A probe-based server selection protocol for differentiated service networks

Quality-of-service (QoS) techniques and server replication are two complementary approaches that can improve the performance observed by users. QoS techniques provide differentiated service to meet the diverse needs of applications; server replication enables load balancing across a set of servers. To combine the two approaches, we need to address one important question: how to select a server among a replicated set that satisfies the user QoS requirement. We propose a probing-based protocol to discover network resources and make reservations for requests in differentiated service networks. This approach optimizes network resource utilization with reasonable signaling overhead. Furthermore, we compare five heuristics that can be used for server selection. We also investigate two methods that can reduce probing overhead, namely caching and the technique of probing from a subset of servers.