





Internet Engineering Task Force (IETF)                    G. Karagiannis
Request for Comments: 7417                           Huawei Technologies
Category: Experimental                                       A. Bhargava
ISSN: 2070-1721                                      Cisco Systems, Inc.
                                                           December 2014


  Extensions to Generic Aggregate RSVP for IPv4 and IPv6 Reservations
             over Pre-Congestion Notification (PCN) Domains

Abstract

   This document specifies extensions to Generic Aggregate RSVP (RFC
   4860) for support of the Pre-Congestion Notification (PCN) Controlled
   Load (CL) and Single Marking (SM) edge behaviors over a Diffserv
   cloud using PCN.

Status of This Memo

   This document is not an Internet Standards Track specification; it is
   published for examination, experimental implementation, and
   evaluation.

   This document defines an Experimental Protocol for the Internet
   community.  This document is a product of the Internet Engineering
   Task Force (IETF).  It represents the consensus of the IETF
   community.  It has received public review and has been approved for
   publication by the Internet Engineering Steering Group (IESG).  Not
   all documents approved by the IESG are a candidate for any level of
   Internet Standard; see Section 2 of RFC 5741.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   http://www.rfc-editor.org/info/rfc7417.

















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Copyright Notice

   Copyright (c) 2014 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
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.





































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Table of Contents

   1. Introduction ....................................................4
      1.1. Objective ..................................................4
      1.2. Overview and Motivation ....................................5
      1.3. Requirements Language and Terminology ......................8
      1.4. Organization of This Document .............................12
   2. Overview of RSVP Extensions and Operations .....................12
      2.1. Overview of RSVP Aggregation Procedures in PCN-Domains ....12
      2.2. PCN-Marking, Encoding, and Transport of
           Pre-congestion Information ................................14
      2.3. Traffic Classification within the Aggregation Region ......14
      2.4. Deaggregator (PCN-Egress-Node) Determination ..............15
      2.5. Mapping E2E Reservations onto Aggregate Reservations ......15
      2.6. Size of Aggregate Reservations ............................16
      2.7. E2E Path ADSPEC Update ....................................16
      2.8. Intra-domain Routes .......................................16
      2.9. Inter-domain Routes .......................................16
      2.10. Reservations for Multicast Sessions ......................16
      2.11. Multi-level Aggregation ..................................16
      2.12. Reliability Issues .......................................17
   3. Elements of Procedures .........................................17
      3.1. Receipt of E2E Path Message by PCN-Ingress-Node
           (Aggregating Router) ......................................17
      3.2. Handling of E2E Path Message by Interior Routers ..........17
      3.3. Receipt of E2E Path Message by PCN-Egress-Node
           (Deaggregating Router) ....................................18
      3.4. Initiation of New Aggregate Path Message by
           PCN-Ingress-Node (Aggregating Router) .....................18
      3.5. Handling of Aggregate Path Message by Interior Routers ....18
      3.6. Handling of Aggregate Path Message by
           Deaggregating Router ......................................18
      3.7. Handling of E2E Resv Message by Deaggregating Router ......19
      3.8. Handling of E2E Resv Message by Interior Routers ..........19
      3.9. Initiation of New Aggregate Resv Message by
           Deaggregating Router ......................................20
      3.10. Handling of Aggregate Resv Message by Interior Routers ...20
      3.11. Handling of E2E Resv Message by Aggregating Router .......21
      3.12. Handling of Aggregate Resv Message by
            Aggregating Router .......................................21
      3.13. Removal of E2E Reservation ...............................21
      3.14. Removal of Aggregate Reservation .........................22
      3.15. Handling of Data on Reserved E2E Flow by
            Aggregating Router .......................................22
      3.16. Procedures for Multicast Sessions ........................22
      3.17. Misconfiguration of PCN-Node .............................22
      3.18. PCN-Based Flow Termination ...............................22




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   4. Protocol Elements ..............................................23
      4.1. PCN Objects ...............................................24
   5. Security Considerations ........................................28
   6. IANA Considerations ............................................29
   7. References .....................................................29
      7.1. Normative References ......................................29
      7.2. Informative References ....................................30
   Appendix A. Example Signaling Flow ................................33
   Acknowledgments ...................................................35
   Authors' Addresses ................................................36

1.  Introduction

1.1.  Objective

   Pre-Congestion Notification (PCN) can support the Quality of Service
   (QoS) of inelastic flows within a Diffserv domain in a simple,
   scalable, and robust fashion.  Two mechanisms are used: admission
   control and flow termination.  Admission control is used to decide
   whether to admit or block a new flow request, while flow termination
   is used in abnormal circumstances to decide whether to terminate some
   of the existing flows.  To support these two features, the overall
   rate of PCN-traffic is metered on every link in the domain, and
   PCN-packets are appropriately marked when certain configured rates
   are exceeded.  These configured rates are below the rate of the link,
   thus providing notification to boundary nodes about overloads before
   any congestion occurs (hence "pre-congestion" notification).  The
   PCN-egress-nodes measure the rates of differently marked PCN-traffic
   in periodic intervals and report these rates to the Decision Points
   for admission control and flow termination; the Decision Points use
   these rates to make decisions.  The Decision Points may be collocated
   with the PCN-ingress-nodes, or their function may be implemented in
   another node.  For more details, see [RFC5559], [RFC6661], and
   [RFC6662].

   The main objective of this document is to specify the signaling
   protocol that can be used within a PCN-domain to carry reports from a
   PCN-ingress-node to a PCN Decision Point, considering that the PCN
   Decision Point and PCN-egress-node are collocated.

   If the PCN Decision Point is not collocated with the PCN-egress-node,
   then additional signaling procedures are required that are out of
   scope for this document.  Moreover, as mentioned above, this
   architecture conforms with Policy-Based Admission Control (PBAC),
   where the Decision Point is located in a node other than the
   PCN-ingress-node [RFC2753].





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   Several signaling protocols can be used to carry information between
   PCN-boundary-nodes (PCN-ingress-node and PCN-egress-node).  However,
   since (1) both the PCN-egress-node and PCN-ingress-node are located
   on the data path and (2) the admission control procedure needs to be
   done at the PCN-egress-node, a signaling protocol that follows the
   same path as the data path, like RSVP, is more suited for this
   purpose.  In particular, this document specifies extensions to
   Generic Aggregate RSVP [RFC4860] for support of the PCN Controlled
   Load (CL) and Single Marking (SM) edge behaviors over a Diffserv
   cloud using Pre-Congestion Notification.

   This document is published as an Experimental document in order to:

   o  validate industry interest by allowing implementation and
      deployment

   o  gather operational experience, particularly related to dynamic
      interactions of RSVP signaling and PCN, and corresponding levels
      of performance

   Support for the techniques specified in this document involves RSVP
   functionality in boundary nodes of a PCN-domain whose interior nodes
   forward RSVP traffic without performing RSVP functionality.

1.2.  Overview and Motivation

   Two main QoS architectures have been specified by the IETF: the
   Integrated Services (Intserv) [RFC1633] architecture and the
   Differentiated Services (Diffserv) architecture ([RFC2475]).

   Intserv provides methods for the delivery of end-to-end QoS to
   applications over heterogeneous networks.  One of the QoS signaling
   protocols used by the Intserv architecture is RSVP [RFC2205], which
   can be used by applications to request per-flow resources from the
   network.  These RSVP requests can be admitted or rejected by the
   network.  Applications can express their quantifiable resource
   requirements using Intserv parameters as defined in [RFC2211] and
   [RFC2212].  The Controlled Load (CL) service [RFC2211] is a form of
   QoS that closely approximates the QoS that the same flow would
   receive from a lightly loaded network element.  The CL service is
   useful for inelastic flows such as those used for real-time media.

