"The problem is the NAT server. In the end the RTP conversation will be
between the two devices behind the NAT - however each thinks
the other device is a public address (actually the same public address
shared by both devices)
The NAT server has to receive RTP packets from a device behind the NAT
and then figure out to 'reflect' it back to the other device behind the
NAT. In general a NAT will not be able to do this. Hence one way audio
of no audio."
>From my understanding of ICE, this is exactly what ICE is supposed to figure
out i.e. figure out whether the other party is "local" or "not local". It
works fine for caller it sends STUN request to caller at it's advertised
media port & gets a response, but the callee doesn't do that. (Both caller
and callee use SipXTapi).
Regards,
Anshuman
----- Original Message -----
From: Jeremy A
Cc: [email protected]
Sent: Thursday, July 05, 2007 6:07 PM
Subject: Re: [sipxtapi-dev] media+ICE issues
Anshuman S. Rawat wrote:
Hi All,
I am facing some ICE issues when I make a call between 2 agents which use
SipXTapi. Scenario is that the 2 agents are behind the same NAT but register
with a public SIP proxy. When I make a call between the 2, there is one way
media. The caller can be heard but the callee is never heard. From ethereal
trace, I can see that the caller completes the ICE procedures (i.e. sends
STUN requests to each candidate in answer) but the callee doesn't do that.
Behaviour is consistent when the caller and callee UAs are switched.
The problem is the NAT server. In the end the RTP conversation will be
between the two devices behind the NAT - however each thinks the other
device is a public address (actually the same public address shared by both
devices)
The NAT server has to receive RTP packets from a device behind the NAT and
then figure out to 'reflect' it back to the other device behind the NAT. In
general a NAT will not be able to do this. Hence one way audio of no audio.
In this case a topology with a SIP registrar/proxy inside the NAT will solve
the problem. Calls that terminate outside the NAT will be redirected
correctly by the proxy/registrar. Calls internally will have no problems at
all.
_______________________________________________
sipxtapi-dev mailing list
[email protected]
List Archive: http://list.sipfoundry.org/archive/sipxtapi-dev/
No virus found in this incoming message.
Checked by AVG Free Edition.
Version: 7.5.476 / Virus Database: 269.10.0/886 - Release Date: 7/4/2007
1:40 PM
_______________________________________________
sipxtapi-dev mailing list
[email protected]
List Archive: http://list.sipfoundry.org/archive/sipxtapi-dev/
