ZTE: OSPF MTU mismatch

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

What this guide covers

Diagnose and fix OSPF MTU mismatch on a ZTE device (ZXR10 / ZXROS).

Most likely cause + fix

Both routers must have identical MTU on the OSPF interface. Match them explicitly.

Diagnostic CLI

show interface brief
# Use the ZXR10 / ZXROS 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 show tech-support and open a ZTE Customer Support case.
• Cross-reference https://support.zte.com.cn for known issues in your release.

Frequently asked questions

Will this work on my specific ZXR10 / ZXROS version?

The procedure reflects current ZXR10 / ZXROS behaviour. Older releases may need minor syntax adjustments: use the CLI help (? or tab-completion) to verify.

Should I open a ZTE Customer 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 ZTE official documentation?

https://support.zte.com.cn, 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 ZTE fix guides → /zte/
• All vendor guides → /vendors/

Related fixes

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

• ZTE: OSPF duplicate router-id
• ZTE: OSPF neighbor stuck ExStart
• ZTE Switch Port auto-negotiation mismatch (speed / duplex): How to Fix
• Best ZTE firewall for branch office
• Best ZTE firewall for enterprise data centre
• Best ZTE firewall for retail store

References

• ZTE support portal: https://support.zte.com.cn
• ZTE knowledge base: https://support.zte.com.cn
• ZTE security advisories: https://support.zte.com.cn/support/news/AnnoucementOverviewLatest.aspx
• Open a case: https://support.zte.com.cn

Reference material, not professional advice. Validate against your specific ZXR10 / ZXROS version and test in a non-production environment before applying.

What changed recently?

Fault diagnosis on a ZTE: device goes faster when you map the symptom to a recent change:

• Did firmware update in the last 7 days?
• Did the network (router, ISP, VPN) change?
• Was the device moved physically?
• Did paired devices (phone, hub, app) update?
• Were any accessories swapped in or out?

The answer narrows the root cause to a manageable subset.

Before you start

A few things to confirm so the ZTE: 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.

How to confirm it's actually fixed

On a ZTE: device, the test is rarely "reboot and see". Use this list:

• Active reproduction: trigger the original failure path on purpose.
• Indirect reproduction: do an activity that would expose the same subsystem.
• Status indicator review: every LED / display / app status should be green.
• 24-hour soak: leave the device under normal load overnight; check the next morning.
• Telemetry check: review the device or app's diagnostic log for new error entries.

When to call ZTE: support instead

Escalate if:

• The same symptom returns within 24 hours of a clean fix.
• You see physical damage (burn marks, swollen battery, cracked PCB).
• The device is in warranty and a hardware replacement is the cheaper outcome.
• Repair requires specialised tools you don't own (alignment jigs, calibration software).
• Following the official path keeps the warranty intact, which matters more than the time spent.

More frequently asked questions

What if my model isn't exactly the same revision?

Cross-check the model code on the rating plate against the manufacturer support page. Major firmware generations sometimes shift the menu path; the option is usually under a similarly-named section.

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.

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.

Will this void my warranty?

Applying official firmware updates and following the user manual will not affect warranty. Opening sealed components, jumping safety circuits, or using third-party parts can void warranty in most jurisdictions.

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.