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Versions: 00 01 02 03 04 05 06 07 rfc3564                               
                                            Francois Le Faucheur, Editor
                                                           Thomas Nadeau
                                                     Cisco Systems, Inc.

                                                           Martin Tatham

                                                          Thomas Telkamp
                                                            David Cooper
                                                         Global Crossing

                                                               Jim Boyle

                                                   Waisum Lai, Co-editor
                                                             Luyuan Fang
                                                               Jerry Ash

                                                              Pete Hicks
                                                            Core Express

                                                             Angela Chiu
                                                         Celion Networks

                                                        William Townsend
                                                          Tenor Networks

                                                          Darek Skalecki
                                                         Nortel Networks

IETF Internet Draft
Expires: May, 2002
Document: draft-ietf-tewg-diff-te-reqts-02.txt         November, 2001

                      Requirements for support of
                Diff-Serv-aware MPLS Traffic Engineering

Status of this Memo

   This document is an Internet-Draft and is in full conformance with
   all provisions of Section 10 of RFC2026. Internet-Drafts are
   Working documents of the Internet Engineering Task Force (IETF), its
   areas, and its working groups.  Note that other groups may also
   distribute working documents as Internet-Drafts.

   Internet-Drafts are draft documents valid for a maximum of six
   months and may be updated, replaced, or obsoleted by other documents
   at any time. It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

Le Faucheur, et. al                                                  1

            Requirements for Diff-Serv Traffic EngineeringNovember 2001

   The list of current Internet-Drafts can be accessed at
   The list of Internet-Draft Shadow Directories can be accessed at


   This document presents the Service Provider requirements for support
   of Diff-Serv aware MPLS Traffic Engineering (DS-TE) as discussed in
   the Traffic Engineering Working Group Framework document [TEWG-FW].

1.      Introduction

1.1.    Problem Statement

   Diff-Serv is becoming prominent in providing scalable network
   designs supporting multiple classes of services.

   In some Diff-Serv networks where optimization of transmission
   resources on a network-wide basis is not sought, MPLS Traffic
   Engineering (TE) mechanisms may simply not be used.

   In other networks, where optimization of transmission resources is
   sought, Diff-Serv mechanisms [DIFF-MPLS] need to be complemented by
   existing MPLS Traffic Engineering mechanisms [TE-REQ] [ISIS-TE]
   [OSPF-TE] [RSVP-TE] [CR-LDP] which operate on an aggregate basis
   across all classes of service. In this case, Diff-Serv and MPLS TE
   both provide their respective benefits.

   Where fine-grained optimization of transmission resources is sought,
   it is necessary to perform traffic engineering at a per-class level
   instead of an aggregate level, in order to further enhance networks
   in performance and efficiency as discussed in [TEWG-FW]. By mapping
   the traffic from a given class of service on a separate LSP, it
   allows this traffic to utilize resources available to the given
   class on both shortest path and non-shortest paths and follow paths
   that meet engineering constraints which are specific to the given
   class. This is what we refer to as "Diff-Serv-aware Traffic
   Engineering (DS-TE)".

   This document focuses exclusively on the specific environments which
   would benefit from DS-TE. Some examples include:

     -    networks where bandwidth is scarce (e.g. transcontinental
     -    networks with significant amounts of delay-sensitive traffic
     -    networks where the relative proportion of traffic across
          classes of service is not uniform

 Le Faucheur et. al                                                  2

            Requirements for Diff-Serv Traffic EngineeringNovember 2001

   This document focuses on intra-domain operation. Inter-domain
   operation is not considered.

1.2.    Definitions

   For the convenience of the reader, relevant Diffserv ([DIFF-ARCH],
   [DIFF-NEW]) definitions are repeated herein.

       Behavior Aggregate (BA): a collection of packets with the same
       codepoint crossing a link in a particular direction.

       PHB Scheduling Class (PSC): A PHB group for which a common
       constraint is that ordering of at least those packets belonging
       to the same microflow must be preserved.

