# Network Functions and Routing Logic

Video Activity
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Time
23 hours 18 minutes
Difficulty
Beginner
CEU/CPE
23
Video Transcription
00:00
Hello and welcome back to I, C and D one interconnecting Cisco Network devices Part one. This is Episode 142 Network and network functions and Routing Logic. I in Trenton. There wouldn't be an instructor for this course us video one over less than 1.4 overview.
00:16
In this episode, we'll be covering some basic networking and routing.
00:21
So our lesson objectives for this we're gonna look at the network layer around 14 logic and what happens at each layer and a quick routing example.
00:30
So quick pre assessment here.
00:32
Where does the hosts and a packet first
00:35
give it a second to think about it and posit video.
00:41
All right, if you guess the default gateway, you'd be correct.
00:47
Are some quick networking layer fording wide so that we're clear what it does? It doesn't really worry about the layers. One into a kind of just lets them figure itself out and kind of let it do its own thing. It's only gonna concern itself with logical details, the trends transmitting data. So worries about specifically how the packet will get from the source and destination looking at the I P addresses.
01:07
So what's gonna happen is a host determines when it goes to send a packet that the destination is not on the same land is going to send the I pee right to the default router. And from the air, the router is gonna determine from this routing table where to send the packet next or the hop.
01:21
Until it was gonna keep doing that until it reaches that final router and found a router will see that it has a connected root for that
01:27
01:30
No, it's going to sing it Sent it on to that server or that destination.
01:37
All right, so kind of a layered look at 14 logics layer three, we're going to see We need to send this packet front to device A.
01:44
It's gonna have the source of destination I p address
01:47
and later to is going to say OK, we need to encapsulate the packet and put it into a data link frame.
01:53
And with the source I p of you know, this device and then the destination of the elected next hop I P address or the Mac address. Excuse me?
02:00
The mayor was just gonna say Okay, let's put it in the ones and zeros and send it over the lines
02:07
car. So quick prodding example here. So P C zero is gonna try and send a packet to servers here at the bottom there.
02:15
So P C zero was gonna send it to router A. Because it determines that the 10 10 50 is not on the same sub net as it's 1921681 50 address.
02:27
So it sends it to his default router, which is router A motor. A looks at the routing table. Has it determines that the
02:34
tender sub net is
02:36
gonna have a next hop address going through its serial one interface to router Be
02:42
so it's going ahead. It down to be here.
02:44
Go and get a pen out.
02:46
So you go from PC
02:47
down the router, eh?
02:49
It looks at the routing table says Okay, we need to go through a serial one. Done. Roger B
02:55
Roger B is gonna do the same thing. Look at the routing table says we need to go through serial zero. It's a router, see,
03:02
and we're down here. Then it says, Okay, I have a connected root for
03:07
the service. Zero is gonna send it through the Ethernet in her face
03:10
down to here.
03:16
Not I pee before header The main things you're gonna want. Look at concern yourself. For I seen the one
03:23
these two things right here the source address and the destination dress.
03:27
So each time the ATI chop is gonna de encapsulate and re encapsulate at the frame level, so it's gonna be encapsulate the frame enters
03:37
and it's gonna look at that destination address and say, OK,
03:39
where do what do I need to go to get to there?
03:43
It's gonna look at that routing table and then figure out what say goes a router Number two. It's gonna put a
03:49
new frame on their data link header that has the destination. Mac address off. Let's say a writer, too.
03:58
But that source and destination stayed there the whole time.
04:02
All right, so quick. Post assessment here, what is removed in every and added every time I pack, it is routed by a router
04:10
off that it just quickly,
04:12
and I'll give you a few seconds to think about the answer here.
04:15
What?
04:16
All right. Hopefully you got the source Mac address in the destination Mac address
04:24
in the next up sober. We're gonna be looking at I p v for addressing.
04:29
We're gonna be looking at the data decimal notation. We're gonna figure out a converted the binary.
04:33
Yeah, I promise. It's not too bad.
04:35
And as always, if you guys have questions, you need help.
04:39
Go ahead and shoot me a message. Otherwise, thank you for Washington this video and look forward to seeing you next one.
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