Topic Index:

Investigating Multicast Communication Individuality/Scalability Tradeoffs

Networked services are at the heart of the on-going information revolution. In this proposal we are most interested in two characteristics of a networked service: 1) {\em Scalability}: the ability of the service to handle a large number of end-users with low per-user cost, and 2) {\em Individuality}: the ability of the service to deal with differing requirements imposed because of heterogeneity in the end-users capabilities and/or heterogeneity of the network paths leading to the end-users. Although a high level of both individuality and scalability are desirable features of any networked service, they are normally conflicting goals that need to be traded-off with each other. Our work aims to investigate this tradeoff from the networking infrastructure's viewpoint. Typically, a networked service provider is required to choose either unicast or multicast as the underlying communication mechanism. In fact unicast and multicast represent the ends of a spectrum with many other possibilities in between. Moving in the direction of multicast gives increased scalability. Whereas moving in the direction of unicast gives increased individuality. The proposed research asks the following questions: 1) In services using multicast communication is it possible to add a level of individuality while sacrificing scalability in a controlled manner? 2) In services using unicast communication, is it possible to improve scalability while controlling how much individuality is sacrificed? 3) Is it possible to not require the labeling of services as unicast or multicast and move the burden of deciding the appropriate network support to a ``generic" interface layer? To answer these questions the research seeks to develop network support mechanisms to navigate the individuality/scalability spectrum; giving multicast services the ability to be more individualized and unicast services the ability to be more scalable.

Multicast Web

  • Ammar, M. H., Almeroth, K., Clark, R. J., Fei, Z., ``Multicast Delivery of Web Pages OR How to make Web servers pushy,'' Proceedings of the Workshop on Internet Server Performance, Madison, Wisconsin, June 1998.

    Multicast Video Distribution

    Multicast Video-on-Demand

    In this project we consider the provision of a scalable and interactive Video-on-Demand service which uses multicast communication to simultaneously serve multiple users with a single video stream. The technique involves a limited amount of synchronization of user requests which is done in a manner that does not detract from the on-demand nature of the system. We propose techniques to provide interactive features such as pause, rewind and fast-forward, thus giving the illusion of a one-to-one service. Simulation studies and experimental prototype implementations indicate that our proposed techniques are feasible and possess the desired properties.     Also see the Interactive Multimedia Jukebox.

    Inter-Receiver Fairness

    Reliable Multicast Mechanisms and Issues

     Response Collection: The following few papers deal with what we have dubbed the Response Collection Paradigm . This can be viewed as "multicast with a purpose". Simply stated, this is the act of gathering information from a set of network locations into a single location. Response collection is typically started with a multicast message soliciting a set of responses which are then sent back to the source of the multicast message. The "implosion" of reponses in such a scenario can cause severe problems of congestion and deadlock in the network and at the source. Our work deals with the modelling of this paradigm and proposals to alleviate the effect of the response implosion. Clearly response collection is an important componet of any multicast protocol requiring feedback and in particular in reliable multicast where feedback maybe required for error recovery and/or rate control.

    Multicast Database

    Receiver-Based Scoping

    Multicast Videotex and Teletext

    IP Multicast over ATM

    See the home page of this project.

    Mbone Participant Behavior Characterization

    See also the home page of this project.

    Other multicast communication work