Section I Administrative BAA Number: BAA 94-07-09 Technical Topic Area: Multicats Services Title: Mechanisms for Supporting and Utilising Internet Multicast Multimedia Technical Point of Contact: J A Crowcroft, P T Kirstein, Z Wang Email: {jon, kirstein, zwang}@cs.ucl.ac.uk Fax: +44 171 387 1397 Mailing Address: Department of Computer Science, University College London Gower St, London WC1E 6BT, England Administrative Point of Contact: Maria Widdowson Email: maria@cs.ucl.ac.uk Fax: +44 171 387 1397 Mailing Address: Department of Computer Science, University College London Gower St, London WC1E 6BT, England Type of Business: Educational. [new page] Section II Summary of Proposal A. Purpose of Proposed Research Multicast has emerged as one of the key enabling technologies for supporting next generation networking applications such as video conferencing. In the past years, there have been considerable reseach activities in the Internet community on multicast routing protocols and multicast-based applications, and significant progress has been made in dveloping and utlising this technology. Nevertheless, there are still many important issues remain unsolved. We believe that the following mechanisms have to be developed before multicast can be used by wider community at a more regular basis. 1. Mechanisms for supporting multicast routing protocols such as core placement strategies for CBT and PIM, Qaulity of Service path selection in multicast tree formation, and unicast support for reverse path calculation. 2. Mechanisms for utilising multicast capability in applications such as feedback control in a multicast environment, management of applications in a multicast group, and reliable multicast transport. 3. Mechanisms for integrating resource management with multicast forwarding, such as interface between forwarding engine and caching issues. The purpose of the proposed research project is to develop novel mechanisms for supporting and utilising Internet multicast. In particular, we will carry out research and development in the the three areas identified above. B. Statement of Work In this section, we ouline the work we intend to carry out in this project. Each task will be elaborated in the Technical Rationale section. 1. Design of a core placement algorithm for CBT and PIM. 2. Investigation into Quality of Service (QoS) support in multicast routing. 3. Study on security issues and protection mechanisms for multicast networks. 4. Investigation into unicast routing support for multicast tree formation with reverse path forwarding 5. Experimentation of feedback traffic control algorithms for multicast-based applications. 6. Investigation into reliable multicast transport protocols based on the concept of Application Layer Framing. 7. Design and implementation of management and control protocols for multicast-based applications. 8. Integration of resource management and multicast forwarding. 9. Investigation of Mobility, Multimedia and Multicast traffic. C. Deliverables The deliverables from this project will be in the form of technical reports, algorithms and software. 1. A core placement algorithm suitable for CBT and PIM, and a technical report detailing the operation of the algorithm. 2. A technical report on QoS support in multicast routing. 3. A technical report on the secuirty issues and protection mechanisms for multicast networks. 4. A algorithm for unicast support for reverse path calculation, and a report detailing its operation. 5. A technical report on the algorithms and performance data of various feedback control algorithms. 6. A technical report on the lessons learnt from design of reliable multicast transport protocols. 7. Software for management and control video conferencing system and a report detailing its design and implementation. 