non-PHP
      behavior acknowledgement flag" in the Flags field of the RRO
      Attribute subobject and MAY send a Path Tear if the Egress
      has not set the "Non-PHP behavior acknowledgement flag". An
      ingress LSR requesting non-PHP behavior MAY also examine the
      label value corresponding to the Egress LSR(s) in the RRO, and
      MAY send a Path Tear if the Egress has assigns a Null label
      value.
  
   2.2. Signaling OOB Mapping Indication
  
      This document defines a single flag to indicate that the normal
      binding mechanism of an RSVP session is overridden.  The actual
      out of band mappings are beyond the scope of this document.  The
      flag is carried in the Attributes Flags TLV of the LSP_ATTRIBUTES
      object defined in [RFC5420] and is defined as follows:
  
  
      Bit Number 7 (TBD): OOB mapping indication flag.
  
      In order to indicate to the Ingress LSR that the Egress LSR
      recognizes the "OOB mapping indication flag", the following new
      bit is defined in the Flags field of the Record Route object
      (RRO) Attributes subobject:
  
      Bit Number 7 (TBD): OOB mapping acknowledgement flag.
  
  
  
  
  
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      An Ingress LSR sets the OOB mapping indication flag to signal the
      Egress LSR that binding of RSVP-TE LSP to an application and
      payload identification is being signaled out of band. This flag
      MUST NOT be modified by any other LSRs in the network. LSRs other
      than the Egress LSRs SHOULD ignore this flag.
  
      When an egress LSR which supports the "OOB mapping indication
      flag", receives a Path message with that flag set, the egress LSR
      MUST set the "OOB mapping acknowledgement flag" in the Flags
      field of the RRO Attribute subobject. The rest of the RSVP
      signaling proceeds as normal.  However, the LSR MUST have
      received the OOB mapping before accepting traffic on the LSP.
      This implies that the egress LSR MUST NOT setup forwarding state
      for the LSP before it receives the OOB mapping.
  
      Note that the payload information SHOULD be supplied by the OOB
      mapping. If the egress LSR receives the payload information from
      OOB mapping then the LSR MUST ignore L3PID in the Label Request
      Object [RFC3209].
  
      If the egress LSR supports the LSP_ATTRIBUTES object but does not
      recognize the Attributes Flags TLV, or supports the TLV as well
      but does not recognize this particular flag, then it SHOULD
      simply ignore the above request.
  
      An ingress LSR requesting OOB mapping MAY examine "OOB mapping
      acknowledgement flag" in the Flags field of the RRO Attribute
      subobject and MAY send a Path Tear to the Egress which has not
      set the "OOB mapping acknowledgement flag".
  
      In deploying applications where Egress LSR receives the binding
      of the RSVP-TE LSP to an application, and payload identification,
      using OOB mechanism, it is important to recognize that OOB
      mapping is sent asynchronously w.r.t. signaling of RSVP-TE LSP.
      Egress LSR only installs forwarding state for the LSP after it
      receives the OOB mapping. In deploying applications using OOB
      mechanism, ingress LSR may need to know when egress is properly
      setup for forwarding (i.e., has received OOB mapping). How
      ingress LSR determines that LSR is properly setup for forwarding
      at the Egress LSR is beyond the scope of this document.
      Nonetheless, if OOB mapping is not received by the egress LSR
      within a reasonable time, a procedure to tear down the LSP is
      defined in section 2.4.
  
  
  
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   2.3. Relationship between OOB and non-PHP flags
  
      Non-PHP behavior desired and OOB mapping indication flags can
      appear and be processed independently of each other. However, as
      mentioned earlier, in the context of application discussed in
      this draft, OOB mapping require non-PHP behavior. An Ingress LSR
      requesting OOB mapping MAY also set non-PHP behavior desired flag
      in the LSP_ATTRIBUTES object in the Path message.
  
   2.4. Egress Procedure for label binding
  
      RSVP-TE signaling completion and the OOB mapping information
      reception happen asynchronously at the Egress. As mentioned in
      Section 2, Egress waits for the OOB mapping before accepting
      traffic on the LSP.
  
