Blue Coat SG800 review

WAN optimisation is going to be one of the hottest topics this year and the large number of vendors entering this market is already testament to this. Content-filtering expert Blue Coat now moves in with its latest SG family of appliances. These offer WAN optimisation but with a few extra tricks up their sleeves.

The SG800 is aimed at core data-centre services, with remote offices having the smaller SG200 appliances deployed to them. As with all optimisation solutions, the SG appliances function as transparent TCP proxies that intercept and optimise all TCP traffic. The SG800 offers the usual mix of optimisation technologies, which include bandwidth management, protocol optimisation and compression. It may be called byte caching by Blue Coat, but the SG800 uses the same pattern-matching techniques as most of the competition, which ensures that all repetitive WAN traffic is removed from the link. Blue Coat’s object caching sets the SG products apart, however. Along with checking data at the byte level, the SG800 can recognise objects such as complete files and cache them. In addition, the appliance can optimise HTTPS traffic, a feature that currently makes Blue Coat unique.

Blue Coat’s heritage also gives it a different slant on WAN optimisation. Whereas the majority of vendors are looking at this as a purely network-related issue, Blue Coat’s history in content filtering has allowed it to approach the problem from a user perspective. Consequently, the appliances are geared up to manage traffic based on criteria such as users and domains. To implement this, all you do is use the smartly designed web interface to configure the appliances to deny all traffic and then add policies and rules to decide what to allow through.

For testing, we called upon a dummynet-based WAN simulator configured for a 2Mb/sec E1 WAN link with a 40ms latency. We placed an SG800 on one side and at one end added a Windows Server 2003 system configured with IIS and FTP services, plus Ipswitch’s iMail Server 8. To represent a remote office, we used an SG200 appliance on the other side of the simulator and connected a Windows Server 2003 system to act as a client. A 4.8MB PowerPoint presentation was used to test a variety of scenarios.

With optimisation turned off, remotely opening the file at the client took 29 seconds, and saving a modification to the server with a new file location took 32 seconds. But with optimisation in action and the file cached these times were reduced to only 3.5 and 5 seconds. Mailing the file as an attachment from the client to the server with no optimisation took 3mins 6secs, while mailing it back took 47 seconds. With the file cached the appliances reduced these times to only 3 and 2.5 seconds. We also saw major improvement for file copy operations, with the same PowerPoint file copied from client to server and back again in 26 seconds and 28 seconds respectively, but only 2 seconds and 1.5 seconds with optimisation activated.

The hardware specification looks a little dated, but our performance tests show the gains the SG800 can deliver. It’s particularly easy to deploy, and there’s no denying Blue Coat is offering a lot more than your average WAN-optimisation appliance.