Bandwidth limitations continue to play a significant role in application performance. Most networks fall into one of two categories. In the first category are low speed networks such as dial up and frame relay. These networks often range in speeds from 56 kbps to 2 Mbps and have many endpoints. While not suitable for large offices, these data rates are common among small branch offices. The second class of wide area networks is high speed networks typically used for data replication and communication between large offices. Unlike small office networks, these networks often range in speed from 45 Mbps to 622 Mbps.

Although networks have continued to improve over time, application traffic has increased at an alarming rate. Bandwidth-efficient client server applications have been replaced with bandwidth- demanding web applications. Where previous generation client server transactions involved tens of kilobytes of data, rich web based portal applications can transfer hundreds of kilobytes per transaction. Files attached to email and accessed across remote file shares have increased in size. Even data replication environments with dedicated high speed links have encountered bandwidth challenges due to increases in the amount of data requiring replication.

For both low speed and high speed networks, provisioning additional bandwidth to meet the increased demand is often prohibitively expensive. Bandwidth prices have not declined as rapidly as expected and networks have been unable to keep up with application demands.

Transparent Data Reduction The F5 WANJet product utilizes a technology called Transparent Data Reduction (TDR) to address these bandwidth challenges. Unlike previous forms of compression, TDR utilizes a two stage compression process to maximize bandwidth savings while minimizing processing latency. The first step of the process (TDR-2) examines the transmitted data to determine if any part of it has been previously sent. If so, the previously transmitted regions are replaced with references. The second step (TDR-1) further compresses the data through the use of dictionary based compression and advanced encoding schemes.