> We have 65 dedicated servers for streaming all clustered together, making the 65 act like 3 servers, with a cluster of 2 for DNS.
Nice setup!
As you said, the most expensive part will be the bandwidth portion of things (usually). Cloud is great for that kind of setup and is essentially what Stream101 is doing, they're running an internal "cloud" network which they can bring services online and offline depending on load capacity requirements.
The security of the machines and the necessary software optimized does take someone who knows what they're doing (to do it right).
Each project is a different beast or monster (depending how you want to look at it)
