Links use four 100 Gbps lanes to provide 400 Gbps of full bandwidth. A healthy link transmits traffic across all four lanes, but a degraded connection—such as a damaged cable or SuperNIC—may limit the number of usable lanes. Instead of dropping the link, Omni-Path employs Dynamic Lane Scaling (DLS) to keep the connection active in a degraded state by using fewer lanes. By default, the system allows a three-lane degraded link, while links with one or two lanes are dropped. Users can modify this setting in the opafm.xml configuration file, if needed.

For additional information, refer to the CN5000 Maintenance and Troubleshooting Guide, Link Width, Downgrades, and opafm.xml.