(Update: Tuesday July 28th: As of 1pm ET, the Windows 10 launch is already massive with traffic over 10Tb/s.) I’ve never used the term “break the Internet” because most of the time people say that, they are simply overhyping an event on the web. But with the volume of downloads that Microsoft is expecting for the launch of Windows 10 and the capacity they have already reserved from third-party CDNs to deliver the software, the Internet is in for some real performance problems this week. Based on numbers I am hearing from multiple sources, Microsoft has reserved up to 40Tb/s per second of capacity from all of the third-party CDNs combined. To put that number in perspective, some of Apple’s recent largest live events on the web have peaked at 8Tb/s. Windows 10 is expected to be five times that and will easily be the largest day/week of traffic ever on the Internet. QoS problems are to be expected, especially since all of the CDNs will be rate limiting their delivery of the 3GB download and many ISPs will max out interconnection capacity in certain cities.
Microsoft keeps changing the date of when the update will initially go live, but as of now, it looks like it will be
available this afternoon (Updated: Will be Tues. morning) for those in the Windows Insider Program and then open up to everyone on Wednesday. That date could get pushed back again, but whatever day it launches, Windows 10 will surely create a new traffic record on the Internet. Microsoft will be using third-party CDNs Akamai, Limelight Networks, Level 3, EdgeCast and a few smaller providers to deliver the downloads. Akamai has the largest share of the traffic with Limelight being number two in volume. Microsoft’s own CDN will handle some of the downloads themselves, but I expect that will make up only a small percentage of the overall volume of delivery.
Unless Windows 10 is a complete flop and people don’t upgrade as quickly as Microsoft expects, Windows 10 is going to create some serious havoc with regards to the user experience. Expect to see some download times in the days, not hours, especially if any other content owners happen to have larger than expected traffic at the same time. Quality of service for downloads could deteriorate really quickly and remain poor for days, if not longer. I’ll be keeping a close eye on the traffic demands and delivery performance and will post the data I get from third-party companies shortly after the download goes live.