Nvidia (Mellanox): default route flapping

By Sai Kiran Pandrala · reviewed by Sai Kiran Pandrala, Editor Last verified: 2026-05-30

What this guide covers

Diagnose and fix default route flapping on a Nvidia (Mellanox) device (Cumulus Linux / NVOS / SONiC).

Most likely cause + fix

A track object or a BGP best-path keeps moving. Stabilise with track + dampening.

Diagnostic CLI

nv show interface
# Use the Cumulus Linux / NVOS / SONiC equivalents of:
#   show ip route / show route
#   show ip bgp summary / show bgp summary
#   show ip ospf neighbor / show ospf neighbor
#   show log | include BGP|OSPF

When the issue persists

• Capture cl-support (Cumulus) / show techsupport (SONiC) and open a Nvidia Enterprise Support case.
• Cross-reference https://docs.nvidia.com/networking/category/etmnetworkingdevices for known issues in your release.

Frequently asked questions

Will this work on my specific Cumulus Linux / NVOS / SONiC version?

The procedure reflects current Cumulus Linux / NVOS / SONiC behaviour. Older releases may need minor syntax adjustments, use the CLI help (? or tab-completion) to verify.

Should I open a Nvidia Enterprise Support case immediately?

Open one if you suspect hardware failure or the symptom persists after a maintenance-window reload. Make sure your support entitlement is active first.

Where can I find the Nvidia (Mellanox) official documentation?

https://docs.nvidia.com/networking/: search the product family + feature name.

Is this procedure safe in production?

Test in a lab or maintenance window first. Capture pre-change state so you can roll back.

Related guides

• All Nvidia (Mellanox) fix guides → /nvidia/
• All vendor guides → /vendors/

Related fixes

Related guides worth a look while you sort this one out:

• Nvidia (Mellanox): BGP route filtered inbound
• Nvidia (Mellanox): static route not installing in RIB
• Nvidia (Mellanox) switch: MAC address flapping between ports
• Best Nvidia (Mellanox) switch for branch office
• Best Nvidia (Mellanox) switch for enterprise data centre
• Best Nvidia (Mellanox) switch for retail store

References

• Nvidia (Mellanox) support portal: https://enterprise-support.nvidia.com/
• Nvidia (Mellanox) knowledge base: https://docs.nvidia.com/networking/
• Nvidia (Mellanox) security advisories: https://www.nvidia.com/en-us/security/
• Open a case: https://enterprise-support.nvidia.com/s/createcase

Reference material, not professional advice. Validate against your specific Cumulus Linux / NVOS / SONiC version and test in a non-production environment before applying.

Why this matters for your day-to-day

A Nvidia device that's misbehaving costs more than the fix itself: lost productivity, missed calls, security risk, even safety risk in some categories. Treating the symptom quickly with a documented procedure is cheaper than letting it persist. The steps above are written to get you back to working in under an hour where possible, and to flag clearly when escalation is the right call.

Before you start

A few things to confirm so the Nvidia device fix goes cleanly:

• Latest firmware downloaded if you're going to update.
• Warranty + support contract status checked, opening sealed parts may void it.
• Backup of current configuration (where applicable) taken.
• Spare parts on hand if you anticipate replacement.
• Adequate workspace, lighting, and time. rushing causes regressions.

Verification checklist

After applying the fix on your Nvidia device, confirm:

• The original symptom is no longer reproducible.
• Related features (status LEDs, app sync, paired accessories) still work.
• The device responds to a soft reboot without the fault returning.
• Any error codes that were on display have cleared.
• Documentation (your service log, the brand companion app) reflects the change.

Escalation guide

For a Nvidia device, the right escalation depends on impact:

• Cosmetic / minor: log a ticket via the Nvidia app or web portal. Response 1-3 business days.
• Mid-impact: phone support. Have your serial number ready.
• Critical (production down, safety issue): in-person dealer / TAC visit. Bring proof of purchase.
• Out of warranty: third-party repair shop with manufacturer-certified technicians.

More frequently asked questions

What if the fix returns after a reboot?

Persistent fault returns mean either: a hardware fault (escalate), a configuration that's being overwritten by a sync source (check cloud profiles), or a regression in a recent firmware update (rollback).

How long does this fix usually take?

Most users complete the steps in 20-45 minutes the first time, and 5-10 minutes on subsequent runs once the menu paths are familiar.

Why is this happening on a brand-new unit?

Out-of-box defects do occur. If you've owned the device under 30 days and the symptom persists after a factory reset, escalate to the seller for replacement under DOA terms before opening a manufacturer support case.

Should I update firmware first or last?

Update firmware first if a release note specifically mentions your symptom. Otherwise, finish the troubleshooting flow first, then update; that way you can isolate whether the update or the underlying fix solved it.

Will the procedure work on the international variant?

Some features and firmware paths are region-locked. Check the model spec sheet to confirm your variant supports the menu option referenced. If you're outside the US/EU, look for the regional support portal.