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

What is autonegociation?

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 relevant capabilities.

Highest common denominator

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.

Provides advanced ethernet test capabilities

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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