Moving more data across network links

Squeezing more data into existing networks has been a common desire since the days of dial-up modems supporting 300 bauds/sec connections.

Compression products have been the dominant method for meeting that goal. Such devices squeeze more information into each link by relying on sophisticated algorithms to examine data flows and strip out redundant information. The sending device converts data into shorter data streams, and the receiving system translates them back into their original form.

Data compression has become so commonplace that router vendors include it as a feature in their products, with most of them consolidating packet headers, the labeling information found in each transmission.

Compression techniques typically operate at the network level and do not deal

with application-specific traffic. Recently, vendors designed data-compression methods that not only shrink packet headers but also compress the application data. Others are moving away from devices that only periodically update application data transmissions to those that examine data in real time.

Performance gains range from 30 percent to as much as 400 percent, depending on an agency's application mix and network configuration.