Network Topologies

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Hey, guys, Welcome to another episode of the S S C P exam print.

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I'm your host, Peter Simple in This is going to be the third lesson in the six domain

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so far. In the sixth of mean, we've taken a look at the O. S. I and T c p i p. Miles. We've taken a look how it requires seven different layers to send data for one part of the network to the other. We've also taken a look at ikey networking, which is an in depth dive on how information is actually sent

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over the network.

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And now finally, in this lesson, we're going to look at networked apologies several of them, in fact. And each one has its own advantages and disadvantages. Depending on the needs of the organization. Let's get started.

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They're deaf. Many different networked apologies that one can use when setting up a network. It's good for the s S e P practitioner to understand that and be familiar with them to know which one might be best for a particular network.

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So the 1st 1 is known as the bust apology.

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This is simply a local area network with a central cable known is a bus to which all the notes connect. Now just one cable data passes back and forth on this main cable

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and all the news, the different computers. They just attach themselves to this main cable and listen for traffic that is destined for them if it best in for them when they pull it in. And then they read it and goes from there. That's how they send information back and forth.

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Advantages of this are adding news. Subaru. He's just

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plug it in and you're good to go. And one node failure doesn't bring down the whole network.

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Now down Thought And this is everything is dependent on the bus. So if this central cable goes, then head of the network,

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it's a trip. All the voices connect to a branching cable,

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so there are several different on hubs or switches involved here, and information travels from one cable to another.

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Another advantage is adding news, not a problem. And if one *** fails, then that doesn't really affect the rest of the network.

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One of the bigger problems is a cable failure similar to the bus, but it's not as bad. The cable failure and a tree wouldn't be as bad as in the bus. If the cable fails for one of these in this in this apology,

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then yes, a certain amount of news would go down and be disabled, but not all of them.

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Whereas with the boss, all the news would be disabled.

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Bringing topology This is a loop, and data is only transmitted in one direction. This is a rain topology data is only transmitted in one direction so that they have each computer attached to this topology can on Lee send direction.

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I could only send information

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one way

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and can only receive information from its downstream neighbors.

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Now the vengeance and this is you can know exactly the amount of weight time of it take to get information to be passed from one spot to the other, and the network can be used as a backbone or a land

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problem with. This is because they're all connected in a ring. If one computer fails, then that breaks the entire ring, and all of the computers would then be disabled.

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MASH network. All nodes were connected to every single other ***

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advantages of this. There's a high level of redundancy. So even if cable goes down or something happens to one of the computers that are attached to this topology than the rest of the computers will still work that can still send information back and forth to each other. This advantage of this

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it's very expensive. Delay all these cables

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in order to have all of them connect to one another can be very expensive expect, especially when there are many computers attached to this kind of network.

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This is the start apology where all of the all the computers or news are connected to one central device, which is usually a hub or a switch or router.

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Plenty of advantages. With this, there are only a few cables on Lee won one cable needed poor per ***, and they're easy to deploy. You just simply hooking new one and you're good to go. Nodes can also easily be added or removed.

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The problem with this is that it's a single point of failure. Something happens to the hub or the switch, then the whole network is inoperable.

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Most communication networks, especially when initiated by a user, is usually from one host to another. So when a person wants to get information they need to request information, they receive it or they send in formation.

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Now a single transmission with one receiving host is called a Unit Cast Transition. This is where you can send a packet only to one person.

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Now there's also a multicast where you can send it to select people. Or there's a broadcast where you can send into every single person in the network.

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Circuits switched networks. This is a dedicated circuit between imports. This circuit is known as always available. It's always dedicated. The two machines they're talking that used this circuit always have this circuit open for them to communicate data.

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Example of this is telephone lines.

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The other one of this is packet switch networks,

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where they do not use a dedicated connection between two endpoints, but instead they send information on a shared network.

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These are for these packets. They are sent from one spot to the other, using what is known as the best path or the quickest way to get to one spot to the other.

