Improving packet delivery performance of BGP during large-scale failures

The border gateway protocol (BGP) is known to take a long time to converge to a steady state following the failure of BGP routers or inter-router links. This has resulted in extensive analysis of BGP convergence delay and a number of schemes have been proposed to reduce this delay. But the convergence delay is a network centric metric and the end-user relevant effects of a failure are better characterized by the packet losses. In this paper we study BGP convergence from the packet delivery perspective and show that a reduction in the convergence delay does not necessarily translate into an improvement in packet delivery. Our measurements provide insights into which BGP modifications are likely to decrease packet loss, and how any shortcomings can be rectified. We also modify a couple of existing techniques, and show how to reduce the packet losses.