Internet Draft Zhigang Kan Document: draft-kan-qos-framework-00.txt Jian Ma Expires: October 2002 Nokia Research Center April 2002 Two-plane and Three-tier QoS Framework for Mobile IPv6 Networks 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." 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 proposes a "two-plane three-tier" QoS framework for mobile IPv6 networks. In this framework the Access Networks are connected with wired backbone through default routers. QoS policies which are implemented in inter-Administration Domains (between Qos Agents) and intra-Administration (between QoS Agent and Local QoS Kan, Ma 1 draft-Kan-QoS-Framework-00.txt April, 2002 Agents) and QoS negotiations are in the control plane. User data is transported in the transport plane. COPS/Diameter is used for exchanging QoS policies. Three-Tier QoS mechanisms mean that QoS mechanisms should be done in three levels. The first level is Inter-Administration Domain QoS mechanisms across neighboring Administration Domains, and the second level is Intra-Administration Domain QoS mechanisms inside each Administration Domain while the third level is edge QoS negotiation and end-to-end QoS negotiation. The aggregate traffic crossing Administration Domain borders is served according to relatively stable, long-lived bilateral agreements. End-to-end QoS support is achieved through the concatenation of such bilateral agreements. QoS signalings are independent of the proposed framework. As an example, the extended Mobile IPv6 signalings that include Binding Update, Binding Request, and Binding Acknowledge are used for end- to-end QoS negotiations and resource advance reservation. Table of Contents 1. Introduction..................................................3 1.1 Conventions used in this document.........................4 2. Terminology...................................................4 3. Two-plane framework...........................................6 3.1 Control Plane.............................................6 3.2 Transport Plane...........................................8 4. Three-tier QoS mechanisms in control plane...................10 4.1 The first tier QoS mechanism.............................10 4.2 The second tier QoS mechanism............................11 4.3 The third tier QoS mechanism.............................11 5. QoS negotiation and QoS signaling............................11 5.1 QoS negotiation..........................................11 5.2 QoS Signalings...........................................12 Kan, Ma Expires October 2002 2 draft-Kan-QoS-Framework-00.txt April, 2002 1. Introduction Over the past several years there has been a considerable amount of research within the field of QoS for wired IP networks. Much less progress has been made in addressing the issue of overall end-to- end QoS framework for wireless mobile IPv6 networks. The current wisdom is that the existing circuit switched and 2G (second generation) wireless systems will eventually evolve/morph into an end-to-end IP platform that provides ubiquitous real-time as well as non-real-time services based on 3G (third generation) wireless IPv6 mobile networks. A QoS framework that provides the end-to-end QoS guarantees for the future network is worth studying. The intention of QoS framework research is to provide a framework for the integration of QoS control and management mechanisms. There are three building blocks which are QoS principles for governing the construction of a generalized QoS framework, QoS Specification for capturing application level QoS requirements and QoS Mechanisms for realizing desired end-to-end QoS behavior in a generalized QoS framework [ACH98]. Five QoS principles which are transparency principle, integration principle, separation principle, performance principle and multiple time scales principle motivated the design of a generalized QoS framework are given in [ACH98]. QoS specification encompasses flow performance specification, level of service, cost of service, QoS management policy and flow synchronisation specification. QoS mechanisms encompasses QoS provision mechanisms, QoS control mechanisms and QoS management mechanisms. QoS provision mechanisms deals with flow establishment and end-to-end QoS re-negotiation phases. To date, most