There is an EC2 kernel with a 1000Hz clock, which I have successfully used to set up Asterisk etc already, but I am wondering if other issues (e.g. transit from London to Dublin to London- our current path)- could cause problems using g729 and maybe 20 simultaneous channels.
Many thanks,
Chris.
Best Answer
Short answer: No.
Longer answer: VOIP services require extremely precise timing, which is practically impossible in any virtualized environment, but almost certainly out of question in a shared environment like EC2 where other people's workloads can affect your system's performance. The best VOIP solutions are dedicated servers, and typically include some kind of dedicated hardware timing source (like a telco line card, even if your system is "pure VOIP").
Beyond the server timing problems you can also expect that the additional round-trip-time delay to get from your desk phone to/from a server "in the cloud" would cause call quality issues (delays long enough that you might start talking over yourself, line echo, etc.) -- This can be noticeable on VOIP systems with as little as 10-15ms latency to the server, but becomes obvious over about 25ms and worse from there.