Riverbed Steelhead boosts WAN data flow

IT always seems to be caught in the middle of the WAN-performance battle: On one hand, users never seem to be happy with an application’s performance; on the other, the bean counters won’t budget for bigger pipes. If more bandwidth isn’t the answer to end-users’ performance problems, then what is?

The solution to improving both response time and circuit utilization is to make the connection more efficient and to reduce the effects of latency. I’ve watched a whole new breed of WAN optimization and acceleration appliances come to market during the past few years, and I’ve seen firsthand what a difference intelligent optimization can make on WAN response time.

Once again, I had Riverbed's Steelhead WAN acceleration and optimization appliances on my test bed, and true to form, the company provided excellent improvements with little tweaking. Release 3 of the RiOS (Riverbed Optimization System) shows a more mature product, with the focus on improving existing features, the addition of greater application support, and much increased capacity. During its time on my bench, Steelhead proved again that it is more than capable of making oversubscribed WAN circuits appear faster than they were while greatly reducing response time, besting previous releases by as much as 20 percent.

I tested three Steelhead appliances: the 200, the 5520, and the 6020. The 5520 (offering 155Mbps of optimized throughput and 15,000 TCP connections) and the 6020 (boasting 310Mbps of optimized throughput and 40,000 TCP connections) are hardware platforms released this year -- as are their cousins, the 3020 and the 3520.

I set up the 5520 as the branch-office appliance and the 6020 as the datacenter unit. (The complete solution requires at least two appliances.) The impish 200 (1Mbps of optimized throughput and 100 TCP connections) came into play during testing of optimization of asymmetric routes (more on this later). My trusty Shunra VE simulated my various WAN conditions, and D-Link DGS-3324SR Gigabit switches tied it all together.

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RiOS has always included optimizations for CIFS and MAPI aimed at reducing the protocols’ chattiness. In RiOS 3, Riverbed builds on this solid foundation with the addition of NFS streamlining. As with CIFS traffic, there is a lot of protocol overhead with NFS that can degrade application response time significantly. RiOS 2.1 performed NFS optimization via data and transport streaming; RiOS 3 does NFS application streaming, allowing for read-ahead and metadata pre-fetching. Unfortunately, I do not have any NFS performance numbers from previous releases, but Riverbed’s internal testing shows a 10-fold improvement in RiOS 3. CIFS traffic gained an improvement of between three and six times compared with last year’s testing.