Self-Generation of Test Packet for Heterogeneous IP Network

Chronic network conditions are caused by performance impairing events that occur intermittently over an extended period of time. Such conditions can cause repeated performance degradation to customers, and sometimes can even turn into serious hard failures. It is therefore critical to troubleshoot and repair chronic network conditions in a timely fashion in order to ensure high reliability and performance in large IP networks. Networks are getting larger and more complex, yet administrators rely on rudimentary tools such as ping and trace to debug problems. We propose an automated and systematic approach for testing and debugging networks called ―Automatic Test Packet Generation‖ (ATPG). ATPG reads router configurations and generates a device-independent model. The model is used to generate a minimum set of test packets to (mini-mally) exercise every link in the network or (maximally) exercise every rule in the network. Test packets are sent periodically, and detected failures trigger a separate mechanism to localize the fault. ATPG can detect both functional (e.g., incorrect firewall rule) and performance problems (e.g., congested queue). ATPG complements but goes beyond earlier work in static checking (which cannot detect liveness or performance faults) or fault localization (which only localize faults given liveness results). We describe our prototype ATPG implementation and results on two real-world data sets: Stanford University’s backbone network and Internet2. We find that a small number of test packets suffices to test all rules in these networks: Using this technique we analyze over five years of failure events in a large regional network consisting of over 200 routers; to our knowledge, this is the largest study of its kind.