Enriching and Impoverishing Types of Write Operations in the Multimedia Quorum-based (MQB) Protocol

Multimedia objects are distributed to peers through downloading and caching in peer-to-peer (P2P) overlay networks. Multimedia objects are characterized in terms of not only data structure but also quality of service (QoS). Replicas of a multimedia object are partially ordered in terms of newness of data structure and QoS. We discuss the multimedia quorum-based (MQB) protocol to synchronize multiple replicas of a multimedia object. We classify write operations on a multimedia object into enriching and impoverishing types of operations. In an enriching operation, some data is added to a replica like an operation to increase the number of colours. In an impoverishing operation, some data in a replica is removed like operation to degrade QoS. If an enriching operation is issued to replicas, the replicas are updated like traditional quorum-based (QB) protocols. On the other hand, every replica in a quorum is not updated in impoverishing operations to reduce communication and computation overheads. On the other hand, an impoverishing operation is just logged in a replica and is not performed on the replica.