The OFDM core includes a subsystem which can automatically transmit a packet in response to a received packet. This behavior is ideal for implementing MAC protocols which require responses at fast time scales (like RTS-CTS or DATA-ACK exchanges). Both the conditions for responding and contents of the response packet are programmable at run-time. The auto response hardware consists of two parts- match units and actors. === Match Units === The auto response match units search for user-specified patterns in received headers. Each unit operates independently.