A Fast-Join Mechanism for Inter-Domain Multicasting

Most multicast routing protocols construct reverse shortest path trees (SPTs) to deliver shared data. However, the use of the reverse SPT presents a challenge in the inter-domain routing environment, as the path from the source to a receiver could be asymmetric to the one used to go from the receiver to the source. A possible approach is to utilize the round-trip joining message but it incurs the demerit of long joining delay. In this paper, we propose a BGP-view based fast-join (BFJ) mechanism, where the receiver domain border router leverages the BGP routing information in the border router of the source domain to identify an efficient joining path. The initial joining message can then be delivered using source routing along the identified path to quickly construct the reverse SPT even in asymmetric routing environment. Subsequent joining messages temporarily label corresponding interfaces at intermediate routers so that requested data packets are steered to the subscriber as soon as possible. The NS2 simulation results show that the proposed BFJ scheme is more efficient than the approach of round-trip joining message even under the favored condition of the latter.