Francois Le Faucheur, Editor Thomas Nadeau Cisco Systems, Inc. Martin Tatham BT Thomas Telkamp David Cooper Global Crossing Jim Boyle Luca Martini Level 3 Communications, LLC Luyuan Fang Waisum Lai Jerry Ash AT&T Pete Hicks Core Express Angela Chiu Celion Networks William Townsend Tenor Networks Darek Skalecki Nortel Networks IETF Internet Draft Expires: November, 2001 Document: draft-ietf-tewg-diff-te-reqts-01.txt June, 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 Le Faucheur, et. al 1 Requirements for Diff-Serv Traffic Engineering June 2001 at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. Abstract 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. Problem Statement Diff-Serv is becoming prominent in providing scalable multi-class of services in IP networks. In some Diff-Serv networks where optimization of transmission resources on a network-wide basis is not sought, MPLS Traffic Engineering mechanisms may simply not be used in complement to Diff- Serv mechanisms. In other networks, where some optimization of transmission resources is sought, Diff-Serv mechanisms ([DIFF-MPLS]) may 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 Diff-Serv Behavior Aggregates. In that case, Diff-Serv and MPLS TE both provides their respective benefits (i.e. Diff-Serv performs service differentiation at every hop, Traffic Engineering achieves better distribution of the aggregate traffic load across the set of network resources). However, they operate independently of each other. In other words, MPLS Traffic Engineering performs Constraint Based Routing and Admission Control with the same set of global constraints for all Behavior Aggregates and without the ability to use different sets of constraints for different Behavior Aggregates. In yet other networks where fine optimization of transmission resources is sought, it may be beneficial 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 a traffic trunk in a given class on a separate LSP, it allows the traffic trunk to utilize resources available to the given class on both shortest path(s) and non- shortest paths and follow paths that meet constraints which are specific to the given class. This is what we refer to as "Diff-Serv- aware Traffic Engineering (DS-TE)". Le Faucheur et. al 2 Requirements for Diff-Serv Traffic Engineering June 2001 This document focuses exclusively on the specific environments which would benefit from DS-TE. In preview, networks where bandwidth is scarce (e.g. transcontinental networks), where high priority traffic can be significant compared to link speed on some links (e.g. service provider networks with very large voice trunks), and where the relative proportion of traffic across Behavior Aggregates is not uniform across the whole topology are examples of networks where Diff-Serv-aware Traffic Engineering may yield significant benefits. This document focuses on intra-domain operations. Inter-domain operations is not considered. Below are examples of specific scenarios where Service Providers require DS-TE. 1.1. Scenario 1: High Proportion of Voice An IP/MPLS network may need to carry a significant amount of VoIP (EF) traffic, compared to its link capacities. For example, 10,000 uncompressed calls at 20ms packetization result in about 1Gbps of IP traffic, which is already significant on an OC-48c based network. In case of topology changes such as link/node failure, EF traffic levels can even approach the link bandwidths. For delay/jitter reasons it is undesirable to carry more than a certain percentage of EF 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 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 VoIP link utilization ratio/percentage. Existing TE mechanisms only allow to do constraint based routing of traffic based on a single bandwidth constraint common to all classes, which does not satisfy the needs described here. 1.2. Scenario 2: Rerouting on Lower Speed facilities An IP/MPLS network may support multiple classes of traffic. Assume that a network topology includes OC48/192s links including {Chicago to New York, New York to Washington DC, Washington DC to Dallas and Dallas to Chicago} and some OC3/12s links along {Chicago to Cleveland, Cleveland to Philadelphia, Philadelphia to New York}. Le Faucheur et. al 3 Requirements for Diff-Serv Traffic Engineering June 2001 Assume also, as in previous scenario, that one (or more) high priority class(es) of service has tight quality requirements which could not be met if there was more traffic of this class on a link than a "moderate" percentage of the link. The OC48/192s and OC3/12s links may have been provisioned so that, in steady state, there will be less high priority traffic than the desired "moderate" percentage. For instance, the amount of high priority