HyperCast - Towards Super-Scalable Multicast Communications
Jorg Liebeherr
Electrical Engineering Department
Polytechnic University
Abstract
Multimedia collaborative applications for the Internet require the availability
of multicast protocols that enhance the basic connectionless IP Multicast
service. A critical requirement of such protocols is their ability to support
a large group of simultaneous users. For this it is crucial that there
exist mechanisms to efficiently exchange control information between the
members of a group. In this paper, we present a new approach for distributing
control information within a multicast group. The goal of our approach
is to scale to very large group sizes (in excess of 100,000 users). Multicast
group members are organized as a logical n-dimensional hypercube, and all
control information is transmitted along the edges of the hypercube. We
analyze the scalability of the hypercube control topology and show that
the hypercube balances the load per member for processing control information
better than existing topologies. We use actual data traces of the group
membership in an MBONE conference to gain insight into the transient changes
of the load at each node. We present a set of protocol mechanisms that
maintain the hypercube topology in a soft-state fashion without requiring
any entity to have global state information.
Luis Gravano
gravano@cs.columbia.edu