Pseudo-active replication of distributed objects in wide-area networks

Discusses how to replicate a server in order to obtain fault-tolerant services. In active replication, all the requests from a client are performed by all the server replicas in the same order. The replicas are placed on heterogeneous computers interconnected in a wide area network, e.g. the Internet, where each communication channel has a different message transmission delay and bandwidth. Hence, the response times of the replicas observed by the clients are not the same. We propose a pseudo-active replication, where the client does not wait for other responses after receiving one response, and slower replicas do not perform every request performed by the faster replicas.