METHODS AND SYSTEMS FOR SPECIFYING AND GENERATING KEYS FOR SEARCHING KEY VALUE TABLES

A network appliance receives a network packet and determines an application identifier for the network packet. Key specification fetching circuits in the processing stages of the network appliance's match-action pipelines can use the application identifiers to read key specifications. The key specifications are stored in memory and may be cached near the processing stages. Key construction circuits in the processing stages can use the key specifications to construct keys. The processing stages can process the network based on the keys because the keys may be used to obtain action indicators from match-action tables. As such, the processing stages can construct and use keys that may be dynamically defined by storing their key specifications in memory.