Traffic Matrix Estimation for Delta Routing

1. Traffic Matrix Estimation for Delta Routing George Porter and Minwen Ji, Ph.D. Compaq/HP Systems Research Center Problem Setup Delta Routing Proposed Optimization • Developed at SRC, this is an enabling technology for this proposal • Take advantage of intranet’s connectivity to the Internet to forward traffic across the private network • Send traffic over Virtual Private Network (VPN) tunnels if intranet is getting congested/overutilized • Enterprises connect their locations together with leased, private lines called an Intranet • Such links are very expensive, and so are usually not overprovisioned • Because of that, congestion can occur • How to avoid this problem? Assumptions • Subset of nodes have Internet connectivity • A link state routing protocol runs on the physical, leased network • To simplify the traffic estimation, we assume no multi-path routing on the physical network Future Work Traffic Matrix Estimation • Implementation in the ns simulator is in progress • First experiment: given various traffic patterns and update frequencies, how accurate is the TM estimation? • Second experiment: as the accuracy of the TM varies, how well can we predict congestion? • Third experiment: overall performance in a large, realistic network topology • Nodes know traffic for (src,dst) pairs that transit through them • For other pairs, they rely on periodic announcements from other nodes Congestion Avoidance • This process is performed at each node independently • Thus, if a bad prediction is made, the distant, congested node will repeat the process Example traffic matrix • Accuracy depends on frequency of periodic updates as well as burstiness of traffic