   The Diffserv architecture can support the differentiated treatment of
   packets in very large-scale environments.  While Intserv and RSVP
   classify packets per flow, Diffserv networks classify packets into
   one of a small number of aggregated flows or "classes", based on the
   Diffserv Codepoint (DSCP) in the packet IP header.  At each Diffserv
   router, packets are subjected to a "Per Hop Behavior" (PHB), which is



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   invoked by the DSCP.  The primary benefit of Diffserv is its
   scalability, since the need for per-flow state and per-flow
   processing is eliminated.

   However, Diffserv does not include any mechanism for communication
   between applications and the network.  Several solutions have been
   specified to solve this issue.  One of these solutions is Intserv
   over Diffserv [RFC2998], including Resource-Based Admission Control
   (RBAC), PBAC, assistance in traffic identification/classification,
   and traffic conditioning.  Intserv over Diffserv can operate over a
   statically provisioned or an RSVP-aware Diffserv region.  When it is
   RSVP aware, several mechanisms may be used to support dynamic
   provisioning and topology-aware admission control, including
   aggregate RSVP reservations, per-flow RSVP, or a bandwidth broker.
   [RFC3175] specifies aggregation of RSVP end-to-end reservations over
   aggregate RSVP reservations.  In [RFC3175], the RSVP generic
   aggregate reservation is characterized by an RSVP SESSION object
   using the 3-tuple <source IP address, destination IP address,
   Diffserv Codepoint>.

   Several scenarios require the use of multiple generic aggregate
   reservations that are established for a given PHB from a given source
   IP address to a given destination IP address; see [RFC4923] and
   [RFC4860].  For example, multiple generic aggregate reservations can
   be applied in situations where multiple end-to-end (E2E) reservations
   using different preemption priorities need to be aggregated through a
   PCN-domain using the same PHB.  Using multiple aggregate reservations
   for the same PHB allows

   o  enforcement of the different preemption priorities within the
      aggregation region

   o  more efficient management of Diffserv resources

   o  sustainment of a larger number of E2E reservations with higher
      preemption priorities during periods of resource shortage

   In particular, [RFC4923] discusses in detail how end-to-end RSVP
   reservations can be established in a nested VPN environment through
   RSVP aggregation.

   [RFC4860] provides generic aggregate reservations by extending
   [RFC3175] to support multiple aggregate reservations for the same
   source IP address, destination IP address, and PHB (or set of PHBs).
   In particular, multiple such generic aggregate reservations can be
   established for a given PHB from a given source IP address to a given
   destination IP address.  This is achieved by adding the concept of a
   Virtual Destination Port and an Extended Virtual Destination Port in



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   the RSVP SESSION object.  In addition to this, the RSVP SESSION
   object for generic aggregate reservations uses the PHB Identification
   Code (PHB-ID) defined in [RFC3140] instead of using the Diffserv
   Codepoint (DSCP) used in [RFC3175].  The PHB-ID is used to identify
   the PHB, or set of PHBs, from which the Diffserv resources are to be
   reserved.

   The RSVP-like signaling protocol required to carry (1) requests from
   a PCN-egress-node to a PCN-ingress-node and (2) reports from a
   PCN-ingress-node to a PCN-egress-node needs to follow the PCN
   signaling requirements defined in [RFC6663].  In addition to that,
   the signaling protocol functionality supported by the PCN-ingress-
   nodes and PCN-egress-nodes needs to maintain logical aggregate
   constructs (i.e., ingress-egress-aggregate state) and be able to map
   E2E reservations to these aggregate constructs.  Moreover, no actual
   reservation state is needed to be maintained inside the PCN-domain,
   i.e., the PCN-interior-nodes are not maintaining any reservation
   state.

   This can be accomplished by two possible approaches:

   Approach (1):

   o  adapting the aggregation procedures of RFC 4860 to fit the PCN
      requirements with as little change as possible over the
      functionality provided in RFC 4860.

   o  hence, performing aggregate RSVP signaling (even if it is to be
      ignored by PCN-interior-nodes).

   o  using the aggregate RSVP signaling procedures to carry PCN
      information between the PCN-boundary-nodes (PCN-ingress-node and
      PCN-egress-node).

   Approach (2):

   o  adapting the aggregation procedures of RFC 4860 to fit the PCN
      requirements with significant changes over RFC 4860 (i.e., the
      aspect of the procedures that have to do with maintaining
      aggregate states and mapping the E2E reservations to aggregate
      constructs are kept, but the procedures that are specific to
      aggregate RSVP signaling and aggregate reservation
      establishment/maintenance are dropped).

   o  hence not performing aggregate RSVP signaling.

   o  piggybacking the PCN information inside the E2E RSVP signaling.




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   Both approaches are probably viable; however, since the operations of
   RFC 4860 have been thoroughly studied and implemented, it can be
   considered that the solution from RFC 4860 can better deal with the
   more challenging situations (rerouting in the PCN-domain, failure of
   a PCN-ingress-node, failure of a PCN-egress-node, rerouting towards a
   different edge, etc.).  This is the reason for choosing Approach (1)
   for the specification of the signaling protocol used to carry PCN
   information between the PCN-boundary-nodes (PCN-ingress-node and
   PCN-egress-node).

   As noted earlier, this document specifies extensions to Generic
   Aggregate RSVP [RFC4860] for support of the PCN Controlled Load (CL)
   and Single Marking (SM) edge behaviors over a Diffserv cloud using
   Pre-Congestion Notification.

   This document follows the PCN signaling requirements defined in
   [RFC6663] and specifies extensions to Generic Aggregate RSVP
   [RFC4860] for support of PCN edge behaviors as specified in [RFC6661]
   and [RFC6662].  Moreover, this document specifies how RSVP
   aggregation can be used to set up and maintain (1) Ingress-Egress-
   Aggregate (IEA) states at Ingress and Egress nodes and (2) generic
   aggregation of end-to-end RSVP reservations over PCN (Congestion and
   Pre-Congestion Notification) domains.

   To comply with this specification, PCN-nodes MUST be able to support
   the functionality specified in [RFC5670], [RFC5559], [RFC6660],
   [RFC6661], and [RFC6662].  Furthermore, the PCN-boundary-nodes MUST
   support the RSVP generic aggregate reservation procedures specified
   in [RFC4860], which are augmented with procedures specified in this
   document.

1.3.  Requirements Language and Terminology

   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 [RFC2119].

   This document uses terms defined in [RFC4860], [RFC3175], [RFC5559],
   [RFC5670], [RFC6661], and [RFC6662].

   For readability, a number of definitions from [RFC3175] as well as
   definitions for terms used in [RFC5559], [RFC6661], and [RFC6662] are
   provided here, where some of them are augmented with new meanings:

   Aggregator
      The process in (or associated with) the router at the ingress edge
      of the aggregation region (with respect to the end-to-end RSVP
      reservation) and behaving in accordance with [RFC4860].  In this



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      document, it is also the PCN-ingress-node.  It is important to
      notice that in the context of this document the Aggregator must be
      able to determine the Deaggregator using the procedures specified
      in Section 4 of [RFC4860] and Section 1.4.2 of [RFC3175].

   Congestion Level Estimate (CLE)
      The ratio of PCN-marked to total PCN-traffic (measured in octets)
      received for a given ingress-egress-aggregate during a given
      measurement period.  The CLE is used to derive the PCN-admission-
      state and is also used by the report suppression procedure if
      report suppression is activated.

   Deaggregator
      The process in (or associated with) the router at the egress edge
      of the aggregation region (with respect to the end-to-end RSVP
      reservation) and behaving in accordance with [RFC4860].  In this
      document, it is also the PCN-egress-node and Decision Point.

   E2E
      End to end

   E2E Microflow
      A microflow where its associated packets are being forwarded on an
      E2E path.

   E2E Reservation
      An RSVP reservation such that:

      (1) corresponding RSVP Path messages are initiated upstream of the
          Aggregator and terminated downstream of the Deaggregator, and

      (2) corresponding RSVP Resv messages are initiated downstream of
          the Deaggregator and terminated upstream of the Aggregator,
          and

      (3) this RSVP reservation is aggregated over an Ingress-Egress-
          Aggregate (IEA) between the Aggregator and Deaggregator.

