[Users] show active calls

[JF]

Because then you will end up having one charging system per service
and you won't be able to easily extend it to support further services
you might want to add.

In IMS it's not the "SIP proxy" that terminates the session when money
runs out. For this B2BUA application servers can be used (similar to
what many people on this list do with Asterisk). IMS CSCFs are
required to be able to terminate SIP sessions on other circumstances,
e.g.:
- at deregistration or registration expiration (makes sense, but not
mandatory in non-pure-IMS scenarios)
- network-initiated session release (not a nice thing and probably
only makes sense in some telco scenarios)
- when receiving "out of radio coverage" indications (also only useful
in 3GPP or other wireless network scenarios)

IMO the dialog statefulness in the proxy would be mostly useful for
implementing triggers to SIP application servers (according to some
criteria, such as IMS IFC), especially in the case of trigerring
B2BUAs, in order to correlate both dialogs (the one going to the B2B
and the one coming out from the B2B into the SIP proxy again). But
this does not require full dialog statefullness.
This separation of routing and application is the IMS concept that IMO
seems to have some value irrelevant of if you're on a 3GPP network, a
TISPAN R1 (DSL) network, or on the Internet. But soon you realise that
in order to support this separation and triggering of services, you
end up needing some of the extensions to SIP and to the "SIP proxy"
that IMS defines.

Perhaps these are all too far-fetched use cases for
dialog-statefulness to make its way into OpenSER. But the single
argument of not having to setup Asterisk in order to be able to
control established sessions with OpenSER is IMO quite important for a
considerable part of the user community.

JF

On 7/19/06, Juha Heinanen <jh at tutpro.com> wrote:
> JF writes:
>
>  > SIP-IPTV perhaps. Why would PSTN calls be the only motivation for
>  > people to pay?
>
> fine, but why should sip proxy be responsible for terminating the ip-tv
> session when money runs out?  why doesn't ip-tv service (sip ua that
> corresponds to pstn gw) do it?
>
> -- juha
>