An improved method and apparatus for recognizing, classifying and processing frames received at a frame processor in a computer network is disclosed. Following receipt of a frame at an input port of a frame processor, source and destination addresses are parsed from the frame. A plurality of lookup tables are provided in a memory, each of which contains a search field and a classification key field. Source or destination addresses are stored in the respective search fields along with other information associated with the frame and a compact classification key is stored in the corresponding classification key field. Searches are performed of the respective search fields within the respective lookup tables to determine whether a match exists between the each of the destination and source addresses and other information and the search field within the lookup tables. In the event the searches yield a match, a classification key associated with each respective address is retrieved. Classification keys corresponding to addresses thus retrieved are concatenated and the concatenated value is employed as the basis for a further search of the search field of another one of the lookup tables to identify a classification key which is employed to specify the manner of further processing of the received frame.