      An E2E RSVP reservation may be a per-flow reservation, which in
      this document is only maintained at the PCN-ingress-node and
      PCN-egress-node.  Alternatively, the E2E reservation may itself be
      an aggregate reservation of various types (e.g., Aggregate IP
      reservation, Aggregate IPsec reservation [RFC4860]).  As per
      regular RSVP operations, E2E RSVP reservations are unidirectional.







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   ETM-Rate
      The rate of excess-traffic-marked (ETM) PCN-traffic received at a
      PCN-egress-node for a given ingress-egress-aggregate in octets
      per second.

   Extended vDstPort (Extended Virtual Destination Port)
      An identifier used in the SESSION that remains constant over the
      life of the generic aggregate reservation.  The length of this
      identifier is 32 bits when IPv4 addresses are used and 128 bits
      when IPv6 addresses are used.

      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 or 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.  In this document, the Extended vDstPort
      should contain the IPv4 or IPv6 address of the Aggregator.

   Ingress-Egress-Aggregate (IEA)
      The collection of PCN-packets from all PCN-flows that travel in
      one direction between a specific pair of PCN-boundary-nodes.  In
      this document, one RSVP generic aggregate reservation is mapped to
      only one ingress-egress-aggregate, while one ingress-egress-
      aggregate is mapped to one or more RSVP generic aggregate
      reservations.  PCN-flows and their PCN-traffic that are mapped
      into a specific RSVP generic aggregate reservation can also be
      easily mapped into their corresponding ingress-egress-aggregate.

   Microflow (from [RFC2474])
      A single instance of an application-to-application flow of
      packets, which is identified by <source address, destination
      address, protocol id> and (where applicable) <source port,
      destination port>.

   PCN-Admission-State
      The state ("admit" or "block") derived by the Decision Point for a
      given ingress-egress-aggregate based on statistics about
      PCN-packet marking.  The Decision Point decides to admit or block
      new flows offered to the aggregate based on the current value of
      the PCN-admission-state.

   PCN-Boundary-Node
      A PCN-node that connects one PCN-domain to a node in either
      another PCN-domain or a non-PCN-domain.





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   PCN-Domain
      A PCN-capable domain; a contiguous set of PCN-enabled nodes that
      perform Diffserv scheduling [RFC2474]; the complete set of
      PCN-nodes that in principle can, through PCN-marking packets,
      influence decisions about flow admission and termination within
      the domain; includes the PCN-egress-nodes, which measure these
      PCN-marks, and the PCN-ingress-nodes.

   PCN-Egress-Node
      A PCN-boundary-node in its role in handling traffic as it leaves a
      PCN-domain.  In this document, the PCN-egress-node also operates
      as a Decision Point and Deaggregator.

   PCN-Flow
      The unit of PCN-traffic that the PCN-boundary-node admits (or
      terminates); the unit could be a single E2E microflow (as defined
      in [RFC2474]) or some identifiable collection of microflows.

   PCN-Ingress-Node
      A PCN-boundary-node in its role in handling traffic as it enters a
      PCN-domain.  In this document, the PCN-ingress-node also operates
      as an Aggregator.

   PCN-Interior-Node
      A node in a PCN-domain that is not a PCN-boundary-node.

   PCN-Node
      A PCN-boundary-node or a PCN-interior-node.

   PCN-Sent-Rate
      The rate of PCN-traffic received at a PCN-ingress-node and
      destined for a given ingress-egress-aggregate in octets per
      second.

   PCN-Traffic, PCN-Packets, PCN-BA
      A PCN-domain carries traffic of different Diffserv Behavior
      Aggregates (BAs) [RFC2474].  The PCN-BA uses the PCN mechanisms to
      carry PCN-traffic, and the corresponding packets are PCN-packets.
      The same network will carry traffic of other Diffserv BAs.  The
      PCN-BA is distinguished by a combination of the Diffserv Codepoint
      (DSCP) and Explicit Congestion Notification (ECN) fields.

   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 [RFC3140].




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   RSVP Generic Aggregate Reservation
      An RSVP reservation that is identified by using the RSVP SESSION
      object for generic RSVP aggregate reservation.  This RSVP SESSION
      object is based on the RSVP SESSION object specified in [RFC4860],
      augmented with the following information:

      o  The IPv4 DestAddress, IPv6 DestAddress should be set to the
         IPv4 or IPv6 destination addresses, respectively, of the
         Deaggregator (PCN-egress-node).

      o  The PHB-ID should be set equal to PCN-compatible Diffserv
         Codepoint(s).

      o  The Extended vDstPort should be set to the IPv4 or IPv6
         destination addresses, of the Aggregator (PCN-ingress-node).

   VDstPort (Virtual Destination Port)
      A 16-bit identifier used in the SESSION that remains constant over
      the life of the generic aggregate reservation.

1.4.  Organization of This Document

   This document is organized as follows.  Section 2 gives an overview
   of RSVP extensions and operations.  The elements of the procedures
   that are used in this document are specified in Section 3.  Section 4
   describes the protocol elements.  The security considerations are
   given in Section 5, and the IANA considerations are provided in
   Section 6.

2.  Overview of RSVP Extensions and Operations

2.1.  Overview of RSVP Aggregation Procedures in PCN-Domains

   The PCN-boundary-nodes (see Figure 1) can support RSVP SESSIONS for
   generic aggregate reservations [RFC4860], which depend on ingress-
   egress-aggregates.  In particular, one RSVP generic aggregate
   reservation matches to only one ingress-egress-aggregate.

   However, one ingress-egress-aggregate matches to one or more RSVP
   generic aggregate reservations.  In addition, to comply with this
   specification, the PCN-boundary-nodes need to distinguish and process
   (1) RSVP SESSIONS for generic aggregate sessions and their messages
   according to [RFC4860] and (2) E2E RSVP SESSIONS and messages
   according to [RFC2205].

   This document locates all RSVP processing for a PCN-domain at
   PCN-boundary-nodes.  PCN-interior-nodes do not perform any RSVP
   functionality or maintain RSVP-related state information.  Rather,



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   PCN-interior-nodes forward all RSVP messages (for both generic
   aggregate reservations [RFC4860] and E2E reservations [RFC2205]) as
   if they were ordinary network traffic.

   Moreover, each Aggregator and Deaggregator (i.e., PCN-boundary-nodes)
   needs to support policies to initiate and maintain, for each pair of
   PCN-boundary-nodes of the same PCN-domain, one ingress-egress-
   aggregate.

                       --------------------------
                      /       PCN-domain         \
         |----|      |                            |      |----|
      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 (PCN-ingress-node)
      Deag  = Deaggregator (PCN-egress-node)
      I     = Interior Router (PCN-interior-node)
      -->   = E2E RSVP reservation
      ==>   = Aggregate RSVP reservation

     Figure 1: Aggregation of E2E Reservations over Generic Aggregate
           RSVP Reservations in PCN-Domains, Based on [RFC4860]

   Both the Aggregator and Deaggregator can maintain one or more RSVP
   generic aggregate reservations, but the Deaggregator is the entity
   that initiates these RSVP generic aggregate reservations.  Note that
   one RSVP generic aggregate reservation matches to only one ingress-
   egress-aggregate, while one ingress-egress-aggregate matches to one
   or more RSVP generic aggregate reservations.  This can be
   accomplished by using for the different RSVP generic aggregate
   reservations the same combinations of ingress and egress identifiers,
   but with a different PHB-ID value (see [RFC4860]).  The procedures
   for aggregation of E2E reservations over generic aggregate RSVP
   reservations are the same as the procedures specified in Section 4 of
   [RFC4860], augmented with the ones specified in Section 2.5.





