Compression is a key ingredient to the ideal reduction system. Keeping the non-commutative nature of deduplication and compression in mind, WAN Optimization systems should first deduplicate incoming traffic and then compress it. Compression is equally useful both when the deduplication engine is identifying a significant number of repetitions, and when the deduplication engine finds itself identifying and learning new patterns. In the former case, compression can opportunistically process multiple small packets exiting the deduplication engine in one fell swoop after each has been deduplicated with very high efficiency. In the latter case, compression can reduce the overhead of informing the remote WAN Optimization solution of a new pattern that needs to be “learned.”
Data compression is a key technology for reducing such stress. It works well for most data, except for real-time multimedia such as Voice over IP (VoIP) or video conferencing which are already compressed and can’t benefit from simple compression techniques. WAN optimization products implement compression in many ways, including standard compression. This method takes streams of data and sends a reduced version of the content across the circuit, saving bandwidth. Standard compression in a WAN environment has many subtleties, including the choice of an algorithm, how compression works across streams, and the interaction between compression and encrypted traffic.