A network device receives a packet that includes a plurality of sets of fields. Sets of fields of the packet are parsed and the field sets are evaluated as soon as they are available to determine whether a processing decision can be made on the packet. Additional field sets may be parsed from the packet and obtained in parallel with determining whether a processing decision can be made, but once it is determined that a processing decision can be made, the evaluating of field sets is terminated such that any further field sets of the packet are ignored for purposes of making a processing decision for the packet.