Last week I was forced to re-load my iPad from scratch. So I fired it up and went through the routine that wipes it clean and re-loads the entire OS from the Apple cloud. As I watched the progress moniker it slowly climbed from 1 hour, then 2 hours, then all the way up to 23 hours – and then it just stayed there. Now I know the iOS, or whatever they call it on the iPad, is big, but 23 hours big? I double-checked the download throughput on my NetEqualizer status screen, and sure enough, it was only running at about 60 to 100kbs, no where near my advertised Business Class 20 megabits. So I did a little experiment. I turned on my VPN tunnel, unplugged my iPad for a minute, and then took some steps to hide my DNS (so Comcast had no way to see my DNS requests). I then restarted my update and sure enough it sped up to about 10 megabits.
To make sure I was not imagining anything I repeated the test.
Without VPN (slow)
With VPN (fast)
So what is going here, does the VPN make things go faster? No not really, but it does prevent Comcast from recognizing my iOS update from Apple and singling it out for slower bandwidth.
Why does Comcast (allegedly) shape my download from Apple?
The long story behind this basically boils down to this: it is likely that Comcast really does not have a big enough switch going out to the Internet to support the deluge of bandwidth needed when a group of subscribers all try to update their devices at once. Especially during peak hours! Therefor, in order to keep basic services from becoming slow, they single out a few big hitters such as iOS updates.