8. Software for kernel implementation of integrated resource management and multicast forwarding. D. Technology Transfer The research results and software from this project will be transfered DoD, HPCC and commercial communities through IAB Research Groups, IETF WGs, other standards and publication channels, and our collaborations with Bellcore, Sun, Cisco, Xerox and BT/MCI. E. Cost, Schedule and Milestones Many of the tasks are closely related to each other and they will be pursued in parallel, therefore we can only provide a coarse shedule and milestones. In the first year, we will concentrate on mechanisms for supporting multicast routing protocols, i.e., Task 1-4 in the Statement of Work. In the second year, we will move onto mechanisms for utilising multicast and integration issues, i.e. Task 5-8 in the Statement of Work. It is not really feasible to associate costs with each tasks in each year. We will list the total costs here and will discuss with the Project Officer as the research progresses. -------------------------------------------------- This was the original submitted budget -------------------------------------------------- The budget below assumes that there will be two researchers fill time on the project, in addition to efforts by the PIs. 1995 1996 total staff 108500 113825 222325 overhead 97650 102533 200183 travel 10000 10000 20000 consumable 7750 7750 15500 maintenance 10850 10850 21700 -------------------------------------------------- This was PTKs revised budget: the budget is about $480K, so this woud be $16K (L10K) per month. I suggest the following monthly budget: Travel $2K Equipment 5 Maintenance 1.5 Consumables 0.5 Labour 3.7 O/H 3.3 This would pay just one person, but woud have a generous equipment and travel and maintenance budget. During this period, we will have a fair number of ACTS and Telematics projects for staff. Do you agree. If you do, we can respond appropriately to ARPA dependig on when they can start the grant. with a 90% O/H, we presumably do not also hav to pay for extra infrastructure people or other central costs; --------------------------------------------------------- F. Proprietary Claims All results from the project will be freely available for ARPA purposes. G. Technical Rationale and Approaches In this section, we provide the necessary backgroud to the work we propose to carry out, discuss the technical approaches we will use and the relationship with other on-going work. UCL has access to an experimental testbed in the UK and further afield in Europe, and possibly onwards to the USA, under the auspices of SuperJANET, BT funding (to run for 1-5 years) and EC funding, and existing ARPA program of work (to end Jan 1995). Unlike the Gigabit program, this network is shared with service traffic from the research and education community, and increasingly, from commercial users. We will make use of this to build experimental platforms for the work described above. Since we can introduce real traffic patters from a real evolving community, we will be able to validate each stage of our work very effectively. UCL has been very active in the area of multicast and multimedia communications. There are currently several projects on multicast routing, multimedia conferencing, congestion control and resource management. Many of the other related projects at UCL will be fed into this project. We are designing a new multicast routing algorithm CBT in collabration with Bell Communication Research (Bellcore). CBT is currently under consideration by the Inter-Domain Multicast Routing Work Group (idmr-wg) of the Internet Engineering Task Force (IETF), where Tony Ballardie from UCL is the co-chair of the idmr-wg. The MICE and PREPARE projects look into large-scale multimedia video conferencing. UCL developed a multicast transport protocol to run over the then new IP multicast service. In the EC MICE project, we have developed a number of tools with partners for end to end multicast support for applications, including congestion control for audio and video conferencing programs; quality and topology monitoring tools for the Mbone; Engineering of RTP mappings for multicasting H.261 compressed video; design of variable loss tolerant audio encodings; design of a next generation shared text editing package based on optimistic consistency end to end multicast protocols. In the current ARPA project, we have developed a Conference Control Channel Protocol, which is compatible with the emerging standards in the IETF. We have also implemented a mechanism called class based queuing, invested by Van Jacobson, to support link sharing and Integrated Internet Services. This is being integrated with RSVP to provide reservations, although how scalable this will be requires further research. We also carried out extensive research on the complexity of QoS routing. We now discuss each task in some detail. 