"Invalid Interface/Circuit ID" on VOSS Boundary Switch (Fabric vs. MSTP)

Dragonfly — Tue, 05 May 2026 12:36:24 GMT

I’m currently setting up a boundary switch using Fabric Engine (VOSS) to bridge two different environments, and I’ve hit a wall with an IS-IS configuration error.

The Setup:

Switch Model: 5520
Software Version: 9.3.2.0
Side A (Legacy): Interconnected to a Cisco switch using MSTP.
Side B (Fabric): Interconnected to an Extreme core using Fabric Connect (SPB/IS-IS).

The Issue: I am trying to provision the NNI (Fabric) port, but the switch rejects the isis enable command with the following error:

"EXTR-01:1(config-if)# isis enable

Error: ISIS - Invalid Interface/Circuit ID"

To rule out configuration errors during this testing phase, I have kept the setup as simple as possible. I am using the default IS-IS Area and standard parameters, identical to the configuration on my two other Extreme switches.

Those two other switches are working perfectly they form adjacencies and see each other without issues. Only this specific "boundary" switch throws the "Invalid Interface/Circuit ID" error when I try to enable IS-IS on the interface

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"Invalid Interface/Circuit ID" on VOSS Boundary Switch (Fabric vs. MSTP)