When deploying Steelhead Mobile clients, there has to be at least one Steelhead WAN accelerator appliance at the datacenter to be the other "end point" for the optimized traffic. Another requirement is the addition of a second appliance, the Steelhead Mobile Controller (SMC), to create the optimization policies and to manage each installed end point. The SMC boosts the cost of the overall deployment a minimum of $12,995, which includes 30 concurrent Mobile licenses. You'll want to keep that in mind when considering software client deployments. The SMC is capable of managing up to 2,000 end points on a single appliance and collects usage and performance statistics for each connected user. These stats are sent over to the core Steelhead appliance for inclusion in its overall performance reporting.

For branch offices with more than 10 users, installing one of the smaller Steelhead appliances, like the model 300 (MSRP $9,995), makes better sense than deploying the software client. But for situations where there are a large number of users in many different locations, Steelhead Mobile fits perfectly and allows these users to see better WAN performance. Another excellent use case is the laptop user who is always on the go. Steelhead Mobile can speed up traffic to and from the central office no matter where the mobile user connects from.

In order to optimize traffic, admins create an end-point acceleration policy using the Web-based UI of the SMC. Each package defines which traffic to accelerate or ignore, any source/destination rules to apply, and whether TCP, CIFS, and MAPI optimizations are enabled. The end-point policy defines the cache size and which controller the client will communicate with. The acceleration and end-point policies are bound together in a deployment package suitable for all Windows clients from Windows 2000 to Vista – sorry, no Mac or Linux support.

Each Mobile client is essentially the same Riverbed operating system found on the appliances, just in miniature. It provides all of the same optimization features, such as TCP/IP optimization, CIFS and MAPI specific optimizations, and Sequenced Data Reduction. SDR proved to be very effective and, as with the appliance, is shared across applications. So if a user FTPs a file to their laptop, then copies it back to the datacenter using CIFS, only the changed part of the file is sent across the WAN.

Steelhead Mobile gives users local control over some optimization features, and also shows how the client has impacted performance. In this screen image, our Steelhead Mobile client shows the amount of data taken off the WAN at 67 percent, equating to an overall performance increase of 3X.

As great as Mobile sounds, there are a couple of shortcomings. Steelhead Mobile can't accelerate NFS and encrypted traffic such as SSL. Remote users logging into the corporate portal using SSL or accessing files on an NFS server won't see any real benefit from installing Mobile. It takes a Steelhead appliance to accelerate this traffic. Also, whereas the Steelhead appliance shares a cache with all users, each Mobile client has its own unique SDR cache. This means that one user can't take advantage of data cached when previously accessed by another user.