Original subtitles

All right, hey, guys, hey, thanks for coming back.

I promise you that.

Yes, I'll be as excited as I was before.

Now, if you happen to notice, I've often mentioned network topologies, so I want to talk a little

bit more about the details that we mentioned in network topologies.

So basically, topology is like a well, I'll tell you what, it literally means a layout plan.

Right?

So a topology describes how computers connect and communicate with each other.

The topology creates the physical and logical structure of devices that make up a network.

Topology is the starting point for understanding the structure and the operation of different network

technologies.

So you could even examine topologies in two main parts, because, like I say, you've got the physical

topology and that's the connection types of the network devices.

So the cables used and their standards and the layout of the cables, the locations of the network devices

on the network.

These are all part of the physical topology.

So secondly, we've got the logical topology, the communication types and the communication protocols

of the devices on the network.

Well, form the logical topology.

So topology alone does not actually clarify many network related issues.

Right?

For example, the type of cable used its maximum length and how many computers will detect whether or

not a cable is in use are not explained just by topology alone.

However, over time, standards have been formed with the effect of market conditions.

So there are different network systems using different technologies.

These technologies even have names such as Ethernet, which you may have heard of token ring or FDI.

So each network technology clarifies issues such as a type of the cable to be used, the maximum length

in the bandwidth, along with the type of topology it uses.

So topologies are generally divided into these two, right, physical and logical.

But who said that in the back, yeah, OK, good.

That's a good question.

So let's actually dig into some of the greater details of this physical topology.

So the physical layout of the devices that make up the network and the cable types used form the physical

topology.

Right.

They're basically six types of physical topologies.

There's common path ring star, extended star mesh and tree.

So take a look at this first one bus topology.

Now in bus topology, communication is carried out on a single cable, and network devices are connected

to this cable.

A single cable, can we call this segment a backbone or even a trunk?

The data sent in the network continues on the line until it reaches the destination or arrives at the

Terminator and passes by all devices on the network.

The bandwidth of the network is shared by the devices on the network.

So basically, coaxial cable is used in this topology, and it's one of the topologies with a lowest

network performance, by the way.

And the maximum distance is 185 meters when using thin coax cable and 500 meters when using thick coax

cable.

Up to 30 network devices can be found on one of these network.

So in this topology, every device connected to the network listens to every transaction and data transmission

on the network.

And if its its own transmission, it gives and receives.

Before any device on the network sends a data packet.

It's got to make sure that the line is not used by anyone else.

If two different devices send data packets to the network at the same time.

Well, you've got a conflict occurring in the priority order will be decided between the two devices.

It's like a boxing ring or something, but it definitely reminds some of maybe the parents and grandparents

of what they used to have for telephone lines.

Right?

The Common Party line.

Anyway, there are some advantages.

It's a very easy day to set up the network and connect your computer to the network to expand the network.

In fact, it might even just take a morning.

It can be set up very quickly for networks that don't require high speed.

Not everything does.

And it certainly requires less length of cable.

Doesn't even need an external device, therefore they don't keep costs down.

But then you got to weigh it against the disadvantages, the cable length that can be used for the main

line and the number of network devices that can be connected to it.

Very limited.

Any damage to the backbone cable affects the entire network and then network becomes inoperable.

A Terminator must be at the end of the cable.

When there is a network problem, it can be difficult and time-consuming to detect and fix the problem.

It is not usually used for a stand alone building network solution.

And it's way slower than other topologies.

Networking, adding a new device increases data density and decreases performance for everyone.

Now, number two, we've got ring topology.

So this ring topology is very interesting, it was developed first by IBM and the layout of the network

is in the form of a ring.

Data transmitted over the network passes through every device on the network until it reaches its destination

because there is only one path between the devices on the network.

So in this topology, the attenuation of the signal on the network is at the lowest level because the

signal is strengthened at each device it encounters and transferred to the next device.

So data transmission over the network is done with the help of a signal called a token.

It's a three byte signal.

The token is constantly circulating on the network, and the device that will send the data uploads

the data to the token.

If the token is empty, it leaves the network again with the destination address.

But the failure of a network device on the ring will cause the entire network to crash.

But as it turns out, ring topology is also divided into two.

There's the classic ring model.

OK, it's logically created by connecting all nodes together in a circle.

If a computer in the ring fails, all network communication is cut off, but collision probability is

low.

Now, coaxial cable was used in the first ring topologies, but currently UTP and STP cables are used

in ring topologies.

First ring topologies.

It works at four megabits per second, then 16 megabits per second.

And there are some Ethernet cards now that are suitable for ring topology and those who work at four

or 16 megabits per second, so.

There you go, a bit more flexibility with either not.

All right, so the next apology on our apology tour is the star wired ring model.

So in Mao or Multi Station Access Unit, data goes in a circle.

Right?

But while hubs transmit all incoming signals to all nodes, mouths transmit incoming signals in a ring

form in only one direction.

That way, all nodes in the network receive the token.

So naturally, there are some advantages.

It's thanks to these tokens at each device is equal in data transmission.

No servers needed for connections between devices.

And growing the network has little impact on performance.

But weigh that against these disadvantages, you've got problems with any of the network devices will

affect the entire network.

Network interface cards and mouse are more expensive than an Ethernet and a switch.

Adding changing or removing devices to the network will affect the entire network.

Next stop, number three, the star topology.

