Above The Cloud

Late last year Microsoft announced the availability of a Content Delivery Network (CDN) in Azure that you can use to distribute your Windows Azure Blobs to over 18 different edges, including Australia.

However this technology is not actually a new offering. Microsoft has been building/leasing CDNs for some time now. Prior to 2007 Microsoft leveraged the CDNs of a variety of companies such as Akamai and Level 3. Then in early 2007 Limelight Networks announced that they were supporting Silverlight with a focus on streaming media, and not long after, a Microsoft and Limelight joint partnership was announced where Microsoft would lease some key CDN technologies from Limelight and start building their own CDN. Rumour spread about Microsoft acquiring the company but those were quickly dismissed.

Like all other things infrastructure related, Global Foundation Services (GFS) is the department that is responsible for Microsoft’s CDN technology. At the end of the day you have to remember that Azure is not the first product to come along that requires massive storage and compute resources. Bing, Virtual Earth, Photo Gallery, Hotmail, etc are all services that require massive scale and Microsoft has been working in data centre technology for a long time. GFS is responsible for all of that and more. In their own words:

Global Foundation Services (GFS) is the engine that powers Microsoft’s Software Plus Services strategy. We focus on smart growth, high efficiency, and delivering a trusted experience to customers and partners worldwide

Microsoft has been building data centres for some time and it makes sense that they would start  improving on their own CDN offering. And even with the Limelight deal in 2007, Microsoft has started scaling back its other outsourced CDN needs, improving on its own CDN capability instead. At the Content Delivery Summit of 2009, the GM of Microsoft’s Edge Computing Network Jeff Cohen released some interesting statistics around Microsoft’s CDN services, as this article states:

..one of the points that really stood out was how quickly Microsoft is moving away from relying on third party CDNs for delivery and instead, using their own internal CDN..

In 2007 about 95% of Microsoft content was delivered by 3rd party CDN, however by the end of 2010 they expect this number to have dropped to a lowly 40%. It would seem that Microsoft is moving away from partner CDNs for small/large file transmissions, opting instead to use its own CDN technology, but sees its video streaming still sitting firmly in the hands of other companies like Akamai and Limelight. It makes sense. As I said before, Microsoft is in the market of building data centres for its various products and has already built data centres all around the world, including this one in Dublin (there was a feasibility study done for an Australian based data centre a couple years ago and Microsoft opted not to build one here yet).

With the release of ASP.NET 4.0 Microsoft are also offering CDN support for various JavaScript libraries such as its ASP.Net Ajax libraries, and the JQuery libraries. Google started with this idea in May of 2008 so Microsoft has been a bit slow to the punch. Google also supports a large variety of Ajax frameworks in its Ajax API CDN whereas Microsoft’s list is still growing.

So this all begs one question: Where does my CDN enabled Azure blob data actually sit? Microsoft or some third party CDN provider? 

Well I hunted around and couldn’t find any specific information stating one way or the other whose CDN the blob storage uses, but I can tell you that it would appear to be hosted on 3rd party CDNs. How do I know for sure? I don’t, but there’s some clues that hint to the fact, and I’ve dropped 2 key clues in this article for you to find. The first one to work out the 2 clues/indicators and post them in a comment to this post will win an Azure T-Shirt! (Australian residents only please).

Is there any real cause for alarm that my blob data could be hosted on a 3rd party CDN provider? Well no – you can only enable CDN availability on blob containers that are public access, which means everyone can get your data anyway.

In a country like Australia where we have communication ministers who want to introduce ISP level internet censorship and telco-providers refusing to improve bandwidth, CDNs will be critical to content delivery speed and adoption of higher quality information (eg HD streaming).