       Ordered Aggregate (OA): a set of BAs that share an ordering
       constraint. The set of PHBs that are applied to this set of
       Behavior Aggregates constitutes a PHB scheduling class.

   We also repeat the following definition from [TE-REQ]:

       Traffic Trunk: an aggregation of traffic flows of the same class
       which are placed inside a Label Switched Path.
       [Note: in the context of the present document, "flows of the
       same class" is to be interpreted as "flows from the same
       Forwarding Equivalence Class which are to be treated
       equivalently from the DS-TE perspective".]

1.3.    Mapping of traffic to LSPs

   A network may have multiple classes of traffic it wishes to service.
   Recalling from [DIFF-MPLS], there are several options on how the
   Diff-Serv Ordered Aggregates (OAs) can be split into multiple
   Traffic Trunks for mapping onto LSPs when using DSTE.

   One option is to split traffic into Traffic Trunks which each
   comprises traffic from multiple OAs. This option is typically used
   when aggregate traffic engineering is deployed using current MPLS TE
   mechanisms. Note that this LSP is then, by definition, an E-LSP as
   defined in [DIFF-MPLS].

   Another option is to split traffic into Traffic Trunks which each
   comprises traffic from a single OA. DS-TE assumes this mode of
   operation. Note that the LSP used to transport such a Traffic Trunk
   may then be an L-LSP (as defined in [DIFF-MPLS]) or may be an E-LSP
   onto which a single (or a subset of the) OA is transported. Thus,
   traffic from a given node to another given node, is split into
   multiple Traffic Trunks which are transported over separate LSPs,
   which can potentially follow a different path through the network.
   DS-TE precisely takes advantage of this fact and indeed computes a
   separate path for each LSP. In so doing, DS-TE can take into account

 Le Faucheur et. al                                                  3

            Requirements for Diff-Serv Traffic EngineeringNovember 2001

   the specific requirements of the Traffic Trunk transported on each
   LSP (e.g. bandwidth requirement, preemption priority). Moreover DS-
   TE can take into account the specific resources which have been
   allocated inside the network to different sets of Traffic Trunks
   (e.g. PHB resources allocated to be used by all the Traffic Trunks
   of a given OA) and specific engineering constraints to be enforced
   for these sets of Traffic Trunks (e.g. limit all Traffic Trunks from
   a given OA to x% of link capacity). In brief, DS-TE achieves per LSP
   constraint based routing with paths that tightly match the specific
   objectives of each Traffic Trunk and of each OA to whom the traffic
   Trunk belongs.

2.      Application Scenarios

2.1.    Scenario 1: Limiting Proportion of Classes on a Link

   An IP/MPLS network may need to carry a significant amount of VoIP
   traffic compared to its link capacity. For example, 10,000
   uncompressed calls at 20ms packetization result in about 1Gbps of IP
   traffic, which is significant on an OC-48c based network. In case of
   topology changes such as link/node failure, VoIP traffic levels can
   even approach the full bandwidth on certain links.

   For delay/jitter reasons it is undesirable to carry more than a
   certain percentage of VoIP traffic on any link. The rest of the
   available link bandwidth can be used to route other classes
   corresponding to delay/jitter insensitive traffic (e.g. Best Effort
   Internet traffic). The exact determination of this "certain"
   percentage is outside the scope of this requirements draft.

   During normal operations, the VoIP traffic should be able to preempt
   other classes of traffic (if these other classes are designated as
   preemptable and they have lower preemption priority),
   so that it will be able to use the shortest available path, only
   constrained by the maximum defined link utilization ratio/percentage
   of the VoIP class.

   Existing TE mechanisms only allow constraint based routing of
   traffic based on a single bandwidth constraint common to all
   classes, which does not satisfy the needs described here. This leads
   to the requirement for DS-TE to be able to enforce a different
   bandwidth constraint for different classes of traffic. In the above
   example, the bandwidth constraint to be enforced for VoIP traffic
   may be the "certain" percentage of each link capacity, while the
   bandwidth constraint to be enforced for the rest of the classes
   might have their own constraints or have access to the rest of the
   link capacity.

