Generalized Anycasting

The Internet is increasingly being viewed as providing services, and not just connectivity. As this view becomes more prevalent, it becomes important to provide, within the Internet, explicit support for the efficient delivery of networked services. An important consideration in the provision of such services is the ability of a service to meet the demands of a large number of users that are geographically wide-spread. It is also important that the user-perceived quality of service (e.g., response time, throughput, reliability) be maintained at an acceptable and competitive (in the case of commercial services) level. This is often referred to as the scalability of the service. In this project, we are investigating replication of servers for providing scalable service, along with the anycasting communication paradigm to identify a good server.

Our work focuses on the design of an infrastructure to provide an application-layer anycasting service. Our design centers around the use of anycast resolvers to perform the ADN to IP address mapping. Clients interact with the anycast resolvers according to a basic query/response cycle: a client generates an anycast query, the resolver processes the query and replies with an anycast response. A key feature of the system is the presence of metric databases, associated with each anycast resolver, containing performance data about servers. The performance data can be used in the selection of a server from a group, based on user-specified performance criteria. We consider metric determination techniques that can be used to maintain the anycast resolver databases. In addition, we investigate how anycast client applications may interface with the anycast resolver.

Publications

Students

Ellen Zegura
Last modified: Fri Oct 1 15:28:49 EDT 1999