of the developments in the area of QoS support have occurred in the context of individual architectural components [HCCB94]. Much less progress has been made in addressing the issue of an overall QoS framework for mobility networks. There has been, however, considerable progress in the separate areas of distributed-systems platforms [HCCB94, APM91], operating systems [BL91, LM93], transport systems [DBLL92, WM93] and multimedia networking [TOP90, CSZ92] support for QoS. In end-systems, most of the progress has been made in the areas of scheduling [LL73, STA95], flow synchronization [GHA90, EDP92]. In networks, research has focused on providing suitable traffic models [KUR93] and service disciplines [ZK91], as well as appropriate admission control and resource reservation protocols [RFC2205]. The above literatures are focused on wired networks or applications. The current state of QoS support in architectural frameworks can be Kan, Ma Expires October 2002 3 draft-Kan-QoS-Framework-00.txt April, 2002 summarized as follows [HCCB94]: incompleteness, lack of mechanisms to support QoS guarantees, and lack of an overall framework. For QoS framework for wireless mobile IPv6 networks the current state is same as the above. The QoS framework proposed in this draft is based on Differenticated Services, IPv6 and Mobile IPv6. Two key characteristics of the framework are: (1) there is a central server which has global information of the whole administration domain, and several local ingress nodes which feed the local information to the central server; and (2) the QoS signaling and transport are separated in that the central server deals with the QoS mechanisms and default router handle actual transport traffic. Based on these two characteristics, many QoS requirements in mobile IPv6 environment can be achieved efficiently. It also provides flexibility for different QoS session management that can be either based on reservation or provisioning. The framework is also easy to integrate with Mobile IPv6. The framework is depicted in this draft, but the detailed protocols about QoS signaligns and QoS policies will be presented in other drafts. Section 3 describes the two-plane framework and its components. Section 4 explains three-tier QoS mechanisms. How the framework guarantees the end-to-end QoS and the three-tier QoS mechanisms are presented in Section 5. 1.1 Conventions used in this document The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119. 2. Terminology MN (mobile node) MN is the device that allows users to communicate, and also provides means of interaction between users and the networks. Traffic is generated/received by MN and may be queued in the MN while waiting for transmission/reception. AN (Access Network) The AN represents the wireless and back-haul infrastructure that provides MNs with wireless access to the wired infrastructure. An AN usually comprises a set of base stations and base station controllers. Kan, Ma Expires October 2002 4 draft-Kan-QoS-Framework-00.txt April, 2002 AD (Administration Domain) An AD has the same management methods, pricing policies and so on. An AD belongs to an administrative organization and an administrative organization may have one or more ADs. An AD includes a backbone and some ANs that directly connect to the backbone. QA (QoS Agent) There is one logical QA in each AD. The QA has the global information about the resources available in the whole domain. The communications between the QAs is through the COPS [RFC2748] protocol or Diameter protocol. The QA is responsible for QoS management mechanisms between the neighboring ADs and responsible for QoS control mechanisms between the LQAs. LQA (Local QoS Agent) LQA is a separate logical entity and maybe incorporated with the default router of the Differentiated Service domain. LQA has the local information about the AN. The MN interacts with LQA, if necessary, when the MN requests certain degrees of QoS in this domain. The LQA is the entity for QoS negotiation and signaling between MN and the network control system, i.e. it is for QoS control. The LQA decides what services are available for each MN. Thus, the LQA is an intelligent entity residing in the control plane for QoS negotiation and signaling. LQAs provide the local information to