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   One significant difference between this document and [RFC4860] is the
   fact that in this document the admission control of E2E RSVP
   reservations over the PCN-core is performed according to the PCN
   procedures, while in [RFC4860] this is achieved via first admitting
   aggregate RSVP reservations over the aggregation region and then
   admitting the E2E reservations over the aggregate RSVP reservations.
   Therefore, in this document, the RSVP generic aggregate RSVP
   reservations are not subject to admission control in the PCN-core,
   and the E2E RSVP reservations are not subject to admission control
   over the aggregate reservations.  In turn, this means that several
   procedures described in [RFC4860] are significantly simplified in
   this document:

   o  Unlike [RFC4860], the generic aggregate RSVP reservations need not
      be admitted in the PCN-core.

   o  Unlike [RFC4860], the RSVP aggregated traffic does not need to be
      tunneled between Aggregator and Deaggregator; see Section 2.3.

   o  Unlike [RFC4860], the Deaggregator need not perform admission
      control of E2E reservations over the aggregate RSVP reservations.

   o  Unlike [RFC4860], there is no need for dynamic adjustment of the
      RSVP generic aggregate reservation size; see Section 2.6.

2.2.  PCN-Marking, Encoding, and Transport of Pre-congestion Information

   The method of PCN-marking within the PCN-domain is specified in
   [RFC5670].  In addition, the method of encoding and transport of
   pre-congestion information is specified in [RFC6660].  The PHB-ID
   (Per Hop Behavior Identification Code) used SHOULD be set equal to
   PCN-compatible Diffserv Codepoint(s).

2.3.  Traffic Classification within the Aggregation Region

   The PCN-ingress marks a PCN-BA using PCN-marking (i.e., a combination
   of the DSCP and ECN fields), which interior nodes use to classify
   PCN-traffic.  The PCN-traffic (e.g., E2E microflows) belonging to an
   RSVP generic aggregate reservation can be classified only at the
   PCN-boundary-nodes (i.e., Aggregator and Deaggregator) by using the
   RSVP SESSION object for RSVP generic aggregate reservations; see
   Section 2.1 of [RFC4860].  Note that the DSCP value included in the
   SESSION object SHOULD be set equal to a PCN-compatible Diffserv
   Codepoint.  Since no admission control procedures over the RSVP
   generic aggregate reservations in the PCN-core are required, unlike
   [RFC4860], the RSVP aggregated traffic need not be tunneled between
   Aggregator and Deaggregator.  In this document, one RSVP generic
   aggregate reservation is mapped to only one ingress-egress-aggregate,



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   while one ingress-egress-aggregate is mapped to one or more RSVP
   generic aggregate reservations.  PCN-flows and their PCN-traffic that
   are mapped into a specific RSVP generic aggregate reservation can
   also easily be classified into their corresponding ingress-egress-
   aggregate.  The method of traffic conditioning of PCN-traffic and
   non-PCN-traffic, as well as the method of PHB configuration, are
   described in [RFC6661] and [RFC6662].

2.4.  Deaggregator (PCN-Egress-Node) Determination

   This document assumes the same dynamic Deaggregator determination
   method as that used in [RFC4860].

2.5.  Mapping E2E Reservations onto Aggregate Reservations

   To comply with this specification, for the mapping of E2E
   reservations onto aggregate reservations, the same methods MUST be
   used as the ones described in Section 4 of [RFC4860], augmented by
   the following rules:

   o  An Aggregator (PCN-ingress-node) or Deaggregator (PCN-egress-node
      and Decision Point) MUST use one or more policies to determine
      whether an RSVP generic aggregate reservation can be mapped into
      an ingress-egress-aggregate.  This can be accomplished by using
      for the different RSVP generic aggregate reservations the same
      combinations of ingress and egress identifiers, but with a
      different PHB-ID value (see [RFC4860]) corresponding to the PCN
      specifications -- in particular, the RSVP SESSION object specified
      in [RFC4860], augmented with the following information:

      o  The IPv4 DestAddress, IPv6 DestAddress MUST be set to the IPv4
         or IPv6 destination addresses, respectively, of the
         Deaggregator (PCN-egress-node); see [RFC4860].  Note that the
         PCN-domain is considered as being only one RSVP hop (for
         generic aggregate RSVP or E2E RSVP).  This means that the next
         RSVP hop for the Aggregator in the downstream direction is the
         Deaggregator and the next RSVP hop for the Deaggregator in the
         upstream direction is the Aggregator.

      o  The PHB-ID (Per Hop Behavior Identification Code) SHOULD be set
         equal to PCN-compatible Diffserv Codepoint(s).

      o  The Extended vDstPort SHOULD be set to the IPv4 or IPv6
         destination addresses of the Aggregator (PCN-ingress-node); see
         [RFC4860].






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2.6.  Size of Aggregate Reservations

   Since (1) no admission control of E2E reservations over the RSVP
   aggregate reservations is required and (2) no admission control of
   the RSVP aggregate reservation over the PCN-core is required, the
   size of the generic aggregate reservation is irrelevant and can be
   set to any arbitrary value by the Deaggregator.  The Deaggregator
   SHOULD set the value of a generic aggregate reservation to a null
   bandwidth.  We also observe that there is no need for dynamic
   adjustment of the RSVP aggregate reservation size.

2.7.  E2E Path ADSPEC Update

   To comply with this specification, for the update of the E2E Path
   ADSPEC, the same methods can be used as the ones described in
   [RFC4860].

2.8.  Intra-domain Routes

   The PCN-interior-nodes maintain neither E2E RSVP nor RSVP generic
   aggregation states and reservations.  Therefore, intra-domain route
   changes will not affect intra-domain reservations, since such
   reservations are not maintained by the PCN-interior-nodes.

   Furthermore, it is considered that by configuration the PCN-interior-
   nodes can distinguish neither RSVP generic aggregate sessions and
   their associated messages [RFC4860] nor E2E RSVP SESSIONS and their
   associated messages [RFC2205].

2.9.  Inter-domain Routes

   The PCN-charter scope precludes inter-domain considerations.
   However, for solving inter-domain route changes associated with the
   operation of the RSVP messages, the same methods SHOULD be used as
   the ones described in [RFC4860] and in Section 1.4.7 of [RFC3175].

2.10.  Reservations for Multicast Sessions

   PCN does not consider reservations for multicast sessions.

2.11.  Multi-level Aggregation

   PCN does not consider multi-level aggregations within the PCN-domain.
   Therefore, the PCN-interior-nodes do not support multi-level
   aggregation procedures.  However, the Aggregator and Deaggregator
   SHOULD support the multi-level aggregation procedures specified in
   [RFC4860] and in Section 1.4.9 of [RFC3175].




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2.12.  Reliability Issues

   To comply with this specification, for solving possible reliability
   issues, the same methods MUST be used as the ones described in
   Section 4 of [RFC4860].

3.  Elements of Procedures

   This section describes the procedures used to implement the aggregate
   RSVP procedure over PCN.  It is considered that the procedures for
   aggregation of E2E reservations over generic aggregate RSVP
   reservations are the same as the procedures specified in Section 4 of
   [RFC4860], except where a departure from these procedures is
   explicitly described in this section.  Please refer to Appendix B of
   [RFC2205] and Section 3 of [RFC4860] for the processing rules and
   error handling for the error cases listed below:

   o  Message formatting errors, e.g., incomplete message

   o  Unknown objects

3.1.  Receipt of E2E Path Message by PCN-Ingress-Node
      (Aggregating Router)

   When the E2E Path message arrives at the exterior interface of the
   Aggregator (PCN-ingress-node), then standard RSVP generic aggregation
   [RFC4860] procedures are used.

3.2.  Handling of E2E Path Message by Interior Routers

   The E2E Path messages traverse zero or more PCN-interior-nodes.  The
   PCN-interior-nodes receive the E2E Path message on an interior
   interface and forward it on another interior interface.  It is
   considered that, by configuration, the PCN-interior-nodes ignore the
   E2E RSVP signaling messages [RFC2205].  Therefore, the E2E Path
   messages are simply forwarded as normal IP datagrams.















