Looking at the RTMP specification, in section 5 (RTMP Chunk Stream) it says:
RTMP Chunk Stream includes its own in-band protocol control messages, and also offers a mechanism for the higher-level protocol to embed user control messages.
What is meant by "higher-level protocol"?
It also specifies: "While RTMP Chunk Stream was designed to work with the Real Time Messaging Protocol (Section 6), it can handle any protocol that sends a stream of messages". Aren't the RTMP Chunk Stream and Real Time Messaging Protocol the same?