Improving BGP Convergence And Reachability Through Stable Path Aggregation (SPAGG)

BGP is the standard inter-domain routing protocol of the internet. It has proven to be scalable enough to accommodate the exceptional growth of the Internet. However, because of the sheer size of the Internet and the complexity of its topology, the behaviour of BGP can be unpredictable sometimes. Researchers have been proposing various changes and enhancements in the past 10 to 15 years to improve the security, stability and convergence of BGP. Some of the solutions have been adopted, but BGP is still suffering from possible deficiencies when it comes to convergence time and stability at specific situations and scenarios. In this thesis, we focus on providing a reasonable solution for the problem of BGP instability but without causing long convergence, which leads eventually into minimizing BGP churn and path exploration. We, first, analyse the current BGP standard protocol and previous proposed solutions. Then, we study current problems associated with a recently proposed improvement, suggest a new algorithm that avoids path selection problem at the aggregator and the path shortening problem. We also describe its implementation in OPNET. Finally, we show the results from our simulation and compare them to the results of previous work suggested. Our results show a great improvement of the convergence of BGP while preserving reachability and optimality all the time.