2.2.    Scenario 2: Maintain relative proportion of traffic classes

 Le Faucheur et. al                                                  4

            Requirements for Diff-Serv Traffic EngineeringNovember 2001

   Suppose an IP/MPLS network supports 3 classes of traffic. The
   network administrator wants to perform Traffic Engineering to
   distribute the traffic load. Assume also that proportion across
   traffic classes varies significantly depending on the
   source/destination POPs.

   With existing TE mechanisms, the proportion of traffic from each
   class on a given link will vary depending on multiple factors
   - in which order the different TE-LSPs are routed
   - the preemption priority associated with the different TE-LSPs
   - link/node failure situations

   This may make it difficult or impossible for the network
   administrator to configure the Diff-Serv PHBs (e.g. queue bandwidth)
   to ensure that each traffic class gets the appropriate treatment.
   This leads again to the requirement for DS-TE to be able to enforce
   a different bandwidth constraint for different classes of traffic.
   This could be used to ensure that, regardless of the order in which
   tunnels are routed, regardless of their preemption priority and
   regardless of the failure situation, the amount of traffic of each
   class routed over a link matches the Diff-Serv scheduler
   configuration on that link for the corresponding class (e.g. queue

   As an illustration of how DS-TE would address this scenario, the
   network administrator may configure the service rate of Diff-Serv
   queues to (45%,35%,20%) for classes (1,2,3) respectively. The
   administrator would then split the traffic into separate Traffic
   Trunks for each class and associate a bandwidth to each LSP
   transporting those Traffic Trunks. The network administrator may
   also want to configure preemption priorities of each LSP in order to
   give highest restoration priority to the highest priority class and
   medium priority to the medium class. Then DS-TE could ensure that
   after a failure, class 1 traffic would be rerouted with first access
   at link capacity but without exceeding its service rate of 45% of
   the link bandwidth. Class 2 traffic would be rerouted with second
   access at the link capacity but without exceeding its allotment.
   Note that where class 3 is the Best-Effort service, the requirement
   on DS-TE may be to ensure that the total amount of traffic routed
   across all classes does not exceed the total link capacity of 100%
   (as opposed to separately limiting the amount of Best Effort traffic
   to 20 even if there was little class 1 and class 2 traffic).

   In this scenario, DS-TE allowed for the maintenance of a more steady
   distribution of classes, even during rerouting. This relied on the
   required capability of DS-TE to adjust the amount of traffic of each
   class routed on a link based on the configuration of the scheduler
   and the amount of bandwidth available for each class.

   Alternatively, some network administrators may want to solve the
   problem by having the scheduler dynamically adjusted based on the

 Le Faucheur et. al                                                  5

            Requirements for Diff-Serv Traffic EngineeringNovember 2001

   amount of bandwidth of the LSPs admitted for each class. This is an
   additional requirement on DS-TE.

2.3.    Scenario 3: Guaranteed Bandwidth Services

   In addition to the Best effort service, an IP/MPLS network operator
   may desire to offer a point-to-point "guaranteed bandwidth" service
   whereby the provider pledges to provide a given level of performance
   (bandwidth/delay/loss...) end-to-end through its network from an
   ingress port to and egress port.  The goal is to ensure all
   "guaranteed" traffic within a subscribed traffic contract, will be
   delivered within stated tolerances.

   One approach for deploying such "guaranteed" service involves:
   - dedicating a Diff-Serv PHB (or a Diff-Serv PSC as defined in
     [DIFF-NEW]) to the "guaranteed" traffic
   - policing guaranteed traffic on ingress against the traffic
     contract and marking the "guaranteed" packets with the
     corresponding DSCP/EXP value

   Where very high level of performance is targeted for the
   "guaranteed" service, it may be necessary to ensure that the amount
   of "guaranteed" traffic remains below a given percentage of link
   capacity on every link. Where the proportion of "guaranteed" traffic
   is high, constraint based routing can be used to enforce such a

   However, the network operator may also want to simultaneously
   perform Traffic Engineering of the rest of the traffic (i.e. non-
   guaranteed traffic) which would require that constraint based
   routing is also capable of enforcing a differnet bandwidth
   constraint, which would be less stringent than the one for
   guaranteed traffic.

