[asterisk-dev] device_state distribution issues

[Olle E. Johansson]

9 nov 2010 kl. 16.26 skrev Russell Bryant:

> On Tue, 2010-11-09 at 11:14 +0100, Klaus Darilion wrote:
>> btw: has someone ever did any performance measuring of devicestate 
>> distribution? I would suspect ais to have much better performance as it 
>> avoids the additional hop of the XMPP server, avoids XML 
>> encoding/parsing and is sent by multicast (good for multiple servers as 
>> it avoids the sequential XMPP ntofications). Thus, for LAN environments 
>> I think ais is much better suited than XMPP.
>> 
>> So, what is now the purpose of res_ais vs. res_jabber?
>> 
>> I think the goal of device state distribution with XMPP is to have 
>> synchronize the device state over between geographically distributed 
>> servers (e.g. main office and branch offices) not for having multiple 
>> Asterisk servers for load balancing.
>> 
>> AIS based state distribution seems very lightweight. Thus, in high 
>> traffic environments where a single server can not handle all the load 
>> (lots of idle traffic due to REGISTER and OPTIONS, transcoding ...) it 
>> allows you to have an Asterisk cluster with one aggregated device state 
>> for each device over the whole cluster. Of course at some point if there 
>> are many nodes and too many state changes then the cluster may collapse 
>> due to the immense ais traffic, but I think state changes are usually 
>> not that much (mostly only when a call is created and hangup) compared 
>> to other load (RTP, idle traffic) and so I think a cluster of 10 servers 
>> or more should not be a problem.
>> 
>> So, do my comments make sense?
> 
> I have not done a performance comparison, but I agree with your
> comments.  That is why I think it makes sense to keep both in the tree,
> even though they provide the same functionality.
> 
And we're adding the same functionality over SIP. It will not only
distribute the states, but also offload Asterisk since you can have the
SIP subscriptions on a separate server.

/O