[SR-Users] IMS-P-CSCF: stripped down version of kamailio.cfg

[Franz Edler]

Dear IMS-experts,

I am trying to reduce the complexity of the IMS implementation by disabling
the functions which are not required for a pure stripped down IMS core
platform.
Therefore I deactivate NAT handling, RTP proxy, SBC, dispatcher etc... in a
first step.
Later on I will add the functions step-by step. According to the
requirements.

Now I discovered an inconsistency in the configuration file (kamilio.cfg) of
P-CSCF.
In main routing logic there is the point where P-CSCF distinguishes an
originating-initial request from a terminating-initial request. This is done
by the code:

	if (!ds_is_from_list()) {
		# Originating from Subscriber:
		route(Orig_Initial);
	} else {
		# Terminating to Subscriber:
		route(Term_Initial);
	}

Unfortunately the function ds_is_from_list() is part of the dispatcher
module which I want to avoid in a first step.
Therefore another criterion must be used to distinguish between originating-
and terminating-initial request.
I therefore propose to use the pseudo-user-name "term" in the Route-URI as a
distinguisher.

What do you think?
I am actually thinking about the correct statement (regular expression) to
do that. Maybe anyone can help.

BR Franz