   Again, this combination of requirements can not be addressed with
   existing TE mechanisms. DS-TE mechanisms allowing enforcement of a
   different bandwidth constraint for guaranteed traffic and for non-
   guaranteed traffic are required.

3.      Detailed Requirements for DS-TE

   This section specifies the functionality that the above scenarios
   require out of DS-TE implementations. Actual technical protocol
   mechanisms and procedures to achieve such functionality are outside
   the scope of this document.

3.1.    DS-TE Compatibility

   While DS-TE is required in a number of situations such as the ones
   described above, it is important to keep in mind that using DS-TE
   may impact scalability (as discussed later in this document) and

 Le Faucheur et. al                                                  6

            Requirements for Diff-Serv Traffic EngineeringNovember 2001

   operational practices. DS-TE should only be used when existing TE
   mechanisms combined with Diff-Serv cannot address the network design
   requirements. Many network operators may choose to not use DS-TE, or
   to only use it in a limited scope within their network.

   Thus, the DS-TE solution must be developed in such a way that:

    (i)    it raises no interoperability issues with existing deployed
           TE mechanisms.
    (ii)   it allows DS-TE deployment to the required level of
           granularity and scope (e.g. only in a subset of the
           topology, or only for the number of classes required in the
           considered network)

3.2.    Class-Types

   The fundamental requirement for DS-TE is to be able to enforce
   different bandwidth constraints for different sets of Traffic

   [TEWG-FW] introduces the concept of Class-Types when discussing
   operations of MPLS Traffic Engineering in a Diff-Serv environment.

   DS-TE refines this definition into the following:

           Class-Type (CT): the set of Traffic Trunks which share the
           exact same Bandwidth Constraint, or set of Bandwidth
           Constraints, on all links, for the purpose of Constraint
           Based Routing and Admission Control.

   Note that different LSPs transporting Traffic Trunks from the same
   CT may be using the same or different preemption priorities as
   explained in more details in section 3.4 below.

   For illustration purposes, let's consider the case of a network
   running 4 Diff-Serv classes of services respectively based on the EF
   PHB, the AF1x PSC, the AF2x PSC and the BE PHB. The network
   administrator may decide to deploy DS-TE in the following way:
        o from every DS-TE Head-end to every DS-TE Tail-end, split
          traffic into 4 Traffic Trunks: one for traffic of each Diff-
          Serv class
        o because the QoS objectives for the AF1x Traffic Trunks and
          for the AF2x Traffic Trunks may be of similar nature (e.g.
          both targeting low loss albeit at different levels perhaps),
          the same (set of) Bandwidth Constraint(s) may be applied
          collectively over the AF1x Traffic Trunks and the AF2x
          Traffic Trunks. Thus, the network administrator may only
          define three CTs: one for the EF Traffic Trunks, one for the
          AF1x and AF2x Traffic Trunks and one for the Best Effort
          Traffic Trunks.

 Le Faucheur et. al                                                  7

            Requirements for Diff-Serv Traffic EngineeringNovember 2001

   DS-TE must support at least 2 CTs and up to a maximum of 8 CTs.
   Those are referred to as CTc, 0 <= c <= MaxCT-1 = 7.

   In a given network, DS-TE must not require the network administrator
   to always deploy the maximum number of CTs. The network
   administrator must be able to deploy only the number of CTs actually

3.3.    Bandwidth Constraints

   We refer to a Bandwidth Constraint Model as the set of rules
   - the maximum number of Bandwidth Constraints; and
   - which CTs each Bandwidth Constraint applies to and how.

   By definition of CT, each CT is assigned either a Bandwidth
   Constraint, or a set of Bandwidth Constraints.

   We refer to the Bandwidth Constraints as BCb, 0 <= b <= MaxBC-1

   Different models of Bandwidth Constraints are conceivable for
   control of the CTs.

