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Versions: 00 01 02 03 04 05 06 07 08 09 10 11 12 RFC 6662

Internet Engineering Task Force                                A. Charny
Internet-Draft                                                  J. Zhang
Intended status: Informational                             Cisco Systems
Expires: December 30, 2010                                G. Karagiannis
                                                               U. Twente
                                                                M. Menth
                                                 University of Wuerzburg
                                                          T. Taylor, Ed.
                                                     Huawei Technologies
                                                           June 28, 2010


    PCN Boundary Node Behaviour for the Single Marking (SM) Mode of
                               Operation
                  draft-ietf-pcn-sm-edge-behaviour-03

Abstract

   Precongestion notification (PCN) is a means for protecting quality of
   service for inelastic traffic admitted to a Diffserv domain.  The
   overall PCN architecture is described in RFC 5559.  This memo is one
   of a series describing possible boundary node behaviours for a PCN
   domain.  The behaviour described here is that for a form of
   measurement-based load control using two PCN marking states, not PCN-
   marked, and excess-traffic-marked.  This behaviour is known
   informally as the Single Marking (SM) PCN edge behaviour.

Status of this Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
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   Drafts is at http://datatracker.ietf.org/drafts/current/.

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   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on December 30, 2010.

Copyright Notice

   Copyright (c) 2010 IETF Trust and the persons identified as the
   document authors.  All rights reserved.



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   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.


Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
     1.1.  Terminology  . . . . . . . . . . . . . . . . . . . . . . .  3
   2.  Assumed Core Network Behaviour for SM  . . . . . . . . . . . .  4
   3.  Node Behaviours  . . . . . . . . . . . . . . . . . . . . . . .  5
     3.1.  Overview . . . . . . . . . . . . . . . . . . . . . . . . .  5
     3.2.  Behaviour of the PCN-Egress-Node . . . . . . . . . . . . .  5
       3.2.1.  Data Collection  . . . . . . . . . . . . . . . . . . .  5
       3.2.2.  Reporting the PCN Data . . . . . . . . . . . . . . . .  5
       3.2.3.  Optional Report Suppression  . . . . . . . . . . . . .  6
       3.2.4.  Optional Calculation and Reporting of Congestion
               Level Estimate . . . . . . . . . . . . . . . . . . . .  6
     3.3.  Behaviour at the Decision Point  . . . . . . . . . . . . .  6
       3.3.1.  Flow Admission . . . . . . . . . . . . . . . . . . . .  7
       3.3.2.  Flow Termination . . . . . . . . . . . . . . . . . . .  7
       3.3.3.  Decision Point Action For Missing Egress Node
               Reports  . . . . . . . . . . . . . . . . . . . . . . .  8
     3.4.  Behaviour of the Ingress Node  . . . . . . . . . . . . . .  8
     3.5.  Summary of Timers  . . . . . . . . . . . . . . . . . . . .  9
   4.  Identifying Ingress-Egress-Aggregates and Their Edge Points  . 10
   5.  Specification of Diffserv Per-Domain Behaviour . . . . . . . . 10
     5.1.  Applicability  . . . . . . . . . . . . . . . . . . . . . . 10
     5.2.  Technical Specification  . . . . . . . . . . . . . . . . . 10
     5.3.  Attributes . . . . . . . . . . . . . . . . . . . . . . . . 11
     5.4.  Parameters . . . . . . . . . . . . . . . . . . . . . . . . 11
     5.5.  Assumptions  . . . . . . . . . . . . . . . . . . . . . . . 12
     5.6.  Example Uses . . . . . . . . . . . . . . . . . . . . . . . 12
     5.7.  Environmental Concerns . . . . . . . . . . . . . . . . . . 12
     5.8.  Security Considerations  . . . . . . . . . . . . . . . . . 12
   6.  Security Considerations  . . . . . . . . . . . . . . . . . . . 13
   7.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 13
   8.  Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 13
   9.  References . . . . . . . . . . . . . . . . . . . . . . . . . . 13
     9.1.  Normative References . . . . . . . . . . . . . . . . . . . 13
     9.2.  Informative References . . . . . . . . . . . . . . . . . . 13
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 14



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1.  Introduction

   The objective of Pre-Congestion Notification (PCN) is to protect 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, to decide whether to admit or block a new flow
   request, and (in abnormal circumstances) flow termination to decide
   whether to terminate some of the existing flows.  To achieve this,
   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 the "pre" of "pre-
   congestion notification").  The level of marking allows decisions to
   be made about whether to admit or terminate individual flows.  For
   more details see [RFC5559].

