Application-specific group communications in distributed servers

Relaxation of the strict consistency requirements usually found in distributed server architectures is advocated, with emphasis placed instead on the inherent ability of the applications implemented by clients and servers to tolerate inconsistency in the state or deal with the inconsistency in an application dependent manner. For example, inconsistency in name binding information may be detected by a client on attempting to access the named object and corrected by a customized protocol. With such a relaxed consistency, operations on the server state often do not require strict coordination among the group members, and may be realized with weak ordering constraints on group messages. Thus a high degree of concurrency and efficiency is possible without compromising correctness. Sample applications are described to illustrate the use of relaxed consistency in designing distributed servers