iOS 7 update traffic

[cabo at tzi.org (Carsten Bormann)]

On Sep 23, 2013, at 15:10, Simon Leinen <simon.leinen at 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.

Gr??e, Carsten