Asterisk and RTCP


I did some test for capturing RTCP packet (with ethereal), but I can’t find any in the “asterisk -> softphone” direction. I ve got RTP packet but no RTCP.

Could you tell me if there is something special to set up ?

I use Asterisk version


i remember seeing some reports a while ago about Asterisk and RTCP, searching found a few, e.g.

and there have been some bug reports on … have you had a search there ?

Thank you very much for the link. It s exaclty what I was looking for (without finding it :/)


The post was written Sat, 23 Oct 2004, and as I can observe the same thing with a recent version, I imagine it hasn’t changed.

If someone have an idea on how to forward RTCP packets sent by peers ?

Thank you :smile: might give you a headstart.

tip: more devs hang out on the -dev list than here.

RTCP is RTP Control Protocol, and as such works in conjunction with RTP. Although UDP port 5004 is assigned to RTP, and UDP port 5005 is assigned to RTCP, they usually need more than a pair of ports for multiple bidirectional traffic which has to be handled by assigning and forwarding a range of ports. While RTP data is carried on an ‘EVEN’ UDP port number the corresponding RTCP packets are carried on the next higher ‘ODD’ port number. So when you forward a range of ports such as 5004 - 31000 (asterisk default RTP range) RTP uses the even UDP ports 5004, 5006, 5008, 5010 and so on, while RTCP uses the odd UDP ports 5005, 5007, 5009, 5011 and so on. I hope this helps.