Constant-time programmable field extraction system and method

A field extraction system quickly extracts information from arbitrary fields of a data packet transferred among entities of a computer network. The system includes a field extractor having synchronously operated hardware circuitry that is programmable to extract the contents of a field from the packet and then to interpret these extracted contents. The programmable hardware-based field extraction system extracts the contents of a field within a fixed amount of time while also providing the flexibility needed to adapt to changing header standards so that information can be extracted from arbitrary fields of, e.g., a header of the packet.