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Home / Troubleshoot / Cisco Nexus vPC Inconsistency
Cisco Nexus · vPC

Cisco Nexus vPC Inconsistency: How to Find and Fix It

By the Tech Matrix engineering team · Updated June 2026

A vPC consistency failure means the two Nexus peers disagree on a parameter that must match. A Type-1 inconsistency can bring the vPC (or VLANs) down — here's how to pinpoint and fix it.

Step 1 — See the vPC status

show vpc
show vpc brief

Look for the consistency status. Type-1 inconsistencies suspend the vPC (or the affected VLANs); Type-2 are less severe but should still be fixed.

Step 2 — Find the mismatched parameter

show vpc consistency-parameters global
show vpc consistency-parameters interface port-channel <id>

These commands list each parameter and its value on both peers side by side — the mismatch is the row where the two columns differ.

Step 3 — Common culprits

  • Spanning-tree mode/region or MST settings differ between peers.
  • MTU mismatch on the vPC member ports or peer-link.
  • Port-channel mode, speed/duplex, or allowed VLANs differ on the two member ports.
  • Peer-link not up or not carrying all vPC VLANs.

Step 4 — Fix

Align the differing parameter on both peers so the values match, then re-check show vpc consistency-parameters. For Type-1 global mismatches the vPC recovers once the values agree; confirm the peer-link and peer-keepalive are healthy.

How Tech Matrix solves this in ~60 seconds

vPC errors mean diffing parameters across two switches line by line. Tech Matrix reads show vpc consistency-parameters on both peers at once, names the exact mismatched setting, and gives the fix for your NX-OS version — with your approval on every command.

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Frequently asked questions

What is a Type-1 vPC inconsistency?

A Type-1 inconsistency is a parameter that must match between vPC peers (e.g., spanning-tree mode, MTU). It suspends the vPC or affected VLANs until the values agree.

How do I check vPC consistency on Nexus?

Run 'show vpc consistency-parameters global' and '... interface port-channel '. They list each parameter on both peers so you can spot the mismatch.

Why is my Nexus vPC suspended?

A Type-1 consistency failure — commonly spanning-tree mode, MTU, or port-channel settings differing between the two peers, or a peer-link problem.