path: root/doc/rfc/rfc4860.txt

Network Working Group                                     F. Le Faucheur
Request for Comments: 4860                                      B. Davie
Category: Standards Track                            Cisco Systems, Inc.
                                                                 P. Bose
                                                         Lockheed Martin
                                                             C. Christou
                                                            M. Davenport
                                                     Booz Allen Hamilton
                                                                May 2007


  Generic Aggregate Resource ReSerVation Protocol (RSVP) Reservations

Status of This Memo

   This document specifies an Internet standards track protocol for the
   Internet community, and requests discussion and suggestions for
   improvements.  Please refer to the current edition of the "Internet
   Official Protocol Standards" (STD 1) for the standardization state
   and status of this protocol.  Distribution of this memo is unlimited.

Copyright Notice

   Copyright (C) The IETF Trust (2007).

Abstract

   RFC 3175 defines aggregate Resource ReSerVation Protocol (RSVP)
   reservations allowing resources to be reserved in a Diffserv network
   for a given Per Hop Behavior (PHB), or given set of PHBs, from a
   given source to a given destination.  RFC 3175 also defines how end-
   to-end RSVP reservations can be aggregated onto such aggregate
   reservations when transiting through a Diffserv cloud.  There are
   situations where multiple such aggregate reservations are needed for
   the same source IP address, destination IP address, and PHB (or set
   of PHBs).  However, this is not supported by the aggregate
   reservations defined in RFC 3175.  In order to support this, the
   present document defines a more flexible type of aggregate RSVP
   reservations, referred to as generic aggregate reservation.  Multiple
   such generic aggregate reservations can be established for a given
   PHB (or set of PHBs) from a given source IP address to a given
   destination IP address.  The generic aggregate reservations may be
   used to aggregate end-to-end RSVP reservations.  This document also
   defines the procedures for such aggregation.  The generic aggregate
   reservations may also be used end-to-end directly by end-systems
   attached to a Diffserv network.





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Table of Contents

   1. Introduction ....................................................3
      1.1. Related IETF Documents .....................................6
      1.2. Organization of This Document ..............................6
      1.3. Requirements Language ......................................7
   2. Object Definition ...............................................7
      2.1. SESSION Class ..............................................8
      2.2. SESSION-OF-INTEREST (SOI) Class ...........................11
   3. Processing Rules for Handling Generic Aggregate RSVP
      Reservations ...................................................13
      3.1. Extensions to Path and Resv Processing ....................13
   4. Procedures for Aggregation over Generic Aggregate RSVP
      Reservations ...................................................14
   5. Example Usage Of Multiple Generic Aggregate Reservations
      per PHB from a Given Aggregator to a Given Deaggregator ........19
   6. Security Considerations ........................................21
   7. IANA Considerations ............................................24
   8. Acknowledgments ................................................25
   9. Normative References ...........................................26
   10. Informative References ........................................26
   Appendix A. Example Signaling Flow ................................28





























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1.  Introduction

   [RSVP-AGG] defines RSVP aggregate reservations that allow resources
   to be reserved in a Diffserv network for a flow characterized by its
   3-tuple <source IP address, destination IP address, Diffserv Code
   Point>.

   [RSVP-AGG] also defines the procedures for aggregation of end-to-end
   (E2E) RSVP reservations onto such aggregate reservations when
   transiting through a Diffserv cloud.  Such aggregation is illustrated
   in Figure 1.  This document reuses the terminology defined in
   [RSVP-AGG].

                    --------------------------
                   /       Aggregation        \
      |----|      |          Region            |      |----|
   H--| R  |\ |-----|                       |------| /| R  |-->H
   H--|    |\\|     |   |---|     |---|     |      |//|    |-->H
      |----| \|     |   | I |     | I |     |      |/ |----|
              | Agg |======================>| Deag |
             /|     |   |   |     |   |     |      |\
   H--------//|     |   |---|     |---|     |      |\\-------->H
   H--------/ |-----|                       |------| \-------->H
                  |                            |
                   \                          /
                    --------------------------

   H       = Host requesting end-to-end RSVP reservations
   R       = RSVP router
   Agg     = Aggregator
   Deag    = Deaggregator
   I       = Interior Router

   -->   = E2E RSVP reservation
   ==>   = Aggregate RSVP reservation

                Figure 1 : Aggregation of E2E Reservations
                     over Aggregate RSVP Reservations

   These aggregate reservations use a SESSION type specified in
   [RSVP-AGG] that contains the receiver (or Deaggregator) IP address
   and the Diffserv Code Point (DSCP) of the Per Hop Behavior (PHB) from
   which Diffserv resources are to be reserved.  For example, in the
   case of IPv4, the SESSION object is specified as:







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      o  Class = SESSION,
         C-Type = RSVP-AGGREGATE-IP4

           +-------------+-------------+-------------+-------------+
           |              IPv4 Session Address (4 bytes)           |
           +-------------+-------------+-------------+-------------+
           | /////////// |    Flags    |  /////////  |     DSCP    |
           +-------------+-------------+-------------+-------------+

   These aggregate reservations use SENDER_TEMPLATE and FILTER_SPEC
   types, specified in [RSVP-AGG], that contain only the sender (or
   Aggregator) IP address.  For example, in the case of IPv4, the
   SENDER_TEMPLATE object is specified as:

      o  Class = SENDER_TEMPLATE,
         C-Type = RSVP-AGGREGATE-IP4

           +-------------+-------------+-------------+-------------+
           |                IPv4 Aggregator Address (4 bytes)      |
           +-------------+-------------+-------------+-------------+

   Thus, it is possible to establish, from a given source IP address to
   a given destination IP address, separate such aggregate reservations
   for different PHBs (or different sets of PHBs).  However, from a
   given source IP address to a given IP destination address, only a
   single [RSVP-AGG] aggregate reservation can be established for a
   given PHB (or given set of PHBs).

   Situations have since been identified where multiple such aggregate
   reservations are needed for the same source IP address, destination
   IP address, and PHB (or set of PHBs).  One example is where E2E
   reservations using different preemption priorities (as per
   [RSVP-PREEMP]) need to be aggregated through a Diffserv cloud using
   the same PHB.  Using multiple aggregate reservations for the same PHB
   allows enforcement of the different preemption priorities within the
   aggregation region.  In turn, this allows more efficient management
   of the Diffserv resources, and in periods of resource shortage, this
   allows sustainment of a larger number of E2E reservations with higher
   preemption priorities.

   For example, [SIG-NESTED] discusses in detail how end-to-end RSVP
   reservations can be established in a nested VPN environment through
   RSVP aggregation.  In particular, [SIG-NESTED] describes how multiple
   parallel generic aggregate reservations (for the same PHB), each with
   different preemption priorities, can be used to efficiently support
   the preemption priorities of end-to-end reservations.





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   This document addresses this requirement for multiple aggregate
   reservations for the same PHB (or same set of PHBs), by defining a
   more flexible type of aggregate RSVP reservations, referred to as
   generic aggregate reservations.  This is achieved primarily by adding
   the notions of a Virtual Destination Port and of an Extended Virtual
   Destination Port in the RSVP SESSION object.

