Lessons · Network switches · what is on the other end
What is on the other end of the cable
CDP reports the devices directly connected to this switch as those devices describe themselves; LLDP is the vendor-neutral equivalent.
Hone is a place to practise programming. This is one of its lessons, written out in full and free to read without an account.
What it is for
A description is what somebody typed once. A neighbour protocol is what the far end is saying now, which catches the cable that was moved and never re-labelled -- especially the uplink, whose far end is not yours to change.
How to think about it
Record the uplink's neighbour and its port before the swap, because the trunk is an agreement between two ends and you are only replacing one of them.
Worked example
enableIn.
show cdp neighborsThis practice switch says it does not implement this. It is a real command, and it needs a topology this simulator has not got -- inventing neighbours would be a bigger fiction than the one it already declares.
show interfaces statusWhat this device CAN tell you about its own ports, which is where you start instead.
Your turn
Show what this switch can tell you about its own ports.
show status
Console into a switch
The trap
Expecting CDP to show you the desk. It shows the neighbour, so a laptop behind a phone is not a neighbour of the switch.