- [Narrator] So let's run back out to our
favorite router, the Corp router.
And let's go ahead and do something
called Cisco Discovery Protocol,
Link Layer Discovery Protocol and then set our host names.
So let me log in here and Cisco Discovery Protocol
starts with Cisco so I think it
would tell you Cisco Propitiatory.
I can get information about my neighbors.
I can get their host name which is the device ID.
The local interface, that's my interface
who I connect to them with.
The capability router switch and then on,
the platform, what type of Cisco device they are, 28113560.
And then the port Id which is the interface I'm
connected to our this Corp router is
connected to on the remote device.
Now these are only directly connected devices.
Now the other command I can use show cdp neighbor detail.
And you can type out the whole thing
but show cdp neighbor detail or show cdp entry asterisk.
Either one is going to give me the same information
as show cdp neighbor plus the IP address of
my neighbor and their IOS version.
So we can see the IP address, the platform,
capability switch, interface, my local interface,
the port ID is their interface, my neighbor's interface
and then also my IOS version.
I can hit the more and now this gives me the IP address.
I can then telnat into these devices or SSH
using these IP addresses and then do show cdp from there.
Because I can't see past them.
I can only see my neighbor.
Now this is a Cisco Proprietary.
Now I could do something like this, no cdp run
and I just turned it off on my device globally.
Now if you wanted to go to an interface,
no cdp enable so cdp run is global.
Cdp enable is interface level.
Just turn it off on a single interface.
This is a great troubleshooting tool
so I'd be careful disabling this
or you have to go turn it back on.
It's a phenomenal troubleshooting tool
to see if your neighbors are there.
Let's run out to my switch.
So if we go out the the Corporate LAN,
we can do show cdp neighbor and I'll still
see my Corp router there because the whole time,
notice it's at 90 seconds and counting down.
It's 180 seconds by default so we're still
gonna get information from the Corp router
even though I turned cdp off.
So that'll be goin' away shortly so I'll do an up arrow.
See then, it's almost doomed here.
The one thing that I also can run is a non-proprietary
version of cdp and that's called lldp.
So I can do lldp and one of the things lldp run
or no lldp run do show lldp.
And we can see the different errors in interface traffic.
Pretty much the same thing, the interfaces.
In this case here, I can no lldp run
but now on the interfaces is where it differs.
So only this, so I'm gonna say lldp
and we can see that we can set it to receive
and or transmit one of the times.
So if I wanted to turn it off, I could say
or just turn off one thing and say no lldp transmit.
But still receive lldp information, pretty simple.
Alright, I wanna show you one more thing.
And I'm gonna run back to my Corp router.
Alright, so now that I'm back at the Corp router,
I'm gonna have a little bit more fun.
Because that's all we ever do here on the Corp router.
So I've turned off cdp so I'm
gonna say config t cdp run, right.
And I don't care about F zero zero,
I just wanna see my neighbors off my serial links.
So I got out of that and then we'll let that run.
It takes about 60 seconds to update.
We don't see anybody yet so I should see in,
within 60 seconds see my updates.
Okay so once I waited a minute and came back
and saw the information I can see LA
and then we'll see my two interfaces to LA
and then we'll see San Francisco pop up.
But notice I have two connections to LA
as you're well aware but now I wanna get their IP address.
I can't remember the IP address.
I wanna telnat to 'em so what do I type in?
Not show to cdp neighbors, close,
show cdp neighbors detail, right.
And now I can see their IP address.
There's 10.6 and 10.10 so let me just
try to ping them real quick, 172.16.10.6.
Alright, that's great and 10.10.
It doesn't, it's not very fun usin' their
IP address when I can set a host name.
So I can create a local host table in here
which we've already done for the San Francisco
router so do show host, okay.
And we can see the San Francisco is in there.
I pinged San Francisco in telnat.
And it resolves it to that address.
So I'm gonna go ahead and add another one.
Check this out ip host 182.16.10.6 space 172.16.10.9.
So now it's gonna use either one of those.
I forgot to type in the name.
That would be helpful, wouldn't it?
LA, what I want it to resolve to.
And now it's either gonna resolve to 10.6 or 10.9.
If that first one doesn't work, use the second one, cool.
So ping LA, nice, now I'm in LA.
So it resolved it right away to 10.6
and brought that up and I can do a show cdp neighbors
and now get the information on the LA router.
Okay, by using some simple commands, great troubleshooting
here with cdp and you could use lldp
and then also set up a local host name.
Now, one last thing show host and notice
it's going to tell me show me what's in here.
If I resolve, then notice my addresses for the LA.
If I resolve addresses from a DNF Server,
those would be put in here
but they won't say permanent, right.
They would just say temp, right.
Because they're in there for a short period of time.
Because you just resolved them from a DNF Server.
Alright so let's go ahead and telnat to the LA router.
Notice if I try to use the host name here
and say LA that it's not gonna work.
Because there's a command that starts with LA.
So it doesn't know it's a host name.
So actually I have to type out the whole command telnat.
And then my password and then now I can do a show ip route
and let's see what we go goin' on.
Don't see any RIP injected routes even
though RIP is running because I've
turned off my other routers, right.
So I'm gonna say config t, I'm gonna turn it off anyways.
No router rip, alright, now let's go ahead
and take a look at what we've got goin' on here.
Directly connected to 10.4 and 10.8 subnets
to the Corp router, show cdp neighbor, show us that as well.
So we'll see, got my LAN switch
and got the Corporate router off.
It's Serial 0/1/0 and Serial 0/0/1.
And so those are the 10.4 and 10.8 subnets respectively
with IP addresses .6 and .10.
The Corp router's .5 and .9.
182 and 6820 is off the LAN
and off the loopback is 192 and 6830.
Alright, that is how we set up our routers.
We understand where each router's at,
what they're directly connected to,
don't have any routing protocols running.
And by the way, to see if you have routing
protocols running, I showed you this before,
but if we remember, show ip protocols
and there's nothing running.
Okay, let's exit back out to the Corp
and get ready to configure IP routing.