1. Core placement and management CBT and PIM require a core-based multicast tree structure. At the present, cores are placed "by hand" based on the topology and group membership distrbution. Automatic core placement and management is an important research issue that has not been solved. The problem is known to be complex. We will develop efficient heuristic algorithms for common case multicast styles and from the knowledge of the traffic distribution. We will also look into the issues such as core selection, placement, setup and error recovery. 2. Quality of Service (QoS) support in multicast routing. It is becoming increasingly clear that traditional routing metrics such as delay and hop-count are inadequate for these new applications which often have stringent quality of service (QoS) requirements. For a network to support diverse QoS requirements, it is necessary for routing to have a more complex model of the network, for example, characterized with multiple metrics such as bandwidth, delay and loss probability, and to be able to find paths that satisfy specific application QoS requirements. We will investigate QoS support in multicast routing based on our early work on the complexity of QoS routing. 3. Security issues for multicast networks. Security issues in multicast networks are of extremely importance as multicast communication is at a substantial increased risk from specific security threats, compared with the same threats in unicast. Since multicast involves one-to-many communications, a single node may affect the whole network. A few incidents on the experimental MBone has shown that an innocent mistake may cause the flooding of the whole MBone. We will first try to identify the sepcific threat either malicious and non-malicious, and investigate protection mechansims based on both presentive and detective approaches. 4. Unicast routing support for multicast tree formation. Multicast algorithm such as DVMRP and PIM use the reverse path of unicast routing to build the multicast tree. However, current unicast routing does not support reverse path calcualtion. Ad-hoc mechanisms have been used to bypass this problem (e.g., a built-in unicast routing protocol in current implementation of DVMRP, and the PATH message in RSVP). In the future, the problem must be addressed in unicast routing. We will investigate mechanisms for integrating and supporting both forward-path and reservse-path forwarding in a unified path calculation. 5. Feedback traffic control algorithms for multicast-based applications. Feedback traffic control has been widely used in the Internet and has been shown working very effectively. Even with the introduction of RSVP and Integrated Internet Services, applications may have to adapt to varying network conditions, since they may be part of an aggregated flow, or simply because they do only require a best effort service. However, feedback control in the multicast envionment poses a difficult problem as the receivers generate an imposion of feedback packets to the source. We will build on the work by Van Jacobson on WB and the work we did at UCL on scalable feedback, and look into area-based feedback schemes. 6. Reliable multicast transport protocols Multicast transport protocols are often considered an "oxymoron", since without complete knowledge of group membership, guarantees of reliable delivery to all interested parties cannot be made. However, using the concepts generally tagged "Application Layer Framing", where applications define the error recovery model to be used for their data, we can attempt to provide models of interaction between applications and the network layer which facilitate design of multicast aware applications. We will carry out experiements with the Nt shared text editor developed at UCL. 7. Management and control protocols for multicast-based applications. Management and control of multicast-based applications such as video conferencing is an active research area. Multicast creates a new way of managing and controling group communication. We will carry out a detailed study on various approaches used in video conferencing control