Now, this I mentioned before is the most widely used physical network topology today.

Every device on the network is connected to the switch or hub in the center.

So roaming of data on the network will depend on the central connection device.

So information sent from a network device will first be processed in the central connection device and

then gets routed to the destination from their.

So it offers higher performance compared to the bus topology.

Now, a problem in the hub where this which.

Will affect the entire network, but a problem in a network device will only affect that network device.

The rest of the network is not affected by this issue.

Twisted pair cables are used in star topologies.

The distance of the network devices to the central connection devices at most 100 meters.

Now the problem of any device in the network can be easily identified by just looking at the lights

on the central connection device.

So when a device is added to the network, the corresponding port light on the harbor switch should

be lit.

And of course, it comes with many advantages.

A few of them are adding new devices to set up an expanding network is really easy.

Any problem with one of the network devices will only affect that device.

Network management and troubleshooting are easier to.

Some of the disadvantages include requiring longer cable lengths compared to a linear topology.

When a harbor switch fails, the entire network becomes inoperable.

They are more expensive to install than linear cousins due to devices such as hubs and switches.

So now we come to number four, the extended star topology.

This is fairly larger and basically enlarged version of the star topology.

The network is expanded by adding new or additional hubs and switches to the hub or switch in the center.

Five, we've got a topology very popular these days and mesh topology, every device in the network

is connected with other devices.

It's mostly used in windows or wide area networks when used in LANs, the local area network.

Each device in the network does not need to be connected with the others.

So in this topology, all computers are connected to other computers by a separate cable.

Now, theoretically, it's the ideal connection time, however, since the number of cables in-between

increases exponentially is the number of terminals increases.

Well, it's only used in very special situations in between a small number of computers in real life.

There are some advantages since there is a connection to other devices over each device.

Communication takes place over other connections, even if there's a problem with any one line.

Now, since the devices are directly connected to each other, data transmission speed is pretty high.

Expansion of the network can be done without affecting other nodes.

But of course, he got to weigh it against the disadvantages, since each device has x minus one connections.

There must be so many ports on the devices which increase the cost.

Cost and complexity are high because way too many cables get used.

Now, here's something interesting number six, the hierarchical tree topology.

This is used to connect different networks, usually networks in star topologies.

Thus, networks can be enlarged.

But unlike the extended star topology, it does not need a central device to connect the networks.

It has the characteristics of common path and star topology.

There is a hierarchical order among the devices on the network in the tree topology, of course.

And at the very beginning of the network is a device that acts as a route, which we will remember from,

well, the way trees grow.

Right, they start at the roots.

Now, connections from other networks are not made on the route.

The branches.

See, here's the metaphor again of the tree represent networks of different topologies and are connected

by the trunk of the tree.

Now, this topology is often used to create backbones of very large networks.

And some advantages will be easy to manage and maintain as a network is segmented.

If you're well trained in it, that is you don't have to worry about it.

Perhaps not yet, anyway.

Hardware and software from different manufacturers will definitely work harmoniously.

It's easy to expand the network, easy to detect and fix errors.

And a problem in one of the segments will not affect the other segment.

Of course, there are some disadvantages.

The length of each segment is limited by the cable used cabling is often difficult compared to other

technologies.

And the problem that will occur in the backbone affects the network traffic in all sections.

It is difficult to install to regulate and maintain.

So now let's talk a little bit about the types of logical topology.

So the communication types and communication protocols of the devices on the network will form this

logical topology.

Two types of logical topology are commonly used.

One is a broadcast topology.

So each computer on a network can release information to the network environment to send information

to one, to several or to all computers on the network without giving any particular priority.

It all works with a principle of first come, first served.

There are three different working modes, so according to this method of delivery, a it's a unique

cast communication.

So communication from one computer to only one other computer.

B is multicast communication, so this is a form of communication between one computer and then more

than one computer.

See, broadcast communication.

It's a type of logical topology where communication takes place from one computer to all the other computers,

right?

So we also have to talk about this number two token ring topology.

So token, right?

These are deposited on the network by a server.

This token governs access to the Network Environment Data Center.

The network is transmitted with his token.

Therefore, collisions in the network are prevented.

As the token travels over the network, it stops by every device and checks to see whether there's data

to be sent and delivered almost like your your Postal Service or not.

Anyway, tokens are three bytes of information circulating between these notes.

All right, so that does it for all of this, you have now taken a marvellous tour of topology.

We've also covered peer to peer network architecture, the client server architecture, file servers,

database servers, transaction servers, web servers.

We covered proxy servers, pans or personal area networks, LANs or local area networks, mands metropolitan

area networks and web and wide area networks.

Wow.

There's a lot, huh?

Because we also did VPNs or virtual private networks, cans, controller area networks, sands storage

area networks, bus topology, ring topology, star topology, mesh topology.

And then we kept it all off with the hierarchical tree topology, which, OK, try to say that three

times fast.

And then we wrapped it all up with broadcast apology and token ring to apology.

Now, if I had told you we were going to learn all of that.

You would never have started this, right?

But you see how just one thing builds on another and another, and then before you know it, it's like,

Wow, you actually know something now.

So thank you so much for listening and playing along.

We've got a whole bunch covered, and I hope you enjoyed it as much as I did.

But there's more there's always more.

All right, so I want to see you in our next lesson.

Until then, have a great day.