[Serdev] TCP problems

[Andrei Pelinescu-Onciul]

On Jan 16, 2007 at 11:28, Katty Xiong <cyyxiong at yahoo.com> wrote:
> 
> Hi Andrei,
> 
> > 
> > > I notice SER and UAS always has one
> > > connection whether we have one or 2 SIPp instance
> > for
> > > UAC. Is this tunable?
> > 
> > No, ser would always try to use an already existing
> > connection (as
> > recommended by the rfc) => only one connection will
> > be used for the same
> > UAS (there is an exception, if there is no
> > connection open and two
> > connection request come simultaneously, 2 different
> > connections might be
> >  temporarily opened, but only one of them will
> > survive).
> 
> I understand SER always tries to use an existing
> connection to the same UAS. But in my case, I
> configure SIPp UAC to invite multiple UASes, which is
> simulated in one SIPp instance. I don't quite
> understand I still see one connection between SER and
> SIPp in this case.
> 
> Could you help me understand this?

If the sipp instance uses the same ip and port for all the simulated
UASes, then ser will use a single connection.
When ser wants to send a message over tcp to some address:port, it first
checks if a connection already exist and if it does it uses it.
If you use tcp aliases (e.g. force_tcp_alias() or tcp_accep_alias=yes + 
 alias in the incoming messages Via), then ser will also look in the
 aliases list (e.g. if 1.2.3.4:32768 is an alias for 1.2.3.4:5060 and
 a connection to 1.2.3.4:32768 is already open, ser will use this
 connection also for messages for 1.2.3.4:5060).


Andrei