Performance evaluation of cheating host in ALM over wireless multi-hop networks

ALM (Application Level Multicast) is one of the promising ways for resolving multicast incentive problem of non-multicast hosts not implementing multicast routing protocol. ALM protocol is implemented in application layer, which means it is easier to be altered by end users than lower layer protocols. Malicious users would like to get higher position in ALM tree because it can obtain higher throughput and lower delay. They also would not like other hosts to be connected because of forwarding burden will bring them wireless throughput degradation. This paper evaluates performance improvement perceived by a malicious user and shows that surprisingly it can obtain performance improvement only with almost 50% probability. We also investigate the reason why this performance effect and show that link sharing with other ALM hosts in long hops is one of the reasons of performance degradation of malicious users.