Original subtitles

Okay so let's complete this lab.

The first step is to verify links using GDP and LDP.

So on call 1

shows GDP numbers after the moment.

We don't see any neighbors show IP interface brief interfaces are up but no neighbors are displaying

shows GDP CTP is enabled on the switch.

What about switch to

shows GDP.

Neighbors noticed the problem CTP is not enabled on switch to now in the real world CTP is enabled on

Cisco devices by default if its not enabled use the command CTP run in global config mode so shows GDP

numbers now shows us that we don't have any neighbors but we are seeing some output that's different

to what we saw previously.

So what I'll do initially is simply make sure that CTP is enabled on all devices shows GDP neighbors

GDP is not enabled so CTP run do something similar on access to

shows GDP neighbors not enabled so CTP run access 3

before I enable it let's confirm not enabled CTP run.

Okay A BACK ON CALL 1 show GDP neighbors notice we are now seeing our neighbors so we can confirm that

CO 2 is connected to our local interfaces gigabit one zero twenty three and one zero 24 CO 2 is using

this port gigabit 123 to connect to our gigabit once there are twenty three quarters gigabit ones there

are 24 interfaces connected to our gigabit there are 24 interface that looks good access one is connected

via gigabit one zero twenty three to our local interface gigabit 1 0 1.

So that looks good.

Access to gigabit ones there are 23.

This interface is connected to gigabit ones there are two also looks good access 3 gigabit ones there

are twenty three is connected to our gigabit 1 0 3 interface so that also looks good so the CTP output

looks correct on call 1 CTP doesn't run on servers so we don't see the server in the output.

What about court 2.

So in court to

show CTP neighbors call 1 looks correct.

Access 1 is using gigabit ones there are 24 to connect to our local 1 0 1 interface that looks good.

Access 2 and 3 are doing something similar so that looks good what we aren't seeing here is the router

so let's check the router.

Sure CTP neighbor CTP is not enabled so CTP run show CTP neighbor now may take it a while.

Just remember with CTP it sends updates out every 60 seconds so it could take up to 60 seconds for you

to see a neighbor relationship.

So you just need to be patient.

Don't assume there's a problem if you don't see a neighbor immediately wait at least a minute and there

you go we can see the broader on court too.

We can see that it's a rotter we can see that it's an eyesore.

We can also see that the other switches in the topology are 36 60s back an eyesore may take it a while

so come back to that on access 1 show CTP neighbor it's got to neighbor relationships want to call 1.

Want to call too.

That looks good typically you don't have to do it both ways.

If you see the neighbor relationship on one side you'll see it on the other side.

That's not always true.

However when you have multi vendor environments HP switches as an example will receive CTP messages

but not send it.

So you may want to check things on both sides.

But remember that when you have multiple vendors or if there's an access list blocking CTP coming interests

which you may see it only on one side that looks good.

So access 3 is seeing call 1 and 2 and again back on Access 2.

We can see call 1 and call 2 so that CBP.

But we're not finished yet.

We need to check an old DP.