Traffic Capacity with RTP proxy enable

Hi,

We need to RTP-Proxy all voice traffic through our sip server, and we are wondering what is the maximum number of simultaneaous calls we can handle (using G729 codec, 10ms frames).

I read somewhere that benchmarks done by Brekeke on Pentium-D 3Ghz showed that 120 simultaneous calls could be achieved with RTP proxy enable.

If we get, let's say, a Quad core CPU (intel Q6600), can we expect to be able to handle 240 simultaneous calls? If we get a dual Quad-core server, can we expect to handle twice more?

Also, one questions, is it possible to always force rtp-proxy? even the user is in a situation where he could do without rtp proxy?

Thanks,

David.

David,

The benchmark you read concerned PBX rtp relay, which is different than SIP Server RTP Relay. If you are only using the sip server than you should be able to relay 3000 simultaneous calls with a P4 3ghz. In PBX relay the packets go thru a software media processor that does things like codec conversion, in SIP relay it just passes the packets thru without any processing, thus the reason it can handle so much more. And yes, I do believe that a multi-processor machine can handle more but I'm not sure how much more.

I have found that by using the PBX relay it helps with dtmf tones.

Nick

Are you sure about this?

I found this reply in the forums :

Because the OnDO SIP Server is a software, the number of maximum simultaneous calls depends on the hardware environment such as CPU power and network bandwidths.
The OnDO SIP Server doesn't have any simultaneous number restriction for both General and Trial Licenses.


Here is a confirmed data on a Pentium D (3.2GHz) with Red Hat Linux.
Number of normal concurrent calls (without RTP relay) is 3000.
Number of RTP relayed concurrent calls is 120.

the 3000 calls seems to be for sip without RTP relay, but if RTP relay is on, it's only 120 (on pendium D 3.2Ghz)

So my question is, can I expect to reach 240 calls with a quad core cpu (Q6600) and double than that with dual-quad core?

And also, is it possible to always rtp the voice even if the situation doesn't require rtp relay?

Thanks,

David.