XAUI
XAUI is a standard for extending the XGMII (10 Gigabit Media Independent Interface) between the MAC and PHY layer of 10 Gigabit Ethernet (10GbE). XAUI is pronounced "zowie", a concatenation of the Roman numeral X, meaning ten, and the initials of "Attachment Unit Interface".
The XGMII Extender, which is composed of an XGXS (XGMII Extender Sublayer) at the MAC end, an XGXS at the PHY end and a XAUI between them, is to extend the operational distance of the XGMII and to reduce the number of interface signals. Applications include extending the physical separation possible between MAC and PHY components in a 10 Gigabit Ethernet system distributed across a circuit board.
Operation
XGMII Extender has the following characteristics:
Simple signal mapping to the XGMII
Independent transmit and receive data paths
Four lanes conveying the XGMII 32-bit data and control
Differential signaling with low voltage swing (1600 mVp-p)
Self-timed interface allows jitter control to the PCS
Shared technology with other 10 Gbit/s interfaces