Automated Testing of Forwarding Policies

Abstract

BGP routers can prove to be challenging to configure, manage and debug owing to their distributed nature. “Propane”, a system aimed at overcoming this, compiles policies at the AS (Autonomous System) level from the network operator down to individual router configurations. In this paper, we propose a testing framework aimed at establishing correctness of the Propane compiler. This generates exhaustive test cases to ensure that valid advertisement sequences lead to actual network traffic paths and that inherent preferences between multiple traffic path choices are exercised. We encode the test generation procedure as a SAT instance on the Propane Product Graph. We simulate the generated tests as individual BGP sessions, verifying network properties in the simulation. The test infrastructure generates and verifies test cases on small networks upto 100routers within a reasonable time interval. This approach paves way for further testing of router configurations’ adherance to more generic policies than Propane itself.