- [Voiceover] Alright, now that we have our vlans down,
and configured our vlans on our switches
one, two, and three, added our respective hosts
and the vlans 10 and 11 on ports 10 and 11
which is nice for us.
I want you to look at these connections
between switches, they're ports 19 and 20,
from one to two, and 21, 22,
and each of them are the same ports on each side
which makes it really nice.
I tried to make this as simple as possible
by using the same port numbers on both sides.
So, let's run out between switch one and switch two
and configure a trunk on ports 19 and 20.
Alright, now that I'm already logged in to my switch,
let's go ahead and take a look
at show int trunk interface trunk
and we should see our trunk ports.
Well we don't have any, so let's go ahead
and configure 19 and 20 as I mentioned.
Interface range, let's do them both.
F 0 19 dash 20, nice,
Switchport mode trunk, what do you think's gonna happen?
Should just trunk right?
Well, not necessarily because some Sysco switches
still run isl and 802 dot 1 q
So let's go force this and tell it which one it is.
If it runs both it'll give you an error like that.
So, switchport trunk encapsulation dot 1 q,
dot 1 q for 802 dot 1 q.
Now when I come in and turn on trunk units
it's going to work.
And these should probably pop up because
the other ports are all dynamic desirable.
So all ports, so 19 and 20 is up,
but I want to do one more thing.
Switchport,
trunk,
native,
vlan 99.
I'm changing my native vlan.
The untagged vlans between switch one and switch two.
You can do this differently on each switch.
Show int trunk.
Okay, we can see that 19 and 20 are on,
they're running 802 dot 1 q,
they're trunking, the native vlan is 99,
and all vlans by default are loud acrost.
Let's do this, since their dynamic desirable
I don't even have to go to the other switch
just do it but I will force them on.
So now we're at switch 21,
so we did 19, 20, and 21, 22.
I need the range command,
f 0 21 dash 22.
So we're gonna turn on the switch.
Use your tab key, switchport trunk encapsulation dot 1 q.
Okay, we're gonna native vlan right now
because we're have a different native vlan on the other side
so I have to go and configure switch two.
I'm not gonna do that quite yet.
So, we did switch port trunk encapsulation,
switchport,
mode trunk on
21 and 22.
So I changed the native vlan on switch one
but I didn't on two.
So, we need to go and look at this
and 21, 22 is up, I'm gonna leave the native vlan the same
so I do show int trunk,
(keyboard clicking)
and we can see all of our four trunk ports that are on,
they are statically on here.
Encapsulation is dot 1 q,
and I have different native vlans between switches
which I can do.
Alright? These are saying what are my untagged frames?
Now let's run out to switch two and change that
so we don't get that message.
Now that comes out, if you see this, through cdp.
So every 60 seconds, we're going to get this error.
I have lost connection to switch two
because I didn't trunk the other side.
So, I'm gonna have to telnet out there.
So I'm on switch two,
we can see we're getting the native vlan mismatch.
Not a problem really.
Just gotta go fix it.
But notice I had to go to the switch to do it.
So I'm gonna say config t interface range
f 0 19 and 20.
First off, I'm gonna say I know they're running dot 1 q
so I should be able to just say switch port mode trunk here.
So although it is running 802 dot 1 q
because it dynamically connected to the other side
and they negotiated using dynamic trunk protocol
to run 802 dot 1 q,
when I tried to statically configure it,
it wouldn't take it because it is set to auto by default.
So I'm gonna say switchport trunk encap dot 1 q.
And then switchport mode trunk,
and then switch port trunk native vlan 99.
Okay so I'm gonna get out of this and see what happens.
Now remember that cdp, that message came from cdp
for every 60 seconds we would get that message so,
and let's see if we're working now.
Okay I see my 19 and 20 are on native vlan 99,
and this is connecting me to my switch one.
So I can go back to my switch one over here
and show interface trunk.
Alright, so now I see all four of my ports.
They are, I have native vlan 99 going to switch two,
native vlan one going to switch three,
and all vlans are loud.