Connectrix: Cisco MDS Isolation of interface (reason: merge requires domains that are not allowed)

Summary: Connectrix: Cisco MDS Isolation of interface (reason: merge requires domains that are not allowed)

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Symptoms



  • Unable to add a new MDS switch to the existing fabric. Core-edge topology.
  • The following error message was observed on the new edge switch:
FCDOMAIN-2-EPORT_ISOLATED: %$VSAN xx%$ Isolation of interface fcx/y (reason: other side Eport indicates isolation)
  • The following error message was observed on the existing Core switch:
FCDOMAIN-2-EPORT_ISOLATED: %$VSAN xx%$ Isolation of interface fcx/y (reason: merge requires domains that are not allowed)
  • No overlapping domain IDs were identified 

Cause

This issue was caused by mis-configuration of the fcdomain distribute feature and the user configured allowed domain ID list.

Some switches in the fabric had 'fcdomain distribute' feature enabled and others had the feature disabled. 

Some switches in the fabric had the correct allowed domain ID list and others did not. 

Resolution

enabled fcdomain distribution on all switches

Affected Products

Connectrix MDS-9396S

Products

Connectrix MDS-9396S
Article Properties
Article Number: 000055689
Article Type: Solution
Last Modified: 20 Oct 2025
Version:  5
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