Application-layer anycasting

The anycasting communication paradigm is designed to support server replication by allowing applications to easily select and communicate with the `best' server, according to some performance or policy criteria, in a group of content-equivalent servers. We examine the definition and support of the anycasting paradigm at the application layer, providing a service that maps anycast domain names into one or more IP addresses using anycast resolvers. In addition to being independent from network-layer support, our definition includes the notion of filters, functions that are applied to groups of addresses to affect the selection process. We consider both metric-based filters (e.g., server response time) and policy-based filters. An expanded version of this work can be found as a technical report.