Speeding up the delivery of applications and data to remote users is the No. 1 goal of WAN acceleration and optimization. Not only does it help get more done over the same amount of bandwidth -- or less -- but WAN optimization appliances reduce response times and overcome latency inherent to long-distance WAN links. Using a combination of file- and byte-segment caching, TCP optimizations, and application-specific acceleration, WAN acceleration appliances help move the data that drives business.

One vendor that I've long wanted to test is Juniper and its WXC line of WAN acceleration appliances. I was originally scheduled to evaluate Juniper's appliances back in early 2007, but due to a scheduling conflict, I was not able to get my hands on the gear. Now, only 18 months later, I was able to finally plug a pair of WXC 1800s into my well-worn WAN acceleration test bench to see how they fared.

The WXC 1800 offers a good mix of application acceleration, TCP optimization, byte-level caching (Network Sequence Cache), and central management. The appliance is one of only a couple WAN optimization appliances I've tested that can handle CIFS traffic that's been signed by SMB (Server Message Block). It also can accelerate SSL-encrypted packets including users with client certificates.

My WAN test bed was laid out as with previous tests: a Shunra VE simulating the various WAN links and impairments, a client PC running Windows XP Pro and MJT Net Macro Scheduler, and a Windows Small Business Server 2003 as the data source and Exchange server. As before, WAN speeds tested were 128kbps with 40ms latency and T1 (1.54Mbps) with 500ms latency and 0.5 percent packet loss.

My WXC 1800s came licensed for a 2Mbps WAN link (up to 64,000 concurrent TCP flows); the system comes standard with two 10/100 Mbps Ethernet ports. A manual bypass switch on the front panel determines if the appliance fails open or fails to wire in the event of a hardware problem. Failing to wires is a nice safety feature for busy WANs.

Installing the pair of appliances took roughly an hour to complete. Part of the setup process entails defining one appliance, typically near the datacenter, as the registration server. The registration server keeps track of all other connected WXCs, including the subnets behind each appliance. This allows Juniper to handle a variety of network topologies, such as hub and spoke and fully meshed. Unlike the Riverbed Steelhead, which automatically sniffs out the other appliances, Juniper requires each appliance be explicitly pointed to the registration server. Juniper argues that this helps admins maintain control over traffic flows and allows for better traffic management.