QA periodically. LQA maintains a table that is then updated by QA periodically too. Based on this table, LQA will mark, police, shape, map, etc. the traffic going through the default router. Comparing to QA, it is less intelligent. The communications between the QA and LQAs through the COPS protocol or Diameter protocol and the communications between the LQA and the default router through the COPS protocol or Diameter protocol too. LQA is responsible for QoS provision mechanisms. DR (Default Router) A router through which the AN connects Kan, Ma Expires October 2002 5 draft-Kan-QoS-Framework-00.txt April, 2002 directly to the backbone network and the traffic from AN to backbone. 3. Two-plane framework The separation principle for the design of a generalized QoS framework states that media transfer, control and management are functionally distinct architectural activities [A92]. The principle states that these tasks should be separated in architectural frameworks; one aspect of separation is the distinction between signalling and media-transfer; flows (which are isochronous in nature) generally require a wide variety of high bandwidth, low latency, non-assured services with some form of jitter correction; on the other hand, signalling (which is full duplex and asynchronous in nature) generally requires low bandwidth, assured- type services with no jitter constraint. In the proposed framework the QoS mechanisms and QoS negotiations are in the control plane and media-transfer is in the transport plane. Three-tier QoS mechanisms mean that QoS mechanisms should be done in three levels. The first level is Inter-AD QoS mechanisms across neighboring ADs, and the second level is Intra-AD QoS mechanisms inside each AD, while the third level is QoS negotiation which includes Edge QoS negotiation and End-to-end QoS negotiation. 3.1 Control Plane QAs and LQAs are responsible for control tasks in an AD. Three-tier control plane includes Inter-AD QoS mechanisms, Intra-AD QoS mechanisms and QoS negotiation which includes Edge QoS negotiation and end-to-end negotiation. QoS negotiation is accomplished by end- to-end QoS signaling which extended the existing Mobile IPv6 mobility management signaling as an example. In the proposed framework, there is at least one QA and several LQA in an AD. LQAs reside generally in the edge of wired backbone networks that connect to wireless network through default router. The QA retains the global information of the domain, and informs LQAs what to do when traffic comes in. The MN has the QoS signaling with LQA, and LQA has the QoS signaling with GQA. The actual traffic generated by MN goes through the default router. The QA and LQA are in control plane while the default routers are in transport plane. By retaining the global information in QA and separating control plane and transport plane, the framework is flexible, easy to add new services, and more efficient for mobile environment. The existing signalings of Mobile IPv6 are extended for QoS signaling. Kan, Ma Expires October 2002 6 draft-Kan-QoS-Framework-00.txt April, 2002 Figure 1 is the overall picture of the control plane in the framework. There are 2 ADs in this figure and AD1 has 2 ANs each of which connects to the backbone and has a LQA. +------------------------------------------+ + +----+ + + AD2 | QA | + + +----+ + +-------------------- A ----------- -------+ | COPS|Diameter First Tier | +-------------------- V -------------------+ + +----+ + + AD1 +------------>| QA |<------------+ + + | +----+ | + +--- | ------------------------------ | ---+ | | Second Tier COPS|Diameter COPS|Diameter | | +----- V ------------------------------ V --------+ + +-----+ +-----+ + + | LQA | | LQA | + + +-----+ +-----+ + +----- A ------------------------------- A -------+ | | Third Tier COPS|Diameter COPS|Diameter | | +-------+ | +===============+ | +-------+ | +--+ | | + +---+ +---+ + | | +--+ | | |BS| | V + +-| R |---| R |-+ + V | |BS| | | +--+ +---+ + | +---+ +---+ | + +---+ +--+ | | |DR |-------+ | | +-------| DR| | | +--+ +---+ + +---+ +---+ + +---+ +--+ | | |BS| | A + | R |---| R | + A | |BS| | | +--+ | | + +---+ +---+ + | | +--+ | +-------+ | +===============+ | +-------+ | | Edge QoS | Signaling Edge QoS | Signaling V V +--+ +--+ |MN| <-------------------------> |CN| +--+ End-to-end QoS Signaling +--+ Figure 1: Control Plane of the framework Kan, Ma Expires October 2002 7 draft-Kan-QoS-Framework-00.txt April, 2002 3.2 Transport Plane User traffic is transported in transport plane. The user data enter the backbone network from AN through default router. How about the backbone network in the transport plane? As we know, for controlling the traffic there are two types of Internet QoS: Integrated Services [IntServ] and Differentiated Services. Integrated Services is based on resource reservation and network resources are apportioned according to an application's QoS requests, and subject to bandwidth management policy. Integrated Services can guarantee QoS for per-flow traffic. Differentiated Services is based on prioritization and network traffic is classified and apportioned network resources according to bandwidth management policy criteria. To enable QoS, classifications give preferential treatment to applications identified as having more demanding requirements. Differentiated Services can guarantee QoS for per-aggregate traffic. While the aggregated behavior state of the Differentiated Services architecture does offer excellent scaling properties, the lack of end-to-end signaling facilities makes such an approach one that cannot operate in isolation within any environment. What appears to be required within the Differentiated Services model is both resource availability signaling from the core of the network to the Differentiated Service boundary and some form of signaling from the boundary to the client application [RFC2990]. In the proposed framework we made use of the ideas of RSVP/IntServ to extend the signalings of Mobile IPv6 as QoS allocation protocol for the per-flow traffic in the AN. When the traffic leaves the AN, per-flow traffic is aggregated to form aggregate-flows in the default router. Moreover Differentiated Service is selected in the backbone network and the QoS for aggregate flows between ADs is guaranteed by the other mechanisms [RFC2996], [FCFB99] and [RFC2998]. Other QoS protocols such as MPLS [MPLS] can be selected in the backbone network too. Figure 2 is a picture about transport plane for end-to-end QoS guarantee. There are two mapping mechanisms in transport plane: Intra-AD mapping and Inter-AD mapping. Because of different QoS mechanisms in ANs and the backbone network, Intra-AD mapping mechanisms can guarantee the traffic between ANs and backbone network with QoS consistency. Inter-AD mapping mechanisms can guarantee the traffic between ADs with QoS consistency. Kan, Ma Expires October 2002 8 draft-Kan-QoS-Framework-00.txt April, 2002 +-----------------------+ ------- ------- +--+ | +--+ +--+ | A A |CN|<----->|BS| |BS| | | | +--+ per | +--+ +----+ +--+ | per-flow | flow +--------| DR |---------+ QoS | +-A -+ guarantee | | Intra-AD | | AN | Aggregate-flow | | | & Mapping V | += V ===========+ ------- | + +---+ +---+ + A | + | R |---| R | + | | + +---+ +---+ + | | BackBone + AD2 | | + | | + +---+ +---+ + | + | R |---| R | + | End + +---+ +---+ + | | +== A ==========+ | to | | | | Inter-AD | End | Aggregate-flow | | & Mapping | QoS | | +== V ==========+ | + +---+ +---+ + Aggregate G + | R |---| R | + flow u + +---+ +---+ + QoS a BackBone + AD1 | | + guarantee r + +---+ +---+ + | a + | R |---| R | + | n + +---+ +---+ + | t +== A ==========+ | e | Intra-AD | e | Aggregate-flow | | & Mapping V | +- V-+ ------- | +--------| DR |---------+ A | | +--+ +----+ +--+ | | | AN | |BS| |BS| | per-flow | | +--+ +--+ | QoS | +--A---------------A----+ guarantee | Per-flow | Per-flow | | | V V | | +--+ +--+ | | |MN| |MN| V V +--+ +--+ ------ ------ Figure 2: Transport Plane of the framework Kan, Ma Expires October 2002 9 draft-Kan-QoS-Framework-00.txt April, 2002 4. Three-tier QoS mechanisms in control plane In [TWOZ99] a two-tier resource management model for the Internet is proposed. The solution resembles the current two-tier routing hierarchy and allows individual administrative domains to independently make their own decisions on strategies and protocols to use for internal resource management. We borrowed some ideas from this paper and the three-tier QoS mechanisms are proposed in the QoS framework. The tenet of our design is what we call three-tier QoS mechanisms. By