   For example, a simple model of separate Bandwidth Constraints per CT
   could be defined. This model is defined by:
   - MaxBC= MaxCT
   - All LSPs supporting Traffic Trunks from CTc use no more than BCc

   For illustration purposes, on a link of 100 unit of bandwidth where
   three CTs are used, the network administrator might then configure
   BC0=30, BC1= 50, BC3=20 such
   - All LSPs supporting Traffic Trunks from CT0 use no more than 30
     (e.g. Voice <= 30)
   - All LSPs supporting Traffic Trunks from CT1 use no more than 50
     (e.g. Premium Data <= 50)
   - All LSPs supporting Traffic Trunks from CT2 use no more than 20
     (e.g. Best Effort <= 20)

   As another example, a "Russian Doll" model of Bandwidth Constraints
   may be defined whereby:
   - MaxBC= MaxCT
   - All LSPs supporting Traffic Trunks from CTc (with 0<=c<=b) use no
     more than BCc

   For illustration purposes, on a link of 100 units of bandwidth where
   three CTs are used, the network administrator might then configure
   BC0=60, BC1= 80, BC3=100 such
   - All LSPs supporting Traffic Trunks from CT0 use no more than 60
     (e.g. Voice <= 60)
   - All LSPs supporting Traffic Trunks from CT0 or CT1 use no more
     than 80 (e.g. Voice + Premium Data <= 80)

 Le Faucheur et. al                                                  8

            Requirements for Diff-Serv Traffic EngineeringNovember 2001

   - All LSPs supporting Traffic Trunks from CT0 or CT1 or CT2 use no
     more than 100 (e.g. Voice + Premium Data + Best Effort <= 100).

   More complex Bandwidth Constraints model can also be conceived.
   Those could involve arbitrary relationships between BCb and CTc.
   Those could also involve additional concepts such as associating
   minimum reserved bandwidth to a CT.

   At the time of writing, it is not clear whether a single model of
   Bandwidth Constraints is sufficient, which one it should be and how
   flexible this model really needs to be and what are the implications
   on the DS-TE technical solution and its implementations.

   We expect that Bandwidth Constraints models will be refined as part
   of the specification of the DSTE technical solution.

3.4.    Preemption

   [TEWG-FW] defines the notion of preemption and preemption priority.
   DS-TE must retain full support of such preemption.

   The preemption attribute defined in [TE-REQ] must be retained and
   applicable across all Class Types. The preemption attributes of
   setup priority and holding priority must retain existing semantics,
   and in particular the preemption must operate independently of Class
   Types. This means that if LSP1 contends with LSP2 for resources,
   LSP1 may preempt LSP2 if LSP1 has a higher preemption priority (i.e.
   lower numerical priority value) regardless of LSP1's OA/CT and
   LSP2's OA/CT.

   In other words, DS-TE must offer eight(8) preemption priority levels
   to be used by an LSP, that are completely orthogonal to that any
   other LSP's attributes (eg LSP's OA, LSP's Class Type, etc.).

   Thus, DS-TE must allow two different LSPs transporting Traffic
   Trunks of the same Class-Type to use different preemption
   priorities, and allow the LSP with higher priority to preempt the
   other one when they contend for resources.

   Similarly, DS-TE must allow two different LSPs transporting Traffic
   Trunks from different Class-Types to use different preemption
   priorities, and allow the LSP with higher priority to preempt the
   other one when they contend for resources.

3.5.    Dynamic Adjustment of Diff-Serv PHBs

   As discussed in section 2.2, DS-TE may support adjustment of Diff-
   Serv PHBs parameters (e.g. queue bandwidth) based on the amount of
   TE-LSPs established for each Class/Class-Type.

 Le Faucheur et. al                                                  9

            Requirements for Diff-Serv Traffic EngineeringNovember 2001

   Where this behavior is supported, it must allow for disabling via
   configuration (thus reverting to PHB treatment with static scheduler
   configuration independent of DS-TE operations).

   The dynamic adjustment must take account of the performance
   requirements of each class when computing required adjustments.

