Statistical vs. Dictionary compression

Statistical compression algorithms are usually employed in single applications where the data is predictive, and consistent, since traffic through networks is inconsistent and unpredictable, it is not very suitable for compressing data on routers.

Dictionary compression algorithms in the other hand are better suited to compressing data on routers. They take advantage of redundancy in the data, and replace them with codes. The symbols represented by the codes are stored in the “dictionary”. This approach is more responsive to data variations and offers more flexibility, which is important when transmitting over Wide Area Networks.

The “dictionary” can also adapt to any data variation to suit the needs of the traffic, by using a larger size dictionary we can improve the compression ratio.