SIP is just the control protocol, and can be negotiated over TCP or UDP. The actual payload is done over RTP, which is a UDP-based protocol.
If you had to add firewall exceptions/PAT config for the TCP SIP traffic, you'll also need to add the same for RTP traffic as well. -- Nathan Clemons On Fri, Apr 23, 2010 at 12:21 PM, <ad...@3a.hu> wrote: > Hi List, > > i have to put an * between two other SIP gateways and due to some > circumstances, i have to use sip over tcp. With 1.6.2.6 this is working > fine: sip gw A (deverto4) sends the call, i hand it over to sip gw B > (ocs) and that's about it. In the other direction however (ocs -> me -> > deverto4) the call setup is complete but there is no audio. > > I can see the audio in the form of tcpdump, but neither party hears the > other side. Tcpdump also shows that while the call setup is via tcp, > the audio is transmitted via udp. I'm guessing this is the reason of > silence. The first setup is working because one of the gateways are > supporting sip over tcp only and * accepts both. > > my setup is pretty simple as * is only handing calls over to the > gateways. Relevant parts are below. > > could anyone please confirm that it is an error, that asterisk sends the > RTP stream via udp and this is the cause of the silence? Is there any > way to tell asterisk to use tcp only? I'm aware of the drawbacks, but i > still need to get this working. > > I'd appreciate any help. > > thanks > adam > > > sip.conf: > > tcpenable=yes > tcpbindaddr=0.0.0.0 > > [ocs] > type=friend > host=192.168.1.1 > context=ocs > qualify=yes > transport=tcp > nat=no > canreinvite=no > disallow=all > allow=alaw > allow=ulaw > > [deverto4] > type=friend > host=172.18.200.4 > context=deverto > qualify=yes > nat=no > canreinvite=yes > transport=tcp > disallow=all > allow=alaw > allow=ulaw > > and the extensions.conf: > > [deverto] > exten => _X.,1,Dial(SIP/${ext...@ocs) > exten => _+X.,1,Dial(SIP/${ext...@ocs) > > [ocs] > exten => _X.,1,Dial(SIP/${ext...@deverto4) > exten => _+X.,1,Dial(SIP/${ext...@deverto4) >
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