Resource lock commit protocol (RLCP) for multimedia object retrieval

Many multimedia presentation applications involve retrieval of objects from more than one collaborating server. Presentations of objects from diierent collaborating servers might be interdependent. For instance, we can consider distributed video servers where blocks of movies are distributed over a set of servers. Here, blocks of a movie from diierent video servers have to be retrieved and presented continuously without any gaps in the presentation. Such applications rst need an estimate of the available network resources to each of the collaborating server in order to identify a schedule for retrieving the objects composing the presentation. A collaborating server can suggest modiications of the retrieval schedule depending on its load. These modiications can potentially aaect the retrieval schedule for other collaborating applications. Hence, a sequence of negotiations have to be carried out with the collaborating servers in order to commit for a retrieval schedule of the objects composing the multimedia presentation. In this paper, we propose an application sub-layer protocol, Resource Lock Commit Protocol (RLCP), for handling the negotiation and commitment of the resources required for a collaborative multimedia presentation application.