Statement of Current Research Interests Multicast-based Scalable Data Dissemination

My current major research focus is on multicast-based scalable data dissemination methods. Any casual user of the Web knows that there is a critical need for scalable data transfer methods. Web servers and networks can be brought to their knees by hot-spot access patterns. Examples of Internet hot spots include news sites such as CNN after the 2000 presidential elections, the NASA site after the Mars Pathhnder landing, and the host site at the Nagano Olympics. In each case millions of clients attempted to simultaneously access the sites. Servers and networks were overwhelmed by the large number of requests, resulting in long delays to retrieve documents. One solution to this scalability problem is multicast. In these hot spot examples, many clients were interested in nearly the same data. Thus, a single server could have served all such requests by multicasting the hot data items to interested clients without any explicit request from the clients. Note that this research will also impact data dissemination in wired and wireless local area networks, as well as satellite links, where broadcasting is the principal mode of communication. Multicast communication raises many data management issues that either do not arise in unicast communication, or that obviously require diierent solutions than the standard methods used in unicast settings. As an illustrative example consider the application of a highly scalable Web server. The objective of the Web server application is to scale to a large client population, and scalability will be accomplished by using the middleware. In the middleware, the server can disseminate data by choosing any combination of the following three schemes: multicast push, multicast pull, and unicast push. In multicast push the server repeatedly sends information to the clients without explicit client requests. For example, television is a classic multicast push system. Multicast push is an ideal t for asymmetric communication links, such as satellites and base station methods, where there is little or no bandwidth from the client to the server. For the same reason, multicast push is also ideal to achieve maximal scalability of Internet hot spots. Hence, generally multicast push should be restricted to hot resources. In multicast pull, the clients make explicit requests for resources, and the server broadcasts the responses to all members of the multicast group. If multiple clients request the same resource at approximately the same time, the server may aggregate these requests, and only broadcast the resource …