traffic may be "relatively" small so that, in steady state, the network administrator knows that it will never exceed 25 % of any link capacity, without having to enforce this via separate constraint based routing or Admission Control. To provide the appropriate level of quality to each class of service, the network administrator only needs to configure the Diff-Serv PHBs (scheduler queues) appropriately. However, under failure of some links, the remaining links may not always be sufficient to ensure that after rerouting, high priority traffic does not exceed the "moderate" percentage on all the links. Consider a failure scenario in the topology above where the Chicago to New York link is down while there is no failure of the OC3/12 links. As traffic is rerouted, it is possible that the jitter sensitive high priority traffic will exceed the desired percentage of link capacity of the links along the shorter, but lower capacity routes. In our scenario, the "relatively small" amount of high priority traffic of 25% worth of OC48/192s may turn into "excessive" amount of high priority traffic on the OC3/12 links. Current TE mechanisms allow high priority traffic to be rerouted separately from the other classes of traffic (i.e. by building separate TE-LSPs for high priority and for other classes). However, current mechanisms only allow route computation to enforce a common bandwidth constraint. Assuming that the network administrator elects to give higher preemption priority to the high priority traffic (in order to maximize its chances of being rerouted and also maximize its chances of being rerouted on its shortest path), this may result in high priority tunnels routed onto the OC3/12 links up to the full capacity of the link. This would result in unacceptable degradation of quality of the high priority traffic. 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 high priority traffic may be the "moderate" percentage of each link capacity, while the bandwidth constraint to be enforced for the rest of the traffic may be the full link capacity. This would result in high priority traffic/voice being rerouted first on the {Chicago to Cleveland}, {Cleveland to Philadelphia} and {Philadelphia to New York} links up to the "moderate" percentage of each of these links and other classes of service to be routed on these links to fill up the remaining capacity. Additional high priority traffic/voice which Le Faucheur et. al 4 Requirements for Diff-Serv Traffic Engineering June 2001 cannot be rerouted over the {Chicago to Cleveland}, {Cleveland to Philadelphia} and {Philadelphia to New York} links because it would exceed their "moderate" percentage, will be rerouted along other paths which excludes these links. 1.3. Scenario 3: Maintain relative proportion of traffic classes 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. Then, with existing Traffic Engineering mechanisms, the proportion of traffic from each class on a given link will vary depending on multiple factors including: - in which order the different TE-LSPs are routed - the preemption priority associated with the different TE-LSPs - failure situations leading to reroute 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 bandwidth). 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 build separate TE LSPs for each class and associate to each LSP the bandwidth need for its class. The network administrator may also want to give highest preemption priority to the highest priority class and medium preemption 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 is 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). Le Faucheur et. al 5 Requirements for Diff-Serv Traffic Engineering June 2001 In this scenario, DS-TE allowed to maintain a somewhat steady distribution of different 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 for that class. Alternatively (or perhaps in addition), some network administrators may want to solve the issue in the opposite way through the scheduler configuration being dynamically tied into the amount of bandwidth of the LSPs admitted for each class. This is an additional requirement on DS-TE. 1.4. Scenario 4: 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 constraint. 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 another 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. 2. Detailed Requirements for DS-TE Le Faucheur et. al 6 Requirements for Diff-Serv Traffic Engineering June 2001 2.1. 