At the moment, rather one acting as PC.
One can ping root of five acting as PC two.
I'll turn off these bugs.
Let's have a look at some show commands.
So first command on router to show interface tunnel zero.
Tunnel zero is up, up.
The hardware type is tunnel.
The IP address on the interface is 10.1 to 3 to 130.
The encapsulation type is tunnel.
The tunnel sources 4.1.121 tunnel destination is four to 1 to 2.2.
The protocol and transport is gry over IP version four.
Notice the empty yew has been reduced for this interface because of the headers used in gray.
The empty u four serial to slash zero or maximum transmission unit four.
Interface 2/0.
Is 1500 bytes.
But the MTU.
For the jury tunnel is 1514.
So 1550 minus one 514 gives us 36 points because of the additional headers used in January, the BTU
is reduced.
In other words, only smaller packets can be transmitted across the cereal link because of the additional
headers added by jury.
Originally we only have a single IP header, but now we have an additional IP header called the delivery
header as well as the header.
And we can see that by doing a Wireshark capture.
So I'm going to capture traffic on cereal to slash one on router three.
Send a ping from router one acting as PC one two out of five acting as PC to.
Here's the ping.
Now remember, originally we would only have a single IP version for header with the payload, but now
we have both the header as well as the order header or delivery header.
So the original packet over here.
As received by writer to.
Doesn't include the gory headers.
So when we do that ping again.
This is the first Ethernet interface on router two.
We can see the ping message with the standard IP version for header and Ethernet header.
But when that goes across the cereal interface, notice Cisco Hdl-c, we see the original header and
payload.
So there's the ping.
But notice once again the additional header.
So we've got the delivery header.
As well as the gry header.
So additional headers have been added when compared to the original packet.
Because of that, the empty view is reduced.
You can only send a maximum packet size of 1514 bytes because of the additional headers.
So once again, on serial
2/0, the MTU is 1500 bytes.
But on the tunnel interface, it's 1514 bytes because of the additional headers.
You can also see some information by using the command show IP interface tunnel zero.
Scrolling up.
Has the Comand tunnel interface zero zero is up up.
IP addresses 10.1 to 3.1 slash 30 broadcast is this.
Aim to use 1476 bytes once again.
Multicast reserved groups joined includes 2 to 4 zero zero ten, which if you remember, is the multicast
group for IRP.
IRP is able to form a neighbor relationship across this tunnel interface in a very similar way to how
you would form it across a serial interface, because this is a point to point link logically directly
from one router to the other.
So as an example, show IP copy neighbor, right two has a neighbor relationship with router four on
this IP address and not on this IP address because the neighbor relationship is formed across the tunnel
show IP JP topology.
We have learnt a Route ten 1 to 0 via ten 132 through tunnel zero and once again rather one is able
to ping router five acting as a PC when we do a trace to ten one, two, two, notice the trace goes
to router two then to write a four through the tunnel and then to right a five router three is not seen
at all in the trace because logically router two is directly connected to router four in the same way.
We're out of five when tracing to ten 111 sends the traffic to write a four.
Then a logically to write a to and then to write a one.