[OpenSIPS-Users] XCAP scalability: Integrated xcap server VS xcap_client mode

[Anca Vamanu]

Hi Inaki,

I don't know where you read that the non integrated XCAP server solution 
is better for large networks. I for sure never said that, but in fact 
always said that the integrated_xcap_server way is more efficient 
preferable if the XCAP server can act in this way.

Anca

Iñaki Baz Castillo wrote:
> Hi, I've read somewhere (but cannot find it right now) that integrated xcap 
> mode (presence module getting XCAP documents vía SQL) is suitable for small 
> environments.
>
> I know that the other way, using xcap_client module, is not really suitable 
> for now as the HTTP request is blocking (the opensips process gets blocked 
> until the XCAP server replies). But let's imagine this issue is solved.
>
> So we have two options:
>
> 1) Integrated server: OpenSIPS presence module gets the documents from the 
> xcap table.
>
> 2) XCAP client mode: OpenSIPS acts as a xcap client to get the documents from 
> the XCAP server.
>
>
> In the option 1:
> - OpenSIPS does a SQL query to get the document (faster than a HTTP request).
> - So the XCAP server is not queried by the presence server (less work for the 
> XCAP server).
> - There could be various XCAP servers running at the same time (perhaps DNS 
> random or a http proxy between clients and XCAP servers), all of them storing 
> the documents in same DB. And the presence document uses directly that DB.
>
>
> In the option 2:
> - OpenSIPS must perform a HTTP request which takes more time than a SQL 
> request (even if the DB is in other host), right?
> - The XCAP server receives a XCAP request from the presence server, so the 
> XCAP server must "work".
> - The xcap client would contact just an unique XCAP server (it would learn the 
> IP after the first DNS resolution, so ramdom DNS is not valid here).
>   - Solution: Using a HTTP proxy between OpenSIPS and various XCAP servers.
>
>
> Is it really the option 2 more suitable in order to favour scalability and big 
> environments?
>
>
>
>