We have developed an experimental approach that allows us to estimate the performance of a large-scale enterprise network to update routing information. This approach was applied to the integration of the UFJ Bank network system on January 15, 2002. The main characteristic of this approach is the application of a formula that represents the delays in updating routing information that accompany reductions in CPU resources. This procedure consists of two steps: one is to estimate the reduction in the availability of CPU resources caused by forwarding of data packets at a router, and the other is to estimate the levels of CPU resources required for replying to a query about a new route and subsequently updating the routing information. These steps were applied to estimate the performance of the network in terms of routing information convergence. The results of our experiments on the network showed that updating the routing information was possible as long as the average level of CPU utilization during any five-minute period at the routers was less than 40%. We were able to apply this guideline and thus confirm the stability of the UFJ Bank network.

BGP might experience a lengthy path exploration process to reach the convergence after the routing changes. found that the BGP rate-limiting timer--MinRouteAdvertisementInterval (MRAI) has an optimal value Mo that achieves the best trade-off between the stability and the convergence speed. In this paper, with the aid of a timed BGP model, we investigate the effects of MRAI and its optimal value Mo for the BGP convergence process. We find that an adequately long MRAI timer can batch-remove candidate paths and ensure the routing stability in the convergence process. There exists a minimal MRAI Ms that achieves the effect, which is also the upper bound of Mo and provides an approximation of Mo. We calculate the approximations of Ms for different settings and estimate the optimal MRAI for the Internet. According to the results, the optimal MRAI for the Internet might be 5-10 times less than the current default value used in the Internet. The simulations taken with SSFNet and the experiments conducted over the Planet-Lab demonstrate the correctness of our analysis.