Content Delivery Networks and SharePoint
In the previous post I covered why someone would need to deal with global SharePoint and the 4 different options that exist to help SharePoint work over long distances. As a reminder, they are:
- Shorten the distance by using a more efficient network (CDN)
- Shorten the distance by staging SharePoint servers closer to the users
- Shorten the distance for some of the content by putting some of the larger content closer to the users
- Increase the efficiency of delivering the content from SharePoint by combing the many packets into a few packets – and compressing as much as possible
In this post I’d like talk about Content Delivery Networks. The goal of a CDN is to either
- Shorten the distance between the servers and the users by utilizing a more efficient network
- Stage content from your sites in regional points of presence (POP) in the CDN
Now different CDN providers have their own “secret sauce” that they can add to the picture to help with performance with either all traffic or with some solution specific traffic. Some CDN providers (like Akamai) will even create guarantees on the quality, speed, reliability, and availability of the delivery of your content. the challenge with some providers is that they have issues when delivering content that requires NTLM authentication (aka SharePoint). This doesn’t mean that it can’t work with SharePoint – they just can’t work with SharePoint in certain use cases. For instance – a CDN with NTLM issues would be fine for a public facing web-site but would fail when trying to us it to accelerate your Intranet. There is a way to work around this – but requires that your site be configured with Forms Based Authentication (or with basic authentication). Now this creates some usability “challenges”. You will need to decide if those will impact you.
As CDN providers deliver traffic – they are are also caching some of this content in POPs along the way. The result is that on the second request for the same content – the distance to deliver it is dramatically shortened.
So by a combination of a more efficient network and caching content along the way – CDN’s have the ability to speed web sites (and SharePoint sites) up for users who are far from the source servers. This speed does come at a technical cost depending on any authentication requires as well as a financial cost.
Here are few CDN providers that come to mind:
A Gartner Analyst I’ve met with while she was being brief by Rackspace is Lydia Leong. Here is a post where she talks about research she is doing in this space. If you’d like to get an analysts perspective on the key players, I’d recommend her.
Lastly – it is possible for you to manually handle the staging of content in a CDN while leaving the delivery of the SharePoint experience alone. Take the scenario where your site has a lot of very large graphic or media files that need to be delivered to your users around the globe. When you publish these items to SharePoint – first stage them in a CDN (like Rackspace CloudFiles) and publish the URL for those assets to SharePoint – and not the assets themselves. This helps with the end user experience. This technique doesn’t work with content that is collaborative in nature – that content has to remain in SharePoint for SharePoint to manage the experience. But for the static content that doesn’t change frequently – it is a good solution.
In the next post I’ll start to deal with staging SharePoint servers closer to your users.
Tags: Akamai, CDN, Content Delivery Network, Gartner, NTLM, SharePoint, SharePoint 2010, SharePoint Architecture, SharePoint Authentication, SharePoint Content Delivery Network
