On Sep 23, 2013, at 15:10, Simon Leinen <simon.leinen@switch.ch> wrote:
Glen Kent writes:
One of the earlier posts seems to suggest that if iOS updates were cached on the ISPs CDN server then the traffic would have been manageable since everybody would only contact the local sever to get the image. Is this assumption correct?
Not necessarily. I think most of the iOS 7 update traffic WAS in fact delivered from CDN servers (in particular Akamai). And many/most large service providers already have Akamai servers in their networks. But they may not have enough spare capacity for such a sudden demand - either in terms of CDN (Akamai) servers or in terms of capacity between their CDN servers and their customers.
I have some anecdotal evidence that a large swatch of Telekom land in Germany was fed from two (2) Limelight servers in Frankfurt (?). Of course, packet loss to them during Wednesday evening was around 50 %. (I VPNed out of Telekom land to get my iOS 7 update, which was then no problem at all; that clearly shows that the access infrastructure wasn't overloaded.) It doesn't help that Apple's update software has no way to make use of the results of a prematurely aborted transfer; this is a recipe for bistable behavior. Grüße, Carsten