[OpenSIPS-Users] LB Re: [OpenSIPS-Business] [OpenSIPS-Devel] OpenSIPS at Amoocon (former AsteriskTag)

[Bogdan-Andrei Iancu]

Hi Stefan,

Stefan Sayer wrote:
>>>> Covered topics are : Load-balancing (using the new load-balancer 
>>>> module) , Presence (deploy presence) and clustering (OpenSIPS + PBX 
>>>> integration):
>>>>
>>>> (1) Load balancing Workshop:
>>>>      http://www.amoocon.de/talks/8
>
> I must say I have not looked into the code but only at
> http://www.opensips.org/pub/events/2009-05-04_Amoocon_Rostock/OpenSIPS_LoadBalancing.pdf 
>
> but I am not convinced: For load balancing that could be done 
> statelessly wrt SIP dialog you are keeping dialog state at the LB.
>
> If you have control over the media servers (as you do with 
> freeswitch/asterisk/yate you mentioned) the same could be achieved 
> much simpler by periodically reporting current load (e.g. in extra 
> header to OPTIONS response or any other SIP message) from the media 
> servers to LB and keeping that information as soft state there.
Well, the original design wanted to cover all the possible cases and not 
to depend on special capabilities of the peers. So, we took into the 
consideration that the peers you are load balancing may be "dummy" peers 
and not able to provide any kind of information about the load...or 
maybe (because of network, access or security pov), the peers cannot 
report the load to you (as example, you may do LB to some phones or GWs 
with no load reporting support or you do LB over some peers you do not 
control (like termination GWs) and they cannot report to you).

So, we tried the generic approach of being a self-sufficient system. But 
you say make perfect sense. This module is a new one and now we start 
testing its functionality under different scenarios. During the 
presentation, I got good feedback on other things to add, like 
integration with bandwidth reservation and limitation for QOS purposes 
(getting reports about jitter , delays and so on from the media servers).

Also what you say it may be an useful add-on - to get the load number 
from the peers, instead of calculating it.

>
> If you need dialog state in some proxy anyway for other purposes of 
> course you have that information, but for a dedicated LB like on p12 I 
> doubt it makes sense.
Correct - the diagram is more from functionality pov and not ncessery 
servers/instances - during the presentation I did mentioned that in that 
case the Proxy and LB could be actually the same opensips instance. Hope 
that Stefan will publish the video recordings of the presentations :)

Regards,
Bogdan