1. A pattern matching method, executing on a data processing system having a controller and a memory, for recognizing one of a plurality of predefined patterns in a data stream received by the data processing system using a recognition network, the recognition network comprising a plurality of nodes, a plurality of transitions connecting the nodes and an amount of memory usable to store node external data of at least one of at least one bit data element, at least one counter data element and at least one other data structure the node external data being other than the data used to record a node state and rules for transitions between nodes, at least some of the nodes including at least one instruction for interacting with the node external data, the method comprising: inputting a stream of data comprising a plurality of ordered data elements; transitioning from a current node of the recognition network to a next node of the transition network, the next node being one of the current node and another node of the recognition network, based on a next one of the plurality of ordered data elements of the stream of data applied to the rules for transitions between nodes; entering the next node; executing, upon entering the next node, if the next node includes at least one instruction for interacting with the node external data that instruction; determining, based upon executing the at least one instruction on the node external data, if an acceptance condition has been met; and outputting, if the acceptance condition has been met and a given node entered, an alert indicating that the acceptance condition has occurred.