[SR-Users] RLS server as SUBSCRIBE proxy?

[Jeremya]

Klaus Darilion wrote:
> 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?

Yes, but also the clients are not very robust, so temporary network
problems gets them giving up. (They are all at one location, so a
co-located aggregator wouldn't have network issues)

>
>> 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?

Yes

>
>> 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).
>
The clients I have include SPA962. They support aggregated dialog
subscriptions as well as individual dialog subscriptions. Perhaps this
is all I need? If so, are there any examples of how to use RLS? As I
said I've read the docs but it ain't clear.

> What is plan-B?

Code it using sipxtapi. I've done subscribe servers and subscribe
clients using it, but the underlying code is ever so broken...

>
> regards
> klaus
>