Switches are Monitors Too!
Tim Nelson, Nicholas DeMarinis, Timothy Adam Hoff, Rodrigo Fonseca, Shriram Krishnamurthi · 2016
Testing and debugging networks /in situ/ is notoriously difficult. Many vital correctness properties involve histories over multiple packets (e.g., prior established connections). Checking such properties requires /cross-packet state/, which cannot be fully captured on stateless switch hardware.