3.6.    Overbooking

   Existing TE mechanisms allow overbooking to be applied on LSPs for
   Constraint Based Routing and admission control. Historically this
   has been achieved in TE deployment through factoring overbooking
   ratios at the time of sizing the LSP bandwidth and/or at the time of
   configuring the Maximum Reservable Bandwidth on links.

   DS-TE must also allow overbooking and must effectively allow
   different overbooking ratios to be enforced for different CTs.

   DS-TE should optionally allow the effective overbooking ratio of a
   given CT to be tweaked differently in different parts of the

3.7.    Restoration

   With existing TE, restoration policies use standard priority
   mechanisms such as, for example, the preemption priority to
   effectively control the order/importance of LSPs for restoration

   DS-TE must ensure that similar application of the  use of standard
   priority mechanisms for implementation of restoration policy are not
   prevented since those are expected to be required for achieving the
   survivability requirements of DS-TE networks.

   Further discussion of restoration requirements are presented in the
   output document of the TEWG Requirements Design Team [SURVIV-REQ].

4.      Solution Evaluation Criteria

   A range of solutions is possible for the support of the DS-TE
   requirements discussed above. For example, some solutions may
   require that all current TE protocols syntax (IGP, RSVP-TE, CR-LDP)
   be extended in various ways.  For instance, current TE protocols
   could be modified to support multiple bandwidth constraints rather
   than the existing single aggregate bandwidth constraint.
   Alternatively, other solutions may keep the existing TE protocols
   syntax unchanged but modify their semantic to allow for the multiple
   bandwidth constraints.

   This section identifies the evaluation criteria that should be used
   to assess potential DS-TE solutions for selection.

 Le Faucheur et. al                                                 10

            Requirements for Diff-Serv Traffic EngineeringNovember 2001

4.1.    Satisfying detailed requirements

   The solution must address all the scenarios described in section 2
   and satisfy all the requirements listed in section 3.

4.2.    Flexibility

        -      number of Class Types that can be supported, compared to
               number identified in Requirements section
        -      number of Classes within a Class-Type

4.3.    Extendibility

        -      how far can the solution be extended in the future if
               requirements for more Class-Types are  identified in the

4.4.    Scalability

        -      impact on network scalability in what is propagated,
               processed, stored and computed (IGP signaling, IGP
               processing, IGP database, TE-Tunnel signaling ,...).
        -      how does scalability impact evolve with number of Class-
               Types/Classes actually deployed in a network. In
               particular, is it possible to keep overhead small for a
               large networks which only use a small number of Class-
               Types/Classes, while allowing higher number of Class-
               Types/Classes in smaller networks which can bear higher

4.5.    Backward compatibility/Migration

        -      backward compatibility/migration with/from existing TE
        -      backward compatibility/migration when
               increasing/decreasing the number of Class-Types actually
               deployed in a given network.

5.      Security Considerations

   The solution developed to address the requirements defined in this
   document must address security aspects. DS-TE is not expected to add
   specific security requirements beyond those of Diff-Serv and
   existing TE.  Networks which employ Diff-Serv techniques might offer
   some protection between classes for denial of service attacks.
   Though depending on how the technology is employed, it is possible
   for some (lower scheduled) traffic to be more susceptible to traffic
   anomalies (which include denial of service attacks) occurring within
   other (higher scheduled) classes.

 Le Faucheur et. al                                                 11

            Requirements for Diff-Serv Traffic EngineeringNovember 2001


   [AF] Heinanen, J et al., "Assured Forwarding PHB Group", RFC2597

   [CR-LDP] Jamoussi et al., "Constraint-Based LSP Setup using LDP",
   draft-ietf-mpls-cr-ldp-05.txt, February 2001

   [DIFF-MPLS] Le Faucheur et al, "MPLS Support of Diff-Serv", draft-
   ietf-mpls-diff-ext-09.txt, April 2001

   [DIFF-NEW] Grossman, "New Terminology for Diffserv", work in
   progress, draft-ietf-diffserv-new-terms-04.txt, March 2001.

