Auto Negotiation and Link Training for 112G SerDes
Electrical cables are now being used instead of optical fibers for short in-rack and top-of-the-rack 400GE connections in data centers to help lower cost and power consumption.
However, when such high data rates are transmitted over electrical cables, the received data stream is severely distorted and requires advanced fine tuning of equalizers before data can be recovered and sampled correctly.
Auto Negotiation allows connected devices to exchange information about their transmission speed and FEC abilities, and agree on a common set of transmission parameters. Link Training is then used to automatically tune the transmit equalizer settings at each device for minimum BER at the selected transmission speed
Download this White Paper for a full tutorial on Auto Negotiation and Link Training for 112G SerDes based 100 Gbps, 200 Gbps, 400 Gbps and 800 Gbps Ethernet, and guidelines for when AN and LT is needed.