Web Server 7.0 supports the cluster-based session replication and failover. The purpose of session failover is to provide high availability to web applications. High availability of web applications is achieved by replicating HTTP sessions from one instance to another server instance of the same server cluster. That is, each HTTP session has a backup copy on a remote instance. In the event of server failure that renders one instance in the cluster unavailable, the cluster still maintains session continuity.