said by CDNguy :Um, no. The CDN providers can only choose from the routes the ISPs advertise. If an ISP only advertises to a CDN from a single link then that's the only link the CDN is gonna use. said by mackey:
Depends on your definition of "throttle." I consider knowingly overloading links or peering points in order to cause a bottleneck, or not doing anything to releave an overload, to be the same thing as throttling. The end result is pretty much the same at least.
As CDN's are the ones who choose which peering link or cheap-o transit provider to flood, your definition of throttling is happening on the CDN side.
CDN's are the ones that control the "best path" performance. ISPs have little control on the link choices.