<title>Multimedia document retrieval system using partially ordered/partially reliable transport service</title>

Abstract

We investigate the benefits of using a partially-ordered/partially-reliable (PO/PR) transport service for multimedia document retrieval over the Internet by implementing a prototype system. We introduce PMSL, a document specification language combining aspects of Little and Ghafoor's OCPN with features for graceful degradation. We then show that for retrieval of PMSL documents, our PO/PR transport protocol (POCv2) provides several benefits over traditional protocols such as TCP or UDP. First, POCv2 provides mechanisms to achieve the reliability and order requirements of individual multimedia objects as specified by a document author. Second, when network conditions are poor (e.g., high loss rates), POCv2 provides for graceful degradation. Finally, POCv2 simplifies application development by providing appropriate mechanisms for synchronization.