this term we mean that QoS mechanisms should be done in three levels. The first level is Inter-AD QoS mechanisms across neighboring ADs, and the second level is Intra-AD QoS mechanisms inside each AD, while the third level is QoS negotiation which includes Edge QoS negotiation and End-to-end QoS negotiation. Following the paradigm of Internet Routing, each AD is free to choose whatever QoS mechanism it deems proper for internal QoS mechanisms as long as its bilateral resource agreements with neighboring ADs are met. These three QoS mechanisms have different time cycle for action. The first tier has the longer time cycle than the other tiers. The third tier is based on per-flow time cycle. 4.1 The first tier QoS mechanism While AN QoS mechanisms can be fined grained (per flow), we require that Inter-NAD QoS agreements such as SLAs are made for the aggregate traffic crossing ADs. Furthermore, Inter-AD agreements should change infrequently at a larger time-cycle than that of individual applications. These two requirements on Inter-AD agreements provide substantial scaling characteristics by decoupling Inter-AD QoS mechanisms from individual end-to-end flows. Note that the QA contacts only its immediate neighbor for all its traffic, although the traffic may head toward various final destinations far away. It is the responsibility of the downstream domain, after agreeing to carry the client traffic, to both guarantee QoS internally as well as request QoS from the downstream neighbors for the portions of the traffic that exit the domain. As we know, end-to-end QoS is provided by the concatenation of Intra-AD QoS mechanisms and bilateral SLAs between neighboring ADs. These agreements specify the amount of traffic belonging to different classes that crosses links connecting adjacent ADs. To ensure that the level of actual traffic is always lower than the negotiated limit, the receiving domain polices incoming traffic, Kan, Ma Expires October 2002 10 draft-Kan-QoS-Framework-00.txt April, 2002 dropping or demoting excess traffic. Knowing that offending traffic will be policed, the sending domain in turn, shapes traffic so that it always remains in profile. 4.2 The second tier QoS mechanism LQAs contact QA to request certain about of resources to cover for the aggregate high quality traffic leaving the AN. Once the agreement is in place, individual applications can request and use portions of the aggregate allocated amount. When and if the allocated resources are exhausted, the LQAs may be able to re- negotiate the agreement with its QA, allocating a larger amount of resources. For example one of the purposes of Intra-AD QoS provisioning mechanisms is to check whether sufficient network resources are available for traffic flowing through each AN and if so to allocate domain resources for this traffic. Each LQA is responsible for QoS provisioning internally. 4.3 The third tier QoS mechanism LQA and default router are responsible for Edge QoS negotiation between MN/CN and the default router when a traffic flow comes. LQA will tell default router how to configure itself if the negotiation is successful. End-to-end QoS negotiation occurs between MN and CN. 5. QoS negotiation and QoS signaling Meeting QoS guarantees in mobility network systems is fundamentally an end-to-end issue, that is, from application to application. In our framework there is a QA acts as the QoS controller for each administrative domain. Neighboring QAs communicate with each other to establish Inter-domain QoS agreements such as SLAs. The aggregate traffic crossing domain borders is served according to relatively stable, long lived bilateral agreements. End-to-End QoS support is achieved through the concatenation of such bilateral agreements. QoS negotiation includes Edge QoS negotiation and end-to-end QoS negotiation. Edge QoS negotiation means the negotiation between MN/CN and default routers. End-to-end QoS negotiation between MN and CN is accomplished by QoS signalings that will be explained in next section as an example. 