(Georgia Institute of Technology, 1996)
Ammar, Mostafa H.; Zegura, Ellen W.; Shah, Viren; Fei, Zongming; Bhattacharjee, Samrat
Server replication is a key approach for maintaining user-perceived quality
of service within a geographically wide-spread network. 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; we further
allow filtering both at the anycast resolver and local to the anycast
client. A key input to the filtering process is metric information
describing the relative performance of replicated servers. We examine the
use of various techniques for maintaining this information at anycast
resolvers.