Reducing the reservation establishment time in IP tunnels by using staged refresh timers

This paper presents a state aggregation mechanism of the RSVP protocol for multicast flows using IP-in-IP tunneling. The mechanism relies on periodic refresh messages between routers to maintain the reservation states (soft-state approach). Because of the loss of tunnel RSVP messages, the mechanism presents a very long latency at reservation establishment. The problem reduces the performance of multimedia applications. We report the use of staged refresh timers in the aggregation mechanism at the set-up procedure of the resource reservation. The simulation results show a significant decrease of the establishment time of multicast sessions.