Abstract: The multimedia communication technology has been improved dramatically with the improvement of networking technology as well as audio/video processing technology. The real time property of multimedia applications has attracted a lot of attention. Future integrated services networks will have to support applications with both diverse traffic characteristic and diverse performance requirements. The real time multimedia application, which is delay sensitive, faces the challenge of satisfying quality of service constraints. The delay is an important performance metric as well as packets loss probability（PLP）, and the bandwidth estimation has become an important metric in call admission control （CAC） and congestion control （CC）. In this paper, based on their statistical characteristics and with the PLP and the delay considered, a computationally simple approximation expression for the equivalent bandwidth of the multimedia applications, is proposed for real time bandwidth estimation and management. The impacts of some relevant parameters are investigated.