An empirical study of router response to large BGP routing table load

Abstract

Anecdotal evidence suggests that misconfiguration of backbone routers occasionally leads to an injection of large routing tables into the BGP routing system. In this paper, we investigate the detailed mechanics of router response to large BGP routing tables. We examine three commercial routers, and find that their responses vary significantly. Some routers exhibit table-size oscillations that have the potential to cause cascading failure. Others need operator intervention to recover from large routing tables. We also find that deployed resource control mechanisms, such as prefix limits and route flap damping, are only partially suceessful in mitigating the impact of large routing tables.