The IT team decided to take a comprehensive look at what we determined were the leading WAN optimization vendors at the time, which initially led us to products from Cisco, Riverbed, Silver Peak Systems, Blue Coat, and Citrix. Because we were using for traffic shaping on our VoIP traffic, we decided to see if they too could meet our broader WAN optimization requirements (this was before Packeteer was acquired by Blue Coat.)

We were quickly able to pare down this list when we could not get Cisco and Citrix to work in our evaluation scenario. Bluecoat and Packeteer were also eliminated since both lacked performing disk-based deduplication for Citrix, which we thought was critical given the repetitive nature of our WAN traffic. Our employees send thousands of versions of the same documents back and forth, much of which is identical. We therefore quickly established that deduplication would have a significant reduction in our WAN bandwidth.

That left Riverbed and Silver Peak Systems, which we moved into live production tests over a several week period. We evaluated these products on a primary WAN connection between our Hong Kong and UK data centers. Then, they went to a live test in our Bangkok office, which has more than 30 attorneys.

While both Riverbed and Silver Peak Systems performed well on a variety of different applications, the real difference came down to the Citrix application. Silver Peak optimizes this traffic while Riverbed did not. Silver Peak has an enormous impact on Citrix's reliability across the WAN; in addition, once we turned off compression and encryption on our Citrix servers, Silver Peak was able to dedupe our Citrix traffic. Its performance with Citrix was a pleasant surprise to us as other WAN optimization vendors told us they could not dedupe Citrix traffic due to its low latency requirements. With Silver Peak, we are seeing 7GB Citrix sessions reduced to 3GB on the WAN, which is an average reduction of 56 percent.

Linklaters believes that Silver Peak's products and roadmap best align with our overall business strategy. Silver Peak's network layer approach to WAN optimization gives us a sense of confidence that we can optimize any applications we want, as evidenced by its ability to handle our Citrix, VoIP and EMC SRDF traffic. In thinking about the future, we did not want to worry about which applications would be supported across our WAN and which would not. Silver Peak's solution combines WAN optimization with traffic shaping. In addition to deduplication and packet loss correction, they provide robust Quality of Service (QoS) capabilities that obviate the need for separate Packeteer products in the Linklaters network.