protcols, and develop a new abstraction of many-to-many communication, and discuss the implication of multicast on traditional distributed computing paradigms. We will experiement with our ideas with the CCCP system we developed at UCL. 8. Integration of resource management and multicast forwarding. Multicast presents a number of challenging problem for resource reservation. Although resource setup protocols such as RSVP have introduced a framework for resource reservation in multicast, many important issues remain unsolved. We will look into various aspects of this problem, such as how to deal with route changes in multicast, how to use traffic shaping to reduce the complexity in mapping the QoS requirements and the network resources, and how to integrate multicast forwarding and resource reservation lookup. H. Key Personnel The principal academics who will be associated with this work are Prof Peter Kirstein and Dr Jon Crowcroft, who will be spending about 20% of their time on the project. Both have been Principal Investigators for ARPA projects and working in the areas of the proposed research for many years. The research workers directly on the project will probably be Dr Zheng Wang and another research follow. Peter Kirstein Peter Kirstein received his undergraduate degree in Mathematics and Electrical Engineering at Cambridge University. He also has a Ph D in Electrical Engineering from Stanford U., and a D.Sc from London U in the same subject. Peter has worked at Stanford U (USA), the Centre of European Nuclear Research (CERN) in Geneva (Switzerland), and the US General Electric, located in Zurich (Switzerland). He is now Professor of Computer Communications Systems and Head of the Department of Computer Science at University College London. Professor Kirstein has been leading research projects in computer communications networks, telematic services, security and multimedia for over 20 years. Most of his current research projects include collaboration with European and US colleagues. Amongst these activities are developments in multimedia, directory and security applications, and piloting them in the Research Community in Europe and elsewhere. Current piloting activities include the PARADISE project in Directory Services, the PASSWORD project in Security Services, the CODA project in access to Chemical Journals in ODA and the MICE project in multimedia conferening. Peter has a number of projects in the high speed network and multimedia area. He is Director of the CEC-sponsored MICE project to pilot multi-way, real-time multimedia services in Europe with links to the US. This work arises out of other activities he has been conducting both with DARPA and the CEC RACE program in Network Management and Distributed Real-Time systems. These activities will be extended over the next couple of years over the emerging ATM infrastructures in the UK and the rest of Europe. Peter is a Fellow of the UK Royal Academy of Engineering, the British Computer Society, the Institute of Physics, and the Institution of Electrical Engineering. He is a Senior Member of the Institution of Electrical and Electronic Engineers. Jon Crowcroft Jon Crowcroft is a senior lecturer in the Department of Computer Science, University College London, where he is respnsible for a number of European and US funded research projects in Multi-media Communications. A recent project just completed worked on protocol migration (Internet and OSI). He has been working in these areas for over 10 years. For the last 3 years he has also been consulting to the Bloomsbury Computing Consortium as a Senior Systems Analyst on the installation of a multi-campus distributed system. He graduated in Physics from Trinity College, Cambridge University in 1979, and gained his MSc in Computing in 1981, and PhD in 1993. He is a member of the ACM, the British Computer Society and the IEE. He will be general chair for the ACM SIGCOMM 94 symposium. He is also on the editorial teams for the Journal of High Speed Networks and IEEE Network. He has over 50 publications. Current Projects which reflect his interests include DARPA funded project building Multimedia over Multiservice Networks, RACE Prepare Project Piloting ATM for Conferencing Systems, ESA Project investigating Load