   Boundary node behaviours specify a detailed set of algorithms and
   edge node behaviours used to implement the PCN mechanisms.  Since the
   algorithms depend on specific metering and marking behaviour at the
   interior nodes, it is also necessary to specify the assumptions made
   about interior node behaviour.  Finally, because PCN uses DSCP values
   to carry its markings, a specification of boundary node behaviour
   must include the per domain behaviour (PDB) template specified in
   [RFC3086], filled out with the appropriate content.  The present
   document accomplishes these tasks for the Single Marking (SM) mode of
   operation.

1.1.  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 [RFC2119].

   In addition to the terms defined in [RFC5559], this document uses the
   following terms:

   Decision Point
      The node that makes the decision about which flows to admit and to
      terminate.  In a given network deployment, this may be the ingress
      node or a centralized control node.  Regardless of the location of
      the Decision Point, the ingress node is the point where the
      decisions are enforced.

   NM-rate
      rate of not-marked PCN traffic in octets per second.  For further
      details see Section 3.2.1.




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   ETM-rate
      rate of excess-traffic-marked PCN traffic in octets per second.
      For further details see Section 3.2.1.

   Congestion level estimate (CLE)
      A value derived from the measurement of PCN packets received at a
      PCN-egress- node for a given ingress-egress-aggregate,
      representing the ratio of excess- traffic-marked to total PCN
      traffic (measured in octets) over a short period.  For further
      details see Section 3.2.4.

   PCN-admission-state
      The state ("admit" or "block") derived by the Decision Point for a
      given ingress-egress-aggregate based on PCN packet marking
      statistics.  The Decision Point decides to admit or block new
      flows offered to the aggregate based on the current value of the
      PCN-admission-state.  For further details see Section 3.3.1.

   Admission decision threshold
      A fractional value to which Decision Point compares the CLE to
      determine the PCN-admission-state for a given ingress-egress-
      aggregate.  If the CLE is below the admission decision threshold
      the PCN-admission-state is set to "admit".  If the CLE is above
      the admission decision threshold the PCN-admission-state is set to
      "block".  For further details see Section 3.3.1.


2.  Assumed Core Network Behaviour for SM

   This section describes the assumed behaviour for nodes of the PCN-
   domain when acting in their role as PCN-interior-nodes.  The SM mode
   of operation assumes that:

   o  on each link the reference rate for the excess traffic meter is
      configured with a PCN-excess-rate to be equal to the PCN-
      admissible-rate for the link;

   o  PCN-interior-nodes perform excess-traffic-metering of packets
      according to the rules specified in [RFC5670].

   o  excess-traffic-marking of packets uses the PCN-Marked (PM)
      codepoint defined in [RFC5696];

   o  no link PCN-threshold-rate is configured, and PCN interior nodes
      perform no threshold-metering.






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3.  Node Behaviours

3.1.  Overview

   This section describes the behaviour of the PCN ingress and egress
   nodes and the Decision Point (which may be collocated with the
   ingress node).  The PCN egress node collects and reports the rates of
   not-marked and excess-traffic-marked PCN traffic to the Decision
   Point.  For a detailed description, see Section 3.2.

   The PCN ingress node enforces flow admission and termination
   decisions.  It also reports the rate of PCN traffic admitted to a
   given ingress-egress aggregate when requested by the Decision Point.
   For details, see Section 3.4.

   Finally, the Decision Point makes flow admission decisions and
   selects flows to terminate based on the information provided by the
   ingress and egress nodes for a given ingress-egress-aggregate.  For
   details, see Section 3.3.