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 operational practices. DS-TE should only be used when existing TE mechanisms combined with Diff-Serv can not 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. Networks which do not require DS-TE must not be impacted in any way. (ii) it allows DS-TE deployment to the required level of granularity and scope (e.g. only in a subset of the topology, e.g. only for the number of Classes required in the considered network) 2.2. Separate Bandwidth Constraints [TEWG-FW] introduces the concept of Class-Types. The fundamental requirement for DS-TE is to be able to enforce different bandwidth constraints for different Class Types rather than a single one. Based on the scenarios of section 1, DS-TE must allow the network operator to configure the bandwidth constraints such that: - DS-TE never routes more than P1% of EF on a given link - DS-TE never routes more than P0% of EF+BE on that link,where P1 and P0 are configurable separately. Just for illustration purposes a network operator may configure P1=70 and P0=100. In this case, DS-TE could have established at a given time, for instance, : - 70% worth of EF and 30% worth of BE, OR - 50% worth of EF and 50% worth of BE, OR - 0% worth of EF and 100% worth of BE. Clearly, DS-TE would never establish more than 70% of EF TE-LSPs even if there was very little or no BE TE-LSPs routed on the link. Where 3 Class-Types are supported (e.g. CT2=EF, CT1=AF1+AF2, CT0=BE) in the scenarios of section 1, DS-TE must allow the network operator to configure the bandwidth constraints such that: - DS-TE never routes more than say P2% of CT2 on a given link - DS-TE never routes more than say P1% of CT2+CT1 on that link. - DS-TE never routes more than say P0% of CT2+CT1+CT0 on that link. Just as an example, the network operator may configure P2=60, P1=80 and P0=100. In that case, DS-TE could have established at a given time, for instance, : Le Faucheur et. al 7 Requirements for Diff-Serv Traffic Engineering June 2001 - 60% worth of EF, 20% worth of AF and 20% worth of BE, OR - 0% worth of EF, 80% worth of AF and 20% worth of BE, OR - 40% worth of EF, 40% worth of AF and 20% worth of BE, OR - 30% worth of EF, 30% worth of AF and 40% worth of BE. Clearly, DS-TE would never establish more than 60% of EF TE-LSPs even if there was very little or no AF and BE TE-LSPs routed on the link. Similarly, DS-TE would never establish more than 80% worth of EF+AF TE-LSPs even if there was very little or no BE TE-LSPs routed on the link. More generally, the bandwidth constraints enforced by DS-TE must allow the following: - if a high priority class does not use up all of its bandwidth, the next highest priority should be able to make use of this unused bandwidth. For instance, in the above example with 3 Class-Types, if CT2/EF is only using 30% (instead of its maximum 60%), then CT1/AF should be able to use up to 50%. However, if CT2/EF is using its 60%, it is obviously necessary to limit CT1/AF to much below 50% (i.e. to 20% in our example) in order to maintain CT2's performance levels. - If a lower priority class (e.g. AF) used some of the unused bandwidth of a higher priority class (e.g. EF), the high priority class should be able to reclaim this bandwidth where necessary (i.e. preempt lower priority class - see section 2.5) - lower priority class-Types (e.g Best Effort) should not be completely starved by higher priority classes. - Highest priority classes, should only be routed away from their shortest path when they would exceed their own bandwidth constraints. They should not be routed away from their shortest path because of lower priority classes. Therefore, where N Class-Types are supported, DS-TE must allow the network operator to configure the following bandwidth constraints: - never route more than P(N-1)% of CT(N-1) on a given link - never route more than P(N-2)% of CT(N-1)+CT(N-2) on that link. - never route more than P(N-3)% of CT(N-1)+CT(N-2)+CT(N-3) on that link. - etc. - never route more than P(0)% of CT(N-1)+CT(N-2)+... + CT(0) on that link, where P(N-1), P(N-2), ..., P(0) are each configurable separately for every link. DS-TE may optionally support additional bandwidth constraints. 2.3. Number of Class-Types Le Faucheur et. al 8 Requirements for Diff-Serv Traffic Engineering June 2001 DS-TE must support a minimum of 4 Class-Types. In a given network, DS-TE must not force the network administrator to support the maximum number of Class-Types. The network administrator must be able to deploy DS-TE for only 2, for only 3 or for 4 Class-Types. DS-TE must minimize the scalability impact when low number of Class- Types are actually deployed. DS-TE should be extensible to support more Class-Types if required. 