Device speeds WAN apps

The NetCelera 400 can cut WAN traffic but is not cheap

Swan Labs’ NetCelera WAN application accelerator can speed up just about any type of TCP-based application, including web and voice over IP (VoIP)-based software.

The NetCelera 200 is an entry-level appliance and is suited to most environments. The higher-performance NetCelera 400 version is suitable for sites supporting very high levels of traffic. Units can be deployed asymmetrically or symmetrically. With symmetrical deploy- ments, appliances are located at both ends of the WAN link.

We tested the NetCelera 400 in an asymmetric configuration. Our results indicate NetCelera improves application performance from the client’s perspective, and can also reduce the amount of work done by application servers. Consequently it is a good choice for firms that have a lot of applications running over WAN links to remote staff.

Symmetric configurations provide the best scope for acceleration. For example, with a NetCelera at a remote site, documents and images can be cached so clients can retrieve them without any significant WAN traffic to the original source.

However, the unit can offer big performance gains in asymmetric setups too. For example, for web acceleration it uses data compression and can greatly reduce the amount of traffic. Such compression is supported by common specifications such as HTTP, and imp- lemented in client software such as Internet Explorer version 4.

The device can also update older Adobe Acrobat files in transit to the latest PDF format, so the client does not need to download all the pages before it can display the first.

We tested the NetCelera 400 by benchmarking the client-side performance of Siebel’s CRM suite running over a simulated WAN link. We used a WAN simulator to control the bandwidth and latency of the link between the NetCelera and the client system.

Configuring the appliance was easy because it works as a reverse-proxy, so deployment simply involved updating our DNS records so client requests were directed to the NetCelera instead of the application server. Thus the NetCelera answered whatever requests it could from its own cache without burdening the application server each time. It forwarded other requests to the main application server.

To accelerate protocols the unit needs to understand how they work, and this information is defined in NetCelera policies. The unit comes with policies to accelerate six applications, including simple HTTP sites and remote office workloads, Plumtree portals, and Microsoft Outlook Web Access.

The Siebel policy is not supplied as standard, but NetCelera units are normally set up by Swan Labs resellers, and they installed and configured this policy for us.

In our tests the time taken to log in to the Siebel application was reduced from about 21 seconds to about nine seconds on a simulated 64kbit/s dial-up line with 10ms latency. Policies can be copied and edited via a web-based interface, which is also used to manage the device.