On communicating finite-state machines. Selected papers that cite this one Parosh Aziz Abdulla and Bengt Jonsson. Verifying programs with unreliable channels. Parosh Aziz Abdulla and Bengt Jonsson. Undecidable verification problems for programs with unreliable channels.
Unreliable channels are easier to verify than perfect channels.
Anatoli N. Chebotarev and Marina K. Morokhovets. Resolution-based approach to computability analysis of interacting automata. Alain Finkel and Pierre McKenzie. Verifying identical communicating processes is undecidable.