5.1 QoS negotiation Kan, Ma Expires October 2002 11 draft-Kan-QoS-Framework-00.txt April, 2002 When a MN moves to a foreign network and wants to communicate with other nodes, it will negotiate with the foreign network through the QoS signalings to guarantee the QoS for its applications. If the foreign network cannot meet MN's QoS requirements, MN can decide whether or not enter this network or re-negotiate with the network with degrading its QoS requirements. Moreover, the foreign network can decide whether or not allow the MN to enter based on the current conditions. The foreign network must inform MN the QoS negotiation results and this is the response of QoS. If the foreign network allows the MN to enter, it will inform MN the successful results through the QoS signalings and reserve required resources for MN based on some QoS management policies. When MN leaves the network, the resources used by MN will be released. After MN is admitted to enter the foreign network, it will inform CN of its QoS requirements for an application through QoS signalings. The CN will decide whether or not communicate with this MN, and CN will inform MN the unsuccessful negotiation result if CN cannot meet MN's QoS requirements. Otherwise the CN will negotiate with the network in which CN is locating based on the MN's QoS requirements. In some cases CN can meet MN's requirements but network cannot. If the CN and the CN's located network all can meet MN's QoS requirements, MN may communicate with CN. The procedures of QoS negotiation has three phases: 1) the negotiation between MN and its located network, 2) the negotiation between MN and CN, 3) the negotiation between CN and its located network. Phase 1 and phase 3 are called Edge QoS negotiation, and Phase 2 is called end-to-end QoS negotiation. The procedures of QoS negotiation are dependent on what QoS Signalings are used. 5.2 QoS Signalings A suite of QoS signalings is necessary for QoS negotiation in order to guarantee per-flow end-to-end QoS. Although RSVP is a popular QoS signaling, we build a new suite of QoS signaling by extending the existing Moible IPv6 signalings other than selecting RSVP based on the following factors: 1) the limitations of RSVP; 2) the existing Moible IPv6 mobility management signalings can be extended for QoS negotiation, and doing so can integrate mobility management within QoS negotiation. Kan, Ma Expires October 2002 12 draft-Kan-QoS-Framework-00.txt April, 2002 The extended Mobile IPv6 signalings for QoS negotiation is divided into two parts: edge QoS signalings and end-to-end QoS signalings. Figure 2 shows the QoS signalings. The stateless-based Differentiated Services [DiffServ] lack of QoS response and there is no explicit negotiation between the application's signaling of the service request and the network's capability to deliver a particular service response. If the network is incapable of meeting the service request, then the request simply will not be honored. In such a situation there is no requirement for the network to inform the application that the request cannot be honored, and it is left to the application to determine if the service has not been delivered. So our QoS signaling can be a complement for DS. The detailed design of the QoS signaling and the procedures of QoS negotiation will be appeared in other draft. References [A92] Lazar, A.A., "A Real-time Control, Management, and Information Transport Architecture for Broadband Networks", Proc. International Zurich Seminar on Digital Communications, pp. 281- 295, 1992. [ACH98] Cristina Aurrecoechea, Andrew T. Campbell, Linda Hauw. A survey of QoS architectures, Multimedia Systems (1998) 6: 138û151 [APM91] APM Ltd (1991) ANSAware 3.0 Implementation Manual. APM Ltd, Poseidon House, Castle Park, Cambridge CB3 0RD, UK Transport Protocol. Comput Commun Rev 17 (5) [BL91] Bulterman DC, Liere R van (1991) Multimedia Synchronisation and UNIX. In: Proc. Second International Workshop on Network and Op-erating System Support for Digital Audio and Video. Springer Verlag, Berlin Heidelberg New York [CSZ92] Clark DD, Shenker S, Zhang L (1992) Supporting Real-Time Appli-cations in an Integrated Services Packet Network: Architecture and Mechanism. In: Proc. ACM SIGCOMM'92, pp 14-26, Baltimore, Md., August 1992 [DBLL92]. Danthine A, Baguette Y, Leduc G, Leonard L (1992) The OSI 95 Connection-Mode Transport Service Enhanced QoS. In: 4th IFIP Con-ference on High-Performance Networking, University of Li ege Belgium [DiffServ]. IETF ôDifferentiated Servicesö