At 08:12 04/03/2008, girish kumar wrote:
Hi,
I have 2 SIP based softphones (Xlite) registered on
IPtel.org SIP service and testing the calls among
them. These 2 softphones are behind different NAT and
IPtel.org SIP proxy is replacing the SDP connection
details in Call setup message (Invite and 200 OK) with
RTPproxy IP/ports. Hence, RTPproxy is relaying the
Voice media stream among them during the call.
Although, both the softphones are behind different NAT
address but these are not Symmetric NATs and hence RTP
can directly flow between these softphone using STUN
discovery.
That's what I'm not sure about. If they were using STUN,
iptelorg:5060 should not have detected them as natted.
Any insight in this?
Is it possible to disable the RTP proxy behaviour
of
IPtel.org SER server for these 2 softphones through
some configuration changes or any special header
parameter in call setup message?
In User Management web interface of
IPtel.org, there
is a option to specify the connectivity realm for a
user account under My Account -> Other tab.
The description of this field is "connectivity realm -
behind the same NAT or possibility to communicate
directly". I believe this field is playing some part
in NAT transversal mechanism of
Iptel.org SER
implementation.
I think too that was thought so, but I think it is
unused at the moment.
Yes, it was meant to work this way. If both phones are configured to
be in the same connectivity realm then the server assumes that they can
reach each other directly and it does not enforce the RTP proxy, no
matter what does the NAT detection algorithm says.
Unfortunately this option is not currently used in the configuration
of the
SIP server.
I will try to put it back as time permits (because I need it myself
for my phones).
Hope that helps, Jan.