My company is looking to have a setup similar to the following:-
An Asterisk implementation that can manage 200 simultaneous calls.
We’re looking towards doing all calls via VoIP using SIP and G729.
What’s the best way to go about doing this?
What would be the specifications on a machine that could handle all 200 simultaneous calls and also perform transcoding of the calls using the G729 codec?
Typically, calls would be made using soft phones that register to the Asterisk box via SIP and use G729 as the voice codec.
Thank you in advance.
Probably 200 Simulate nous calls is not simple installation. Can you think of giving more information. How many Locations / PSTN lines and extensions you anticipate apart from simult. calls.
You biggest issue will be with bandwidth, you will need a lot! G729 uses about 32KB per call per direction. 200 * 2 * 32 = 12.5 MB/s or 2 DS2 lines. You dont necessarily need 200 two way connections as silence is not transmiteed and usually only one side of the conversation is talking at a time but if you squeeze the bandwith too low the call quality will suffer.
http://www.voip-info.org/wiki-Bandwidth+consumption
Also I would plan on at least 2 servers, figure about 100 simultaneous calls per server.
All these calls will be taking place in a single location. No PSTN lines will be in use. All the calls should be placed through our VoIP provider thus the opt to use G729 codecs.
[quote]You biggest issue will be with bandwidth, you will need a lot! G729 uses about 32KB per call per direction. 200 * 2 * 32 = 12.5 MB/s or 2 DS2 lines. You dont necessarily need 200 two way connections as silence is not transmiteed and usually only one side of the conversation is talking at a time but if you squeeze the bandwith too low the call quality will suffer.
voip-info.org/wiki-Bandwidth+consumption
Also I would plan on at least 2 servers, figure about 100 simultaneous calls per server.[/quote]
As per calculations, I was under the impression that each G729 call would use about 14Kbps of bandwidth including network overhead. Which would take me to about 2.8Mbps of bandwidth. Was I mistaken?
Let me try to clarify a little more.
We want to do 200 simultaneous calls.
For all these 200 calls, we want to use G729 format.
All these calls will be placed through our VoIP provider most likely using soft phones.
What would the specifications be of a machine that could handle the transcoding of 200 simultaneous G729 calls?
Is my calculation of the bandwidth requirement correct? If not, what would be the bandwidth requirement of the 200 simultaneous calls?
If a machine that can handle 200 simultaenous G729 calls is not feasible, what would be the specifications on a box that could do half of that volume?
Thank you for your responses so far.
Use the link I posted to get to the list of bandwidth calculators. The bandwith you came up with is for one side of the call only. As I said before its not a good idea to assume all calls will have one side be 100% silent at all times (background noises are not silence) so you need to double your numbers.
As for server size any dual processor box less than 2 years old will do fine. If you are not recording calls than the disk subsystem doesnt matter at all - you can run SCSI or SATA without any problems. If your recording I would suggest 15K rpm SCSI disks in either raid 0 (no redundancy) RAID 5 or RAID10 for good write performance. 2GB of RAM is plenty.