      In order to avoid unnecessary use of the resources and possible
      block-holing of traffic, if the OOB mapping information is not
      received within a reasonable time, Egress MAY trigger a Path
      Error message with the error code/sub-code "Notify Error/ no OOB
      mapping received" for all affected LSPs. If available, and where
      notify requests were included when the LSPs were initially setup,
      Notify messages (as defined in [RFC3473]) MAY also be used for
      delivery of this information to the Ingress LSR. An Egress LSR
      MAY implement a cleanup timer for this purpose. The time-out
      value is a local decision at the Egress, with a RECOMMENDED
      default value of 60 seconds.
  
   3. Security Considerations
  
      This document does not introduce any new security issues above
      those identified in [RFC3209], [RFC5420] and [RFC4875].
  
  
   4. IANA Considerations
  
   4.1. Attribute Flags for LSP_ATTRIBUTES object
  
      The following new flags are being defined for the Attributes
      Flags TLV in the LSP_ATTRIBUTES object.  The numeric values are
      to be assigned by IANA.
  
      o  Non-PHP behavior desired flag - Bit Number 6 (Suggested
         value).
  
      o  OOB mapping indication flag - Bit Number 7 (Suggested value).
  
  
  
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      These flags are only to be used in the Attributes Flags TLV on a
      Path message. These flags have corresponding new flags to be used
      in the RRO Attributes subobject. As per RFC5420 [RFC5420], the
      bit numbering in the Attribute Flags TLV and the RRO Attributes
      subobject is identical.  That is, the same attribute is indicated
      by the same bit in both places.  Specifically, the numeric values
      for the corresponding new flags to be used in the RRO Attributes
      subobject are to be assigned by IANA.
  
      o  OOB mapping acknowledgement flag - Bit Number 6 (Suggested
         value).
  
      o  Non-PHP behavior acknowledgement flag - Bit Number 7
         (Suggested value).
  
      For Error Code = 25 "Notify Error" (see [RFC3209]) the following
      sub-code is defined.
  
            Sub-code                    Value
            --------                    -----
  
            No OOB mapping received     12 (TBD)
  
  
   5. Acknowledgments
  
      The authors would like to thank Yakov Rekhter for his suggestions
      on the draft.
  
  
   6. References
  
   6.1. Normative References
  
      [RFC5420] A. Farrel, D. Papadimitriou, J. P. Vasseur and A.
                Ayyangar, "Encoding of Attributes for  Multiprotocol
                Label Switching (MPLS) Label Switched Path (LSP)
                Establishment Using RSVP-TE", RFC 5420, February 2006.
  
      [RFC3209] D. Awduche, L. Berger, D. Gan, T. Li, V. Srinivasan,
                and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP
                Tunnels", RFC 3209, December 2001.
  
      [RFC4875] R. Aggarwal, D. Papadimitriou, S. Yasukawa, et al,
                "Extensions to RSVP-TE for Point-to-Multipoint TE
                LSPs", RFC 4875.
  
  
  
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      [RFC3473]  L. Berger, Editor, "Generalized Multi-Protocol Label
                Switching (GMPLS) Signaling Resource ReserVation
                Protocol-Traffic Engineering (RSVP-TE) Extensions", RFC
                3473, January 2003.
  
  
   6.2. Informative References
  
      [MVPN] E. Rosen, R. Aggarwal et al, "Multicast in MPLS/BGP IP
                VPNs", draft-ietf-l3vpn-2547bis-mcast-08.txt, work in
                progress.
  
      [VPLS] R. Aggarwal, et al, "Propagation of VPLS IP Multicast
                Group Membership Information", draft-raggarwa-l2vpn-
                vpls-mcast-ctrl-00.txt, work in progress.
  
      [MPLS-TP-Framework] M. Bocci, S. Bryant, et al, "A Framework for
                MPLS in Transport Networks",
                draft-ietf-mpls-tp-framework-06, work in progress.
  
   Author's Addresses
  
  
      Zafar Ali
      Cisco Systems, Inc.
      Email: zali@cisco.com
  
      George Swallow
      Cisco Systems, Inc.
      Email: swallow@cisco.com
  
      Rahul Aggarwal
      Juniper Networks
      rahul@juniper.net
  
  
   Copyright Notice
  
  
      Copyright (c) 2009 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 in effect on the date of
      publication of this document
     (http://trustee.ietf.org/license-info). Please review these
  
  
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