Apparatus for detecting a predetermined pattern in a data stream, method for detecting a predetermined pattern in a data stream, and method in a network interface for identifying a predetermined pattern in a data packet

摘要

A network interface in a workstation computer includes a pattern matching circuit to enable the workstation computer to wake up to perform prescribed operations requested by a remote workstation. The pattern recognition circuit includes a pattern memory configured for storing a pattern entry for at least a portion of a predetermined pattern. The pattern entry includes a pattern data field and a second field specifying a number of bytes in the input data stream to be ignored prior to comparison with the pattern data field. The pattern matching circuit also includes a comparator for comparing the pattern data field with a selected group of bytes from the data stream. Pattern match logic determines whether the received data packet includes the predetermined pattern based on the comparison result. The second field enables the comparator to selectively ignore a number of bytes in the data stream prior to comparison with a pattern data field, minimizing the amount of null data values that need to be stored in pattern memory. Hence, the second data field enables efficient compression of pattern data in memory.