A hybrid bootstrap mechanism for multicast routing in PIM-SM

In many multicast routing protocols, Protocol Independent Multicast - Sparse Mode (for short, PIM-SM) has been studied and implemented. Data transmission in the PIM-SM domain is performed on a shared tree. The shared tree has a Rendezvous Point (RP) which plays a central role of the data transmission. The bootstrap mechanism is one of the methods to discover the RP dynamically in the PIM-SM domain. However, because the mechanism needs data flooding for all routers to find the RP, some traffic or congestion is prone to occur on the domain. The processing of the mechanism is also time-consuming. In this paper, a hybrid bootstrap mechanism in PIM-SM is proposed and its performance is evaluated. Since the proposed method consists of distributed and centralized processes, it is called a hybrid one. The key for the proposed method is that the role of the RP selection is played in a Bootstrap Router, not that a Designated Router, since the RP-Set distribution is not performed. Especially, the proposed method dose not need the flooding and can be reduced the processing time efficiently to discover the RP. Simulation results show that the proposed method can reduce the processing time by more than 40% compared with that of the conventional one.