[Freeswitch-users] Re ceiving only RTP packets

rajprithiv89 rajkumar.kanniappan at sasken.com
Fri Apr 27 15:44:32 MSD 2012


we are using csipsimple android voip application which uses Freeswitch as
SIP/Media server.

We established voip calls between two android clients(A, B) by enabling SRTP
in both the sides. 

Now the problem observed here is, when we captured the packet flow in
wireshark, the client which initiates the call(A) is sending SRTP packets
and the client which receives the call sends only RTP packets and the
FreeSwitch sends SRTP packets to both the clients.

We have tested FreeSwitch with other application, there also we ended up in
the same problem(one sided SRTP packets flow).
Also we have tested the same CSipSimple application with Asterisk server. It
works fine by sending SRTP packets from both the clients.

When i captured the Wireshark packets SDP contains:

>From A to Server:

m= audio 4006 RTP/SAVP 98 97 99

>From Server to B

m = audio 31562 RTP/SAVP 3 98 99 9
m = audio 31562 RTP/AVP 3 98 99 9
(sends two media line, one for SRTP and one for RTP)

>From B to Server(Negotiation done)

m = audio 4014 RTP/SAVP 3 96
m = audio 0 RTP/AVP 3 98 99 9   (This is to inform, B is not going to use
RTP by putting the port number as 0)

>From Server to A(Negotiation done)

m = audio 32338 RTP/SAVP 3 96

But in the end,
A is sending SRTP packets
Server is sending SRTP packets
B is sending only RTP packets (But in the negotiation RTP/AVP port was 0)

View this message in context: http://old.nabble.com/Receiving-only-RTP-packets-tp33758451p33758451.html
Sent from the Freeswitch-users mailing list archive at Nabble.com.

Join us at ClueCon 2011 Aug 9-11, 2011
More information about the FreeSWITCH-users mailing list