Traffic Matrix Estimation for Delta Routing Problem Setup
Traffic Matrix Estimation for Delta Routing Problem Setup George Porter and Minwen Ji, Ph. D. Compaq/HP Systems Research Center Delta Routing • Enterprises connect their locations together with leased, private lines called an Intranet • Developed at SRC, this is an enabling technology for this proposal • Such links are very expensive, and so are usually not overprovisioned • Take advantage of intranet’s connectivity to the Internet to forward traffic across the private network • Because of that, congestion can occur Proposed Optimization • Send traffic over Virtual Private Network (VPN) tunnels if intranet is getting congested/overutilized • 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 • Nodes know traffic for (src, dst) pairs that transit through them • For other pairs, they rely on periodic announcements from other nodes Node 1 2 3 4 5 1 2. 9 4. 0 4. 1 1. 2 2 1. 5 0. 3 0. 7 3 2. 7 3. 0 0. 4 4. 9 4 0. 6 0. 1 4. 3 • Implementation in the ns simulator is in progress Congestion Avoidance • Second experiment: as the accuracy of the TM varies, how well can we predict congestion? 5 2. 2 3. 3 3. 9 4. 3 0. 8 Example traffic matrix • Accuracy depends on frequency of periodic updates as well as burstiness of traffic • First experiment: given various traffic patterns and update frequencies, how accurate is the TM estimation? • Third experiment: overall performance in a large, realistic network topology • This process is performed at each node independently • Thus, if a bad prediction is made, the distant, congested node will repeat the process
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