Where Is the Debugger for My Software-Defined Network?

Download Now Date Added: Aug 2012
Format: PDF

The behavior of a Software-Defined Network is controlled by programs, which like all software, will have bugs - but this programmatic control also enables new ways to debug networks. This paper introduces ndb, a prototype network debugger inspired by gdb, which implements two primitives useful for debugging an SDN: breakpoints and packet back-traces. The authors show how ndb modifies forwarding state and logs packet digests to rebuild the sequence of events leading to an errant packet, providing SDN programmers and operators with a valuable tool for tracking down the root cause of a bug.