I'm in the market for a dedicated server for VOIP, Other than the server configuration what are the technical criteria that I should look at?
My experience is with asterisk, so here are some things I remember looking for. Be sure that the datacenter is providing plenty of bandwidth. I know VOIP doesn't use a lot, but if you are planning to host several hundred calls at once, bandwidth can start to add up. As for the server itself, get plenty of RAM and a decent CPU. Not all VOIP clients use the same codecs when talking to each other, so transcoding (converting one codec to another, i.e. ulaw/alaw<->GSM, Speeks<->alaw/ulaw, etc,etc) can take up a few extra cycles. If you plan on offering voicemail, plenty of storage and a fast HD are certainly necessary. I don't know your setup/requirements/expertise are/is but spend some time playing with AsteriskNOW. For larger systems, I prefer compiling the software, but AsteriskNOW is a complete point-and-click OS-on-a-disk that will help you get up to speed on how a VOIP system works as well as a nice interface with some resource monitoring. For smaller production installations, it works just fine out of the box.
Thanks for your ideas ,do I have to look at latency , Ping time , Jitter etc. If I have to look at them how should I check before purchasing the server? Does it matter where my users and call termination servers are located?
Latency and ping time is a good indicator, but assuming the datacenter is well connected, 6 times out of 10 latency issues will come from the user's ISP (home dsl, coffee-house hotspot, etc) rather than your server. Definitely maybe If you are in Mexico, and your customers are in Mexico, you will "typically" get better performance with a server located in Mexico. VOIP forums will probably give you a slew of different stories. The internet can be finicky at times. Ask what the datacenter's upline is - this can help. If they will not tell you or do not know - take your money elsewhere. Keep in mind here that this would be for a really large deployment; If you have only 10 users across a couple countries, get a server that is close, but large enough to be well-connected.
Shan... Thanks really depends on your traffic, if you have more than 500 simultaneous calls then you must have 10+gb ram and enough bandwidth.
If you need a lot of resource you should looking at Cloud Computing, like Amazon Web Services (aws.amazon.com/ec2). Here you can add and remove servers on fly, depending on loading and amount of calls.