Enterasys D2 D2G124-12P Cli Reference Manual page 243

Mode
Switch command, read‐only.
Usage
Exceptional conditions causing a port to be placed in listening or blocking state include a Loop
Protect event, receipt of disputed BPDUs, and loopback detection.
Example
This example shows how to display the non‐forwarding reason on
D2(rw)->show spantree nonforwardingreason port ge.1.1
The non-forwarding reason for port ge.1.1
show spantree nonforwardingreason
ge
.1.1:
on SID 0 is None
D-Series CLI Reference 6-51