BranchCache is a technology that Microsoft released with Windows 7 and Server 2008 R2 which can have a profound effect on where users actually source their content and the bandwidth consumed in retrieving that data.

It’s fairly common in today’s work world to see global enterprises have multiple branch offices with users who regularly access data from a single centralized datacenter. If you take a look at the data that these users are commonly requesting, you’ll quickly realize that there is often a significant amount of data that is repetitive between the branch users.

BranchCache is a technology designed to cut down on the unnecessary round trips from the branch office to the datacenter for data. By keeping an accessible copy of the content in the local branch, there will be a significant reduction in bandwidth used, and users will often be able to get the content faster than retrieving it from the distant datacenter.

BranchCache-Diagram-b3

BIG-IP LTM can provide significant value when deploying BranchCache for HTTP/S in the datacenter. By leveraging the power of our iRules, you can offload the content hash creation to the BIG-IP, allowing your web servers to focus on what they best, serving content. BIG-IP also has the intelligence to optionally cache those hashes, accelerating the solution for subsequent requests.

Into the weeds……..

I wouldn’t dare wrap up this post without a technical discussion on the solution. If you are still reading this, then you’re probably aware of how the basics of BranchCache work. When the initial request from a BranchCache enabled client for the content comes in, the W2008 R2 server will create and send the hash values of the content back instead of actual content. The client can then use these hash values to determine if any local caches already have the content. By enabling the iRule below, the BIG-IP that is sitting in front of your web servers will actually offload that hash creation from your servers by grabbing the content from the servers, creating the hash values and sending them to client.

BIG-IP creates and sends the hash, offloading this costly process from the server
BIG-IP caches those hash values to accelerate subsequent requests
This is all compatible with OneConnect!!
No F5 equipment is needed for this solution in the branch office
This works for HTTP traffic with the hosted and distributed models of BranchCache

Interested in the iRule? Check it out here –>

http://devcentral.f5.com/wiki/default.aspx/iRules/MicrosoftBranchCacheHashOffload.html

As always, feel free to reach out to me with any questions or concerns!