September 20th, 2012 by Craig Labovitz

Apple released the latest version of its eagerly anticipated IOS update Wednesday. In the minutes immediately following the 1pm EST release, massive numbers of iDevice users clearly raced to download the update.

The below graph shows normalized iTunes traffic across a random sample of several North American Internet providers over the last week. On Wednesday, iTunes backbone traffic spiked to consume an amazing average 7-12 percent of backbone traffic. This iTunes surge is roughly equivalent to abruptly switching on a new Internet service on the scale of YouTube or Netflix. The numbers are even larger if we just look at traffic consumer Internet providers.

Most of the update traffic came from edge CDN infrastructure or direct peering with CDN distribution infrastructure (mainly Akamai). iTunes traffic volumes remained elevated through late Thursday night (EST).

In many Internet backbones, the IOS6 release traffic spike handily outpaced the surges seen during previous IOS updates. Mostly, the millions of downloads appear to have gone without incident. But in a few networks, the IOS traffic flood overwhelmed backbone circuits leading to brief outages and periods of degraded Internet performance.