Xena Autoneg & Link Training White Paper

Autonegotiation and Link Training on new PAM-4 based 400GE 200GE, 100GE and 50GE interfaces
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PAM-4 Auto-Negotiation & Link Training White Paper

Autonegotiation is a tried and tested process where a device is connected to a network through an Ethernet interface, and the end points of a link share information on various capabilities relevant for the communication.

The autonegotiation process determines the highest common denominator among the end point capabilities, and these will be used for the communication.
Link Training is another process that can take place when a device is connected to a high-speed Ethernet port through a copper cable or backplane. In this case it is important that the characteristics of the transmitted signal are tuned to be optimally carried over the copper cable.

Xena’s 7-speed dual-media test module Thor-400G-7S-1P supports the new PAM4 based 400GE, 200GE, 100GE and 50GE speeds defined in the IEEE 802.3bs and 802.3cd standards, in addition to new and legacy NRZ based versions of the 100GE, 50GE, 40GE, 25GE and 10GE standards. Installed in a ValkyrieBay or ValkyrieCompact chassis, it provides advanced Ethernet test capabilities up to Layer 3.

This White Paper looks at Autonegotiation and Link Training and explains how Thor-400G-7S-1P supports these functions for the new PAM4 based 400GE 200GE, 100GE and 50GE data rates.

Auto-negotiation & Link Training White Paper Contents

  • Introduction
  • The PAM4 Line Code
  • Autonegotiation
  • Link Training
  • No Autonegotiation, No Link Training
  • No Autonegotiation, Link Training
  • Autonegotiation and Link Training
  • Thor-400G-7S-1P
  • Manual Tuning of Transmitter Characteristics
  • Conclusion