Delay performance evaluation of high speed protocols for multimedia communications

Multimedia applications integrate a variety of media namely, audio, video, images, graphics, text, and data, each of which has different quality of service (QoS) requirements. To study the support of multimedia traffic on high speed protocols, we examine two significant metrics: delay fairness and worst-case delay performance. Four members of reservation-based high speed protocols are studied DQDB (distributed queue dual bus), CRMA (cyclic reservation multiple access), DQMA (distributed queue multiple access), and FDQ (fair distributed queue). The first part of this work presents delay fairness study of the protocols under various input traffic. Both access delay and message delay experienced by individual network nodes are measured to illustrate their fairness performance. The second part conducts worst-case delay experiments. Too worst-case scenarios of a test message are studied. The delay experienced by this message under varied inter-node distance is measured. The simulation results show that DQDB has the worst fairness performance. CRMA and DQMA present mixed results. FDQ proves itself to be a very fair protocol. The results also suggest that to there is no singe metric to justify a new protocol. Comparing our results with previous results on throughput evaluation of multimedia traffic support, we found that the two results are strongly correlated the fairer a protocol is, the better it is for supporting heterogeneous traffic under heavy network load