Balancing for SPace Craft Control Systems, FUME project looking to multicast forwarding. Zheng Wang Zheng Wang received his B.Eng degree in Electronic Engineering from Zhejiang Univeristy, China, in 1985, and his PhD in Computer Science from University College London, England, in 1992, respectively. He has been a research fellow at University College London (UCL) since 1992, where he is working on multimedia communications and high performance networking. Prior to joining UCL, he was with Cambridge University from 1990 to 1992. His current interests include resource management, routing, multicast and protocol design. He has published over 20 papers in the above areas. I. Cost Breakdown The following cost estimation is based on exchange rate of 1 pound to 1.55 dollar, and inflation rate of 5%. ============================NEEDS REVISION======================= The project will require 2 full time research follows (RFs). In addition, there would be a number of support staff who are budgeted under the Departmental Overhead. staff 1995 1996 RF1 46500 48825 RF2 62000 65100 subtotal 108500 113925 overhead 97650 102533 The majority of the equipment, such as servers, workstations, local and international communications, will be provided by the Department and other projects. equipment 1995 1996 0 0 The project will have close link with IETF activities and other ARPA-related projects in the US. We have budgeted 3 trips to IETF meetings and 1 trip to the ARPA PI meeting. We will continue to use multimedia conferencing facilities in collaborating with researchers in the US and working group discussion in the IETF. traval 1995 1996 10000 10000 The costs of the proposed project over a two-year period is given below: 1995 1996 total staff 108500 113825 222325 overhead 97650 102533 200183 travel 10000 10000 20000 consumable 7750 7750 15500 maintenance 10850 10850 21700 ============================NEEDS REVISION======================= J. Bibliography Bacarisse, B, J Crowcroft M Riddoch, and S Wilbur, "The Design and Implementation of a Protocol for Remote Procedure Call", Proceedings UK IT '88, Swansea, July 1988.. Ballardie, Crowcroft Tsuchiya, "Core Based Trees," Proc ACM SIGCOMM 93, San Francisco, September 1993. Crowcroft J, "FDDI and Broadband ISDN. Interconnection", ACTES Telematiques a Grande Vitesse, Workshop, Liege, March 1989. Crowcroft J, "Policy Routing and Protocol Hierarchies", International Symposium on Local Communications Systems Management, p. North Holland, IFIP, Sep, 1990. Crowcroft J, "Multimedia Application Requirements for Multicast Communications Services," Proceedings of INET 93, San Francicso, August 1993. Crowcroft J, "TCP/IP - Co-existence and migration to OSI - paths to follow", The Interoperability Workshop", Oct/Nov, 1990, London. Crowcroft J, "CMOS Ethernet Drivers," UCL Internal Note 1832, January 1986. Crowcroft J and K Paliwoda , "Reliable Multicast Protocols", Proceedings of the Alvey 88 IT Conference. Crowcroft J and I Wakeman, "Traffic Analysis of some UK-US Academic Network Data", INET '91, International Networking Conference, Copenhagen, June '91 Crowcroft J and M Riddoch, Managing the Interconnection of LANs", Proceedings of IFIP Conference Berlin, North Holland, 1988. Crowcroft J and K Paliwoda , "A Multicast Transport Protocol", Proceedings of the ACM SIGCOMM 88 Symposium, 1988. Crowcroft J, "International Internetworking", Connexions Magazine, Volume 2, No. 4, Published by Advanced Computing Environments, April 1988. Crowcroft J and M Riddoch, "High Speed Interconnection of LANs", Proc Alvey 88 IT Conference, July 1988. Crowcroft J, "The X Windows Protocol over the ISO Transport Service", Proc Networks 90, Online, Dec 1989. Crowcroft J, "Experience with The X Windows Protocol over OSI Protocols", First European X Users Group Conference, Sep 1990. Crowcroft J, "Entries on "Metropolitan Area Networks" and "Gateways", Encyclopedia of Computer Science & Engineering, 1991. Crowcroft J, "Campus Communications", Elsevier, 1991. Crowcroft J, P Kirstein, and D Timm, "Multimedia TeleConferencing over International Packet Switched Networks", Computer Communications, Butterworth, April, 1991. Crowcroft J and M d'Inverno, "Text Based Real Time Computer Conferencing: Specification, Design and