   The notion of Virtual Destination Port was introduced in [RSVP-IPSEC]
   to address a similar requirement (albeit in a different context) for
   identification and demultiplexing of sessions beyond the IP
   destination address.  This document reuses this notion from
   [RSVP-IPSEC] for identification and demultiplexing of generic
   aggregate sessions beyond the IP destination address and PHB.  This
   allows multiple generic aggregate reservations to be established for
   a given PHB (or set of PHBs), from a given source IP address to a
   given destination IP address.

   [RSVP-TE] introduced the concept of an Extended Tunnel ID (in
   addition to the tunnel egress address and the Tunnel ID) in the
   SESSION object used to establish MPLS Traffic Engineering tunnels
   with RSVP.  The Extended Tunnel ID provides a very convenient
   mechanism for the tunnel ingress node to narrow the scope of the
   session to the ingress-egress pair.  The ingress node can achieve
   this by using one of its own IP addresses as a globally unique
   identifier and including it in the Extended Tunnel ID and therefore
   within the SESSION object.  This document reuses this notion of
   Extended Tunnel ID from [RSVP-TE], simply renaming it Extended
   Virtual Destination Port.  This provides a convenient mechanism to
   narrow the scope of a generic aggregate session to an Aggregator-
   Deaggregator pair.

   The RSVP SESSION object for generic aggregate reservations uses the
   PHB Identification Code (PHB-ID) defined in [PHB-ID] to identify the
   PHB, or set of PHBs, from which the Diffserv resources are to be
   reserved.  This is instead of using the Diffserv Code Point (DSCP) as
   per [RSVP-AGG].  Using the PHB-ID instead of the DSCP allows explicit
   indication of whether the Diffserv resources belong to a single PHB
   or to a set of PHBs.  It also facilitates handling of situations
   where a generic aggregate reservation spans two (or more) Diffserv
   domains that use different DSCP values for the same Diffserv PHB (or
   set of PHBs) from which resources are reserved.  This is because the
   PHB-ID allows conveying of the PHB (or set of PHBs) independently of
   what DSCP value(s) are used locally for that PHB (or set of PHBs).

   The generic aggregate reservations may be used to aggregate end-to-
   end RSVP reservations.  This document also defines the procedures for
   such aggregation.  These procedures are based on those of [RSVP-AGG],
   and this document only specifies the differences from those.



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   The generic aggregate reservations may also be used end-to-end
   directly by end-systems attached to a Diffserv network.

1.1.  Related IETF Documents

   This document is heavily based on [RSVP-AGG].  It reuses [RSVP-AGG]
   wherever applicable and only specifies the necessary extensions
   beyond [RSVP-AGG].

   The mechanisms defined in [BW-REDUC] allow an existing reservation to
   be reduced in allocated bandwidth by RSVP routers in lieu of tearing
   that reservation down.  These mechanisms are applicable to the
   generic aggregate reservations defined in the present document.

   [RSVP-TUNNEL] describes a general approach to running RSVP over
   various types of tunnels.  One of these types of tunnel, referred to
   as a "type 2 tunnel", has some similarity with the generic aggregate
   reservations described in this document.  The similarity stems from
   the fact that a single, aggregate reservation is made for the tunnel
   while many individual flows are carried over that tunnel.  However,
   [RSVP-TUNNEL] does not address the use of Diffserv-based
   classification and scheduling in the core of a network (between
   tunnel endpoints), but rather relies on a UDP/IP tunnel header for
   classification.  This is why [RSVP-AGG] required additional objects
   and procedures beyond those of [RSVP-TUNNEL].  Like [RSVP-AGG], this
   document also assumes the use of Diffserv-based classification and
   scheduling in the aggregation region and, thus, requires additional
   objects and procedures beyond those of [RSVP-TUNNEL].

   As explained earlier, this document reuses the notion of Virtual
   Destination Port from [RSVP-IPSEC] and the notion of Extended Tunnel
   ID from [RSVP-TE].

1.2.  Organization Of This Document

   Section 2 defines the new RSVP objects related to generic aggregate
   reservations and to aggregation of E2E reservations onto those.
   Section 3 describes the processing rules for handling of generic
   aggregate reservations.  Section 4 specifies the procedures for
   aggregation of end-to-end RSVP reservations over generic aggregate
   RSVP reservations.  Section 5 provides example usage of how the
   generic aggregate reservations may be used.

   The Security Considerations and the IANA Considerations are discussed
   in Sections 6 and 7, respectively.






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   Finally, Appendix A provides an example signaling flow that
   illustrates aggregation of E2E RSVP reservations onto generic
   aggregate RSVP reservations.

1.3.  Requirements Language

   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 [KEYWORDS].

2.  Object Definition

   This document reuses the RSVP-AGGREGATE-IP4 FILTER_SPEC, RSVP-
   AGGREGATE-IP6 FILTER_SPEC, RSVP-AGGREGATE-IP4 SENDER_TEMPLATE, and
   RSVP-AGGREGATE-IP6 SENDER_TEMPLATE objects defined in [RSVP-AGG].

   This document defines:

      - two new objects (GENERIC-AGGREGATE-IP4 SESSION and GENERIC-
        AGGREGATE-IP6 SESSION) under the existing SESSION Class, and

      - two new objects (GENERIC-AGG-IP4-SOI and GENERIC-AGG-IP6-SOI)
        under a new SESSION-OF-INTEREST Class.

   Detailed description of these objects is provided below in this
   section.

   The GENERIC-AGGREGATE-IP4 SESSION and GENERIC-AGGREGATE-IP6 SESSION
   objects are applicable to all types of RSVP messages.

   This specification defines the use of the GENERIC-AGG-IP4-SOI and
   GENERIC-AGG-IP6-SOI objects in two circumstances:

      - inside an E2E PathErr message that contains an error code of
        NEW-AGGREGATE-NEEDED in order to convey the session of a new
        generic aggregate reservation that needs to be established.

      - inside an E2E Resv message in order to convey the session of the
        generic aggregate reservation onto which this E2E reservation
        needs to be mapped.

   Details of the corresponding procedures can be found in Section 4.

   However, it is envisioned that the ability to signal, inside RSVP
   messages, the Session of another reservation (which has some
   relationship with the current RSVP reservation) might have some other
   applicability in the future.  Thus, those objects have been specified
   in a more generic manner under a flexible SESSION-OF-INTEREST class.



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   All the new objects defined in this document are optional with
   respect to RSVP so that general RSVP implementations that are not
   concerned with generic aggregate reservations do not have to support
   these objects.  RSVP routers supporting generic aggregate IPv4 or
   IPv6 reservations MUST support the GENERIC-AGGREGATE-IP4 SESSION
   object or the GENERIC-AGGREGATE-IP6 SESSION object, respectively.
   RSVP routers supporting RSVP aggregation over generic aggregate IPv4
   or IPv6 reservations MUST support the GENERIC-AGG-IP4-SOI object or
   GENERIC-AGG-IP6-SOI object, respectively.

