[SR-Users] RLS server as SUBSCRIBE proxy?

[Klaus Darilion]

Jeremya wrote:
> Hi,
> 
> My situation is that I have a number of SIP end points (server) that 
> support SUBSCRIBE method on various resources they hold. Primarily these 
> are dialog resources, but include arbitrary other resources with custom 
> MIME types.
> 
> I also have a large number of SIP end-points (clients) that use 
> SUBSCRIBE to resources held by these end-points. Some of these  
> end-points are standard phones (SPA-962) monitoring dialog state. Other 
> end points are custom clients that monitor a variety of custom resources 
> and MIME types.
> 
> I have got to the point where the number of SUBSCRIBE clients is making 
> it impractical for the SUBSCRIBE sources to support them.

Why? What it your problem? To many active subscriptions on the servers?

> I want to make a SUBSCRIBE proxy server that makes arbitrary SUBSCRIBE 
> requests to my SIP end points (server) and in turn accepts SUBSCRIBE 
> requests from my consumer SIP clients (Phones etc). In effect the server 
> would aggregate SUBSCRIBE requests into a single SUBSCRIBE to a target 
> resource.

So, instead of A subscribing to X at the server and B subscribing X at 
the server, you want Kamailio to "intercept" this subscription and 
instead Kamailio is only making a single subscription to the server 
which holds the data of X?

> Ideally the SUBSCRIPTION would be dynamic, generated by the SUBSCRIBE 
> requests from the SIP phones and other clients, but this can be static.

I think the resources for the ougoing subscription would be available 
inside the modules (pua module) but I think another module would be 
needed which does the aggregation.

> I've read the documentation for the RLS module in Kamailio but I can't 
> actually figure out what it does. It may do what I want (if only in some 
> database mode) but I'd appreciate advice as to whether to pursue this as 
> an option or go to plan-B

RLS module implements resource list subscriptions: E.g. instead of A 
subscrbing to X, Y and Z A has only a single subscription to "foobar" 
and the RLS module will extend this single subscription into 3 
subscription. (thus decreasing the load on the client, but not on the 
presence server).

What is plan-B?

regards
klaus