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3.3.  Receipt of E2E Path Message by PCN-Egress-Node
      (Deaggregating Router)

   When receiving the E2E Path message, the Deaggregator (PCN-egress-
   node and Decision Point) performs the regular procedures of
   [RFC4860], augmented with the following rules:

   o  The Deaggregator MUST NOT perform the RSVP-TTL vs. IP TTL-check
      (TTL = Time To Live) and MUST NOT update the ADSPEC Break bit.
      This is because the whole PCN-domain is effectively handled by E2E
      RSVP as a virtual link on which integrated service is indeed
      supported (and admission control performed) so that the Break bit
      MUST NOT be set; see also [RSVP-PCN-CL].

   The Deaggregator forwards the E2E Path message towards the receiver.

3.4.  Initiation of New Aggregate Path Message by PCN-Ingress-Node
      (Aggregating Router)

   To comply with this specification, for the initiation of the new RSVP
   generic aggregate Path message by the Aggregator (PCN-ingress-node),
   the same methods MUST be used as the ones described in [RFC4860].

3.5.  Handling of Aggregate Path Message by Interior Routers

   The Aggregate Path messages traverse zero or more PCN-interior-nodes.
   The PCN-interior-nodes receive the Aggregate Path message on an
   interior interface and forward it on another interior interface.  It
   is considered that, by configuration, the PCN-interior-nodes ignore
   the Aggregate Path signaling messages.  Therefore, the Aggregate Path
   messages are simply forwarded as normal IP datagrams.

3.6.  Handling of Aggregate Path Message by Deaggregating Router

   When receiving the Aggregate Path message, the Deaggregator
   (PCN-egress-node and Decision Point) performs the regular procedures
   of [RFC4860], augmented with the following rules:

   o  When the received Aggregate Path message by the Deaggregator
      contains the RSVP-AGGREGATE-IPv4-PCN-response or RSVP-AGGREGATE-
      IPv6-PCN-response PCN objects, which carry the PCN-sent-rate, then
      the procedures specified in Section 3.18 of this document MUST be
      followed.








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3.7.  Handling of E2E Resv Message by Deaggregating Router

   When the E2E Resv message arrives at the exterior interface of the
   Deaggregator (PCN-egress-node and Decision Point), then standard RSVP
   aggregation procedures of [RFC4860] are used, augmented with the
   following rules:

   o  The E2E RSVP SESSION associated with an E2E Resv message that
      arrives at the external interface of the Deaggregator is
      mapped/matched with an RSVP generic aggregate and with a PCN
      ingress-egress-aggregate.

   o  Depending on the type of the PCN edge behavior supported by the
      Deaggregator, the PCN admission control procedures specified in
      Section 3.3.1 of [RFC6661] or [RFC6662] MUST be followed.  Since
      no admission control procedures over the RSVP aggregate
      reservations in the PCN-core are required, unlike [RFC4860], the
      Deaggregator does not perform any admission control of the E2E
      reservation over the mapped generic aggregate RSVP reservation.
      If the PCN-based admission control procedure is successful, then
      the Deaggregator MUST allow the new flow to be admitted onto the
      associated RSVP generic aggregation reservation and onto the PCN
      ingress-egress-aggregate; see [RFC6661] and [RFC6662].  If the
      PCN-based admission control procedure is not successful, then the
      E2E Resv MUST NOT be admitted onto the associated RSVP generic
      aggregate reservation and onto the PCN ingress-egress-aggregation.
      The E2E Resv message is further processed according to [RFC4860].

   How the PCN-admission-state is maintained is specified in [RFC6661]
   and [RFC6662].

3.8.  Handling of E2E Resv Message by Interior Routers

   The E2E Resv messages traversing the PCN-core are IP addressed to the
   Aggregating router and are not marked with Router Alert; therefore,
   the E2E Resv messages are simply forwarded as normal IP datagrams.















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3.9.  Initiation of New Aggregate Resv Message by Deaggregating Router

   To comply with this specification, for the initiation of the new RSVP
   generic aggregate Resv message by the Deaggregator (PCN-egress-node
   and Decision Point), the same methods MUST be used as the ones
   described in Section 4 of [RFC4860], augmented with the following
   rules:

   o  The size of the generic aggregate reservation is irrelevant (see
      Section 2.6) and can be set to any arbitrary value by the
      PCN-egress-node.  The Deaggregator SHOULD set the value of an RSVP
      generic aggregate reservation to a null bandwidth.  We also
      observe that there is no need for dynamic adjustment of the RSVP
      generic aggregate reservation size.

   o  When [RFC6661] is used and the ETM-rate measured by the
      Deaggregator contains a non-zero value for some ingress-egress-
      aggregate (see [RFC6661] and [RFC6662]), the Deaggregator MUST
      request the PCN-ingress-node to provide an estimate of the rate
      (PCN-sent-rate) at which the Aggregator (PCN-ingress-node) is
      receiving PCN-traffic that is destined for the given ingress-
      egress-aggregate.

   o  When [RFC6662] is used and the PCN-admission-state computed by the
      Deaggregator on the basis of the CLE is "block" for the given
      ingress-egress-aggregate, the Deaggregator MUST request the
      PCN-ingress-node to provide an estimate of the rate
      (PCN-sent-rate) at which the Aggregator is receiving PCN-traffic
      that is destined for the given ingress-egress-aggregate.

   o  In the above two cases and when the PCN-sent-rate needs to be
      requested from the Aggregator, the Deaggregator MUST generate and
      send to the Aggregator a (refresh) Aggregate Resv message that
      MUST carry one of the following PCN objects (see Section 4.1),
      depending on whether IPv4 or IPv6 is supported:

      o  RSVP-AGGREGATE-IPv4-PCN-request

      o  RSVP-AGGREGATE-IPv6-PCN-request

3.10.  Handling of Aggregate Resv Message by Interior Routers

   The Aggregate Resv messages traversing the PCN-core are IP addressed
   to the Aggregating router and are not marked with Router Alert;
   therefore, the Aggregate Resv messages are simply forwarded as normal
   IP datagrams.





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3.11.  Handling of E2E Resv Message by Aggregating Router

   When the E2E Resv message arrives at the interior interface of the
   Aggregator (PCN-ingress-node), then standard RSVP aggregation
   procedures of [RFC4860] are used.

3.12.  Handling of Aggregate Resv Message by Aggregating Router

   When the Aggregate Resv message arrives at the interior interface of
   the Aggregator (PCN-ingress-node), then standard RSVP aggregation
   procedures of [RFC4860] are used, augmented with the following rules:

   o  The Aggregator SHOULD use the information carried by the PCN
      objects (see Section 4) and follow the steps specified in
      Section 3.4 of [RFC6661] and [RFC6662].  If the "R" flag carried
      by the RSVP-AGGREGATE-IPv4-PCN-request or RSVP-AGGREGATE-IPv6-PCN-
      request PCN objects is set to ON (see Section 4.1), then the
      Aggregator follows the steps described in Section 3.4 of [RFC6661]
      and [RFC6662] on calculating the PCN-sent-rate.  In particular,
      the Aggregator MUST provide the estimated current rate of
      PCN-traffic received at that node and destined for a given
      ingress-egress-aggregate in octets per second (the PCN-sent-rate).
      The way this rate estimate is derived is a matter of
      implementation; see [RFC6661] or [RFC6662].

   o  The Aggregator initiates an Aggregate Path message.  In
      particular, when the Aggregator receives an Aggregate Resv message
      that carries one of the following PCN objects -- RSVP-AGGREGATE-
      IPv4-PCN-request or RSVP-AGGREGATE-IPv6-PCN-request -- with the
      "R" flag set to ON (see Section 4.1), the Aggregator initiates an
      Aggregate Path message and includes the calculated PCN-sent-rate
      in the RSVP-AGGREGATE-IPv4-PCN-response or RSVP-AGGREGATE-
      IPv6-PCN-response PCN objects (see Section 4.1), which MUST be
      carried by the Aggregate Path message.  This Aggregate Path
      message is sent towards the Deaggregator (PCN-egress-node and
      Decision Point) that requested the calculation of the
      PCN-sent-rate.

