Performance Comparison of Video Transport over ATM and ServerNet Interconnects

We have developed fully functional Video Server and Client applications which can transmit, receive, decom-press and display compressed video over various networks. Our video transport allows dynamic rate control feedback, loss detection and repair request from Clients to the Server. Our experiments show how feedback-before-degradation scheme for rate adaptation maintains desired QoS for video playback. We demonstrate how the playback degradation occurs and what happens if corrective measures are not taken to improve the situation. We attribute this degradation to increased internal kernel buuering which consumes scarce CPU resource. While comparing the ATM performance of our video applications with that of ServerNet, we observe that ServerNet, which provides improved hardware delivery guarantees, can signiicantly reduce host CPU resource consumption serving video streams. We determine the maximum number of streams which can be served for each of these two interconnects. The appropriate user-level packet sizes for the served video are also determined for each case.