The Uni-N IC includes an Ethernet media access controller (MAC). As a separate I/O channel on the Uni-N IC, it can operate at its full capacity without degrading the performance of other peripheral devices. The Uni-N IC provides DB-DMA support for the Ethernet interface.
The MAC implements the link layer. It is connected to a PHY interface IC that provides 10-BaseT, 100-BaseT, or 1000-BaseT operation over a standard twisted-pair interface. The operating speed of the link is automatically negotiated by the PHY and the bridge or router to which the Ethernet port is connected. For information about the port, see Ethernet Port.