Paving the Way for NFV: Simplifying Middlebox Modifications Using StateAlyzr.

Important Network Functions Virtualization (NFV) scenarios such as ensuring middlebox fault tolerance or elasticity require redistribution of internal middlebox state. While many useful frameworks exist today for migrating/ cloning internal state, they require modifications to middlebox code to identify needed state. is process is tedious and manual, hindering the adoption of such frameworks. We present a framework-independent system, StateAlyzr, that embodies novel algorithms adapted from program analysis to provably and automatically identify all state that must be migrated/cloned to ensure consistent middlebox output in the face of redistribution. We find that StateAlyzr reducesman-hours required for code modification by nearly 20×. We apply State-Alyzr to four open source middleboxes and find its algorithms to be highly precise. We find that a large amount of, but not all, live state matters toward packet processing in these middleboxes. StateAlyzr's algorithms can reduce the amount of state that needs redistribution by 600- 8000× compared to naive schemes.