A Study of Multicast Routing Instabilities

Prashant Rajvaidya and Kevin C.  Almeroth
Department of Computer Science
University of California--Santa Barbara
Santa Barbara, CA 93106-5110
{prash, almeroth}@cs.ucsb.edu
 
Native multicast is critical for scaling the delivery of 
high bandwidth data like audio and video to large-numbers 
of receivers. Although the first large scale deployment 
of multicast took place over a decade ago, multicast 
routing has not been particularly stable and, therefore, 
assuring robust data delivery has been challenging. In 
this paper, we present an in-depth analysis of the 
routing instabilities in the multicast infrastructure. 
Our results are based on Multiprotocol Border Gateway 
Protocol (MBGP) routing tables. We identify underlying 
inconsistencies among routing views at different routers 
and characterize instabilities by evaluating temporal 
and spatial variations in these views. Finally, we explore
some of the potential causes of these instabilities.