Dynamic Manycasting Hierarchies

Abstract

This paper addresses the need for intermediate handling of multicast data while it traverses the net from a multicast source to its receivers. The proposed concept of dynamic manycasting hierarchies is a fusion of both multicast and anycast methodologies. The concept is designed to be transparent and does not require any modifications to be made to the existing multicast and anycast delivery protocols.

By adding a distributed intermediate entity that keeps track of receivers and dynamically selects the best way to deliver multicast data we not only achieve faster data delivery and higher level of security, but also provide a framework for future protocol extensions and added functionality without making any global changes to the multicasting protocols themselves.

In particular, manycasting hierarchies address the problem of having anycast addresses as members of multicast groups, shifting the load from a multicast source. Since there is a number of servers that replicate the data from a source there are also less failures caused by congestion and routing problems. Another important factor is that the transmission of data to end-clients is not limited to multicast per se, and can be done based on an end-client's requet using various protocols, including unicast, broadcast, and reliable multicast.

Finally, by using interim source hopping, where various parts of a multicast message are being received by a client from different sources, a potentially high level of security can be achieved. Since the manycasting hierarchy that performs an extra security function on multicast data knows about its end-clients, it is much easier to provide verification and authentication and it is no longer necessary to utilize complex reliable multicast disciplines that would otherwise be used by an end-client to talk to a multicast source.