This value indicates whether the switch was able to detect that the device connected to the other end of this Ethernet link is itself using auto-negotiation, as opposed to being fixed to a manual speed/duplex setting. Administrators check this when diagnosing duplex-mismatch problems, since a mismatch commonly occurs when one side auto-negotiates and the other is manually fixed. For example, a value of not-detected(2) would tell an admin the remote device likely has a fixed speed/duplex configuration, prompting them to check whether the local port's settings match it exactly.