Multihomed Multicasting by Overlay Proxies

Compared with traditional IP Multicast, overlay multicast is not only flexible in functionality but also compatible with current network infrastructure. Therefore it is emerging as an effective solution for most group communications over the Internet. Affected by end-host overlay systems, the overlay multicast routing problem is studied under a single homed model in most literatures. Under this model each MSN (multicast service node) only has one access link to the Internet. This is no longer applicable to those fixed MSN, which may have multiple access links to the physical network. In order to solve the problem correctly, we propose a multihomed proxy model in this paper to describe the overlay network more accurately. We also develop a general solution to the routing problem under our model, which includes a path selection process and a multicast routing process. In the end we design an OMMP (overlay multicast over multihomed proxy) architecture, which integrates all MSNs into one framework to realize the overlay multicast service under our model.