Patent ID: 7051078

Claim:
A hierarchical memory structure for use in matching a data string having a plurality of fields, the memory structure comprising: a top-level associative memory; and at least one next-level associative memory operably coupled to the top-level associative memory so as to receive an output therefrom, wherein the top-level associative memory is configured to receive and match one or more of the fields of the data string and, in response to detecting a match, providing an output to the next-level associative memory, the output of the top-level associative memory has a length that is shorter than a length of the one or more fields of the data string; and the at least one next-level associative memory is configured to receive and match the output from the top-level associative memory plus one or more other fields of the data string or one or more values derived therefrom and, in response to detecting a match, outputting a result.