PMTA: Potential-Based Multicast Tree Algorithm with Connectivity Restricted Hosts

A large number of overlay protocols have been developed, almost all of which assume each host has two-way communication capability. However, this does not hold as the deployment of firewalls and Network Address Translators (NAT) is widespread in the current Internet, which is a challenge to the design and implementation of overlay models and protocols. In this paper, we present Potential-based Multicast Tree Algorithm (PMTA) to enhance the multicast tree construction in presence of connectivity restricted hosts. We evaluate PMTA and previous multicast tree protocols based on real Internet end-to-end delay datasets. According to evaluation results, PMTA outperforms those protocols in terms of all metrics. PMTA reduces ARDP by 26%, and it also results in 23%-54% reduction in average overlay latencies. As the results suggest, PMTA can build efficient and effective multicast tree and is suitable for Internet multicast applications in the presence of connectivity restricted hosts.