2.1.  SESSION Class

   o GENERIC-AGGREGATE-IP4 SESSION object:
                  Class = 1 (SESSION)
                  C-Type = 17

               0           7 8          15 16         23 24          31
              +-------------+-------------+-------------+-------------+
              |               IPv4 DestAddress (4 bytes)              |
              +-------------+-------------+-------------+-------------+
              | Reserved    |     Flags   |          PHB-ID           |
              +-------------+-------------+-------------+-------------+
              |          Reserved         |         vDstPort          |
              +-------------+-------------+-------------+-------------+
              |                    Extended vDstPort                  |
              +-------------+-------------+-------------+-------------+
               0           7 8          15 16         23 24          31

   IPv4 DestAddress (IPv4 Destination Address)

      IPv4 address of the receiver (or Deaggregator).

   Reserved

      An 8-bit field.  All bits MUST be set to 0 on transmit.  This
      field MUST be ignored on receipt.

   Flags

      An 8-bit field.  The content and processing of this field are the
      same as for the Flags field of the IPv4/UDP SESSION object (see
      [RSVP]).









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   PHB-ID (Per Hop Behavior Identification Code)

      A 16-bit field containing the Per Hop Behavior Identification Code
      of the PHB, or of the set of PHBs, from which Diffserv resources
      are to be reserved.  This field MUST be encoded as specified in
      Section 2 of [PHB-ID].

   Reserved

      A 16-bit field.  All bits MUST be set to 0 on transmit.  This
      field MUST be ignored on receipt.

   VDstPort (Virtual Destination Port)

      A 16-bit identifier used in the SESSION that remains constant over
      the life of the generic aggregate reservation.

   Extended vDstPort (Extended Virtual Destination Port)

      A 32-bit identifier used in the SESSION that remains constant over
      the life of the generic aggregate reservation.  A sender (or
      Aggregator) that wishes to narrow the scope of a SESSION to the
      sender-receiver pair (or Aggregator-Deaggregator pair) SHOULD
      place its IPv4 address here as a network unique identifier.  A
      sender (or Aggregator) that wishes to use a common session with
      other senders (or Aggregators) in order to use a shared
      reservation across senders (or Aggregators) MUST set this field to
      all zeros.

   o GENERIC-AGGREGATE-IP6 SESSION object:
                  Class = 1 (SESSION)
                  C-Type = 18



















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               0           7 8          15 16         23 24          31
              +-------------+-------------+-------------+-------------+
              |                                                       |
              +                                                       +
              |                                                       |
              +               IPv6 DestAddress (16 bytes)             +
              |                                                       |
              +                                                       +
              |                                                       |
              +-------------+-------------+-------------+-------------+
              | Reserved    |     Flags   |          PHB-ID           |
              +-------------+-------------+-------------+-------------+
              |          Reserved         |         vDstPort          |
              +-------------+-------------+-------------+-------------+
              |                                                       |
              +                                                       +
              |                     Extended vDstPort                 |
              +                                                       +
              |                        (16 bytes)                     |
              +                                                       +
              |                                                       |
              +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
               0           7 8          15 16            25 26       31

   IPv6 DestAddress (IPv6 Destination Address)

      IPv6 address of the receiver (or Deaggregator).

   Reserved

      An 8-bit field.  All bits MUST be set to 0 on transmit.  This
      field MUST be ignored on receipt.

   Flags

      An 8-bit field.  The content and processing of this field are the
      same as for the Flags field of the IPv6/UDP SESSION object (see
      [RSVP]).

   PHB-ID (Per Hop Behavior Identification Code)

      A 16-bit field containing the Per Hop Behavior Identification Code
      of the PHB, or of the set of PHBs, from which Diffserv resources
      are to be reserved.  This field MUST be encoded as specified in
      Section 2 of [PHB-ID].






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   Reserved

      A 16-bit field.  All bits MUST be set to 0 on transmit.  This
      field MUST be ignored on receipt.

   VDstPort (Virtual Destination Port)

      A 16-bit identifier used in the SESSION that remains constant over
      the life of the generic aggregate reservation.

   Extended vDstPort (Extended Virtual Destination Port)

      A 128-bit identifier used in the SESSION that remains constant
      over the life of the generic aggregate reservation.  A sender (or
      Aggregator) that wishes to narrow the scope of a SESSION to the
      sender-receiver pair (or Aggregator-Deaggregator pair) SHOULD
      place its IPv6 address here as a network unique identifier.  A
      sender (or Aggregator) that wishes to use a common session with
      other senders (or Aggregators) in order to use a shared
      reservation across senders (or Aggregators) MUST set this field to
      all zeros.

2.2.  SESSION-OF-INTEREST (SOI) Class

   o GENERIC-AGG-IP4-SOI object:
                  Class = 132
                  C-Type = 1

            0           7 8          15 16         23 24          31
            +-------------+-------------+-------------+-------------+
            |                           | SOI         |GEN-AGG-IP4- |
            |       Length (bytes)      | Class-Num   |SOI C-Type   |
            +-------------+-------------+-------------+-------------+
            |                                                       |
            //  Content of a GENERIC-AGGREGATE-IP4 SESSION Object  //
            |                                                       |
            +-------------+-------------+-------------+-------------+

   Content of a GENERIC-AGGREGATE-IP4 SESSION Object:

      This field contains a copy of the SESSION object of the session
      that is of interest for the reservation.  In the case of a
      GENERIC-AGG-IP4-SOI, the session of interest conveyed in this
      field is a GENERIC-AGGREGATE-IP4 SESSION.







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   o GENERIC-AGG-IP6-SOI object:
                  Class = 132
                  C-Type = 2

            0           7 8          15 16         23 24          31
            +-------------+-------------+-------------+-------------+
            |                           | SOI         |GEN-AGG-IP6- |
            |       Length (bytes)      | Class-Num   |SOI C-Type   |
            +-------------+-------------+-------------+-------------+
            |                                                       |
            //  Content of a GENERIC-AGGREGATE-IP6 SESSION Object  //
            |                                                       |
            +-------------+-------------+-------------+-------------+

   Content of a GENERIC-AGGREGATE-IP6 SESSION Object:

      This field contains a copy of the SESSION object of the session
      that is of interest for the reservation.  In the case of a
      GENERIC-AGG-IP6-SOI, the session of interest conveyed in this
      field is a GENERIC-AGGREGATE-IP6 SESSION.

   For example, if a SESSION-OF-INTEREST object is used inside an E2E
   Resv message (as per the procedures defined in Section 4) to indicate
   which generic aggregate IPv4 session the E2E reservation is to be
   mapped onto, then the GENERIC-AGG-IP4-SOI object will be used, and it
   will be encoded like this:

             0           7 8          15 16         23 24          31
            +-------------+-------------+-------------+-------------+
            |                           | SOI         |GEN-AGG-IP4- |
            |       Length (bytes)      | Class-Num   |SOI C-Type   |
            +-------------+-------------+-------------+-------------+
            |               IPv4 DestAddress (4 bytes)              |
            +-------------+-------------+-------------+--+----------+
            | Reserved    |     Flags   |          PHB-ID           |
            +-------------+-------------+-------------+-------------+
            |          Reserved         |         vDstPort          |
            +-------------+-------------+-------------+-------------+
            |                    Extended vDstPort                  |
            +-------------+-------------+-------------+-------------+
             0           7 8          15 16         23 24          31

   Note that a SESSION-OF-INTEREST object is not a SESSION object in
   itself.  It does not replace the SESSION object in RSVP messages.  It
   does not modify the usage of the SESSION object in RSVP messages.  It
   simply allows conveying the Session of another RSVP reservation
   inside RSVP signaling messages, for some particular purposes.  In the
   context of this document, it is used to convey, inside an E2E RSVP



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   message pertaining to an end-to-end reservation, the Session of a
   generic aggregate reservation associated with the E2E reservation.
   Details for the corresponding procedures are specified in Section 4.

