The first hour of iOS 9 availability was overshadowed by “Software Update Failed, An error occurred when downloading iOS 9” message received by thousands of users worldwide.
According to the information provided by experts the first suggestion that the problem with downloading iOS 9 was caused by an overload on Apple’s content delivery network (CDN) has proved unfounded.
Reasons Why Apple Created CDN
Dan Rayburn, an analyst with Frost & Sullivan bases his conclusion on data collected from different Internet service providers and CDN vendors. It seems that the situation with erroneous mobile operating system upgrade is not new to Apple as there are always some troubles with the deployment of the upgrade.
Constant wish of Apple users to receive and use updates as soon as it is possible played old Harry with Apple. For example, one of the Internet service providers received data about 13Tbps traffic from apple.com in the morning of the iOS 9 release day. Still the traffic was being delivered in such a way that prevented overloading of networks. Moreover, all ISPs and CDN vendors were ready and prepared for overloading so they exceeded their capacity.
Apple has its own CDN that was created to control the content shipped over the Internet, more than that, the company takes an advantage of numerous data centers where Apple servers are situated as well as rents capacity from the biggest ISPs. As a result, the company has a possibility to provide upgrades to the users without overloading.
The whole lot iOS 9 downloading engaged 8% – 15% of traffic of the U.S. ISPs and taking into consideration preparedness of providers, could not affect their work much.
One of the advantages that Apple has over others is that there is a clear notion of the traffic patterns so the specialists of the company are prepared for any issues with capacity.
All this together allows to make a conclusion that there were no capacity problems with the downloading – the issue was with installation and software itself.