A packet eligible time calculation mechanism for providing temporal QoS for multicast routing

In this paper, we propose a packet eligible time calculation mechanism and its associated information update method to provide temporal QoS to multicast services, in terms of delay bound coupled with inter-message delay jitter bound and/or bounded inter-destination delay jitter bound. We assume the availability of a multicast tree on which the delay between a source and any destination falls within the end-to-end delay bound. We then exploit the idea of artificially delaying transmission of data packets until their eligible times, and model each router as a regulator followed by a packet scheduler. A data packet is not eligible to be scheduled until the current time is greater than or equal to its eligible time. For each temporal QoS required, we derive the appropriate packet eligible times. We also devise an information update method to collect/update in a decentralized manner the parameters needed in the calculation of packet eligible times. With all the parameters available, an intermediate router can calculate packet eligible times and the upper bound on the buffers needed in order to fulfill the QoS. Finally, we validate the proposed mechanism in terms of the probability of locating feasible-multicast trees and message overheads, and scalability with event-driven simulations