[Asterisk-Users] Asterisk, enterprise edition (New subject)

[Nick Bachmann]

> Nick Bachmann wrote:
>
>>Yes, I've played with it a bit.  It's pretty simplistic... the
>>clustering just keeps several servers in sync with each other.  I
>>suppose that would be easy to do with Asterisk, especially if
>>configuration data was stored in a RDBMS that could do replication.
>>Even now, setting up a copy/reload routine isn't difficult.
>>It also seems that if you had a load balancer set up in front of your *
>>servers to balance the call requests, you'd have enough clustering to
>>keep one failure from taking down the whole system. Since the load
>>balancer keeps an affinity table (and monitors to make sure the servers
>>aren't going down) all VoIP connections could end up at the same * box
>>once they had been allocated, unless a server goes down, in which case
>>the call probably gets dropped. Any planned downtime could be made
>>without any disruptions, since you could stop the load balancer from
>>allocating any more connections to the * box and use 'stop when
>>convenient' to wait for all current calls to end.
>>Nick
>>
>>
>>
> As long as what ever system is used only presents a single IP address
> on  the network, the reason being that if a SIP UA is behind NAT the
> NAT  router will have opened a path for the response from the server it
>  contacted, if the request was offloaded to another IP address then the
>  response would not get through..

Yes, most load balancers have an "affinity table" (depending on your
vendor-speek) that pairs client and server IPs.
> Also the servers in the "cluster" would have to share SIP registration
> information so that all servers would know all availible UA's and all
> servers would have to communicate to that UA on the same IP address..

I forgot that... the VOCAL stuff also shares registration data.  It can't
be too hard for Asterisk to do this as well.
> These things could have major issues when it came to the RTP streams..

The affinity table makes the RTP stuff OK, but I agree that sharing SIP
registrations is a concern.
Nick