Implementation", Proceedings IEEE Infocomm 91, vol. 2, pp 1114-1126, p. IEEE, April 1991. Crowcroft J, P Kirstein, and D Timm, "Multimedia TeleConferencing over International Packet Switched Networks", Proceedings IEEE TriComm 91, Conference on Communications Software, , April 1991. Crowcroft J, "JANET IP Network Service"," Connexions Magazine, Published by Advanced Computing Environments, June 1991. Crowcroft J, "JANET IP Network Service"," Connexions Magazine, Published by Advanced Computing Environments, June 1991. Crowcroft J and R Bradshaw, , "DoD Internet Protocols and JANET", EARN/RARE IAB Networking Conference/Blois, Elsevier, May 1991. Crowcroft J and I. Wakeman, "Multimedia Packet Teleconferencing Systems and Workstations," EurOpen Forum for Open Systems, vol. 11, no. 3, pp. 2-6, Autumn 1991. Crowcroft J, S. Hailes, M. Handley, A. Jena, D. Lewis, and I. Wakeman, "Some Multimedia Traffic Characterisation and Measurement Results," RN/92/29, April 1992. Crowcroft Jon and Jon Crowcroft and Jon Crowcroft "Bandwidth Requirements for Multimedia," 2nd European Network Users Forum, Windsor, Jan 1993. ISBN 1 873611 06 4 Lloyd P., Crowcroft J "Routing Issues in Internetworking Local Area Networks, Proc. Networks '84, 217-230, p. Online, July 1984. Eliasz A, S Bavan, and J Crowcroft "Adaptive Network Management Using Neural Computing", 3rd RACE TMN Workshop, Heathrow, August 1989. Eliasz A and J Crowcroft "Some Investigations into Policy Based Routing Schemes and Systems"," International Symposium on Local Communications Systems Management, North Holland IFIP, Sep, 1990. Hailes S, Jon Crowcroft and Ian Wakeman, "Communications Abstractions for Compressed Continuous Media," In progress. Crowcroft J, Hall, R., "A distributed approach to loading in a networked environment" ," Ring Technology Local Area Networks. Kirstein P and J Crowcroft , "International Research Network Links", Proceedings RARE High Speed Networks Conference, Febuary 1991, Brussels. Kirstein P and J Crowcroft "International Research Network Links", Proceedings RARE High Speed Networks Conference, Febuary 1991, Brussels. Lewis D and J Crowcroft "Prepare Multimedia Testbed," Proc of RACE Broadband Island Confernce, Athens, September 1993. Onions J and J Crowcroft "Network Time Protocol (NTP) over the OSI Remote Operations Service."," RFC 1165 , p. SRI NIC., 1990 June. Pavlou G, J Cowan, and J Crowcroft "A Generic Management Information Base Browser," UCL Internal Note, December 1991. Wilbur S, Crowcroft J, and Murayama Y, MAC Layer Security Measures in Local Area Networks, IFIP LAN SEC Workshop, Berlin, May 1989. Seo, Crowcroft Leddy, Spilling, Topolcic, and Laws,, "SATNET Measurements Task Force", BBN Report 7501, Bolt Beranek and Newman, Oct 1990. Seo, K and J Crowcroft "The SATNET Distributed Measurement Experiment", Proceedings of the ACM SIGCOMM 88 Symposium. Wakeman I, Jon Crowcroft, Zheng Wang and Dejan Sirovica, "Layering considered harmful," IEEE Network 16 July 1991. Adams C J, GC Adams, AG Waters, I Leslie, and PT Kirstein, "Protocol architecture of the UNIVERSE project," Universe Project Report, pp. 379-383, 1983. Cerf VG and PT Kirstein, "Issues in Packet-Network Interconnection," Proc. of IEEE, Vol. 66, No. 11, pp. 1386- 1408, November 1978. Crowcroft J, P Kirstein, and D Timm, "Multimedia TeleConferencing over International Packet Switched Networks", Proceedings IEEE TriComm 91, Conference on Communications Software, April 1991. Kirstein P and J Crowcroft , "International Research Network Links", Proceedings RARE High Speed Networks Conference, Febuary 1991, Brussels. Kirstein P and et al, "The UNIVERSE Project," Proc. ICCC82, pp. 442-447, North Holland, London, September 1982. Kirstein P and T. Daniel, "The Provision of UK-US Services for Non-Subsidised Users by the UCL Gateway Service Project," in UCL Internal Note 1664, 1984. Kirstein P, "Upgrading the intercontinental links for research collaboration with emphasis on the UK-US scene,Amsterdam in EARN/RARE networking conference, Killarney, Eire, May 15-17 1990, p. 13, May 1990. Kirstein P and R. Beckwith, "Experiences with the University of London Interactive Video Education Networ,Amsterdam RN/90/61, p. 20, October 1990. Kirstein P, "An Introduction to International Research Networks (Fat