In the apology we have two routers and two PCs.
This is a newly configured typology.
The rod is just booted up and have no configuration.
So for example show IP interface brief on Rotto one shows that all interfaces are shut down and no IP
addresses are configured.
What I'll do is no shut interface serial to slash zero the wanting to face on a one and I'll do something
similar on Radha to get it to also has no configuration so no shut
show IP interface brief as you can see the interfaces are up on both sides.
Show interface serial to slash a zero.
What I'd like to point out is the kept isolation used which is Dayle see by default on Cisco routers
serial interfaces use HTL see as the encapsulation.
So what we could do is go into that interface and give the rod an IP address of say 10 to one or two
to one and use a slash 30 mosque will do something similar on router to IP Address tendered one to two
to two
Ken Rodda one thing right.
Two yes it can can route a two ping Route 1.
Yes it can show run interface serial to slash is zero.
All we had to do was know shut the interface.
We didn't have to configure an encapsulation.
We didn't have to configure clock rate you only have to configure a clock rate.
If you using a back to back cable and your router is the DC side of the cable here both sides of the
DTV.
So we didn't have to configure a clock rate.
Let's have a look at HPLC frames.
So do we shock capture
on ones serial interface.
What we can see here is the protocol Schoeni slop
but notice we've got H.M.S. and then the Siska slop protocol which is used for configuration.
Here we have SCDP message so Cisco HDL seizing kept isolation used at least to noticed the protocol
is referenced as 2000 which is Cecka discovery protocol and we can see information about the device.
So Rotto one he's a 37 25 and is using interface serial to slash 0 his Rodek to also using serial interface
to slash zero.
If you do a ping
we should see I see MP and there we go.
So I see MP
Atli to it's once again HD see.
So if we look at the actual frame being kept isolation type is a deal see it's not ethernet so on those
wanting to face we using an HDL C encapsulation.
Notice the protocol reference is the famous x 0 x 800 which means IP version for at least three years
IP version for you can see the source IP address and destination IP address in the packet
the protocol Sainty So I see impy you can see it's an echo.
He has the ECA reply scrolling back to the top.
It's once again HTL see there's the protocol type.
So the IP address is 10 1 1 2 going to 10 1 to 1 and it's an echo reply.
So Cisco HTL C C D HDL C has this particle field denoting the Hialeah protocol that's IP version for
let's configure IP version 6.
So IPV 6 address 2001 colon colon one colon colon one slash 64 on roaded to interface serial to slashes
zero IPV six address three thousand and one colon one colon colon two slash 64 so paying 2001 Colan
one colon to Ping's succeeds in y shock capture.
We see the ICMP messages.
So this is the ping from Rodda one to rodded to notice the protocol type 86 Dee-Dee.
It's a different protocol type IP version for Cisco HDL HDFC logic to run multiple Hialeah protocols
across the same link because of this protocol field.
So once again there is IP version 6 and scrolling up here is IP version for and here is CGP all using
different protocol types.
So the layer to encapsulation here is referencing a Hialeah protocol.
We would see something similar on an Ethernet frame.
So on Rotto one interface if the zero slushes zero no Schutt IP address 10 1 1 1 2 4 5 2 4 5 2 4 5 0
on the PC will give it an IP address of 10 to 1 to 1 but 11 with the mosque
and all set the gateway to 10 to 1 1 to 1 so paying $10 1 to 1 PC can ping Rato 1.
And if we start to capture on that interface so we're going to capture traffic on the router.
Notice the frame is Ethernet to let's send a ping again.
So there is an ICMP packet.
Notice the protocol type for IP version for is zero or 800 which is what we saw on the HTL see frame.
So here's the deal see.
Notice the particle field.
So when you send packets across a router the shoji quite clearly that relate to encapsulation changes.
But the high layer protocols are maintained or kept encapsulation used cheare is Ethernet to be kept
solution used here is HTL see encapsulation here would be Ethernet to once again.
In this example somebody to interface if zero slashes zero no Shutt IP address turned out one to 3 to
one as an example.
PC to IP Address tendered one to three or 12 put the mosque in default gateway
paying $10 one to three to one that works.
Only enable writing protocol here quickly to allow the writers to talk to each other and this will give
us another protocol to capture in why shark
so enable people from all interfaces.
Sort of capture on the scene to face.
So we have three Why shot captures going serial interface the safety net interface and the see the NET
interface PC one should always be has converged be able to ping PC to which it can so the pings are
succeeding.
Let's have a look at the frame over here on the Ethan It segment.
So there's the frame you can see the Ethan a type is Ethan a two source MAC address destination MAC
address which is the Rodda protocol these are provision for just to prove that that serrata
show interface 0 0.
Notice the MAC address is C 2 0 1
3 0 8 0 0 0 0 which is correct.
So the PC is sending the traffic to the local router using Ethernet too.
In other words Ethernet encapsulation at least three the source and destination are the two PCs on the
HD all see capture
there's the same IP addresses of the PCs at least three but notice at least two being kept isolation
is HTL see and there are no MAC addresses MAC addresses only used on Ethernet.
They're not used in HDL C HDL C links are point to point.
There's no need to have MAC addresses anything that you send out of this interface is going to arrive
at this interface and vice versa whereas Ethernet allows a multiple devices to connect to the same segment.
So there's no need to have MAC addresses in HDL C. It simply references the Hialeah protocol and specifies
that this is a unicast packet.
What about on the side.
So here's the pain source and destination IP addresses are the same.
Notice however that it's Ethernet once again.
So Ethan it too in this case the source MAC address is Rodda to show interface fast Ethernet is 0 0.
Notice the MAC address see 2 0 2 3 8 4 zeros.
That's the router talking to the PC in this case PC to the Ethan that type field specifies IP version
for the highly protocol and he has an IP packet and he has the I see MP information
being kept selection changes on every link MAC addresses are used on the Ethernet segments MAC addresses
are not used in HDL C.