3.2.  Behaviour of the PCN-Egress-Node

3.2.1.  Data Collection

   The PCN-egress-node MUST meter received PCN traffic in order to
   derive periodically the following rates for each ingress-egress-
   aggregate passing through it:

   o  NM-rate: octets per second of PCN traffic in packets which are not
      PCN- Marked;

   o  ETM-rate: octets per second of PCN traffic in PCN-Marked packets.

   It is RECOMMENDED that the interval, Tcalc, between calculation of
   these quantities be in the range of 100 to 500 ms to provide a
   reasonable tradeoff between signalling demands on the network and the
   time taken to react to impending congestion.

   The PCN-traffic SHOULD be metered continuously and the intervals
   themselves SHOULD be of equal length, to minimize the statistical
   variance introduced by the measurement process itself.

3.2.2.  Reporting the PCN Data

   If the report suppression option described in the next sub-section is
   not enabled, the PCN-egress-node MUST report the latest values of NM-
   rate and ETM-rate to the Decision Point each time that it calculates
   them.



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3.2.3.  Optional Report Suppression

   Report suppression MUST be provided as a configurable option.  If
   this option is enabled, the PCN-egress-node MUST NOT send a report to
   the Decision Point for a given ingress-egress-aggregate whenever all
   of the following conditions are satisfied:

   o  ETM-rate was zero in the latest interval.

   o  ETM-rate was zero in the next most recent interval.

   o  Less than time Tmaxnorep has elapsed since the last time the PCN-
      egress-node sent a report to the Decision Point for the given
      aggregate, where Tmaxnorep is a configurable value.

   The above procedure ensures that at least one report is sent per
   period Tmaxnorep.  This provides some protection against loss of
   egress reports and also demonstrates to the Decision Point that both
   the PCN-egress-node and the communication path between the two nodes
   are in operation.  However, depending on the transport used for
   reporting, the operator may choose to set Tmaxnorep to an effectively
   infinite value.  For example, the transport may include its own keep-
   alive signalling at a sufficient frequency that PCN keep-alive is
   redundant.

3.2.4.  Optional Calculation and Reporting of Congestion Level Estimate

   The calculation and reporting of congestion level estimates (CLE)
   MUST be provided as a configurable option at the PCN-egress-node.  If
   this option is enabled, the PCN-egress-node MUST calculate the
   current value for CLE for each ingress-egress-aggregate in each
   measurement interval and include this in its report (along with the
   current values of NM-rate and ETM-rate).  The CLE is equal to the
   ratio:

      ETM-Rate / (NM-rate + ETM-rate)

   if any PCN traffic was observed, or zero otherwise.

3.3.  Behaviour at the Decision Point

   Operators may choose to deploy just flow admission, or just flow
   termination, or both.  The Decision Point MUST implement both
   mechanisms, but configurable options MUST be provided to activate or
   deactivate PCN-based flow admission and flow termination
   independently of each other at a given Decision Point.





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3.3.1.  Flow Admission

   The Decision Point determines the PCN-admission-state for a given
   ingress-egress-aggregate each time it receives a report from the
   egress node.  It makes this determination on the basis of the
   congestion level estimate (CLE), calculated as described in
   Section 3.2.4.  If the CLE is provided in the egress node report, the
   Decision Point SHOULD use the reported value.  If the CLE was not
   provided in the report, the Decision Point MUST calculate it.  The
   Decision Point MUST compare the reported or calculated CLE to an
   admission decision threshold CLElimit.  If the CLE is less than the
   threshold, the PCN-admission-state for that aggregate MUST be set to
   "admit"; otherwise it MUST be set to "block".

      It is RECOMMENDED that the admission decision threshold for SM be
      set fairly low, in the order of 0.05.  The admission decision
      threshold MAY vary for different flows based on policy.

   If the PCN-admission-state for a given ingress-egress-aggregate is
   "admit", the Decision Point SHOULD allow new flows to be admitted to
   that aggregate.  If the PCN-admission-state for a given ingress-
   egress-aggregate is "block", the Decision Point SHOULD NOT allow new
   flows to be admitted to that aggregate.  These actions MAY be
   modified by policy in specific cases, but such policy intervention
   risks defeating the purpose of using PCN..

