PAM4 Auto-Neg & Link Training

Learn about Auto-Neg & Link Training on PAM4/NRZ and how Valkyrie can test these functions, together with Teledyne LeCroy's SierraNet Protocol Analyzer

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.

Autonegotiation 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. It also has the unique advantage of also being able to test the NRZ-based speeds: 100GE, 50GE, 40GE, 25GE and 10GE. Installed in a ValkyrieBay or ValkyrieCompact chassis, it provides advanced Ethernet test capabilities up to Layer 3.

Learn more about troubleshooting Auto-negotiation and Link Training for the new PAM4-based 400GE 200GE, 100GE and 50GE data rates using Xena’s Thor-400G-7S-1P & Teledyne LeCroy’s SierraNet protocol analyzer.


  • The NRZ and PAM4 Line Code
  • Forward Error Correction (FEC)
  • Auto Negotiation (AN)
  • Link Training (LT)
  • No Auto negotiation, No Link Training
  • No Auto negotiation, Link Training
  • Auto negotiation and Link Training
  • Xena Thor-400G-7S-1P test module
  • Xena Thor-100G-5S-4P test module
  • Teledyne SierraNet M648 protocol analyzer
  • How does SierraNet Analyzer help?
  • Implementing Auto Negotiation at PAM4-based Data Rates
  • Manual Tuning of Transmitter Characteristics
  • Conclusion

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