Replication with QoS support for a Distributed Multimedia System

Replicating data and services at multiple networked computers increases the service availability, fault-tolerance and quality of service (QoS) of distributed multimedia systems. In this paper, we discuss some relevant design and implementation issues of a replication mechanism for a distributed multimedia system medianode[1] which is a software infrastructure to share multimedia-enhanced teaching materials among lecture groups. To identify new replication requirements, we first study the characteristics of presentational media types which are handled in medianode, then extract new replica units and granularities which have not been considered and not supported in existing replication mechanisms. Based on the new requirements and the result of feature surveys, we implemented a replication mechanism for medianode. The next working step is to evaluate the efficiency of our replica maintenance mechanism.