2.4. Number of Classes DS-TE should not constrain the number of classes that can be grouped in a Class-Type. 2.5. Preemption 2.5.1. Preemption Within a Class-Type DS-TE must support multiple preemption priorities within a given Class-Type (i.e. between two TE LSPs from the same Class-Type). Preemption within a Class-Type must operate in a similar way to how preemption operates in existing TE: expanding on the description of preemption in [TEWG-FW], a traffic trunk of Class-Type CTx, say "A", can preempt another traffic trunk of same Class-Type CTx, say "B", only if *all* of the following five conditions hold: (i) "A" has a relatively higher priority than "B", (ii) "A" contends for a resource utilized by "B" (including link bandwidth which must satisfy all the bandwidth constraints relevant to CTx), (iii) the resource cannot concurrently accommodate "A" and "B" based on certain decision criteria, (iv) "A" is preemptor enabled, and (v) "B" is preemptable. DS-TE must also allow the network operator to configure the TE-LSPs of a given Class-Type so that they are all at the same preemption priority and thus do not preempt each other. 2.5.2. Preemption Across Class-Types DS-TE must support multiple preemption priorities across Class-Types (i.e. between two TE LSPs from different Class-Types). Preemption across Class-Types must operate in the following way: Le Faucheur et. al 9 Requirements for Diff-Serv Traffic Engineering June 2001 a traffic trunk of Class-Type CTx, say "A", can preempt another traffic trunk of another Class-Type CTy, say "B", only if *all* of the following five conditions hold: (i) "A" has a relatively higher priority than "B", (ii) "A" contends for a resource utilized by "B" (including link bandwidth which must satisfy all the bandwidth constraints relevant to CTx). In other words, where preemption is used across Class-Types, the high priority traffic in one Class- Type must have the ability to pre-empt lower priority traffic, but only while still within the constraint of the maximum bandwidth available to that Class-Type., (iii) the resource cannot concurrently accommodate "A" and "B" based on certain decision criteria, (iv) "A" is preemptor enabled, and (v) "B" is preemptable. As an example, let's consider the case described in section 2.2 where the following bandwidth constraints are configured: - DS-TE never routes more than say 70% of EF on a given link - DS-TE never routes more than 100% of EF+BE on that link. Let's assume that DS-TE has actually established at a given time: - 50% worth of EF TE-LSPs and - 50% worth of BE TE-LSPs. Let's also assume that a new EF TE-LSP worth 10% now needs to be established and contends for this link. Then, DS-TE must allow preemption across Class-Types so that, if so desired by the network administrator, it is possible to preempt 10% worth of already established BE TE-LSPs in order to establish the new EF TE-LSP. Note that in this case, preemption is applicable because the new EF TE-LSP contends for link bandwidth which satisfy all the bandwidth constraints relevant to EF (new EF TE-LSPs of 50+10% would be below 70%, and new EF+BE TE-LSPs of 50+10+50-10% would be within 100%). Let's assume that the above preemption took place and DS-TE now has actually established: - 60% worth of EF TE-LSPs and - 40% worth of BE TE-LSPs. Let's also assume that another new TE-LSP worth 15% now needs to be established. Then, preemption of BE TE-LSPs is not applicable because the new EF TE-LSP would contend for link bandwidth which would not satisfy the bandwidth constraints relevant to EF (new EF TE-LSPs of 60+15% would exceed the 70%). DS-TE must also allow the network operator to configure the TE-LSPs so that preemption across Class-Types is precluded. 2.6. Resource Class Affinity Le Faucheur et. al 10 Requirements for Diff-Serv Traffic Engineering June 2001 [TE-REQ] defines Resource class attributes associated with links and defines resources affinity attributes associated with a traffic trunk which can be used to specify the class of links which are to be explicitly included or excluded from the path of the traffic trunk. Because these attributes already have an open semantic and can be used to implement whatever policy is required by the Service Provider, no new attributes, nor extensions on existing attributes are required. The only requirement on DS-TE is to allow separate configuration of Resource Class Affinity attributes on the traffic trunks corresponding to each different Class of Service. 2.7. Traffic Mapping This section describes the requirement for an LSR which is the Head- end of Diff-Serv-aware Traffic Engineering LSPs to map incoming traffic onto these LSPs. DS-TE must allow each Diff-Serv-aware Traffic Engineering LSP to be configured with the following attributes: - the set of Diff-Serv class(es) (more precisely "Ordered Aggregate") that it can transport in accordance with [DIFF-MPLS] - the Class-Type that must be taken into account so that Constraint Based Routing enforces the relevant bandwidth constraints. DS-TE must support mapping of incoming traffic onto Diff-Serv-aware Traffic Engineering LSPs in accordance with [DIFF-MPLS] so that only packets that belong to the (set of) Behavior Aggregate(s) transported over a given Diff-Serv-aware TE LSP should be mapped to that LSP. In particular, where the Head-end LSR is also the MPLS Edge LSR, determination of the Behavior Aggregate (and thus determination of the egress Diff-Serv-aware TE LSP) is based on the Diffserv Codepoint (DSCP) in the packet header. 