3.  Processing Rules for Handling Generic Aggregate RSVP Reservations

   This section presents extensions to the processing of RSVP messages
   required by [RSVP] and presented in [RSVP-PROCESS].  These extensions
   are required in order to properly process the GENERIC-AGGREGATE-IP4
   or GENERIC-AGGREGATE-IP6 SESSION object and the RSVP-AGGREGATE-IP4 or
   RSVP-AGGREGATE-IP6 FILTER_SPEC object.  Values for referenced error
   codes can be found in [RSVP].  As with the other RSVP documents,
   values for internally reported (API) errors are not defined.

   When referring to the new GENERIC-AGGREGATE-IP4 and GENERIC-
   AGGREGATE-IP6 SESSION objects, IP version will not be included, and
   they will be referred to simply as GENERIC-AGGREGATE SESSION, unless
   a specific distinction between IPv4 and IPv6 is being made.

   When referring to the [RSVP-AGG] RSVP-AGGREGATE-IP4 and RSVP-
   AGGREGATE-IP6 SESSION, FILTER_SPEC, and SENDER_TEMPLATE objects, IP
   version will not be included, and they will be referred to simply as
   RSVP-AGGREGATE, unless a specific distinction between IPv4 and IPv6
   is being made.

3.1.  Extensions to Path and Resv Processing

   The following PATH message processing changes are defined:

      o When a session is defined using the GENERIC-AGGREGATE SESSION
        object, only the [RSVP-AGG] RSVP-AGGREGATE SENDER_TEMPLATE may
        be used.  When this condition is violated in a PATH message
        received by an RSVP end-station, the RSVP end-station SHOULD
        report a "Conflicting C-Type" API error to the application.
        When this condition is violated in a PATH message received by an
        RSVP router, the RSVP router MUST consider this as a message
        formatting error.

      o For PATH messages that contain the GENERIC-AGGREGATE SESSION
        object, the VDstPort value, the Extended VDstPort value, and the
        PHB-ID value should be recorded (in addition to the
        destination/Deaggregator address and source/Aggregator address).
        These values form part of the recorded state of the session.
        The PHB-ID may need to be passed to traffic control; however the
        vDstPort and Extended VDstPort are not passed to traffic control
        since they do not appear inside the data packets of the
        corresponding reservation.




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   The following changes to RESV message processing are defined:

      o When a RESV message contains a [RSVP-AGG] RSVP-AGGREGATE
        FILTER_SPEC, the session MUST be defined using either the RSVP-
        AGGREGATE SESSION object (as per [RSVP-AGG]) or the GENERIC-
        AGGREGATE SESSION object (as per this document).  If this
        condition is not met, an RSVP router or end-station MUST
        consider that there is a message formatting error.

      o When the RSVP-AGGREGATE FILTER_SPEC is used and the SESSION type
        is GENERIC-AGGREGATE, each node uses data classifiers as per the
        following:

        * to perform Diffserv classification the node MUST rely on the
          Diffserv data classifier based on the DSCP only.  The relevant
          DSCP value(s) are those that are associated with the PHB-ID of
          the generic aggregate reservation.

        * If the node also needs to perform fine-grain classification
          (for example, to perform fine-grain input policing at a trust
          boundary) then the node MUST create a data classifier
          described by the 3-tuple <DestAddress, SrcAddress, DSCP>.

          The relevant DSCP value(s) are those that are associated with
          the PHB-ID of the generic aggregate reservation.

          Note that if multiple generic aggregate reservations are
          established with different Virtual Destination Ports (and/or
          different Extended Virtual Destination Ports) but with the
          same <DestAddress, SrcAddress, PHB-ID>, then those cannot be
          distinguished by the classifier.  If the router is using the
          classifier for policing purposes, the router will therefore
          police those together and MUST program the policing rate to
          the sum of the reserved rate across all the corresponding
          reservations.

4.  Procedures for Aggregation over Generic Aggregate RSVP Reservations

   The procedures for aggregation of E2E reservations over generic
   aggregate RSVP reservations are the same as the procedures specified
   in [RSVP-AGG] with the exceptions of the procedure changes listed in
   this section.

   As specified in [RSVP-AGG], the Deaggregator is responsible for
   mapping a given E2E reservation on a given aggregate reservation.
   The Deaggregator requests establishment of a new aggregate
   reservation by sending to the Aggregator an E2E PathErr message with
   an error code of NEW-AGGREGATE-NEEDED.  In [RSVP-AGG], the



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   Deaggregator conveys the DSCP of the new requested aggregate
   reservation by including a DCLASS Object in the E2E PathErr and
   encoding the corresponding DSCP inside.  This document modifies and
   extends this procedure.  The Deaggregator MUST include in the E2E
   PathErr message a SESSION-OF-INTEREST object that contains the
   GENERIC-AGGREGATE SESSION to be used for establishment of the
   requested generic aggregate reservation.  Since this GENERIC-
   AGGREGATE SESSION contains the PHB-ID, the DCLASS object need not be
   included in the PathErr message.

   Note that the Deaggregator can easily ensure that different
   Aggregators use different sessions for their Aggregate Path towards a
   given Deaggregator.  This is because the Deaggregator can easily
   select VDstPort and/or Extended VDstPort numbers which are different
   for each Aggregator (for example, by using the Aggregator address as
   the Extended VDstPort) and can communicate those inside the GENERIC-
   AGGREGATE SESSION included in the SESSION-OF-INTEREST object.  This
   provides an easy solution to establish separate reservations from
   every Aggregator to a given Deaggregator.  Conversely, if reservation
   sharing were needed across multiple Aggregators, the Deaggregator
   could facilitate this by allocating the same VDstPort and Extended
   VDstPort to the multiple Aggregators, and thus including the same
   GENERIC-AGGREGATE SESSION inside the SESSION-OF-INTEREST object in
   the E2E PathErr messages sent to these Aggregators.  The Aggregators
   could then all establish an Aggregate Path with the same GENERIC-
   AGGREGATE SESSION.

   Therefore, various sharing scenarios can easily be supported.
   Policies followed by the Deaggregator to determine which Aggregators
   need shared or separate reservations are beyond the scope of this
   document.

   The Deaggregator MAY also include in the E2E PathErr message (with an
   error code of NEW-AGGREGATE-NEEDED) additional RSVP objects which are
   to be used for establishment of the newly needed generic aggregate
   reservation.  For example, the Deaggregator MAY include in the E2E
   PathErr an RSVP Signaled Preemption Priority Policy Element (as
   specified in [RSVP-PREEMP]).