3.13.  Removal of E2E Reservation

   To comply with this specification, for the removal of E2E
   reservations, the same methods MUST be used as the ones described in
   Section 4 of [RFC4860] and Section 5 of [RFC4495].








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3.14.  Removal of Aggregate Reservation

   To comply with this specification, for the removal of RSVP generic
   aggregate reservations, the same methods MUST be used as the ones
   described in Section 4 of [RFC4860] and Section 2.10 of [RFC3175].
   In particular, should an aggregate reservation go away (presumably
   due to a configuration change, route change, or policy event), the
   E2E reservations it supports are no longer active.  They MUST be
   treated accordingly.

3.15.  Handling of Data on Reserved E2E Flow by Aggregating Router

   The handling of data on the reserved E2E flow by the Aggregator
   (PCN-ingress-node) uses the procedures described in [RFC4860],
   augmented with the following:

   o  Regarding PCN-marking and traffic classification, the procedures
      defined in Sections 2.2 and 2.3 of this document are used.

3.16.  Procedures for Multicast Sessions

   No multicast sessions are considered in this document.

3.17.  Misconfiguration of PCN-Node

   In an event where a PCN-node is misconfigured within a PCN-domain,
   the desired behavior is the same as that described in Section 3.10.

3.18.  PCN-Based Flow Termination

   When the Deaggregator (PCN-egress-node and Decision Point) needs to
   terminate an amount of traffic associated with one ingress-egress-
   aggregate (see Section 3.3.2 of [RFC6661] and [RFC6662]), then
   several procedures for terminating E2E microflows can be deployed.
   The default procedure for terminating E2E microflows (i.e.,
   PCN-flows) is as follows; see, for example, [RFC6661] and [RFC6662].

   For the same ingress-egress-aggregate, select a number of E2E
   microflows to be terminated in order to decrease the total incoming
   amount of bandwidth associated with one ingress-egress-aggregate by
   the amount of traffic to be terminated.  In this situation, the same
   mechanisms for terminating an E2E microflow can be followed as the
   mechanisms specified in [RFC2205].  However, based on a local policy,
   the Deaggregator could use other ways of selecting which microflows
   should be terminated.  For example, for the same ingress-egress-
   aggregate, select a number of E2E microflows to be terminated or to
   reduce their reserved bandwidth in order to decrease the total




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   incoming amount of bandwidth associated with one ingress-egress-
   aggregate by the amount of traffic to be terminated.  In this
   situation, the same mechanisms for terminating an E2E microflow or
   reducing bandwidth associated with an E2E microflow can be followed
   as the mechanisms specified in Section 5 of [RFC4495].

4.  Protocol Elements

   The protocol elements in this document are using the elements defined
   in Section 4 of [RFC4860] and Section 3 of [RFC3175], augmented with
   the following rules:

   o  The DSCP value included in the SESSION object SHOULD be set equal
      to a PCN-compatible Diffserv Codepoint.

   o  The Extended vDstPort SHOULD be set to the IPv4 or IPv6
      destination addresses of the Aggregator (PCN-ingress-node); see
      [RFC4860].

   o  When the Deaggregator (PCN-egress-node and Decision Point) needs
      to request the PCN-sent-rate from the PCN-ingress-node (see
      Section 3.9 of this document), the Deaggregator MUST generate and
      send a (refresh) Aggregate Resv message to the Aggregator that
      MUST carry one of the following PCN objects (see Section 4.1),
      depending on whether IPv4 or IPv6 is supported:

      o  RSVP-AGGREGATE-IPv4-PCN-request

      o  RSVP-AGGREGATE-IPv6-PCN-request

   o  When the Aggregator receives an Aggregate Resv message that
      carries one of the following PCN objects -- RSVP-AGGREGATE-
      IPv4-PCN-request or RSVP-AGGREGATE-IPv6-PCN-request, with the "R"
      flag set to ON (see Section 4.1) -- then the Aggregator MUST
      generate and send to the Deaggregator an Aggregate Path message
      that carries one of the following PCN objects (see Section 4.1),
      depending on whether IPv4 or IPv6 is supported:

      o  RSVP-AGGREGATE-IPv4-PCN-response

      o  RSVP-AGGREGATE-IPv6-PCN-response










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4.1.  PCN Objects

   This section describes four types of PCN objects that can be carried
   by the (refresh) Aggregate Path or the (refresh) Aggregate Resv
   messages specified in [RFC4860].

   These objects are as follows:

      o  RSVP-AGGREGATE-IPv4-PCN-request

      o  RSVP-AGGREGATE-IPv6-PCN-request

      o  RSVP-AGGREGATE-IPv4-PCN-response

      o  RSVP-AGGREGATE-IPv6-PCN-response

   o  RSVP-AGGREGATE-IPv4-PCN-request: PCN request object, when IPv4
      addresses are used:

      Class = 248 (PCN)
      C-Type = 1 (RSVP-AGGREGATE-IPv4-PCN-request)

      +-------------+-------------+-------------+-------------+
      |     IPv4 PCN-ingress-node Address (4 bytes)           |
      +-------------+-------------+-------------+-------------+
      |     IPv4 PCN-egress-node Address (4 bytes)            |
      +-------------+-------------+-------------+-------------+
      |     IPv4 Decision Point Address (4 bytes)             |
      +-------------+-------------+-------------+-------------+
      |R|     Reserved                                        |
      +-------------+-------------+-------------+-------------+




















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   o  RSVP-AGGREGATE-IPv6-PCN-request: PCN object, when IPv6 addresses
      are used:

      Class = 248 (PCN)
      C-Type = 2 (RSVP-AGGREGATE-IPv6-PCN-request)

      +-------------+-------------+-------------+-------------+
      |                                                       |
      +                                                       +
      |                                                       |
      +     IPv6 PCN-ingress-node Address (16 bytes)          +
      |                                                       |
      +                                                       +
      |                                                       |
      +-------------+-------------+-------------+-------------+
      |                                                       |
      +                                                       +
      |                                                       |
      +     IPv6 PCN-egress-node Address (16 bytes)           +
      |                                                       |
      +                                                       +
      |                                                       |
      +-------------+-------------+-------------+-------------+
      |                                                       |
      +                                                       +
      |                                                       |
      +     Decision Point Address (16 bytes)                 +
      |                                                       |
      +                                                       +
      |                                                       |
      +-------------+-------------+-------------+-------------+
      |R|     Reserved                                        |
      +-------------+-------------+-------------+-------------+


















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   o  RSVP-AGGREGATE-IPv4-PCN-response: PCN object, IPv4 addresses
      are used:

      Class = 248 (PCN)
      C-Type = 3 (RSVP-AGGREGATE-IPv4-PCN-response)

      +-------------+-------------+-------------+-------------+
      |     IPv4 PCN-ingress-node Address (4 bytes)           |
      +-------------+-------------+-------------+-------------+
      |     IPv4 PCN-egress-node Address (4 bytes)            |
      +-------------+-------------+-------------+-------------+
      |     IPv4 Decision Point Address (4 bytes)             |
      +-------------+-------------+-------------+-------------+
      | PCN-sent-rate                                         |
      +-------------+-------------+-------------+-------------+




































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   o  RSVP-AGGREGATE-IPv6-PCN-response: PCN object, IPv6 addresses
      are used:

      Class = 248 (PCN)
      C-Type = 4 (RSVP-AGGREGATE-IPv6-PCN-response)

      +-------------+-------------+-------------+-------------+
      |                                                       |
      +                                                       +
      |                                                       |
      +     IPv6 PCN-ingress-node Address (16 bytes)          +
      |                                                       |
      +                                                       +
      |                                                       |
      +-------------+-------------+-------------+-------------+
      |                                                       |
      +                                                       +
      |                                                       |
      +     IPv6 PCN-egress-node Address (16 bytes)           +
      |                                                       |
      +                                                       +
      |                                                       |
      +-------------+-------------+-------------+-------------+
      |                                                       |
      +                                                       +
      |                                                       |
      +     Decision Point Address (16 bytes)                 +
      |                                                       |
      +                                                       +
      |                                                       |
      +-------------+-------------+-------------+-------------+
      | PCN-sent-rate                                         |
      +-------------+-------------+-------------+-------------+

   The fields carried by the PCN object are specified in [RFC6663],
   [RFC6661], and [RFC6662]:

   o  The IPv4 or IPv6 address of the PCN-ingress-node (Aggregator) and
      the IPv4 or IPv6 address of the PCN-egress-node (Deaggregator):
      together, they specify the ingress-egress-aggregate to which the
      report refers.  According to [RFC6663], the report should carry
      the identifier of the PCN-ingress-node (Aggregator) and the
      identifier of the PCN-egress-node (Deaggregator) (typically their
      IP addresses).

   o  Decision Point Address: specifies the IPv4 or IPv6 address of the
      Decision Point.  In this document, this field MUST contain the IP
      address of the Deaggregator.