3.3.2.  Flow Termination

   When the report from the egress node that the PCN-admission-state
   computed on the basis of the CLE is "block" for the given ingress-
   egress-aggregate, the Decision Point MUST request the PCN-ingress-
   node to provide an estimate of the rate (Admit-Rate) at which PCN-
   traffic is being admitted to the aggregate.

      If the Decision Point is collocated with the ingress node, the
      request and response are internal operations.

   The Decision Point MUST then wait, for both the requested rate from
   the ingress node and the next report from the egress node.  If this
   next egress node report also includes a non-zero value for the ETM-
   Rate, the Decision Point MUST determine an amount of flow to
   terminate in the following steps:

   1.  The sustainable aggregate rate (SAR) for the given ingress-
       egress-aggregate is estimated by the product:

          SAR = U * NM-Rate




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       for the latest reported interval, where U is a configurable
       factor less than one which is the same for all ingress-egress-
       aggregates.

   2.  The amount of traffic that must be terminated is the difference:

          Admit-Rate - SAR,

       where Admit-Rate is the value provided by the ingress node.

   If the difference calculated in the second step is positive, the
   Decision Point SHOULD select flows to terminate, until it determines
   that the PCN traffic admission rate will no longer be greater than
   the estimated sustainable aggregate rate.  If the Decision Point
   knows the bandwidth required by individual flows (e.g., from resource
   signalling used to establish the flows), it MAY choose to complete
   its selection of flows to terminate in a single round of decisions.

   Alternatively, the Decision Point MAY spread flow termination over
   multiple rounds to avoid over-termination.  If this is done, it is
   RECOMMENDED that enough time elapse between successive rounds of
   termination to allow the effects of previous rounds to be reflected
   in the measurements upon which the termination decisions are based
   (see [I-D.satoh-pcn-performance-termination] and sections 4.2 and 4.3
   of [Menth08-sub-9]).

3.3.3.  Decision Point Action For Missing Egress Node Reports

   If the Decision Point fails to receive reports from a given egress
   node for a configurable interval Tfail, it SHOULD cease to admit
   flows to that aggregate and raise an alarm to management.  This
   provides some protection against the case where congestion is
   preventing the transfer of reports from the egress node to the
   Decision Point.  If a report is subsequently received from the egress
   node concerned, the Decision Point MUST restart failure timing and
   resume making admission and termination decisions based on the
   reports it receives.

3.4.  Behaviour of the Ingress Node

   The PCN-ingress-node MUST provide the estimated current rate of
   admitted PCN traffic (octets per second) for a specific ingress-
   egress-aggregate when the Decision Point requests it.  The way this
   rate estimate is derived is a matter of implementation.

      For example, the rate that the PCN-ingress-node supplies MAY be
      based on a quick sample taken at the time the information is
      required.  It is RECOMMENDED that such a sample be based on



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      observation of at least 30 PCN packets to achieve reasonable
      statistical reliability.

3.5.  Summary of Timers

   Table 1 summarizes the timers implied by the preceding procedures.
   Tcol and Trep are reset upon expiry.  Tmon is reset by management
   action or by receipt of a report from the egress node concerned.

   +-------+----------+--------------+-----------+---------------------+
   | Timer | Location | Incidence    | Limit     | Action on Expiry    |
   +-------+----------+--------------+-----------+---------------------+
   | Tcol  | Egress   | One per node | Tcalc     | Calculate and       |
   |       | node     |              |           | possibly report     |
   |       |          |              |           | NM-rate, ETM-rate   |
   |       |          |              |           | and optionally CLE  |
   |       |          |              |           | for each IEA.       |
   | -     | -        | -            | -         | -                   |
   | Trep  | Egress   | One per IEA  | Tmaxnorep | Send a report for   |
   |       | node     | if report    |           | that IEA at the     |
   |       |          | suppression  |           | next expiry of      |
   |       |          | is enabled.  |           | Tcol.               |
   | -     | -        | -            | -         | -                   |
   | Tmon  | Decision | One per      | Tfail     | Assume failure and  |
   |       | point    | egress node  |           | cease to admit      |
   |       |          |              |           | flows passing       |
   |       |          |              |           | through that egress |
   |       |          |              |           | node.               |
   +-------+----------+--------------+-----------+---------------------+

                      IEA = ingress-egress-aggregate

              Table 1: Timers Used For the CL Edge Behaviour

   The value of Tcalc SHOULD be configurable, and is RECOMMENDED to be
   of the order of 100 to 500 ms.

