[pcouture]

Most large players in heavy load content ( like live video streaming ) run double failover systems these days. Even if your running systems on S3 piping it through Akamai, you can't guarantee that they won't drop you when your load gets too high. So you have to setup a sister chain going through another origin and cdn.

But even at that if you start talking 100k+ clients you can't offload them all at the same time so you end up having to create this custom origin/mid tier distribution system...

Very annoying. I'd like to see CDN's being held liable if they go down or drop you entirely.

[Terretta]

I'm not aware of any real CDNs dropping someone for "load getting too high". Also, for a real CDN, 100k+ clients isn't noticeable.

If you're talking about the "unlimited traffic" or "price too good to be true" commodity delivery resellers, their business models are sometimes built on overselling and like a cell provider, those will throttle or drop you.

That said, a "network of networks" is a great strategy beyond a certain level of traffic. Nine Systems built a great business on that principle for video streaming until purchased by Akamai. Balancing video over multiple CDNs is a service we offer as well.

Finally, if your CDN SLA doesn't hold the CDN liable for going down, you're doing it wrong.

[moe]

In video-streaming 100k+ clients equates to 25+ GBit/s. Yes, that is noticable, even for a "real CDN".