Asterisk IAX/SIP Gateway Specs


I have a project where I need to support up to 600 simultanious calls. The call flow is very basic - the agent picks up a phone and dials a number that goes through the IAX trunk to another Asterisk box over WAN. The calls will be established for the whole shift, and there is no need for any features such as transcoding/VM/recording aside from the function described.

From what I understand, CPU is going to be the bottleneck here, however, I read in one of the threads that extra cores on a single CPU does not increase performance of the server. I am having troubles believing it, does anyone have any information about it?

Based on my testing, I am looking at getting 2 servers, one to act as hot standby, with the following specs:

2 x Quad-core Intel Xeon E5506 (2.13 GHz, 4MB L3)
4 x 2 GB DDR3 RAM (Unbuffered)
4 x 146GB 10k HDDs

Does anyone else have similar setups, and could you include your server configuration/number of simultanious calls/load?



Extra cores should provide some increase in throughput, but this depends on the exact instruction mix and will be significantly less than a factor of 2.

I believe the original reason for multiple cores is to maximise the duty cycle of L1 cache memory. Any single core might be doing slow, e.g. floating point operations, leaving the fast L1 memory idle.

Even multiple processors may not help if the access part is non-local and the processing is memory bound.

I suspect that the Asterisk instruction mix is fairly memory intensive, so may not get much benefit from additonal cores.

Thanks for your reply,

would anyone have specific examples of single systems working for 600 simultanious calls? Any suggestions for the setup?