ROSELAND, N.J. - Expand Networks is making it possible to prioritize traffic so important applications get the bandwidth they need over low-bandwidth WAN connections.

The company is announcing quality-of-service software called Instant QoS for its Accelerator appliance that can reserve bandwidth for designated applications. Until now, Accelerator could only compress traffic.

Accelerators are placed between LANs and WAN routers where they analyze traffic, cache selected parts of packets so these parts didn't have to be sent repetitively over the link and compress traffic before they enter the WAN. The devices are placed at each site and decompressed incoming packets. Now the devices enforce QoS preferences.

Expand says it will compete now against the likes of Packeteer, which specializes in bandwidth management, but Expand is shooting for smaller sites where customers need less-expensive devices.

Users at freight-forwarding and warehousing firm Geologistics say Instant QoS is exactly what they have been looking for.

"We've got issues with salespeople downloading e-mails with large attachments. It slows down our operations applications," says Morey Straus, international network manager for the firm in Santa Ana, Calif. Straus says adding Instant QoS to the company's current Accelerators will let him give preference to AS/400 Server and Citrix traffic that gets bogged down by large e-mails despite compression.

Geologistic sites have 64K or 128K bit/sec WAN connections, he says. He says he will designate a certain percentage of the WAN bandwidth capacity to the most important applications, a separate percentage to traffic of intermediate importance and leave the rest for all other applications.

Straus says he considered Packeteer for Geologistics' network but, "We couldn't afford to deploy it to all our sites."

Packeteer gear with QoS costs $4,500 to $30,000.

Straus says the company has used the Priority Queuing features on its Cisco routers to try to prioritize applications, but bulky low-priority traffic still affects performance.

The Accelerator gear Geologistics uses costs about $2,000 and has let the company avoid buying more bandwidth for its European offices, where a 64K bit/sec connection costs $50,000 per year.