CDP or Cisco Discovery Protocol is a Cisco proprietary protocol.
LLDP or Link Layer Discovery Protocol is an industry standard protocol.
LLDP is not enabled by default on Cisco devices so you will need to enable LLDP.
On your Cisco devices if you wanna use LLDP instead of CDP.
LLDP is very useful when you have a multi vendor environments.
So if you're using Cisco with HPE or Juniper or another vendor you may wanna use LLDP. So on core 1
show LLDP neighbors.
Notice we see something very similar.
We can see our access switches and we can see core 2, on core 2 show LLDP neighbors we can see access
switch 1 and 2 we can see core 1 connected via two links access 3
and in this example, we are seeing the router twice for some reason that could simply be a problem with
Packet Tracer.
This is the correct output because the router is connected via gigabit 0 0 0 instead of gigabit 0 0 1 that's
connected to the Internet.
So that's probably a packet tracer problem.
Show LLDP neighbors on access 1.
We can see the two core switches that looks good.
Access 2 show LLDP neighbors we can see something similar.
Show LLDP neighbors on access 3.
We can see the two core switches.
So notice with CDP you can use the command show CDP to see CDP information.
You can also use the command show LLDP to see LLDP information CDP sends updates every 60 seconds.
LLDP sends updates every 30 seconds hold time for CDP is 180 seconds, LLDP is 120 seconds so slight difference
in time as you have similar kind of information such as show LLDP neighbors details or detail to see
detailed information about neighbors. So as an example we can see a device connected to gigabit 1 0
23.
It's a layer 3 switch.
We can see the name which is core 2.
We can see the port information we can see the operating system used.
We can see the other interface used by core 2.
Something similar could be done with CDP, so show CDP neighbors detail will allow us to see detailed information
about our neighbors. So there's the command core 2 36 50 running this version of operating system and
we can see other information about that neighbor.
Spend some time looking at the output of CDP and LLDP. For the exam
you need to be able to read this output. So show CDP entry access 1 shows us detailed information for
one device called access 1, that's its name interface that we're using is gigabit 1 0 1 the outgoing
port in other words the port on the other side is gigabit 1 0 23 which is correct. On core 1 local port
is this port on the other side is gigabit 1 0 23 we can see operating system version once
again and other information about the device.
So spend a bit of time looking at both a little DP and DP output make sure that you can interpret the
output.