Resource- and quality-aware application-level service multicast

Current multimedia application deployment tends to rely on composable service systems, where a complex multimedia service can be composed dynamically from multiple simpler ones distributed widely in the Internet. Related to such a scenario is the problem of finding efficient service paths that meet end-to-end requirements. Work has been done in discovering unicast service paths. However, considering that resources are limited, for distributed multimedia applications that may have a single sender but multiple heterogeneous end-users, it is demanding to build service trees to minimize resource usages by means of sharing. We present a resource- and quality-aware application-level multicast Service Path Finding protocol (mc-SPF/sup Q/) that constructs, for each application, a more economical service tree instead of independent service paths. Bandwidth and proxy machine resource savings can be achieved by applying the application-layer multicast concept to deliver data through the service tree. mc-SPF/sup Q/ Is resource- and quality-aware, in that service paths are discovered with resource availability and client's quality demand in mind. Our simulation results show that: (1) compared to unicast service path finding solutions, mc-SPF/sup Q/ is superior; (2) the proxy load balancing feature makes the protocol achieve better path finding success rates in the face of resource scarcity; (3) reserving different portions of resources for service requests of different qualities affects the service path finding success rate and the average quality of service.