RED-VBR A Renegotiation-Based Approach to Support Delay-Sensitive VBR Video.pdf

RED-VBR: A Renegotiation-Based Approach to SupportDelay-Sensitive VBR VideoHui Zhang Edward W. KnightlySchool of Computer Science ECE DepartmentCarnegie Mellon University Rice Universityhzhang@cs.cmu.edu knightly@ece.rice.edu To Appear in ACM Multimedia Systems Journal AbstractPrevious approaches to supporting video on packet-switched networks include deterministic service, sta-tistical service, predicted service, and feedback-based schemes. These schemes represent dierent tradeosin quality of service (QOS), achievable network utilization, and method of dealing with overload. In thispaper, we propose a new service called REnegotiated Deterministic Variable Bit Rate Service (RED-VBR)that attempts to strike an ecient balance with the above tradeos. The approach is based on deterministicguarantees with client controlled renegotiation of trac and QOS parameters and graceful adaptation duringoverload periods. We introduce a connection admission control algorithm for RED-VBR which bounds therenegotiation failure probability. We evaluate the scheme using two traces of MPEG-compressed video andshow that, even with simple renegotiation polices and relatively low renegotiation frequencies, high networkutilization in the range of 50% to 80% can be achieved. For trac that is bursty over long intervals, thisrepresents a 100% to 150% improvement in network utilization compared to deterministic service. Comparedto statistical and predicted service, our approach allows more graceful and client-controlled QOS degradationduring overload periods.1 Introduction and MotivationFuture integrated services networks will have to support applications with diverse trac characteristics andperformance requirements. There are three important types of trac for future integrated services networks:constant bit rate or CBR trac, delay-sensitive variable bit rate or VBR trac, and best-eort trac. Amongthese, delay-sensitive VBR trac poses a unique challenge. While resource reservation sche