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   o  "R": 1-bit flag that, when set to ON, signifies, according to
      [RFC6661] and [RFC6662], that the PCN-ingress-node (Aggregator)
      MUST provide an estimate of the rate (PCN-sent-rate) at which the
      PCN-ingress-node (Aggregator) is receiving PCN-traffic that is
      destined for the given ingress-egress-aggregate.

   o  "Reserved": 31 bits that are currently not used by this document
      and are reserved.  These SHALL be set to 0 and SHALL be ignored on
      reception.

   o  PCN-sent-rate: the estimate of the rate at which the PCN-ingress-
      node (Aggregator) is receiving PCN-traffic that is destined for
      the given ingress-egress-aggregate.  It is expressed in
      octets/second; its format is a 32-bit IEEE floating-point number.
      The PCN-sent-rate is specified in [RFC6661] and [RFC6662].

5.  Security Considerations

   The security considerations specified in [RFC2205], [RFC4860], and
   [RFC5559] apply to this document.  In addition, [RFC4230] and
   [RFC6411] provide useful guidance on RSVP security mechanisms.

   Security within a PCN-domain is fundamentally based on the controlled
   environment trust assumption stated in Section 6.3.1 of [RFC5559] --
   in particular, that all PCN-nodes are PCN-enabled and are trusted to
   perform accurate PCN-metering and PCN-marking.

   In the PCN-domain environments addressed by this document, Generic
   Aggregate RSVP messages specified in [RFC4860] are used for support
   of the PCN Controlled Load (CL) and Single Marking (SM) edge
   behaviors over a Diffserv cloud using Pre-Congestion Notification.
   Hence, the security mechanisms discussed in [RFC4860] are applicable.
   Specifically, the INTEGRITY object [RFC2747] [RFC3097] can be used to
   provide hop-by-hop RSVP message integrity, node authentication, and
   replay protection, thereby protecting against corruption and spoofing
   of RSVP messages and PCN feedback conveyed by RSVP messages.

   For these reasons, this document does not introduce significant
   additional security considerations beyond those discussed in
   [RFC5559] and [RFC4860].











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6.  IANA Considerations

   IANA has modified the "Class Names, Class Numbers, and Class Types"
   subregistry of the "Resource Reservation Protocol (RSVP) Parameters"
   registry, to add a new Class Number and assign four new C-Types under
   this new Class Number, as described below; see Section 4.1:

   Class
   Number   Class Name                                  Reference
   -------  ----------------------                      -------------
   248      PCN                                         RFC 7417

   Class Types or C-Types - 248 PCN

   Value    Description                        Reference
   ------   ------------------------------     ------------
   1        RSVP-AGGREGATE-IPv4-PCN-request    RFC 7417
   2        RSVP-AGGREGATE-IPv6-PCN-request    RFC 7417
   3        RSVP-AGGREGATE-IPv4-PCN-response   RFC 7417
   4        RSVP-AGGREGATE-IPv6-PCN-response   RFC 7417

7.  References

7.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997,
              <http://www.rfc-editor.org/info/rfc2119>.

   [RFC2205]  Braden, R., Ed., Zhang, L., Berson, S., Herzog, S., and S.
              Jamin, "Resource ReSerVation Protocol (RSVP) -- Version 1
              Functional Specification", RFC 2205, September 1997,
              <http://www.rfc-editor.org/info/rfc2205>.

   [RFC3140]  Black, D., Brim, S., Carpenter, B., and F. Le Faucheur,
              "Per Hop Behavior Identification Codes", RFC 3140,
              June 2001, <http://www.rfc-editor.org/info/rfc3140>.

   [RFC3175]  Baker, F., Iturralde, C., Le Faucheur, F., and B. Davie,
              "Aggregation of RSVP for IPv4 and IPv6 Reservations",
              RFC 3175, September 2001,
              <http://www.rfc-editor.org/info/rfc3175>.

   [RFC4495]  Polk, J. and S. Dhesikan, "A Resource Reservation Protocol
              (RSVP) Extension for the Reduction of Bandwidth of a
              Reservation Flow", RFC 4495, May 2006,
              <http://www.rfc-editor.org/info/rfc4495>.




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   [RFC4860]  Le Faucheur, F., Davie, B., Bose, P., Christou, C., and M.
              Davenport, "Generic Aggregate Resource ReSerVation
              Protocol (RSVP) Reservations", RFC 4860, May 2007,
              <http://www.rfc-editor.org/info/rfc4860>.

   [RFC5670]  Eardley, P., Ed., "Metering and Marking Behaviour of
              PCN-Nodes", RFC 5670, November 2009,
              <http://www.rfc-editor.org/info/rfc5670>.

   [RFC6660]  Briscoe, B., Moncaster, T., and M. Menth, "Encoding Three
              Pre-Congestion Notification (PCN) States in the IP Header
              Using a Single Diffserv Codepoint (DSCP)", RFC 6660,
              July 2012, <http://www.rfc-editor.org/info/rfc6660>.

   [RFC6661]  Charny, A., Huang, F., Karagiannis, G., Menth, M., and T.
              Taylor, Ed., "Pre-Congestion Notification (PCN) Boundary-
              Node Behavior for the Controlled Load (CL) Mode of
              Operation", RFC 6661, July 2012,
              <http://www.rfc-editor.org/info/rfc6661>.

   [RFC6662]  Charny, A., Zhang, J., Karagiannis, G., Menth, M., and T.
              Taylor, Ed., "Pre-Congestion Notification (PCN) Boundary-
              Node Behavior for the Single Marking (SM) Mode of
              Operation", RFC 6662, July 2012,
              <http://www.rfc-editor.org/info/rfc6662>.

   [RFC6663]  Karagiannis, G., Taylor, T., Chan, K., Menth, M., and P.
              Eardley, "Requirements for Signaling of Pre-Congestion
              Information in a Diffserv Domain", RFC 6663, July 2012,
              <http://www.rfc-editor.org/info/rfc6663>.

7.2.  Informative References

   [RFC1633]  Braden, R., Clark, D., and S. Shenker, "Integrated
              Services in the Internet Architecture: an Overview",
              RFC 1633, June 1994,
              <http://www.rfc-editor.org/info/rfc1633>.

   [RFC2211]  Wroclawski, J., "Specification of the Controlled-Load
              Network Element Service", RFC 2211, September 1997,
              <http://www.rfc-editor.org/info/rfc2211>.

   [RFC2212]  Shenker, S., Partridge, C., and R. Guerin, "Specification
              of Guaranteed Quality of Service", RFC 2212,
              September 1997, <http://www.rfc-editor.org/info/rfc2212>.






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   [RFC2474]  Nichols, K., Blake, S., Baker, F., and D. Black,
              "Definition of the Differentiated Services Field (DS
              Field) in the IPv4 and IPv6 Headers", RFC 2474,
              December 1998, <http://www.rfc-editor.org/info/rfc2474>.

