Compression devices show why smaller is better

One of the fastest paybacks in IT comes from WAN compression. Put compression boxes at both ends of a link and increase throughput without buying more bandwidth. The result is that applications respond faster without signing on for the additional monthly expense of a bigger WAN connection.

Take international specialty-packaging company Pactiv, with U.S. headquarters in Lake Forest, Ill. Last year it installed a manufacturing application called Manufacturing Pro at 12 sites in Europe that are connected by a hub-and-spoke frame relay network. The new application slowed traffic so much that some 128K bit/sec links would need doubling to support fast enough response times, says Matt Haynes, Pactiv's network manager. That doubling of bandwidth would have doubled or even tripled the price of some circuits, he says.

Before buying that extra bandwidth though, Pactiv tried Expand Networks' Accelerator compression gear, which shrank traffic enough to eliminate the need to pay for fatter pipes. Based on avoiding that additional cost, the appliances paid for themselves within six and a half months, Haynes says.

Makers of specialty compression equipment such as Expand, Peribit Networks and ITWorx share a basic concept: Their appliances examine network traffic for patterns that repeat and then replace them with shorter patterns. These abbreviations reduce the number of bits that cross the wire, easing congestion. Depending on the type of traffic, compression can reduce it by more than 95%, with vendors promising to cut traffic at least in half.

The boxes sit between WAN routers and WAN links. If they fail, they become passive and traffic passes as if they were part of the wire.

Peribit and Expand have added basic traffic-shaping to their equipment, and traffic-shaping specialist Packeteer has added compression. Experts say Peribit's and Expand's traffic shaping doesn't stand up to Packeteer's, and Packeteer's compression lags behind Peribit's and Expand's.

Some router vendors also support compression in their gear, but customers report finding shortcomings with that architecture.