   The [RSVP-AGG] procedures for processing of an E2E PathErr message
   received with an error code of NEW-AGGREGATE-NEEDED by the Aggregator
   are extended correspondingly.  On receipt of such a message
   containing a SESSION-OF-INTEREST object, the Aggregator MUST trigger
   establishment of a generic aggregate reservation.  In particular, it
   MUST start sending aggregate Path messages with the GENERIC-AGGREGATE
   SESSION found in the received SESSION-OF-INTEREST object.  When an
   RSVP Signaled Preemption Priority Policy Element is contained in the
   received E2E PathErr message, the Aggregator MUST include this object



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   in the Aggregate Path for the corresponding generic aggregate
   reservation.  When other additional objects are contained in the
   received E2E PathErr message and those can be unambiguously
   interpreted as related to the new needed generic aggregate
   reservation (as opposed to related to the E2E reservation), the
   Aggregator SHOULD include those in the Aggregate Path for the
   corresponding generic aggregate reservation.  The Aggregator MUST use
   as the Source Address (i.e., as the Aggregator Address in the Sender-
   Template) for the generic aggregate reservation, the address it uses
   to identify itself as the PHOP (RSVP previous hop) when forwarding
   the E2E Path messages corresponding to the E2E PathErr message.

   The Deaggregator follows the same procedures as described in
   [RSVP-AGG] for establishing, maintaining and clearing the aggregate
   Resv state.  However, a Deaggregator behaving according to the
   present specification MUST use the generic aggregate reservations and
   hence use the GENERIC-AGGREGATE SESSION specified earlier in this
   document.

   This document also modifies the procedures of [RSVP-AGG] related to
   exchange of E2E Resv messages between Deaggregator and Aggregator.
   The Deaggregator MUST include the new SESSION-OF-INTEREST object in
   the E2E Resv message, in order to indicate to the Aggregator the
   generic aggregate session to map a given E2E reservation onto.
   Again, since the GENERIC-AGGREGATE SESSION (included in the SESSION-
   OF-INTEREST object) contains the PHB-ID, the DCLASS object need not
   be included in the E2E Resv message.  The Aggregator MUST interpret
   the SESSION-OF-INTEREST object in the E2E Resv as indicating which
   generic aggregate reservation session the corresponding E2E
   reservation is mapped onto.  The Aggregator MUST not include the
   SESSION-OF-INTEREST object when sending an E2E Resv upstream towards
   the sender.

   Based on relevant policy, the Deaggregator may decide at some point
   that an aggregate reservation is no longer needed and should be torn
   down.  In that case, the Deaggregator MUST send an aggregate
   ResvTear.  On receipt of the aggregate ResvTear, the Aggregator
   SHOULD send an aggregate PathTear (unless the relevant policy
   instructs the Aggregator to do otherwise or to wait for some time
   before doing so, for example in order to speed up potential re-
   establishment of the aggregate reservation in the future).

   [RSVP-AGG] describes how the Aggregator and Deaggregator can
   communicate their respective identities to each other.  For example,
   the Aggregator includes one of its IP addresses in the RSVP HOP
   object in the E2E Path that is transmitted downstream and received by
   the Deaggregator once it traversed the aggregation region.
   Similarly, the Deaggregator identifies itself to the Aggregator by



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   including one of its IP addresses in various fields, including the
   ERROR SPECIFICATION of the E2E PathErr message (containing the NEW-
   AGGREGATE-NEEDED Error Code) and in the RSVP HOP object of the E2E
   Resv message.  However, [RSVP-AGG] does not discuss which IP
   addresses are to be selected by the Aggregator and Deaggregator for
   such purposes.  Because these addresses are intended to identify the
   Aggregator and Deaggregator and not to identify any specific
   interface on these devices, this document RECOMMENDS that the
   Aggregator and Deaggregator SHOULD use interface-independent
   addresses (for example, a loopback address) whenever they communicate
   their respective identities to each other.  This ensures that
   respective identification of the Aggregator and Deaggregator is not
   impacted by any interface state change on these devices.  In turn,
   this results in more stable operations and considerably reduced RSVP
   signaling in the aggregation region.  For example, if interface-
   independent addresses are used by the Aggregator and the
   Deaggregator, then a failure of an interface on these devices may
   simply result in the rerouting of a given generic aggregate
   reservation, but will not result in the generic aggregate reservation
   having to be torn down and another one established.  Moreover, it
   will not result in a change of mapping of E2E reservations on generic
   aggregate reservations (assuming the Aggregator and Deaggregator
   still have reachability after the failure, and the Aggregator and
   Deaggregator are still on the shortest path to the destination).

   However, when identifying themselves to real RSVP neighbors (i.e.,
   neighbors that are not on the other side of the aggregation region),
   the Aggregator and Deaggregator SHOULD continue using interface-
   dependent addresses as per regular [RSVP] procedures.  This applies
   for example when the Aggregator identifies itself downstream as a
   PHOP for the generic aggregate reservation or identifies itself
   upstream as a NHOP (RSVP next hop) for an E2E reservation.  This also
   applies when the Deaggregator identifies itself downstream as a PHOP
   for the E2E reservation or identifies itself upstream as a NHOP for
   the generic aggregate reservation.  As part of the processing of
   generic aggregate reservations, interior routers (i.e., routers
   within the aggregation region) SHOULD continue using interface-
   dependent addresses as per regular [RSVP] procedures.

   More generally, within the aggregation region (i.e., between
   Aggregator and Deaggregator) the operation of RSVP should be modeled
   with the notion that E2E reservations are mapped to aggregate
   reservations and are no longer tied to physical interfaces (as was
   the case with regular RSVP).  However, generic aggregate reservations
   (within the aggregation region) as well as E2E reservations (outside
   the aggregation region) retain the model of regular RVSP and remain
   tied to physical interfaces.




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   As discussed above, generic aggregate reservations may be established
   edge-to-edge as a result of the establishment of E2E reservations
   (from outside the aggregation region) that are to be aggregated over
   the aggregation region.  However, generic aggregate reservations may
   also be used end-to-end by end-systems directly attached to a
   Diffserv domain, such as Public Switched Telephone Network (PSTN)
   gateways.  In that case, the generic aggregate reservations may be
   established by the end-systems in response to application-level
   triggers such as voice call signaling.  Alternatively, generic
   aggregate reservations may also be used edge-to-edge to manage
   bandwidth in a Diffserv cloud even if RSVP is not used end-to-end.  A
   simple example of such a usage would be the static configuration of a
   generic aggregate reservation for a certain bandwidth for traffic
   from an ingress (Aggregator) router to an egress (Deaggregator)
   router.

   In this case, the establishment of the generic aggregate reservations
   is controlled by configuration on the Aggregator and on the
   Deaggregator.  Configuration on the Aggregator triggers generation of
   the aggregate Path message and provides sufficient information to the
   Aggregator to derive the content of the GENERIC-AGGREGATE SESSION
   object.  This would typically include Deaggregator IP address, PHB-ID
   and possibly VDstPort.  Configuration on the Deaggregator would
   instruct the Deaggregator to respond to a received generic aggregate
   Path message and would provide sufficient information to the
   Deaggregator to control the reservation.  This may include bandwidth
   to be reserved by the Deaggregator (for a given <Deaggregator,
   PHB-ID, VDstPort> tuple).

