Some switch.
One, we're going to shut this interface down to force traffic to go via the hub.
So interface gigabit.
Zero.
To shut it down.
Show interface gigabit.
Zero three.
Switch port.
The support gigabyte zero three is acting as a trunk using editor one q.
All VLANs are allowed.
So let's do a capture on The Hub.
We were receiving previous information and notice the difference here.
He has an attitude and one q header.
So we have ethernet.
But notice the type is not IP version for the type is ed to one Q so the type is 0x8 100 rather than
0x0 800 for IP.
So 83 one keyframe.
We can see here that the VLAN ID for this previous RT message is VLAN.
One per VLAN spanning tree sends what are called PDAs on every VLAN.
So here we can see some spanning tree information.
And as we scroll down, we can see that as an example, CDP and HTTP messages or in this case, HTTP
is sent as an untagged frame so we can see some HTTP information arriving here.
And that will continue on.
So let's do a ping.
From rather to acting as PC to to write a for and see if we can see why the frames are not permitted.
So ICMP is showing nothing.
So we can see a broadcast here.
This is an op message saying who has ten one, two, four.
So.
In this OP message.
And I'll just stop that capture for a moment.
Here's the op.
You can see it's an Ethernet two frame.
With a broad cost.
So the destination is a broad cost source.
MAC address is the MAC address of router two.
We can see that by looking at the interface.
So show interface if zero.
Slash zero.
Notice there's the Mac address of the router.
And there it is shown in the why shock capture.
But notice the type is once again ETA 2 to 1 Q And the VLAN is set to VLAN two.
So in other words, the router is sending the frame untagged to the switch.
But when it goes across this link, it's going as a tagged frame.
The switch is setting the VLAN tag to two because it arrived on this port which is in VLAN two.
I'm just reset that capture.
And what I want to show you is.
On this port is going to show us untagged.
So it's standard Ethernet, but on this one it's going to show us tagged because the switch is tagging
the frame.
So I'll do the ping again.
Now this is the frame to the switch from the router and we'll do a search for ARP.
You can see there's the op traffic from.
The router to a broadcast address.
It's untagged.
This is the type for app.
There is no ADA 2 to 1 q header here at all.
But when we look for ARP on the link between the switches, notice you can see the ADA 2 to 1 CU tag
set to two.
So the traffic.
Is arriving here is untagged and the switch is tagging it to send the frame to switch to.
The problem here is when the traffic hits switch to switch to is not configured with trunking.
This is just an access port in VLAN one.
So that traffic will be sent onto this port but not out of this port which is in VLAN two.
So let's switch to let's see if we can see that show interface trunk.
At the moment, no interfaces are trunking.
Show interface gigabit zero three.
And let's put switch port at the end.
So show interfaces gigabit.
Zero three switch port.
This interface gigabit zero three is enabled.
It's set for negotiation of trunking, so it's in a VLAN one.
This port belongs to VLAN one.
It's an access port.
No trunking is enabled, so traffic from router two is simply going to be sent out of this port.
So let's do a CAPTCHA there to prove that.
And then we'll do a CAPTCHA on this port to check if any traffic arrives on this port.
So there's the Wireshark capture.
Do the ping again on router two.
I'll do a.
Full time for OP.
I notice there's the broadcast traffic from ten 1 to 2, which is rather to.
Asking for the Mac address of ten 1 to 4.
So rather two is asking for the MAC address of root of four, but it never receives it.
So what you'll also notice here is there is no editor or one Q Tag.
So the frame was sent untagged here.
It was sent tagged across here, arrived here.
But this port was configured as an access port in VLAN one, so the traffic was simply copied out of
this port in VLAN one with no tag.
The traffic never arrived on this port.
So let's prove that to a captcha here.
We'll do the ping again and try and falter for up.
And what you'll notice is there's no traffic because the traffic is arriving on an access port, port
one.
It's only going to be sent out of this port, which is port one.
It's not going to be sent out of this port at all.
So let's stop all captures.
And then what we'll do now is configure this port to be a trunk port and this port would be a trunk
port.
But we'll leave this port shut down for the moment so that we can see the traffic being captured.