SMART : scalable multimedia rapid rate control for multicast transport

Abstract

Scalable Multimedia RApid Rate Control for Multicast Transport (SMART) is a protocol for receiving layer-encoded multicast multimedia session over a heterogeneous network. This thesis presents a new information sharing and traffic control algorithm between hosts and multicast routers for rapid layer adaptation and prompt congestion recovery of scalable multimedia in a multi cast session. Raising subscription level requires available network capacity. Since simple receiver-driven layer adaptation in the multicast multimedia session over a wide area network may drive the network into a persistently congested state, receivers need to know other receivers```` subscription status and reflect this knowledge to its own adaptation. SMART is designed for prompt rate control for real-time layer-encoded and transmitted multimedia over the heterogeneous multicast network. It newly de fines the dependency information of Internet Group Management Protocol version 2 (IGMPv2), and extends this protocol operation and functionality to support rate control of layered multicast multimedia. This protocol extension is called IGMPv2-DX (Dependency Extension.) SMART preserves backward-compatibility for receivers to gradually raise/drop layers, reflecting available network capacity, which is used in previous researches. Moreover with SMART , multimedia session receivers can adapt their subscription level to the optimal as fast as possible, remarkably reducing the adaptation latency. This feature is called Fast Learning of Newcomer. Congestion recovery can be do ne even faster than the successive leave-group operations. When a receiver detects a big congestion that cannot be recovered with a simple layer drop, it multicasts an Emergency Drop Request (EDQ) message, and a immediately neighboring multicast router for pre-specified time blocks forwarding the associated group to the downstream network where the receiver belongs. This feature is called Emergency Router Blocking. Signaling mec...