Editing XAUI (section)

==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 mV<sub>p-p</sub>)
* Self-timed interface allows [[jitter]] control to the PCS
* Shared technology with other 10&nbsp;Gbit/s interfaces
* Shared functionality with other 10&nbsp;Gbit/s Ethernet blocks
* Utilization of [[8b/10b encoding]]

The following is a list of the major concepts of XGXS and XAUI:
* The optional XGMII Extender can be inserted between the Reconciliation Sublayer and the PHY ([[physical layer]]) to transparently extend the physical reach of the XGMII and reduce the interface pin count from 72 to 16.
* The XGMII is organized into four lanes with each lane conveying a data octet or control character on each edge of the associated clock. The source XGXS converts bytes on an XGMII lane into a self-clocked, serial, 8b/10b encoded data stream. Each of the four XGMII lanes is transmitted across one of the four XAUI lanes.
* The source XGXS converts XGMII Idle control characters (interframe) into an 8b/10b code sequence. The destination XGXS recovers clock and data from each XAUI lane and deskews the four XAUI lanes into the single-clock XGMII.
* The destination XGXS adds to or deletes from the interframe as needed for clock rate disparity compensation prior to converting the interframe code sequence back into XGMII Idle control characters.
* The XGXS uses the same code and coding rules as the 10GBASE-X PCS and PMA specified in Clause 48 of the IEEE 802.3 Specification.
* Each of the 4 Receive and Transmit lanes operates at a rate of 3.125&nbsp;Gbit/s.
* Capabilities have been built into XAUI to overcome the inter-lane [[Parallel communication|signal-skewing]] problems using a type of automatic de-skewing. Signals can be launched at the transmitter end of a XAUI line without precisely matching the [[routing]] of the four lanes, and the signals will be automatically de-skewed at the receiver.<ref name="std">{{cite book |title= IEEE Std 802.3-2008 Section 4 |chapter= Clause 47. XGMII Extender Sublayer (XGXS) and 10 Gigabit Attachment Unit Interface (XAUI) |pages= 211–224 |year= 2008 |publisher= [[Institute of Electrical and Electronics Engineers]] |url= https://standards.ieee.org/getieee802/download/802.3-2008_section4.pdf |archive-url= https://web.archive.org/web/20100215084014/http://standards.ieee.org/getieee802/download/802.3-2008_section4.pdf |url-status= dead |archive-date= February 15, 2010 |access-date= May 9, 2011 }}</ref>