Analysis of Routing Characteristics in the Multicast Infrastructure

Prashant Rajvaidya, and  Kevin C. Almeroth
Department of Computer Science
University of California
Santa Barbara, CA 93106-5110
{prash, almeroth}@cs.ucsb.edu

As the multicast-capable part of the Internet continues to evolve,
important questions to ask are whether the protocols are operating
correctly, the topology is well connected, and the routes are stable.
A critical step in being able to answer these questions is to monitor
the traffic and network operation.  In this paper, we analyze
characteristics of the multicast infrastructure over the last three
years using monitoring data collected from several key routers.
Specifically, we focus on analyzing two characteristics of the
infrastructure: size and stability.  The size analysis
focuses on counting the number of connected hosts and networks, and
analyzing how the size of the infrastructure has changed over past
three years.  Second, the stability analysis focuses on
examining persistence, prevalence, and visibility  
of routes across the topology.  From our analyses, we identify a
number of problems with multicast routing and their effect on the
connectivity of certain multicast networks. Moreover, we offer insight
into the evolution and future of multicast in the Internet.

Keywords: Multicast, Network Management, Routing, MBGP, Monitoring.