   In the absence of E2E microflow reservations, the Aggregator can use
   a variety of policies to set the DSCP of packets passing into the
   aggregation region and how they are mapped onto generic aggregate
   reservations, thus determining whether they gain access to the
   resources reserved by the aggregate reservation.  These policies are
   a matter of local configuration, as is typical for a device at the
   edge of a Diffserv cloud.















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5.  Example Usage Of Multiple Generic Aggregate Reservations per PHB
    from a Given Aggregator to a Given Deaggregator

   Let us consider the environment depicted in Figure 2 below.  RSVP
   aggregation is used to support E2E reservations between Cloud-1,
   Cloud-2, and Cloud-3.

                 I----------I               I----------I
                 I  Cloud-1 I               I  Cloud-2 I
                 I----------I               I----------I
                       |                      |
                    Agg-Deag-1------------ Agg-Deag-2
                       /                        \
                      /      Aggregation         |
                     |         Region            |
                     |                           |
                     |                       ---/
                      \                     /
                       \Agg-Deag-3---------/
                             |
                        I----------I
                        I  Cloud-3 I
                        I----------I

    Figure 2 : Example Usage of Generic Aggregate IP Reservations

   Let us assume that:

      o The E2E reservations from Cloud-1 to Cloud-3 have a preemption
        of either P1 or P2.

      o The E2E reservations from Cloud-2 to Cloud-3 have a preemption
        of either P1 or P2.

      o The E2E reservations are only for Voice (which needs to be
        treated in the aggregation region using the EF -Expedited
        Forwarding- PHB).

      o Traffic from the E2E reservations is encapsulated in aggregate
        IP reservations from Aggregator to Deaggregator using Generic
        Routing Encapsulation [GRE] tunneling.

   Then, the following generic aggregate RSVP reservations may be
   established from Agg-Deag-1 to Agg-Deag-3 for aggregation of the end-
   to-end RSVP reservations:

   (1) A first generic aggregate reservation for aggregation of Voice
       reservations from Cloud-1 to Cloud-3 requiring use of P1:



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          *  GENERIC-AGGREGATE-IP4 SESSION:
                  IPv4 DestAddress = Agg-Deag-3
                  vDstPort = V1
                  PHB-ID = EF
                  Extended VDstPort = Agg-Deag-1

          *  STYLE = FF or SE

          *  IPv4/GPI FILTER_SPEC:
                  IPv4 SrcAddress = Agg-Deag-1

          *  POLICY_DATA (PREEMPTION_PRI) = P1

   (2) A second generic aggregate reservation for aggregation of Voice
       reservations from Cloud-1 to Cloud-3 requiring use of P2:

          *  GENERIC-AGGREGATE-IP4 SESSION:
                  IPv4 DestAddress = Agg-Deag-3
                  vDstPort = V2
                  PHB-ID = EF
                  Extended VDstPort = Agg-Deag-1

          *  STYLE = FF or SE

          *  IPv4/GPI FILTER_SPEC:
                  IPv4 SrcAddress = Agg-Deag-1

          *  POLICY_DATA (PREEMPTION_PRI) = P2

       where V1 and V2 are arbitrary VDstPort values picked by Agg-
       Deag-3.

   The following generic aggregate RSVP reservations may be established
   from Agg-Deag-2 to Agg-Deag-3 for aggregation of the end-to-end RSVP
   reservations:

   (3) A third generic aggregate reservation for aggregation of Voice
       reservations from Cloud-2 to Cloud-3 requiring use of P1:

          *  GENERIC-AGGREGATE-IP4 SESSION:
                  IPv4 DestAddress = Agg-Deag-3
                  vDstPort = V3
                  PHB-ID = EF
                  Extended VDstPort = Agg-Deag-2

          *  STYLE = FF or SE





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          *  IPv4/GPI FILTER_SPEC:
                  IPv4 SrcAddress = Agg-Deag-2

          *  POLICY_DATA (PREEMPTION_PRI) = P1

   (4) A fourth generic aggregate reservation for aggregation of Voice
       reservations from Cloud-2 to Cloud-3 requiring use of P2:

          *  GENERIC-AGGREGATE-IP4 SESSION:
                  IPv4 DestAddress = Agg-Deag-3
                  vDstPort = V4
                  PHB-ID = EF
                  Extended VDstPort = Agg-Deag-2

          *  STYLE = FF or SE

          *  IPv4/GPI FILTER_SPEC:
                  IPv4 SrcAddress = Agg-Deag-2

          *  POLICY_DATA (PREEMPTION_PRI) = P2

       where V3 and V4 are arbitrary VDstPort values picked by Agg-
       Deag-3.

       Note that V3 and V4 could be equal to V1 and V2 (respectively)
       since, in this example, the Extended VDstPort of the GENERIC-
       AGGREGATE Session contains the address of the Aggregator and,
       thus, ensures that different sessions are used from each
       Aggregator.

6.  Security Considerations

   In the environments addressed by this document, RSVP messages are
   used to control resource reservations for generic aggregate
   reservations and may be used to control resource reservations for E2E
   reservations being aggregated over the generic aggregate
   reservations.  To ensure the integrity of the associated reservation
   and admission control mechanisms, the RSVP Authentication mechanisms
   defined in [RSVP-CRYPTO1] and [RSVP-CRYPTO2] may be used.  These
   protect RSVP message integrity hop-by-hop and provide node
   authentication as well as replay protection, thereby protecting
   against corruption and spoofing of RSVP messages.  These hop-by-hop
   integrity mechanisms can be naturally used to protect the RSVP
   messages used for generic aggregate reservations and to protect RSVP
   messages used for E2E reservations outside the aggregation region.
   These hop-by-hop RSVP integrity mechanisms can also be used to
   protect RSVP messages used for E2E reservations when those transit
   through the aggregation region.  This is because the Aggregator and



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   Deaggregator behave as RSVP neighbors from the viewpoint of the E2E
   flows (even if they are not necessarily IP neighbors).

   [RSVP-CRYPTO1] discusses several approaches for key distribution.
   First, the RSVP Authentication shared keys can be distributed
   manually.  This is the base option and its support is mandated for
   any implementation.  However, in some environments, this approach may
   become a burden if keys frequently change over time.  Alternatively,
   a standard key management protocol for secure key distribution can be
   used.  However, existing key distribution protocols may not be
   appropriate in all environments because of the complexity or
   operational burden they involve.

   The use of RSVP Authentication in parts of the network where there
   may be one or more IP hops in between two RSVP neighbors raises an
   additional challenge.  This is because, with some RSVP messages such
   as a Path message, an RSVP router does not know the RSVP next hop for
   that message at the time of forwarding it.  In fact, part of the role
   of a Path message is precisely to discover the RSVP next hop (and to
   dynamically re-discover it when it changes, say because of a routing
   change).  Hence, the RSVP router may not know which security
   association to use when forwarding such a message.  This applies in
   particular to the case where RSVP Authentication mechanisms are to be
   used for protection of RSVP E2E messages (e.g., E2E Path) while they
   transit through an aggregation region and where the dynamic
   Deaggregator determination procedure defined in [RSVP-AGG] is used.
   This is because the Aggregator and the Deaggregator behave as RSVP
   neighbors for the E2E reservation, while there may be one or more IP
   hops in between them, and the Aggregator does not know ahead of time
   which router is going to act as the Deaggregator.

