Implementation of the DiffServ-based multicast gateway

There exists a wide variety of video multicast applications that often requires QoS. This paper presents a DiffServ-based multicast media gateway for adaptive video applications in DiffServ multicasting. It restricts data to be distributed using a limited number of multicast addresses (channels). To guarantee QoS and scalability, the proportional fairness scheduling strategy is proposed for layered media flows to determine the approximate QoS parameters. In order to differentiate traffic with different QoS within a multicast channel, a small number of undefined DS codepoints (DSCP) are reserved for marking packets, and dynamic associations between DSCPs and service types are maintained in output ports of routers. The proposed PFS strategy has been experimentally tested on several layered-video streams. The experimental results of the DiffServ-based multicast gateway system on DiffServ networks also reveal the capability for dynamic bandwidth adjustment in various networking situations.