working group. See http://www.ietf.org/html-charters/diffserv-charter.html [EDP92] Escobar J, Deutsch D, Partridge C (1992) Flow Synchronisation Pro-tocol. In: IEEE GLOBECOMí¯92, Orlando, Fl., Kan, Ma Expires October 2002 13 draft-Kan-QoS-Framework-00.txt April, 2002 June 1992 Williamson R (1990) A Survey of Light-Weight Transport Protocols for High-speed Networks. IEEE Trans on Commun [FCFB99] Baker, F., Iturralde, C., Le Faucher, F., Davie, B., Aggregation of RSVP for IPv4 and IPv6 Reservations, draft-baker- rsvp-aggregation-01.txt (work in progress). Internet Draft, Internet Engineering Task Force, December 1999 [GHA90] Little TDC, Ghafoor A (1990) Synchronisation Properties and Storage Models for Multimedia Objects. IEEE J Sel Areas Commun (3): 229-238 [HCCB94] Hutchison D, Coulson G, Campbell A, Blair G (1994) Quality of Service Management in Distributed Systems. In: Sloman M (ed) Network and Distributed Systems Management, Chapter 11, Addison Wesley, Reading, Mass. [IntServ] IETF ôIntegrated Servicesö working group. See http://www.ietf.org/html-charters/intserv-charter.html [IMT97] ITU-R Rec. M.687-2, "International Mobile Telecommunications-2000 (IMT-2000)", 1997. [KUR93] Kurose JF (1993) Open Issues and Challenges in Providing Quality of Service Guarantees in High-Speed Networks. ACM Comput Commun Rev 23 (1): 6-15 [LL73] Liu C, Layland J (1973) Scheduling Algorithms for Multiprogramming in Hard Real Time Environment, J ACM [LM93] Leslie IM, McAuely D, Mullender SJ (1993) Pegasus Operating Systems Support for Distributed Multimedia Systems, Oper Syst Rev 27 (1) [MPLS] IETF ôMultiprotocol Label Switchingö working group. See http://www.ietf.org/html.charters/mpls-charter.html and http://www.ietf.org/ids.by.wg/mpls.html [NS2] The network simulator û ns û 2, http://www.isi.edu/nsnam/ns/ [RAP] IETF ôRAPö working group. See http://www.ietf.org/html- charters/rap-charter.html [RFC2205] Braden, R., Ed., et. al., "Resource Reservation Protocol (RSVP) -Version 1 Functional Specification", RFC 2205, September 1997. [RFC2748] Boyle, J., Cohen, R., Durham, D., Herzog, S., Raja, R. and A. Sastry, "The COPS (Common Open Policy Service) Protocol", RFC 2748, January 2000. Kan, Ma Expires October 2002 14 draft-Kan-QoS-Framework-00.txt April, 2002 [RFC2753] Yavatkar, R., Pendarakis, D. and R. Guerin, "A Framework for Policy Based Admission Control", RFC 2753, January 2000. [RFC2996] Bernet, Y., "Format of the RSVP DCLASS Object", RFC 2996, November 2000. [RFC2998] Bernet, Y., Yavatkar, R., Ford, P., Baker, F., Zhang, L., Speer, M., Braden, R., Davie, B., Wroclawski, J. and E. Felstaine, "A Framework for Integrated Services Operation Over DiffServ Networks", RFC 2998, November 2000. [RFC2990] G. Huston. "Next steps for the IP QoS Architecture", RFC2990, Novermber 2000. [STA95] Stankovic et al. (1995) Implications of Classical Scheduling Results for Real-Time Systems, IEEE Comput (Special Issue on Scheduling and Real-Time Systems) [TOP90] Topolcic C (1990) Experimental Internet Stream Protocol, Version 2 (ST-II). Internet Request for Comments No. 1190 RFC1190, October [TWOZ99] A. Terzis, L. Wang, J. Ogawa, and L. Zhang, A two-tier resource management model for the Internet, in Proc.IEEE Global Internet 99, Dec. 1999. [WM93] Wolfinger B, Moran M (1991) A Continuous Media Data Transport Service and Protocol for Real-time Communication in High- Speed Net-works. In: Second International Workshop on Network and Operating System Support for Digital Audio and Video, IBM ENC, Heidelberg, Germany [ZK91] Zhang H, Keshav S (1991) Comparison of Rate-Based Service Disci-plines. ACM SIGCOMM Acknowledgments We would like to thank all who have contributed to this paper, in particular the authors of [TWOZ99] and our investigators in the project. Author's Address Zhigang Kan Nokia China R&D Center Nokia House 1, No.11, He Ping Li Dong Jie, Beijing,100013 PRC Kan, Ma Expires October 2002 15 draft-Kan-QoS-Framework-00.txt April, 2002 Phone: +86-10-6539 2828-2829 zhigang.kan@nokia.com Jian Ma Nokia China R&D Center Nokia House 1, No.11, He Ping Li Dong Jie, Beijing,100013 PRC Phone: +86-10-6539 2828-2883 Jian.J.Ma@nokia.com Full Copyright Statement Copyright (C) The Internet Society (1999). All Rights Reserved. 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