   In that situation, one approach is to share the same RSVP
   Authentication shared key across all the RSVP routers of a part of
   the network where there may be RSVP neighbors with IP hops in
   between.  For example, all the Aggregators or Deaggregators of an
   aggregation region could share the same RSVP Authentication key,
   while different per-neighbor keys could be used between any RSVP
   router pair straddling the boundary between two administrative
   domains that have agreed to use RSVP signaling.

   When the same RSVP Authentication shared key is to be shared among
   multiple RSVP neighbors, manual key distribution may be used.  For
   situations where RSVP is being used for multicast flows, it might
   also be possible, in the future, to adapt a multicast key management
   method (e.g.  from IETF Multicast Security Working Group) for key
   distribution with such multicast RSVP usage.  For situations where
   RSVP is being used for unicast flows across domain boundaries, it is
   not currently clear how one might provide automated key management.



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   Specification of a specific automated key management technique is
   outside the scope of this document.  Operators should consider these
   key management issues when contemplating deployment of this
   specification.

   The RSVP Authentication mechanisms do not provide confidentiality.
   If confidentiality is required, IPsec ESP [IPSEC-ESP] may be used,
   although it imposes the burden of key distribution.  It also faces
   the additional issue discussed for key management above in the case
   where there can be IP hops in between RSVP hops.  In the future,
   confidentiality solutions may be developed for the case where there
   can be IP hops in between RSVP hops, perhaps by adapting
   confidentiality solutions developed by the IETF MSEC Working Group.
   Such confidentiality solutions for RSVP are outside the scope of this
   document.

   Protection against traffic analysis is also not provided by RSVP
   Authentication.  Since generic aggregate reservations are intended to
   reserve resources collectively for a whole set of users or hosts,
   malicious snooping of the corresponding RSVP messages could provide
   more traffic analysis information than snooping of an E2E
   reservation.  When RSVP neighbors are directly attached, mechanisms
   such as bulk link encryption might be used when protection against
   traffic analysis is required.  This approach could be used inside the
   aggregation region for protection of the generic aggregate
   reservations.  It may also be used outside the aggregation region for
   protection of the E2E reservation.  However, it is not applicable to
   the protection of E2E reservations while the corresponding E2E RSVP
   messages transit through the aggregation region.

   When generic aggregate reservations are used for aggregation of E2E
   reservations, the security considerations discussed in [RSVP-AGG]
   apply and are revisited here.

   First, the loss of an aggregate reservation to an aggressor causes
   E2E flows to operate unreserved, and the reservation of a great
   excess of bandwidth may result in a denial of service.  These issues
   are not confined to the extensions defined in the present document:
   RSVP itself has them.  However, they may be exacerbated here by the
   fact that each aggregate reservation typically facilitates
   communication for many sessions.  Hence, compromising one such
   aggregate reservation can result in more damage than compromising a
   typical E2E reservation.  Use of the RSVP Authentication mechanisms
   to protect against such attacks has been discussed above.

   An additional security consideration specific to RSVP aggregation
   involves the modification of the IP protocol number in RSVP Path
   messages that traverse an aggregation region.  Malicious modification



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   of the IP protocol number in a Path message would cause the message
   to be ignored by all subsequent RSVP devices on its path, preventing
   reservations from being made.  It could even be possible to correct
   the value before it reached the receiver, making it difficult to
   detect the attack.  Note that, in theory, it might also be possible
   for a node to modify the IP protocol number for non-RSVP messages as
   well, thus interfering with the operation of other protocols.  It is
   RECOMMENDED that implementations of this specification only support
   modification of the IP protocol number for RSVP Path, PathTear, and
   ResvConf messages.  That is, a general facility for modification of
   the IP protocol number SHOULD NOT be made available.

   Network operators deploying routers with RSVP aggregation capability
   should be aware of the risks of inappropriate modification of the IP
   protocol number and should take appropriate steps (physical security,
   password protection, etc.) to reduce the risk that a router could be
   configured by an attacker to perform malicious modification of the
   protocol number.

7.  IANA Considerations

   IANA modified the RSVP parameters registry, 'Class Names, Class
   Numbers, and Class Types' subregistry, and assigned two new C-Types
   under the existing SESSION Class (Class number 1), as described
   below:

   Class
   Number  Class Name                            Reference
   ------  -----------------------               ---------

        1  SESSION                               [RFC2205]

           Class Types or C-Types:

            17   GENERIC-AGGREGATE-IP4           [RFC4860]
            18   GENERIC-AGGREGATE-IP6           [RFC4860]















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   IANA also modified the RSVP parameters registry, 'Class Names, Class
   Numbers, and Class Types' subregistry, and assigned one new Class
   Number for the SESSION-OF-INTEREST class and two new C-Types for that
   class, according to the table below:

   Class
   Number  Class Name                            Reference
   ------  -----------------------               ---------

      132  SESSION-OF-INTEREST                   [RFC4860]

           Class Types or C-Types:

              1  GENERIC-AGG-IP4-SOI             [RFC4860]
              2  GENERIC-AGG-IP6-SOI             [RFC4860]

   These allocations are in accordance with [RSVP-MOD].

8.  Acknowledgments

   This document borrows heavily from [RSVP-AGG].  It also borrows the
   concepts of Virtual Destination Port and Extended Virtual Destination
   Port from [RSVP-IPSEC] and [RSVP-TE], respectively.

   Also, we thank Fred Baker, Roger Levesque, Carol Iturralde, Daniel
   Voce, Anil Agarwal, Alexander Sayenko, and Anca Zamfir for their
   input into the content of this document.  Thanks to Steve Kent for
   insightful comments on usage of RSVP reservations in IPsec
   environments.

   Ran Atkinson, Fred Baker, Luc Billot, Pascal Delprat, and Eric Vyncke
   provided guidance and suggestions for the security considerations
   section.


















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9.  Normative References

   [IPSEC-ESP]    Kent, S., "IP Encapsulating Security Payload (ESP)",
                  RFC 4303, December 2005.

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

   [PHB-ID]       Black, D., Brim, S., Carpenter, B., and F. Le
                  Faucheur, "Per Hop Behavior Identification Codes", RFC
                  3140, June 2001.

   [RSVP]         Braden, R., Ed., Zhang, L., Berson, S., Herzog, S.,
                  and S. Jamin, "Resource ReSerVation Protocol (RSVP) --
                  Version 1 Functional Specification", RFC 2205,
                  September 1997.

   [RSVP-AGG]     Baker, F., Iturralde, C., Le Faucheur, F., and B.
                  Davie, "Aggregation of RSVP for IPv4 and IPv6
                  Reservations", RFC 3175, September 2001.

   [RSVP-CRYPTO1] Baker, F., Lindell, B., and M. Talwar, "RSVP
                  Cryptographic Authentication", RFC 2747, January 2000.

   [RSVP-CRYPTO2] Braden, R. and L. Zhang, "RSVP Cryptographic
                  Authentication -- Updated Message Type Value", RFC
                  3097, April 2001.

   [RSVP-IPSEC]   Berger, L. and T. O'Malley, "RSVP Extensions for IPSEC
                  Data Flows", RFC 2207, September 1997.

