Original subtitles

The reason why we see up traffic rather than I see impede traffic.

He's on Ethernet before two devices can communicate.

They need to use up to discover one another's MAC addresses.

So before ICMP traffic can even be sent right to acting as PC needs to send an op to discover Rodda

force MAC address.

But it never discovers that because the traffic never reaches route before so it never receives an opera

apply and therefore cannot send ICMP traffic switch to interface range.

Kickabout 0 2 2 3 switch port trunk and kept solution topped one key switch port mode trunk switch port

No negotiate at the moment interface gigabit 0 to on switch to is shut down.

I'll just do the same here to prove the point we are forcing the traffic basically to go via the hub

so that we can do a wide shot capture and see traffic on the network.

So now let's start another one shot capture

Ken wrote to ping Rato for now noticed the pings succeeds.

If we look at our traffic we can see the OP topless we shall capture for the moment.

That's the broadcast asking for MAC address associated with IP address 10 1 to 4.

As you can see it's a broadcast sent from router to.

It's an edit to the one cue frame.

So in the Added to that one key portion once again we can see that the villain is too.

There is the OP's request looking for the MAC address associated with IP address 10 1 to 4.

Here's the reply.

What you'll also notice is the villain ID he's too so it's coming back as a tagged frame from 10 1 to

4 to 10 1 to 2.

So there's the OP reply.

It's not a broadcast because it knows the MAC address of router to a ready so it goes directly to the

MAC address of router 2 and then if we scroll down a bit further we can see the ICMP echo messages.

So he has an echo from 10 1 to 2 to 10 1 to 4.

Once again notice the villain ideas too.

He has the reply from 10 1 to 4 so it's an echo reply to 10 1 to 2.

A villain ID is 2 so those frames are being tagged between the two devices.

Let's stop that capture and started again in jenius 3.

Now what about traffic from Rotto 1 2 rodders 3 that's using the land one which is the untagged villaine

Serrato one.

Pinging router 3 pings succeeds router to pinging wrote a four ping succeeds.

I'll just full for ICMP.

So there's the ICMP message from Rodda one to three.

Notice it's a standard Ethernet frame.

The ether type is IP version 4.

There is no editor one Q tagging on the echo or the Ecca reply.

It's stented Ethan at frame's because that's the native land scrolling down.

However his route to pinging Rotto for.

And notice once again there is the tag.

So let's put router 1 and router 3 into Vilain 10 and see how that affects the tagging of traffic.

Switch one violent 10 interface gigabit 00 switch port access.

If we land 10 do something similar on switch to the land 10 interface kickabout 0 0 switch port access

the land 10.

So now when rodded one pings Rajshree what happens.

Now it might take a while because spending needs to converge

so can switch one shows spending tree

for violent 10 ports no forwarding.

So let's do the ping again.

Notice the ping now succeeds and you know was shock capture.

Scroll right down.

What we should see now is the villaine number as an example is a violent 10.

So IDs 10 can see the hexadecimal there's the decimal set it to in the Ethernet frame noticed that type

is a sort of one key in edit to the one cue the type is IP version 4 indicating that provision for is

used at least three is the ping.

Here's the reply.

But notice once again the villain number is the last 10.

If I change this violent to villaine 11 as an example with the pings succeed so Villani 11 rather interface

Keiga but zero zero switch port access the line 11 made the mistake of putting interface Villani 11.

I should have said simply Villani Levan to create the villain.

But in this case the switch to create the villain for me need to be careful with that because some switches

won't do that for you but you can see Villani Levan has been created.

Gigabit 0 is in Villani 11.

So this part is in Villani 11 as portals and violent 10 can write a one ping rodder three and you can

see at the moment it can't you know why shock capture Rodda one still has a cached MAC address for rodder

3.

So it's sending ICMP traffic.

But notice it's tagged with Villani 11 and no reply is received back because the traffic never gets

to rodders 3.

This port has in Villon 10 this port is in Villani 11.

So the traffic never reaches the port.

You can see that once again by doing a capture

helping wrote is free from Route One.

And what you'll notice in the output here is there is no up and no ICMP traffic received on this port

at all.

Even though we're not a one is pinging router three on the capture between the switches we can see the

ICMP traffic with the line 11 but the switch when it receives traffic on line 11 he's not going to force

it out of this port or this port.

So essentially goes nowhere.

It's going to be dropped by the switch because there are no access ports in Villani Lavonne.

So the traffic never hits rodded three but on switch to if we created Villani Leben and then went on

to the port and put it into the line 11 what we see now is that the pings do succeed.

Once again it may take a while.

Spending three to converge can see the pings arriving noticed nine one three is the sequence number

pings are arriving at switch to

but we may need to just wait a while for spending three to converge.

And there you go.

She just converged so we can see the ping from Route One to rotas 3 using Villani 11.

And there's a reply on Villani 11 so physically this typology looks as follows.

Just ignore the hub for the moment.

So pretend that the hub is not there.

Physically We've got two PCs connected to switch one and two PCs connected to switch two.

But logically rather one acting as PC one and router three acting as PCs three are connected to each

other and two and four connected to each other.

They are totally separated from each other and won't be able to ping each other unless we enable interval

and routing on one of the switches and configure default gateways on the PCs to talk to each other via

their default gateway.