   Trep is active only when report suppression is enabled.  The value of
   Tmaxnorep SHOULD be configurable.  The appropriate value depends on
   the transport used to carry the egress node reports.  For unreliable
   transport, Tmaxnorep is RECOMMENDED to be of the order of one second.

   The value of Tfail MUST be configurable.  When unreliable transport
   is used, the value of Tfail is RECOMMENDED to be of the order of 3 *
   Tmaxnorep if report suppression is enabled, and of the order of 3 *
   Tcalc if report suppression is not enabled.  When reliable transport
   is used, the operator may choose to provide similar values for Tfail
   or may choose to disable report timing by setting an effectively



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   infinite value for Tfail.


4.  Identifying Ingress-Egress-Aggregates and Their Edge Points

   The operation of PCN depends on the ability of the ingress and egress
   nodes to identify the aggregate to which each flow belongs.  The
   egress node also needs to associate an aggregate with the address of
   the ingress node for receiving reports, if the ingress node is the
   Decision Point.

   The means by which this is done depends on the packet routing
   technology in use in the network.  In general, classification of
   individual packets at the ingress node (for enforcement and metering
   of admission rates) and at the egress node must use the content of
   the outer packet header.  The process may well require configuration
   of routing information in the ingress and egress nodes.


5.  Specification of Diffserv Per-Domain Behaviour

   This section provides the specification required by [RFC3086] for a
   per-domain behaviour.

5.1.  Applicability

   This section draws heavily upon points made in the PCN architecture
   document, [RFC5559].

   The PCN SM boundary node behaviour specified in this document is
   applicable to inelastic traffic (particularly video and voice) where
   quality of service for admitted flows is protected primarily by
   admission control at the ingress to the domain.  In exceptional
   circumstances (e.g. due to network failures) already-admitted flows
   may be terminated to protect the quality of service of the remainder.
   The SM boundary node behaviour is more likely to terminate too many
   flows under such circumstances than some alternative PCN boundary
   node behaviours.

   Single-Marking requires no extension to the baseline PCN encoding
   described in [RFC5696], thus reducing the work expected to be
   performed in the data path of the high-speed routing equipment, and
   saving valuable real estate in the packet header.

5.2.  Technical Specification

   The technical specification of the PCN SM per domain behaviour is
   provided by the contents of [RFC5559], [RFC5696], [RFC5670], and the



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   present document.

5.3.  Attributes

   The purpose of this per-domain behaviour is to achieve low loss and
   jitter for the target class of traffic.  Recovery from overloads by
   flow termination should happen within 1-3 seconds.

5.4.  Parameters

   The SM per-domain behaviour specifies three timers, two at the PCN-
   egress- node and one at the PCN-ingress-node; see Section 3.5.
   Reference rates must be specified at each interior router for the
   PCN-excess-rate on each link; see Section 2.  An admission decision
   threshold must be specified at each PCN-ingress-node; see
   Section 3.3.1.  A fraction U must be specified at each PCN-ingress-
   node, with a common value over the whole domain; see Section 3.3.2.

   In the list that follows, note that most PCN-ingress-nodes are also
   egress nodes, and vice versa.  Furthermore, the ingress nodes may be
   collocated with Decision Points.

   Parameters at the PCN-ingress-node:

   o  Filters for distinguishing PCN from non-PCN inbound traffic.

   o  The DSCP(s) to be used to mark PCN traffic.

   o  Reference rates on each inward link for the PCN-excess-rate; see
      Section 2.

   o  The information needed to distinguish PCN traffic belonging to a
      given ingress-egress-aggregate.

   Parameters at the PCN-egress-node:

   o  The calculation interval Tcalc.

   o  Whether report suppression is enabled and, if so, the value of
      Tmaxnorep, the maximum interval between reports for a given
      ingress-egress-aggregate.

   o  Whether calculation and reporting of congestion level estimates is
      enabled at the PCN-egress-node.

   o  The information needed to distinguish PCN traffic belonging to a
      given ingress-egress-aggregate.




