[SIP SIMPLE client] [Blink] beginner SylkServer hiccups

Saúl Ibarra Corretgé saul at ag-projects.com
Tue Apr 26 09:18:52 CEST 2011

> Referring to the first posting quoted below… The presence or absence of
> audio didn't have anything to do with the transport of the SIP packets,
> but rather the tls or tcp setting of the MSRP Transport in Blink. A
> setting of tcp causes an msrp:// URI in Blink's INVITE, and a
> corresponding msrp:// URI in SylkServer's 200 OK. A setting of tls
> causes msrps:// URIs in both cases. This makes sense. What does not make
> sense is in the tcp case, the URI from SylkServer contained the box's
> public IP (the wrong interface), while in the tls case the URI contained
> the (private) IP of the Blink client. In effect it mirrored the URI of
> the INVITE. Or, does this make sense and I'm simply not aware of the
> underlying logic?

I don't I fully understand what you mean here, can you provide a SIP 
trace please?

> In both cases the c= line was correct for the private IP of the
> corresponding UA, yet Blink only recognized the audio when the MSRP
> transport was set to tls. I verified the IP addresses and ports of the
> RTP and RTCP packets were as described in the INVITE and 200 OK. This
> one doesn't make sense to me either.

So when trying to use TCP (for MSRP) the session is stablished at the 
SIP level but then is terminated? Please enable notification trace for 
this scenario.

> Even when the tcp setting was used in Blink, and the URI contained the
> public IP of the SylkServer on port 2855, I still didn't see the
> SylkServer machine listening on any interface on port 2855.

SylkServer doesn't need to listen there, a new listener is spawned when 
an incoming connection is received.


Saúl Ibarra Corretgé
AG Projects

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