   [RSVP-MOD]     Kompella, K. and J. Lang, "Procedures for Modifying
                  the Resource reSerVation Protocol (RSVP)", BCP 96, RFC
                  3936, October 2004.

10.  Informative References

   [BW-REDUC]     Polk, J. and S. Dhesikan, "A Resource Reservation
                  Protocol (RSVP) Extension for the Reduction of
                  Bandwidth of a Reservation Flow", RFC 4495, May 2006.

   [GRE]          Farinacci, D., Li, T., Hanks, S., Meyer, D., and P.
                  Traina, "Generic Routing Encapsulation (GRE)", RFC
                  2784, March 2000.

   [RSVP-PREEMP]  Herzog, S., "Signaled Preemption Priority Policy
                  Element", RFC 3181, October 2001.




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   [RSVP-PROCESS] Braden, R. and L. Zhang, "Resource ReSerVation
                  Protocol (RSVP) -- Version 1 Message Processing
                  Rules", RFC 2209, September 1997.

   [RSVP-TE]      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.

   [RSVP-TUNNEL]  Terzis, A., Krawczyk, J., Wroclawski, J., and L.
                  Zhang, "RSVP Operation Over IP Tunnels", RFC 2746,
                  January 2000.

   [SIG-NESTED]   Baker, F. and P. Bose, "QoS Signaling in a Nested
                  Virtual Private Network", Work in Progress, February
                  2007.




































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Appendix A.  Example Signaling Flow

   This appendix does not provide additional specification.  It only
   illustrates the specification detailed in Section 4 through a
   possible flow of RSVP signaling messages.  This flow assumes an
   environment where E2E reservations are aggregated over generic
   aggregate RSVP reservations.  It illustrates a possible RSVP message
   flow that could take place in the successful establishment of a
   unicast E2E reservation that is the first between a given pair of
   Aggregator/Deaggregator.









































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           Aggregator                              Deaggregator

    E2E Path
   ----------->
                (1)
                           E2E Path
                   ------------------------------->
                                                       (2)
                    E2E PathErr(New-agg-needed,SOI=GAx)
                   <----------------------------------
                    E2E PathErr(New-agg-needed,SOI=GAy)
                   <----------------------------------
                (3)
                         AggPath(Session=GAx)
                   ------------------------------->
                         AggPath(Session=GAy)
                   ------------------------------->
                                                       (4)
                                                           E2E Path
                                                          ----------->
                                                       (5)
                         AggResv (Session=GAx)
                   <-------------------------------
                         AggResv (Session=GAy)
                   <-------------------------------
                (6)
                     AggResvConfirm (Session=GAx)
                   ------------------------------>
                     AggResvConfirm (Session=GAy)
                   ------------------------------>
                                                       (7)
                                                           E2E Resv
                                                          <---------
                                                       (8)
                           E2E Resv (SOI=GAx)
                   <-----------------------------
                (9)
      E2E Resv
   <-----------

   (1) The Aggregator forwards E2E Path into the aggregation region
       after modifying its IP protocol number to RSVP-E2E-IGNORE

   (2) Let's assume no Aggregate Path exists.  To be able to accurately
       update the ADSPEC of the E2E Path, the Deaggregator needs the
       ADSPEC of Aggregate Path.  In this example, the Deaggregator
       elects to instruct the Aggregator to set up Aggregate Path states
       for the two supported PHB-IDs.  To do that, the Deaggregator



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       sends two E2E PathErr messages with a New-Agg-Needed PathErr
       code.  Both PathErr messages also contain a SESSION-OF-INTEREST
       (SOI) object.  In the first E2E PathErr, the SOI contains a
       GENERIC-AGGREGATE SESSION (GAx) whose PHB-ID is set to x.  In the
       second E2E PathErr, the SOI contains a GENERIC-AGGREGATE SESSION
       (GAy) whose PHB-ID is set to y.  In both messages the GENERIC-
       AGGREGATE SESSION contains an interface-independent Deaggregator
       address inside the DestAddress and appropriate values inside the
       vDstPort and Extended vDstPort fields.

   (3) The Aggregator follows the request from the Deaggregator and
       signals an Aggregate Path for both GENERIC-AGGREGATE Sessions
       (GAx and GAy).

   (4) The Deaggregator takes into account the information contained in
       the ADSPEC from both Aggregate Paths and updates the E2E Path
       ADSPEC accordingly.  The Deaggregator also modifies the E2E Path
       IP protocol number to RSVP before forwarding it.

   (5) In this example, the Deaggregator elects to immediately proceed
       with establishment of generic aggregate reservations for both
       PHB-IDs.  In effect, the Deaggregator can be seen as anticipating
       the actual demand of E2E reservations so that resources are
       available on the generic aggregate reservations when the E2E Resv
       requests arrive, in order to speed up establishment of E2E
       reservations.  Assume also that the Deaggregator includes the
       optional Resv Confirm Request in these Aggregate Resv.

   (6) The Aggregator merely complies with the received ResvConfirm
       Request and returns the corresponding Aggregate ResvConfirm.

   (7) The Deaggregator has explicit confirmation that both Aggregate
       Resvs are established.

   (8) On receipt of the E2E Resv, the Deaggregator applies the mapping
       policy defined by the network administrator to map the E2E Resv
       onto a generic aggregate reservation.  Let's assume that this
       policy is such that the E2E reservation is to be mapped onto the
       generic aggregate reservation with PHB-ID=x.  The Deaggregator
       knows that a generic aggregate reservation (GAx) is in place for
       the corresponding PHB-ID since (7).  The Deaggregator performs
       admission control of the E2E Resv onto the generic aggregate
       reservation for PHB-ID=x (GAx).  Assuming that the generic
       aggregate reservation for PHB-ID=x (GAx) had been established
       with sufficient bandwidth to support the E2E Resv, the
       Deaggregator adjusts its counter, tracking the unused bandwidth
       on the generic aggregate reservation.  Then it forwards the E2E
       Resv to the Aggregator including a SESSION-OF-INTEREST object



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       conveying the selected mapping onto GAx (and hence onto
       PHB-ID=x).

   (9) The Aggregator records the mapping of the E2E Resv onto GAx (and
       onto PHB-ID=x).  The Aggregator removes the SOI object and
       forwards the E2E Resv towards the sender.

Authors' Addresses

   Francois Le Faucheur
   Cisco Systems, Inc.
   Village d'Entreprise Green Side - Batiment T3
   400, Avenue de Roumanille
   06410 Biot Sophia-Antipolis
   France
   EMail: flefauch@cisco.com

   Bruce Davie
   Cisco Systems, Inc.
   1414 Massachusetts Ave.
   Boxborough, MA 01719
   USA
   EMail: bds@cisco.com

   Pratik Bose
   Lockheed Martin
   700 North Frederick Ave.
   Gaithersburg, MD 20879
   USA
   EMail: pratik.bose@lmco.com

   Chris Christou
   Booz Allen Hamilton
   13200 Woodland Park Road
   Herndon, VA 20171
   USA
   EMail: christou_chris@bah.com

   Michael Davenport
   Booz Allen Hamilton
   Suite 390
   5220 Pacific Concourse Drive
   Los Angeles, CA 90045
   USA
   EMail: davenport_michael@bah.com






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