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Welcome to this lecture in which are going to talk about network topology.

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We are going to first discuss the definition of a network topology, and then we will see the different

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types of network topology.

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Now, just a topographical map is a type of a map that shows the shape of the terrain, the physical

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topology of the network is also a type of a map, defined the specific characteristics of a network,

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such as where all the workstations and other devices are located and the precise arrangement of all

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the physical media, such as cables.

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On the other hand, the logical topologies we covered earlier delineate how data moves through the network.

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Now, even though these two topologies are usually a lot alike, a particular network can actually have

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physical and logical topologies that are very different.

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Now, the first apology that we are going to see is the best apology.

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Now, this type of topology is the most basic one of all the bunches of technologies, and it really

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does sort of resemble a bus, but more like the ones that have been in a wreck anyway.

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The bus topology consists of two distinct and terminated ends with each of its computers connecting

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to one unbroken cable running its entire length.

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Now, back in the day, we used to attach computers to the main cable with wire taps, but this didn't

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work all so well, began using drop cables in the place.

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Now, even though all the computers on this kind of network see all the data flowing through the cable,

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only one computer, which the data is specifically addressed to, actually gets the data.

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For example, if the first PC wants to send data to the printer, only the printer will be able to receive

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the data because the data is meant only for the printer and not for the notes.

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Moreover, the Bush apology is very easy to install if you want to add a new PC, you just have to slip

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T into the main cable anywhere you want to connect a device.

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Best apology is easy to install, and it's not very expensive, partly because it doesn't require as

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much cable as the other types of physical topologies, but it has some drawbacks.

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For instance, it is hard to troubleshoot, change or move, and it really doesn't offer much in the

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way of fault lines because everything is connected to that single cable.

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This means that any fault in the cable would basically bring the whole network down.

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Now, you may be wondering, what is the definition of fault tolerance, by the way, for Lawrence?

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Is the capability of a computer or a network system to respond to a condition automatically, often

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resolving it, which reduces the impact on the system?

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For example, if something brings down the fault, tolerance will act automatically to resolve the issue

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and then bring back the networks to its original position.

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Moving ahead now, we will have a look at this tart apology.

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Astarte topologies connections are connected to a central point with their own individual cables or

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wireless connections, you'll often find that central support inhabited by a device like a hub, a switch

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or an access point.

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Don't worry about the storm such as hub and switches.

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We are going to see all these storms in the network devices section.

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Start apology offer a lot of advantages over the best apology, making it more widely used, even though

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it obviously requires more physical media.

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One of its best features is that because each computer or network segment is connected to the central

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device individually, if the cable fails, it only brings down the machine or the network segment related

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to the point of failure.

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Now, this makes the network much more tolerant as well as a lot easier to troubleshoot.

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Another great thing about to start topology is that it's a lot more scalable.

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All you have to do is if you want to add to it a new cable device, just connect the new device to the

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central hub or the switch.

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And you are done.

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As you can see on the screen, all the six computers are connected directly to the hub.

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So if you want to add a new computer, you just have to attach the new cable to the hub.

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Then start apology is easier to troubleshoot because if one PC fails, we can see that which PC has

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is not responding and thus we can troubleshoot why the network is not responding.

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But in this case, if the central device fails, then that is a huge issue.

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And since it is easy to troubleshoot start topology, more fault tolerance is provided and although

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it is called a star topology, it also looks like a bike wheel with spokes connecting to the hub in

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the middle of the wheel.

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So to sum up the star apology, uh, here's a list of benefits you gain by going with it, new stations

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can be added or removed easily and quickly.

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Then a single cable failure won't bring down the entire network as it did in the case of both topology.

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Then start topology is relatively easy to troubleshoot.

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But there are also a couple of disadvantages to using Astarte apology, the first one is the total installation

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cost can be higher because if you want to add a new device, you would require new cables.

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And since if you want if there are 100 devices in the network, you'll need 100 different cables to

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connect to the hub and therefore there is more cost.

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And lastly, it has a single point of failure, the hub of the central device.

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Now, that's it for this lecture.

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In the next lecture, we will cover the ring topology and the topology.