Brief summary of definitions in:
- MDP v 0.1: https://rfc.zeromq.org/spec/7/
- MDP v 0.2: https://rfc.zeromq.org/spec/18/
- Majordomo Management Interface (MMI): https://rfc.zeromq.org/spec/8/
and OpenCMW protocol extension proposal (pdf, spreadsheet source):
