Evaluation of multimedia quorum-based synchronization protocols

We discuss how to efficiently make replicas of a multimedia object consistent. Multimedia objects are characterized in terms of not only data structure but also quality of service (QoS). There are two types of write operations: enriching and impoverishing types. Some data is added to a replica in an enriching type while removed in an impoverishing type. Computation resources are spent to materialize, i.e. physically update replicas of a multimedia object. We discuss an extended multimedia quorum-based (EMQB) protocol to reduce the processing overhead of each replica. Here, a replica is not materialized in an impoverishing type of write operation. Even in an enriching type of write operation, only some number, not necessarily all, of replicas in a write quorum are updated. Hence, a newest materialized replica may not be found in a read quorum. Replicas are randomly selected to be in a read quorum until an updated replica is found in the quorum. The EMQB protocol is evaluated in terms of the total processing overhead of replicas. We show that the processing overhead of each replica can be reduced in the EMQB protocol.