   [ISIS-TE] Smit, Li, IS-IS extensions for Traffic Engineering, draft-
   ietf-isis-traffic-02.txt, September 2000.

   [OSPF-TE] Katz, Yeung, Traffic Engineering Extensions to OSPF,
   draft-katz-yeung-ospf-traffic-04.txt, August 2001.

   [RSVP-TE] Awduche et al, "RSVP-TE: Extensions to RSVP for LSP
   Tunnels", draft-ietf-mpls-rsvp-lsp-tunnel-08.txt, February 2001.

   [TEWG-FW] Awduche et al, A Framework for Internet Traffic
   Engineering, draft-ietf-tewg-framework-04.txt, April 2001.

   [TE-REQ] Awduche et al, Requirements for Traffic Engineering over
   MPLS, RFC2702, September 1999.

   [SURVIV-REQ] W.S. Lai, D. McDysan, J. Boyle, M. Carlzon, R. Coltun,
   T, Griffin, E. Kern, and T. Reddington, "Network Hierarchy and
   Multilayer Survivability," work in progress, October 2001.

Authors' Address:

   Francois Le Faucheur
   Cisco Systems, Inc.
   Village d'Entreprise Green Side - Batiment T3
   400, Avenue de Roumanille
   06410 Biot-Sophia Antipolis
   Phone: +33 4 97 23 26 19
   Email: flefauch@cisco.com

   Martin Tatham
   Adastral Park,
   Martlesham Heath,
   Ipswich IP5 3RE

 Le Faucheur et. al                                                 12

            Requirements for Diff-Serv Traffic EngineeringNovember 2001

   Phone: +44-1473-606349
   Email: martin.tatham@bt.com

   Thomas Telkamp
   Global Crossing
   Olympia 6
   1213 NP Hilversum
   The Netherlands
   Phone: +31 35 655 651
   Email: telkamp@gblx.net

   David Cooper
   Global Crossing
   960 Hamlin Court
   Sunnyvale, CA 94089
   Phone: (916) 415-0437
   Email: dcooper@gblx.net

   Jim Boyle
   Protocol Driven Networks, Inc.
   1381 Kildaire Farm Road #288
   Cary, NC 27511
   Phone: (919) 852-5160
   Email: jboyle@pdnets.com

   Luyuan Fang
   AT&T Labs
   200 Laurel Avenue
   Middletown, New Jersey 07748
   Phone: (732) 420-1921
   Email: luyuanfang@att.com

   Gerald R. Ash
   AT&T Labs
   200 Laurel Avenue
   Middletown, New Jersey 07748
   Phone: (732) 420-4578
   Email: gash@att.com

   Wai Sum Lai
   AT&T Labs
   200 Laurel Avenue
   Middletown, New Jersey 07748
   Phone: (732) 420-3712
   Email: wlai@att.com

   Pete Hicks
   CoreExpress, Inc
   12655 Olive Blvd, Suite 500

 Le Faucheur et. al                                                 13

            Requirements for Diff-Serv Traffic EngineeringNovember 2001

   St. Louis, MO 63141
   Phone: (314) 317-7504
   Email: pete.hicks@coreexpress.net

   Angela Chiu
   Celion Networks
   1 Sheila Drive, Suite 2
   Tinton Falls, NJ 07724
   Phone: (732) 747-9987
   Email: angela.chiu@celion.com

   William Townsend
   Tenor Networks
   100 Nagog Park
   Acton, MA 01720
   Phone: +1 978-264-4900
   Email: btownsend@tenornetworks.com

   Thomas D. Nadeau
   Cisco Systems, Inc.
   250 Apollo Drive
   Chelmsford, MA 01824
   Phone: (978) 244-3051
   Email: tnadeau@cisco.com

   Darek Skalecki
   Nortel Networks
   3500 Carling Ave,
   Nepean K2H 8E9
   Phone: (613) 765-2252
   Email: dareks@nortelnetworks.com

 Le Faucheur et. al                                                 14