Pipes).,Amsterdam 1988 International Communications Conference in Tel Aviv., 18th July 1988. Kirstein P and Stephen E. Kille, Mail Converting Relaying Functions in the CCIRN Community Operating, April 1989. Wilbur S R and PT Kirstein, "The Universe Catenet Its Protocols and Lessons,Amsterdam IEE Computers and Digital Techniques, May 1985. Wakeman I, "Emerging High Speed Transfer Protocols,Amsterdam Third IEE Conference on Telecommunications, IEE, Edinburgh, March 1991. Wakeman I, "Packetised Video: Options for interaction between the User, the Network and the Codec", The Computer Journal, BCS, London, February 1993. Wilson F, Ian Wakeman, and Walter Smith, "Quality of Service Parameters for Commercial Application of Video Telephony,Amsterdam Human Factors in Telecommunication Symposium, Darmstadt, Germany, March 1993. Wakeman I, Atanu Ghosh, and Jon Crowcroft "The design and implementation of Class Based Queueing in a Streams Module, Usenix 95. Wakeman I, Jean Bolot, Thierry Turletti, and Jon Crowcroft "Multicast Congestion Control in the distribution of Variable Bit Rate Video in the Internet,Amsterdam Sigcomm94, London, August 1994. Wakeman I, Dave Lewis, and Jon Crowcroft "Traffic Analysis of trans-Atlantic traffic,Amsterdam Proceedings of INET92, Internet Society, Kobe, Japan, June 1992. Wakeman I, Dave Lewis, and Jon Crowcroft "Traffic Analysis of trans-Atlantic traffic,Amsterdam Computer Communications, vol. 16, no. 6, p. 376,388, Butterworth-Heinemann, June 1993. Wakeman I, and Jon Crowcroft "A Combined Admission and Congestion Control Scheme for Variable Bit Rate Video,Amsterdam To be published in Journal of Distributed Systems Engineering, October 1992. Wang Z, "Model of Network Faults", Proceedings of the First International Symposium on Integrated Network Management, Boston, USA, May 1989. Wang Z, J. Crowcroft "Shortest Path First with Emergency Exits", Proceedings of ACM SIGCOMM'90, Philadelphia, USA, Sept. 1990. Wang Z, J. Crowcroft "A New Congestion Control Scheme: Slow Start and Search (Tri-S)", ACM Computer Communication Review, Vol 21, No 1, Jan. 1991. Wang Z, J. Crowcroft I. Wakeman, "A Simple TCP Extension for High-Speed Paths", ACM Computer Communication Review, Vol 22, No 1, Jan. 1992. Wang Z, "Routing and Congestion Control in Datagram Networks", PhD Thesis, Department of Computer Science, University College London, UK, February 1992. Wang Z, J. Crowcroft "A Fluid Model Approximation to Quantitative Information Feedback in Congestion Control", Proc. of IEEE 7th International Phoenix Conference on Computers and Communications, Arizona, USA, April 1992. Wang Z, J. Crowcroft "Analysis of Shortest-Path Routing Algorithms in a Dynamic Environment", ACM Computer Communication Review, Vol 22, No 2, April 1992. Wang Z, J. Crowcroft "Eliminating Periodic Packet Losses in the 4.3-Tahoe BSD TCP Congestion Control Algorithm", ACM Computer Communication Review, Vol 22, No 2, April 1992. Wang Z, J. Crowcroft "A Two-Tier Address Structure for the Internet: a solution for the address space exhaustion problem", RFC-1335, SRI International, USA, May 1992. Wang Z, J. Crowcroft "SEAL Detects Cell Misordering (A Note on Using CCITT 32-Bit CRC for Detecting Mis-ordering in ATM Networks)", IEEE Network, Vol 6, No 3, July 1992. Wang Z, "The Extended Internet Protocol (EIP)", RFC-1385, SRI International, USA, July 1992. Wang Z, J. Crowcroft "Analysis of Burstiness and Jitter in Real Time Communications", ACM SIGCOMM'93, San Francisco, USA, Sept 1993. Wang Z, J. Crowcroft "A Unified Framework for Multicast Forwarding", the Fourth International Workshop on Network and Operating System Support for Digital Audio and Video, Lancaster, UK, November 1993. Wang Z, J. Crowcroft "Analysis of Burstiness and Jitter in Multimedia Communications", IEEE GLOBECOM'93, Texas, USA, Dec 1993. Wang Z, J. Crowcroft "A Dual-Window Model for Flow and Congestion Control", The Distributed Computing Engineering Journal, Institute of Physics/British Computer Society/IEE, Vol 1, No 3, page 162-172, May 1994. Wang Z, J. Crowcroft "A Unified Framework for Multicast Forwarding", Lecture Notes in Computer Science, Vol 846, pp 252-258, Springer-Verlag, 1994. Wang Z, J. Crowcroft "QoS Routing for Supporting Resource Reservation", submitted for publication.