HP ProCurve 6120G/XG Configuration Manual page 524

Troubleshooting
Troubleshooting Approaches
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C-6
For the downlink and ISL ports, troubleshooting can be done from the OA
Web interface. These ports are controlled from both the OA and the switch
configuration. A port state is a combination of OA Enable/Disable state
and the switch Enable/Disable state. The port is not Enabled until both
the OA and the switch agree that it is Enabled.