Ethernet interface module

Abstract

An Ethernet interface module comprises a first full duplex port, a second duplex port, a first path coupling the first duplex port and the second full duplex port, a second path coupling the second full duplex port and the first full duplex port, a first queue disposed in the first path, a second queue disposed in the second path, a third path comprising at least a portion of the first queue coupling the receive and transmit portions of the first port, a fourth path comprising at least a portion of the second queue coupling the receive and transmit portions of the second port, execution apparatus operable responsive to a command to alter the state of said Ethernet interface module, or the contents of said received frame to produce a return frame comprising fields of a received frame that are modified, or both.

What is claimed is: 
     
         1 . An Ethernet interface module configured to couple a device to an Ethernet network, said Ethernet interface module comprising:
 a first full duplex port comprising a receive portion and a transmit portion;   said first full duplex port is operable to transfer frames between said Ethernet network and said device;   a second full duplex port comprising a second receive portion and a second transmit portion;   said second duplex port is operable to transfer frames between said network and said device;   a first path coupling said first duplex port and said second full duplex port;   a second path coupling said second full duplex port and said first full duplex port;   a first queue disposed in said first path;   a second queue disposed in said second path;   a third path coupling said first receive portion and said first transmit portion, said third path comprising at least a portion of said first queue;   a fourth path coupling said second receive portion and said second transmit portion, said fourth path comprising at least a portion of said second queue;   evaluation apparatus coupled to said first queue and to said second queue, said evaluation apparatus operable to determine from a received destination address in a received frame from one of said first full duplex port or said second full duplex port whether said received frame is addressed to said device;   each said received frame comprises a source address field comprising a source address, a destination address field comprising a destination address, and a command field utilized to provide a command; and   said evaluation apparatus operable to determine whether a received frame is addressed to said device and to determine whether said command is executable by said Ethernet interface module;   execution apparatus to perform an operation based on the contents of said command field if said evaluation apparatus identifies said received frame as appropriate for said Ethernet interface module, said operation altering the state of said Ethernet interface module, or the contents of said received frame to produce a return frame comprising fields of said received packet that are modified, or both;   said Ethernet interface module is operable such that if a first communication link is present at said first full duplex port and a second communication link is present at said second full duplex port, each said received frame received on one of said first full duplex port or said second full duplex port is forwarded out the other of said first full duplex port or said second full duplex port as a forwarded frame with modified or unmodified fields.