Has anyone pre-emptively opened multiple ports in Asterisk to listen for separate RTP data streams?
Several examples exist of configuring it to send data streams out from the server, but none for listening.
A kludge-y way to do it is to use a traffic generator (e.g., sipp) to send a message into a specified port in Asterisk so it responds by opening up the stream, but surely there’s a better way; internally generating an empty message to accomplish the same thing is somewhat better, but explicitly opening up a specific port number on a managed E1/T1 device is most desired.
Asterisk does support multiple streams per session, but, at least in earlier versions, they have to have different media types. It is possible that later versions also support multiple audio streams, however I think that is unlikely because I don’t know how it would distinguish them internally.
The message used to request this is called SDP and it is used by all SIP sessions.
On startup, want to listen on multiple ports for incoming RTP streams from an external source (3rd-party system over a network), without requiring call setup.
Again, a very back-door method requires an external app to be used on the OS cmd line in the following manner:
… and Asterisk chan_sip.c code itself modified to find if a specific local RTP port should be used based on a cidnum lookup and passing a port to res_rtp_asterisk to use.
“You still haven’t answered why” … not sure what you’re looking for that I didn’t provide … when I see what that is, I’ll migrate over to the development support forum.