Caller Mode versus Listener Mode
There are two methods that streaming servers use to ingest incoming connections: caller mode, and listener mode. Briefly, caller mode opens the client connection; listener mode listens for incoming connections.
With Red5 Pro, SRT streaming is only available via listener mode. That is, you set up the streaming target via the API call, and then publish the SRT stream to the server via the port designated in your parameters. The SRT stream is pushed to the Red5 Pro server.
IP-cameras, Unicast, and Multicast sources are available via caller mode. In these cases, the stream is active, and the API call establishes the connection to Red5 Pro. The streams are pulled to the Red5 Pro server.