   [RFC2475]  Blake, S., Black, D., Carlson, M., Davies, E., Wang, Z.,
              and W. Weiss, "An Architecture for Differentiated
              Services", RFC 2475, December 1998,
              <http://www.rfc-editor.org/info/rfc2475>.

   [RFC2747]  Baker, F., Lindell, B., and M. Talwar, "RSVP Cryptographic
              Authentication", RFC 2747, January 2000,
              <http://www.rfc-editor.org/info/rfc2747>.

   [RFC2753]  Yavatkar, R., Pendarakis, D., and R. Guerin, "A Framework
              for Policy-based Admission Control", RFC 2753,
              January 2000, <http://www.rfc-editor.org/info/rfc2753>.

   [RFC2998]  Bernet, Y., Ford, P., Yavatkar, R., Baker, F., Zhang, L.,
              Speer, M., Braden, R., Davie, B., Wroclawski, J., and E.
              Felstaine, "A Framework for Integrated Services Operation
              over Diffserv Networks", RFC 2998, November 2000,
              <http://www.rfc-editor.org/info/rfc2998>.

   [RFC3097]  Braden, R. and L. Zhang, "RSVP Cryptographic
              Authentication -- Updated Message Type Value", RFC 3097,
              April 2001, <http://www.rfc-editor.org/info/rfc3097>.

   [RFC4230]  Tschofenig, H. and R. Graveman, "RSVP Security
              Properties", RFC 4230, December 2005,
              <http://www.rfc-editor.org/info/rfc4230>.

   [RFC4923]  Baker, F. and P. Bose, "Quality of Service (QoS) Signaling
              in a Nested Virtual Private Network", RFC 4923,
              August 2007, <http://www.rfc-editor.org/info/rfc4923>.

   [RFC5559]  Eardley, P., Ed., "Pre-Congestion Notification (PCN)
              Architecture", RFC 5559, June 2009,
              <http://www.rfc-editor.org/info/rfc5559>.












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   [RFC6411]  Behringer, M., Le Faucheur, F., and B. Weis,
              "Applicability of Keying Methods for RSVP Security",
              RFC 6411, October 2011,
              <http://www.rfc-editor.org/info/rfc6411>.

   [RSVP-PCN-CL]
              Le Faucheur, F., Charny, A., Briscoe, B., Eardley, P.,
              Babiarz, J., and K. Chan, "RSVP Extensions for Admission
              Control over Diffserv using Pre-congestion Notification
              (PCN)", Work in Progress, draft-lefaucheur-rsvp-ecn-01,
              June 2006.








































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Appendix A.  Example Signaling Flow

   This appendix is based on Appendix A of [RFC4860].  In particular, it
   provides an example signaling flow of the specifications detailed in
   Sections 3 and 4.

   This signaling flow assumes an environment where E2E reservations are
   aggregated over generic aggregate RSVP reservations and applied over
   a PCN-domain.  In particular, the Aggregator (PCN-ingress-node) and
   Deaggregator (PCN-egress-node) are located at the boundaries of the
   PCN-domain.  The PCN-interior-nodes are located within the
   PCN-domain, between the PCN-boundary-nodes, but are not shown in the
   diagram below.  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 Aggregator-Deaggregator
   pair.

        Aggregator (PCN-ingress-node)     Deaggregator (PCN-egress-node)

      E2E Path
     ----------->
                  (1)
                             E2E Path
                     ------------------------------->
                                                               (2)
                      E2E PathErr(NEW-AGGREGATE-NEEDED,SOI=GApcn)
                     <----------------------------------------
   (3)
                           AggPath(Session=GApcn)
                     ------------------------------->
   (4)
                                                             E2E Path
                                                            ----------->
                                                         (5)
                           AggResv (Session=GApcn) (PCN object)
                     <-------------------------------
   (6)
                       AggResvConfirm (Session=GApcn)
                     ------------------------------>
   (7)
                                                             E2E Resv
                                                            <---------
                                                         (8)
                             E2E Resv (SOI=GApcn)
                     <-----------------------------
                  (9)
        E2E Resv
     <-----------



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

   (2) Let's assume that 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 an
       Aggregate Path state for the PCN PHB-ID.  To do that, the
       Deaggregator sends an E2E PathErr message with a
       NEW-AGGREGATE-NEEDED PathErr code.

       The PathErr message also contains a SESSION-OF-INTEREST (SOI)
       object.  The SOI contains a GENERIC-AGGREGATE SESSION (GApcn)
       whose PHB-ID is set to the PCN PHB-ID.  The GENERIC-AGGREGATE
       SESSION contains an interface-independent Deaggregator address
       inside the DestAddress and appropriate values inside the vDstPort
       and Extended vDstPort fields.  In this document, the Extended
       vDstPort SHOULD contain the IPv4 or IPv6 address of the
       Aggregator.

   (3) The Aggregator follows the request from the Deaggregator and
       signals an Aggregate Path for the GENERIC-AGGREGATE SESSION
       (GApcn).

   (4) The Deaggregator takes into account the information contained in
       the ADSPEC from both Aggregate Paths and updates the E2E Path
       ADSPEC accordingly.  The PCN-egress-node MUST NOT perform the
       RSVP-TTL vs. IP TTL-check and MUST NOT update the ADSPEC Break
       bit.  This is because the whole PCN-domain is effectively handled
       by E2E RSVP as a virtual link on which integrated service is
       indeed supported (and admission control performed) so that the
       Break bit MUST NOT be set; see also [RSVP-PCN-CL].  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 the generic aggregate reservation.  In
       effect, the Deaggregator can be seen as anticipating the actual
       demand of E2E reservations so that the generic aggregate
       reservation is in place when the E2E Resv request arrives, in
       order to speed up establishment of E2E reservations.  Here it is
       also assumed that the Deaggregator includes the optional
       ResvConfirm Request in the Aggregate Resv message.

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





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   (7) The Deaggregator has explicit confirmation that the generic
       aggregate reservation is 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 the PCN PHB-ID=x.  After the
       previous step (7), the Deaggregator knows that a generic
       aggregate reservation (GApcn) is in place for the corresponding
       PHB-ID.  At this step, the Deaggregator maps the generic
       aggregate reservation onto one ingress-egress-aggregate
       maintained by the Deaggregator (as a PCN-egress-node); see
       Section 3.7.  The Deaggregator performs admission control of the
       E2E Resv onto the generic aggregate reservation for the PCN
       PHB-ID (GApcn).  The Deaggregator also takes into account the PCN
       admission control procedure as specified in [RFC6661] and
       [RFC6662]; see Section 3.7.  If one or both of the admission
       control procedures (the PCN-based admission control procedure
       described in Section 3.3.1 of [RFC6661] or [RFC6662], and the
       admission control procedure specified in [RFC4860]) are not
       successful, then the E2E Resv is not admitted onto the associated
       RSVP generic aggregate reservation for the PCN PHB-ID (GApcn).
       Otherwise, assuming that the generic aggregate reservation for
       the PCN (GApcn) 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 conveying the selected
       mapping onto GApcn (and hence onto the PCN PHB-ID).

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

Acknowledgments

   We would like to thank the authors of [RSVP-PCN-CL], since some ideas
   used in this document are based on the work initiated in
   [RSVP-PCN-CL].  Moreover, we would like to thank Bob Briscoe, David
   Black, Ken Carlberg, Tom Taylor, Philip Eardley, Michael Menth, Toby
   Moncaster, James Polk, Scott Bradner, Lixia Zhang, and Robert Sparks
   for the provided comments.  In particular, we would like to thank
   Francois Le Faucheur for contributing a significant amount of text,
   in addition to his comments.






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Authors' Addresses

   Georgios Karagiannis
   Huawei Technologies
   Hansaallee 205
   40549 Dusseldorf
   Germany

   EMail: Georgios.Karagiannis@huawei.com


   Anurag Bhargava
   Cisco Systems, Inc.
   7100-9 Kit Creek Road
   PO Box 14987
   Research Triangle Park, NC  27709-4987
   United States

   EMail: anuragb@cisco.com
































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