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Abstract
The Border Gateway Protocol (BGP) is currently the only Internet routing protocol used to maintain connectivity between autonomous systems. Empirical measurements have shown that there can be considerable delay in the protocol's convergence after routing changes. The sources of such delay have proven difficult to pinpoint. In an effort to better understand these issues, we use the SSFNet simulator to explore the impact of various parameters on BGP convergence time in a collection of simple network topologies. We explore the relationship between convergence time and the interval associated with a BGP-specific timer used to limit the rate at which update messages are transmitted. We observe that for each simulated network there is an optimal value for the rate-limiting timer that minimizes convergence time. This leads us to a preliminary conjecture that the currently recommended rate-limiting interval of 30 seconds may be too large and may be an important factor in observed delayed convergence.