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   o  The marking rules for re-marking PCN traffic leaving the PCN
      domain.

   Parameters at each interior node:

   o  A reference rates on each link for the PCN-excess-rate; see
      Section 2.

   Parameters at the Decision Point:

   o  Activation/deactivation of PCN-based flow admission.

   o  Activation/deactivation of PCN-based flow termination.

   o  The admission decision threshold CLElimit.

   o  The fraction U used to derive the supportable aggregate rate from
      the NM-rate;

   o  The maximum interval Tfail between reports from a given egress
      node, for detecting failure of communications with that node.

   o  The information needed to map between each ingress-egress-
      aggregate and its edgepoints, particularly the corresponding
      ingress node.

5.5.  Assumptions

   Assumed that a specific portion of link capacity has been reserved
   for PCN traffic.

5.6.  Example Uses

   The PCN SM behaviour may be used to carry real-time traffic,
   particularly voice and video.

5.7.  Environmental Concerns

   The PCN SM per-domain behaviour may interfere with the use of end-to-
   end ECN due to reuse of ECN bits for PCN marking.  See Appendix B of
   [RFC5696] for details.

5.8.  Security Considerations

   Please see the security considerations in Section 6 as well as those
   in [RFC2474] and [RFC2475].





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6.  Security Considerations

   [RFC5559] provides a general description of the security
   considerations for PCN.  This memo introduces no new considerations.


7.  IANA Considerations

   This memo includes no request to IANA.


8.  Acknowledgements

   The authors thank Ruediger Geib for his useful comments.  Toby
   Moncaster provided a detailed review of the CL edge behaviour draft,
   the results of which also appear in this document.


9.  References

9.1.  Normative References

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

   [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.

   [RFC2475]  Blake, S., Black, D., Carlson, M., Davies, E., Wang, Z.,
              and W. Weiss, "An Architecture for Differentiated
              Services", RFC 2475, December 1998.

   [RFC5559]  Eardley, P., "Pre-Congestion Notification (PCN)
              Architecture", RFC 5559, June 2009.

   [RFC5670]  Eardley, P., "Metering and Marking Behaviour of PCN-
              Nodes", RFC 5670, November 2009.

   [RFC5696]  Moncaster, T., Briscoe, B., and M. Menth, "Baseline
              Encoding and Transport of Pre-Congestion Information",
              RFC 5696, November 2009.

9.2.  Informative References

   [I-D.satoh-pcn-performance-termination]
              Satoh, D., Ueno, H., and M. Menth, "Performance Evaluation



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              of Termination in CL-Algorithm (Work in progress)",
              July 2009.

   [Menth08-sub-9]
              Menth, M. and F. Lehrieder, "PCN-Based Measured Rate
              Termination", July 2009, <http://www3.informatik.uni-
              wuerzburg.de/~menth/Publications/papers/
              Menth08-Sub-9.pdf>.

   [RFC3086]  Nichols, K. and B. Carpenter, "Definition of
              Differentiated Services Per Domain Behaviors and Rules for
              their Specification", RFC 3086, April 2001.


Authors' Addresses

   Anna Charny
   Cisco Systems
   300 Apollo Drive
   Chelmsford, MA  01824
   USA

   Email: acharny@cisco.com


   Xinyan (Joy) Zhang
   Cisco Systems
   300 Apollo Drive
   Chelmsford, MA  01824
   USA


   Georgios Karagiannis
   U. Twente


   Phone:
   Email: karagian@cs.utwente.nl













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Internet-Draft       PCN SM Boundary Node Behaviour            June 2010


   Michael Menth
   University of Wuerzburg
   Am Hubland
   Wuerzburg  D-97074
   Germany

   Phone: +49-931-888-6644
   Email: menth@informatik.uni-wuerzburg.de


   Tom Taylor (editor)
   Huawei Technologies
   1852 Lorraine Ave
   Ottawa, Ontario  K1H 6Z8
   Canada

   Phone: +1 613 680 2675
   Email: tom111.taylor@bell.net

































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