[OpenSER-Devel] TCP error

Iñaki Baz Castillo ibc at in.ilimit.es
Thu Feb 14 18:48:46 CET 2008


El Thursday 14 February 2008 18:43:32 Klaus Darilion escribió:
> Iñaki Baz Castillo schrieb:
> > El Thursday 14 February 2008 17:46:45 Klaus Darilion escribió:
> >> Either the Contact is wrong or the TCP session is gone.
> >
> > Probably TCP session is gone, since I have never "Contacts" related
> > problems with UDP clients.
>
> Depends on the SIP client and you NAT dedection methods. Eg.
> eyebeam/xlite is smart and learns the public TCP socket from Via header
> in response and then registers this contact. But for example SNOM is
> dumb - it uses STUN (of course this gives you only the public UDP port)
> and then uses the UDP port in the Contact, although the public TCP port
> will be different usually.
>
> Except eyebeam/xlite I do not know any SIP client which handles TCP NAT
> traversal fine. Usually all other clients need a
> fix_nated_contact/register.
>
> If you already do NAT traversal then it really maybe that the session is
> gone - some dumb phones register and then shut down the TCP connection.
> And other phones keep the TCP connection open but close it when a CRLF
> is received.
>
> Conclusion: Currently SIP clients do not handle TCP as good as UDP.

Ok, thanks for the explanation. I've never investigated SIP over TCP so I'm 
not familiar with its issues yet, issues that obviously do exist :(

Thanks a lot ;)



-- 
Iñaki Baz Castillo
ibc at in.ilimit.es



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