2.8. Dynamic Adjustment of Diff-Serv PHBs As discussed in section 1.4, 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. 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. 2.9. Multiple TE Metrics Le Faucheur et. al 11 Requirements for Diff-Serv Traffic Engineering June 2001 This document does not specifically discuss the need for multiple TE metrics which is already work in progress. However, we note that DS- TE can make immediate use of multiple TE metrics once those are available simply by allowing TE-LSPs for different Classes of Service to be routed based on a different TE Metric. 3. Solution Evaluation Criteria Multiple solutions can be thought of in order to support the Diff- Serv-aware 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 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. 3.1. Satisfying detailed requirements The solution must address all the scenarios described in section 1 and satisfy all the requirements listed in section 2. 3.2. Flexibility - number of Class Types that can be supported, compared to number identified in Requirements section - number of Classes within a Class-Type 3.3. Extendibility - how far can the solution be extended in the future if requirements for more Class-Types are identified in the future. 3.4. 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 overhead) Le Faucheur et. al 12 Requirements for Diff-Serv Traffic Engineering June 2001 3.5. Backward compatibility/Migration - backward compatibility/migration with/from existing TE mechanisms - backward compatibility/migration when increasing/decreasing the number of Class-Types actually deployed in a given network. 4. 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. References [TE-REQ] Awduche et al, Requirements for Traffic Engineering over MPLS, RFC2702, September 1999. [TEWG-FW] Awduche et al, A Framework for Internet Traffic Engineering, draft-ietf-tewg-framework-04.txt, April 2001. [OSPF-TE] Katz, Yeung, Traffic Engineering Extensions to OSPF, draft-katz-yeung-ospf-traffic-04.txt, August 2001. [ISIS-TE] Smit, Li, IS-IS extensions for Traffic Engineering, draft- ietf-isis-traffic-02.txt, September 2000. [RSVP-TE] Awduche et al, "RSVP-TE: Extensions to RSVP for LSP Tunnels", draft-ietf-mpls-rsvp-lsp-tunnel-08.txt, February 2001. [DIFF-MPLS] Le Faucheur et al, "MPLS Support of Diff-Serv", draft- ietf-mpls-diff-ext-09.txt, April 2001 [CR-LDP] Jamoussi et al., "Constraint-Based LSP Setup using LDP", draft-ietf-mpls-cr-ldp-05.txt, February 2001 [DIFF-NEW] Grossman, "New Terminology for Diffserv", work in progress, draft-ietf-diffserv-new-terms-04.txt, March 2001. Le Faucheur et. al 13 Requirements for Diff-Serv Traffic Engineering June 2001 Authors' Address: Francois Le Faucheur Cisco Systems, Inc. Village d'Entreprise Green Side - Batiment T3 400, Avenue de Roumanille 06410 Biot-Sophia Antipolis France Phone: +33 4 97 23 26 19 Email: flefauch@cisco.com Martin Tatham BT Adastral Park, Martlesham Heath, Ipswich IP5 3RE UK 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 E-mail: telkamp@gblx.net David Cooper Global Crossing 960 Hamlin Court Sunnyvale, CA 94089 USA Phone: +1 916 415 0437 E-mail: dcooper@gblx.net Jim Boyle Level 3 Communications, LLC. 1025 Eldorado Blvd. Broomfield, CO, 80021 USA Email: jboyle@Level3.net Luca Martini Level 3 Communications, LLC. 1025 Eldorado Blvd. Broomfield, CO, 80021 USA Email: luca@level3.net Le Faucheur et. al 14 Requirements for Diff-Serv Traffic Engineering June 2001 Luyuan Fang AT&T Labs 200 Laurel Avenue Middletown, New Jersey 07748 USA Phone: +1 732 420-1921 Email: luyuanfang@att.com Gerald R. Ash AT&T Labs 200 Laurel Avenue Middletown, New Jersey 07748 USA Phone: +1 732 420-4578 Email: gash@att.com Wai Sum Lai AT&T Labs 200 Laurel Avenue Middletown, New Jersey 07748 USA Phone: +1 732 420-3712 Email: wlai@att.com Pete Hicks CoreExpress, Inc 12655 Olive Blvd, Suite 500 St. Louis, MO 63141 USA Phone: (314) 317-7504 Email: pete.hicks@coreexpress.net Angela Chiu Celion Networks 1 Sheila Drive, Suite 2 Tinton Falls, NJ 07724 Phone: +1-732 747 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: +1-978-244-3051 Email: tnadeau@cisco.com Le Faucheur et. al 15 Requirements for Diff-Serv Traffic Engineering June 2001 Darek Skalecki Nortel Networks 3500 Carling Ave, Nepean K2H 8E9 Phone: +1-613-765-2252 Email: dareks@nortelnetworks.com Le Faucheur et. al 16