Broadcom BCM57414 Adapter FEC CL74 Setting Confirmation (VMware ESXi 8.0)

Products

• VMware vSphere ESXi

Issue/Introduction

• Need to verify if Broadcom BCM57414 10/25Gb adapters is correctly respecting and utilizing Forward Error Correction (FEC) CL74 (Fire Code) settings within VMware ESXi 8.0 environments.
• FEC improves link stability and signal integrity for 25Gb links. By default, NIC settings are set to auto-negotiate, allowing the adapter to retrieve FEC configuration directly from the connected network switch port.
• Successful FEC utilization depends on hardware stack consistency, including switch port configuration, driver/firmware compatibility, and identical settings on both link ends to prevent connectivity failure.

Environment

Host: VMware ESXi 8.0   

Hardware: Broadcom BCM57414 10/25Gb adapters   

Supported FEC Modes:

• CL74 (Fire Code / Base-R FEC): Often used for shorter distances or copper (DAC) cables.   
• CL91 / CL108 (Reed-Solomon FEC): The IEEE 802.3by standard for 25G.

Resolution

For the network card to successfully use CL74 FEC, the network configuration must be identical across thehardware stack.

Ensure the following requirements are met:

• Matching Link Settings: The settings on both the NIC and the switch must match exactly. If they differ, the connection will fail.
• Switch Configuration: The physical port on the network switch must support CL74 and be explicitly set to use it.
• Auto-Negotiation Enabled: The adapter must be set to auto-negotiate. Because the Broadcom BCM57414 controller supports multiple FEC modes (both CL74 and CL91/CL108 Reed-Solomon), auto-negotiation allows the NIC to receive the correct CL74 instruction from the switch.
• Confirm Controller Support: The Broadcom BCM57414 controller architecture natively supports both CL74 and Reed-Solomon (CL91/CL108) modes.   
• Drivers and Firmware: Verify that both driver and firmware are fully updated and compatible.
• Verifying the Setup: Use a manufacturer diagnostic tool, such as niccli, to check which FEC mode is active. Important Note: Many Broadcom diagnostic tools default to displaying Clause 91 (25G RS-FEC) logic. Ensure the output explicitly confirms CL74/Base-R to verify that Fire Code is actively running.
• UEFI: Ensure that NIC FEC is also enabled accordingly at the UEFI of the ESXi server.

Additional Information

Broadcom Ethernet Network Adapter User Guide

Broadcom NetXtreme-E User Manual

Switch Vendor Naming: Be aware that different switch vendors may use unique terminology; for instance, Juniper may refer to CL108 as fec108. 

Please also refer Broadcom KB article for known symptom : ESXi hosts "not responding" due to bnxtnet driver "hot reset"