04-11-2012 11:37 AM
AN = Automatic speed negotiation is enabled (but current speed is undefined, most likely no device is connected)
Nx = Negotiated x Gbps, thus N4 = negotiated 4Gbps, N2 = negotiated 2Gbps
xG =port speed is fixed at x Gbps; to tell whether a device is successfully connected check if the next column reads "Online".
Hope this helps a bit,