Hello and welcome back to I see anyone interconnecting Cisco networking devices. Part one,
this is episode 132 least line winds and HDL. See,
I am threatened. Arrow and I will be your instructor for this course. The last video you only went over the lesson 1.3 overview.
In this episode, we'll be covering what is the least land
at least lying when and what the HDL see layer to protocol is
so they're learning objectives. For this lesson is we're gonna learn about Lisa and
their speeds and how they hook up to each other. And then at the end, we're gonna look at H D L C. Which the high level Datalink control protocol.
So quick, pre assessment here before we get begin,
what is the least like next to you? Might not know this yet. Feel Frito Research. Otherwise, just wait a few seconds and we'll get at it,
All right? Hopefully you figured it out. Otherwise, it is Theseus E s U D s. You should be explained in just a moment here,
but first, we're gonna go with at least line. So what it is is what it does is if you have multiple remote sites that needed connect as if they're right next to each other.
This will essentially act is a super long cross over cable, so it'll go from router to router.
This is also referred to as a point of point blank, or it might be referred to as a T one line.
So the company that is utilizing these lines is only renting it or leasing it. Theis P generally actually owns the line, and it may actually go through multiple Teleco central Central offices
before reaching the company's oversight.
So the customer he needs to have his router, CSU D issue and a serial interface.
Now, a lot of times the router,
we'll have the sear on her face and a C. D. S. You and CSU combining the one in the picture. There is a wick interface for a T one line interface
for the most Cisco routers. I have a few of those on my rack.
We're going to be one device or the router kind of Syria in her face that connects to an external C S u D s u
measure in a few different ways, so t one used to always. Here is 1.544 megabits per second, the slower speed direction multiples of 64 kilobytes per second. But all the higher T speeds are multiples at 1.54
For if you look at the bottom, Schardt, there you have the North American Standard T ones and then the Europe, which is E
now building a least life for a lab because it's not real practical to try and set it up otherwise. So if you have to routers with serial interface is depending on it. You need to have a D, C E and a DT cable this you will have the female end. The DT will have the male end
if you're looking at pictures of right there. These are the Vida 35 connectors, the older style looking ones.
And then it's a smart serial, which is the smaller little connector there.
So what you'll do is you'll connect the
both ends, the smart serial into your switches or your routers. Excuse me
the D. C. Or the vida 35 larger connectors to each other.
Now you want to actually do those the D. C E. And you have to configure a clock rate a router.
The easiest way IRS always remembered. Um, remember D. C versus DT. Which one had to run clock? Right? Is
clock rate starts with a C D. C. Has a C. I don't know why that always stuck with me. Hopefully, it helps you
some other ones you can do for a lab if you don't because I don't have those cables per se. I have these cities bottom ones in the middle. I have had both smart zeros on both ends of one's a DC end, and one is a DTs so kind of avoids having to buy two different cables.
So if you want, you can look at be there those options. If you run a physical home lab
now, the age deal. See basics. So Valise line has no predetermined layer to protocol. They either used the HDL see usually or the point to point protocol.
Now each deal see, actually is less work to do than an Ethernet frame because, like you said it works, is a crossover cable on. It knows that there's essentially only one destination on that layer to
so it's very similar to an Internet frame here. So if you look at the flag on the far left, it's kind like the preamble of the evidence D. A kind of list of recognizable patterns commits to let them receiving node that a new frame is arriving.
The Everetts there is like a destination address of the Ethernet frame
control. It's not used too much anymore. I won't go over that. A test doesn't cover it too well.
That type is going to be the layer three packet.
The idea of the layer three packet that's encapsulate inside. So again, I p four, maybe six. We looked at the ether types a little bit
is for one last few lessons,
and the F. C s is again used for the field. You for error detection.
Now, the standard I S O version does not have the type field Cisco actually implemented and their proprietary version of age deal see.
So, for example, if we look at the
pictures at the bottom there, if we have a packet that is going for frame,
I was going from P C one to pc to left to right.
PC one is going to send the frame to route to the router
as an Ethernet frame or 802.3.
And what the rotors rudder is gonna do is, do you encapsulate that eats in that frame?
It was going to encapsulate it and HDL see Frame sent it over that leased lines over the router be the router B's gonna de encapsulate that a steel see frame encapsulated an Ethernet frame or 802.3 frame
and send it over to PC to.
So it's not too bad.
May I remove that? Remove their
so quick post assessment on this? Hopefully you remember. So what does the Syrian her face on a router connect to before connecting to the police line again? I'll give you a few seconds to look it up real quick,
all right, Hopefully you got it. It is again the CSU. Do you see that is the intermediary device
that is between the router and the least line.
Or it could be built into that serial interface. It's on the router
next up, so we're looking at some of the different land technologies that exist on routers,
and, as always, if you didn't have questions. Or if you need help, go ahead and send me a message.
Otherwise, thank you for washing this episode. I look forward to seeing you and arrest, of course.