More and more application acceleration vendors are realizing that to provide customers with more complete WAN optimization products they need to add wide-area file services (WAFS) as well.

Following companies such as Expand Networks and Riverbed Technology, F5 Network's WANJet 4.0 release is the most recent example of additional WAFS capabilities being coupled with application acceleration wares.

WANJet appliances, which F5 acquired with Swan Labs last year, have been upgraded to accelerate access to Common Internet File System files, Microsoft's commonly used format for network file sharing. The WANJet 4.0 could help users in offices with centralized file servers retrieve and edit documents faster, F5 says. Industry watchers say the devices could be used to replace file servers in branch offices as a way to speed backup of remote data.

WANJet appliances use a dual-sided, symmetric architecture, meaning enterprise customers install an appliance between the router and the switch in the data center and another one sits in the remote or branch location. The devices sit at either end of the WAN connections examining packet flows, compressing traffic, shaping it and optimizing TCP to improve throughput.

According to F5 Networks' Ameet Dhillon, director of product management, WANJet 4.0 includes software that employs Transparent Data Reduction, which also speeds traffic over WAN links. The feature enables the software to store blocks of data in RAM as they are sent so that when the same block is required in later transmissions, it doesn't have to be sent across the wire. Instead, the sending machine sends a brief cue that indicates what previously sent block to use. The receiving WANJet pulls that block from memory and sends it along to the local machine that requested it.

"This is high-speed pattern matching, not file caching," Dhillon says.

Expected to be generally available next month, entry-level pricing of WANJet 4.0 starts at $1,795 per appliance.

Ann Bednarz is associate news editor at Network World.