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All the packets obviously need to be in the correct order, so if they aren't, then you have to wait for the packets to come in because not every packet takes the same path. If one pack it's going one way and there is from the network congestion or

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it would all Sunday at the time would take to get there is longer.

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Packet might be rerouted through a different way on the network

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virtual circuits.

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These are circuits usually used in like virtual lands. On these provide a connection between endpoints. The accident was like a physical circuit for these air circuits that you can send information back and forth, but they

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they kind of don't they kind of don't exist.

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There's no riel dedicated physical circuit. It's simply a virtual one. Now there's two different kinds of virtual circuits.

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This is a permanent virtual circuit where the carrier configured. There's the circus roots and the switched virtual circuit, which is configured dynamically violent routers in the network

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carrier since multiple access. This is a protocol which uses the absence. Print your presence off a signal on a wire as permission to speak.

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So in order to make sure that the packets don't hit each other, they need. There's no need to be a way to let a computer know when to send a packet on a wire. So that's this is where carrier sense multiple access comes in. If it doesn't detect that there's

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any type of

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action on the wire, might sense of information, or if it detects that there is,

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uh, information on the wire, then it won't send anything. Now there's two variations of this. The 1st 1 is collision of wings.

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This requires devices to announce transmitting by using a jamming signal. So when they are one of the computer is about to send information or packet over the network. They send out an alert saying, Hey, don't anybody said anything? I'm about to send something.

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The other one is collision detection. This listens for packets on the wire before transmitting data. If they don't hear anything than they safely assume that they can use the wire to send information

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token passing on Lee. One device may transmit at a time, and devices can only transmit if they have. If they possess the token. Now, this is basically a substitution for a lack of carrier sense off accessing. So instead of listening,

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everybody knows if you have the token, you could transmit data.

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If you don't. Then you cannot send anything on. And then the token goons back and forth to the different *** in the network.

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Even that course played a major role in the lands. Sense of his first developed in the 19 eighties. Um well, can this a little bit more later? But this is usually have networks are put together through money from that court.

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And you have the token ring.

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Well, we looked a little bit. This is very similar to the rink topology, where each device gets its data from its neighbor in one direction and can only pass it to the next station that's on the wire.

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Now suppose that, um, station A, in this example wants to send something to station. See?

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Well, they wait until they have the token ring on. Then they send the information and the only direction they can, which would be either station your station D. Let's say they can only send a station d, so they send the station. D

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Station D now has the token on the information, and they realize it's not for them. So they sent it to station. See Feitian see realizes it's for them on dhe Then they received the information and send the token to go to the next spot.

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Fiber distributed data interface f d D I. This is another one of those token passing architecture, but this uses to bring this uses information that flows in opposite directions.

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So this isn't This is a way to provide a redundancy in case one off the workstations goes down.

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So let's say, for example, that the

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um information is passing in a clockwise and counterclockwise motion. And then the work station on the very bottom decided to become inoperable, so it's no longer available. Instead of the whole network being disabled, the two rings can can continue to send information back and forth

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through the other three

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because the two information flows go in opposite directions.

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Multi protocol label switching. This offers mechanisms for Pak Tik traffic

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and multi service functionality. So in normal, rounding a packet is sent to a router and then from there, the routing table router looks up the next step in the destination on its routing table and sends the packet to the next round.

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Well with multi protocol label switching

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when the packet first is received by the first rounder. The first Ratter calculates the entire destination to that the packet needs to take, and then it simply applies a label to that pack it and sends it on its way when it gets to the next round. Er

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that Ratter does not have to look up the next destination in the round table,

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but rather it just looked at the label,

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sees where it's supposed to go and then just sends it on its way. This is really, really great. Thio provide relief for network congestion, and it uses less. Resource is

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in today's lecture. We discussed networked apologies and concepts.

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Quiz time.

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What network topology consists of all nodes being connected to one central device.

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Is it a mesh be star

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C bus or D tree?

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If you said be star than you are correct, remember, the device in the centre is usually a switch or hub, and all the other voices are attached to it.