Data Domain: Network Interfaces May Go Down Due to Intel Workaround Configuration

Network interfaces unexpectedly go down.
Interfaces may fail to recover following a reboot, failover, or link transition event.
Connectivity may be temporarily restored by reseating optics or resetting switch ports.
Intermittent network connectivity alerts may be reported.
Repeated link up/down events may be observed in logs.
Alerts similar to the following may be present:

EVT-NETM-00001: Network interface connectivity is down
EVT-NETM-00002: Network interface connectivity is intermittent

The Intel workaround intended for M14MK dual-rate 10Gb/25Gb transceivers remained enabled after the affected interfaces were migrated to 25Gb-only transceivers.
The workaround forces a 10Gb operating parameter while the interface is configured for 25Gb operation, creating a speed mismatch during link initialization and renegotiation events.

Review the Autosupport to verify both the installed transceiver type and the configured Intel workaround.
Verify the transceiver type
From the Autosupport, review Transceiver Details for Interface and confirm the installed optic part number.
Example:

Before

Transceiver Details for Interface "eth8a":
Vendor PN : M14MK
Transceiver Details for Interface "eth8b":
Vendor PN : M14MK

After 

Transceiver Details for Interface "eth8a"
Vendor PN : W4GPP
Transceiver Details for Interface "eth8b"
Vendor PN : W4GPP

Verify the Intel workaround configuration
From the Autosupport configuration section, look for entries similar to:

config_master.net.options.intel_workaround.eth8a = 10000
config_master.net.options.intel_workaround.eth8b = 10000

If 25Gb-only transceivers are installed and the Intel workaround is still configured, remove the workaround from the affected interfaces.:

net option reset intel_workaround.eth8a
net option reset intel_workaround.eth8b

After the workaround is removed, the interfaces can negotiate and operate at the configured speed without the conflict.

The Intel workaround referenced in kb Data Domain auto negotiating to 10 Gbps may not be possible with certain switches is intended for specific M14MK transceiver scenarios. If M14MK optics are later replaced with 25Gb-only transceivers, the workaround may no longer be required and can lead to link-speed conflicts. W4GPP is one example of a 25Gb-only transceiver, but the guidance applies to any 25Gb-only optic.