show cdp neighbors command shows two devices connected through the same local port?
I have a Cisco 3560 that when I issue the "show cdp neighbors" command I get the following results:
Switch1#show cdp neighbors
Device ID Local Intrfce Holdtme Capability Platform Port ID
Switch2 Gig 0/3 169 S I WS-C3560-4Gig 0/4
Switch3 Gig 0/3 96 S I WS-C3560-4Gig 0/2
the question is why is this showing that Gig0/3 is being used twice to connect to two different devices. I have verified there is no hub connected to this port and in fact Switch3 is not connected to Switch1 at all yet it still shows up in the CDP table.
I have cleared the CDP table on every device at this location and still get the same results. Any ideas or thoughts?
Try disconnecting the cable and reconnecting it back. That might clear CDP. I have seen it where the CDP doesn't show the neighbor at all and by disconnecting and reconnecting the cable, it works fine.
Is there a patch panel between these switches? Can you get them connected together without anything in between using a brand new cross over cable? I would want to rule out layer 1 / cabling.
If you have any non CDP aware gear in the mix CDP frames are forwarded to all ports like any other multicast. I ran into this will Dell switches in between two Ciscos already...