[SR-Users] unregister user when kamailio looses TCP connection.

[Andreas Granig]

Hi Vitaliy,

On 09/24/2013 12:45 AM, Vitaliy Aleksandrov wrote:
>> The patch only handles the case where a tcp connection is directly
>> made to the registrar, as no event route is fired, right?
> You are right. Current version works only when registrar accepts tcp
> connections.
> Anyway it's a good idea to call event_route[] when kamailio looses a tcp
> connection to give user a chance to process it somehow.
>
> On the one hand it's great when experienced user can achieve what he
> wants by different ways depending on the situation, but on the other it
> makes a mess for new kamailio users.

I think the implementation is fine for "normal" use cases where you just 
have one combined registrar/proxy, which is probably what new kamailio 
users are starting with.

The reason I'd love to see an event-route is to handle cases for scaled 
architectures, where you have load-balancers/edge-servers accepting 
tcp/tls connections from clients and forward them to a back-end farm of 
registrars/proxies e.g. via udp.

The implementation of that event-route would be completely independent 
of the current solution anyways, because it won't hook up with usrloc 
(on the edge proxies there is usually no usrloc loaded), rather than 
having the code somewhere in the core and just firing an event-route, 
where the system developer can do arbitrary actions (like creating a 
custom sip message to be sent to the back-end servers, which triggers an 
unregister there). Honestly I have no clue yet as of how to actually do 
that. Firing the event-route would be the rather easy part I guess, but 
do we have all the information needed to do an unregister on the 
back-end registrar? Probably the only info we have is the source 
ip/port/proto of the disconnected client, so we'd need some logic in the 
registrar/usrloc module on the back-end registrar to match a location 
entry with that info somehow.

I'm just throwing in some thoughs on that topic for further discussions, 
so no clear idea how to accomplish that from my side.

Andreas