Network Topologies (Star, Bus, Ring, Mesh, Ad hoc, Infrastructure, & Wireless Mesh Topology)

Summary

This video script delves into network topologies, explaining the layout of network communications. It covers wired topologies like star, ring, bus, and mesh, highlighting their advantages and disadvantages. The star topology is common but has a single point of failure, while ring and bus are less used due to their limitations. Mesh offers high redundancy but is expensive. The script also explores wireless topologies, including infrastructure, ad hoc, and wireless mesh, emphasizing their applications and benefits, especially the redundancy and flexibility of wireless mesh networks.

Takeaways

• 🌟 A network topology refers to the layout of how a network communicates with different devices, with wired and wireless categories.
• 🔌 The star topology is the most common wired topology, where all devices connect to a central point like a hub or switch, ensuring that a failure in one device or cable doesn't affect the network.
• 🚫 A disadvantage of the star topology is the single point of failure, where if the central hub or switch fails, the entire network goes down.
• 🔗 Ring topology connects each computer to two neighbors in a closed loop, which is easy to install and troubleshoot but can be disrupted by a single failure.
• 🚧 The bus topology, now rarely used, connects devices to a single cable backbone and requires terminators at both ends to prevent signal reflection.
• 🔄 Mesh topology provides high redundancy with each device connected to every other device, but it can be expensive due to the extensive cabling and network cards required.
• 🌐 The internet is an example of a mesh topology, with numerous routers worldwide ensuring data rerouting in case of failures.
• 📡 Infrastructure wireless topology combines wired and wireless devices, with a wireless access point acting as a bridge between the two types of networks.
• 💡 Ad hoc wireless topology is a simple, peer-to-peer network without relying on infrastructure, useful for quick setups but with each device managing its own security.
• 🌐 Wireless mesh topology is similar to wired mesh but without the need for cables, allowing wireless access points to interconnect and provide seamless internet access with redundancy.
• 🔄 In a wireless mesh, if one access point fails, others will reroute data, ensuring continuous internet access and demonstrating the redundancy of the system.

Q & A

What is a network topology?

A network topology refers to the layout of how a network communicates with different devices, defining the way nodes (e.g., computers, switches) are connected and organize the flow of information.

What are the two main categories of network topologies mentioned in the script?

The two main categories of network topologies mentioned are wired and wireless topologies.

Why is the star topology the most common wired topology?

The star topology is common because it allows all computers to be connected to a central point, such as a hub or switch, making it easy to manage and troubleshoot, though it has a single point of failure.

What is the main advantage of a star topology?

The main advantage of a star topology is that if one computer fails or a cable breaks, the other computers remain unaffected because each has its own cable connection to the central point.

What is the single point of failure in a star topology?

In a star topology, the central hub or switch is the single point of failure. If it fails, all computers connected to it lose network access.

What is a ring topology and how does it differ from a star topology?

A ring topology is a network configuration where each computer is connected to two others, forming a closed loop. Unlike the star topology, the ring topology is rarely used today and if one computer fails, it disrupts the entire network.

Why is the bus topology considered old technology?

The bus topology is considered old technology because it uses a single cable or backbone to which all devices connect, and it requires terminators at both ends. It's less flexible and more susceptible to signal reflection issues compared to modern topologies.

What is the main advantage of a mesh topology?

The main advantage of a mesh topology is its high redundancy level. Even if one or more connections fail, the computers can still communicate with each other through alternative paths.

Why are mesh topologies expensive to implement on local area networks (LANs)?

Mesh topologies are expensive on LANs due to the extensive amount of cabling and network cards required to connect each device to every other device on the network.

How does the internet exemplify a mesh topology?

The internet exemplifies a mesh topology because it consists of numerous interconnected routers worldwide that route data along different paths. This redundancy ensures that even if some routers fail, data will still be rerouted to reach its destination.

What is the purpose of a wireless access point in an infrastructure wireless topology?

In an infrastructure wireless topology, a wireless access point acts as a bridge between the wireless and wired networks, allowing wireless devices to connect to the network via the access point which is connected to the wired infrastructure.

What is an Ad hoc wireless topology and how does it differ from infrastructure wireless topology?

An Ad hoc wireless topology is a simple, peer-to-peer network that does not rely on any infrastructure such as routers or access points. It differs from infrastructure wireless topology in that it does not require a central device or wired infrastructure for devices to connect to each other.

How does a wireless mesh topology differ from a wired mesh topology?

A wireless mesh topology is similar to a wired mesh topology in that devices are interconnected, but the key difference is that the connections in a wireless mesh are established wirelessly, eliminating the need for extensive cabling.

What is the benefit of a wireless mesh topology in terms of redundancy?

A wireless mesh topology offers redundancy because if one or more access points fail, the other access points can reroute the data, ensuring continuous internet access for connected devices.

Outlines

00:00

🔌 Wired Network Topologies Overview

This paragraph introduces the concept of network topologies, explaining that they define the layout of network communication among devices. It covers two main categories: wired and wireless. The star topology is highlighted as the most common wired topology, where all devices connect to a central hub or switch, ensuring that a single device's failure does not impact the network. However, a central hub's failure can cause a network-wide outage. The ring topology, where each device is connected in a closed loop, is mentioned as being easy to install but vulnerable to a single point of failure. The bus topology, an older technology, is described as cost-effective but requiring careful termination to avoid signal reflection issues. Lastly, the mesh topology is introduced, offering high redundancy through multiple connections between devices but is noted for its high cost and limited use in local area networks due to the extensive cabling required.

05:03

📡 Wireless Network Topologies Explained

The second paragraph delves into wireless network topologies, starting with the infrastructure topology, which combines wired and wireless devices and operates similarly to the star topology, with a wireless access point bridging the wireless and wired networks. This setup can be scaled with multiple access points. The ad hoc topology is described as a simple, peer-to-peer network without the need for infrastructure, where devices are directly responsible for security. It's ideal for quick, temporary network setups. The wireless mesh topology is compared to its wired counterpart, with devices interconnected wirelessly, allowing for a seamless and redundant internet connection across multiple access points. This setup eliminates the need for extensive cabling and can automatically reroute data if an access point fails, ensuring continuous connectivity.

Keywords

💡Network Topologies

Network topologies refer to the architectural arrangement of interconnected devices within a network. They define the way data flows and how devices communicate with each other. In the video, various types of network topologies are discussed, each with its own advantages and disadvantages, to illustrate the different ways a network can be structured to meet specific needs.

💡Star Topology

Star topology is a common network configuration where all devices are connected to a central hub or switch. It is highlighted in the script as a topology where data passes through the central point to reach its destination. The script mentions the advantage of isolation in case of device failure, but also the disadvantage of a single point of failure with the central hub or switch.

💡Ring Topology

Ring topology is a network layout where each device is connected to two neighbors, forming a closed loop. The script explains that data packets are sent around the ring until they reach their final destination. It is noted for its ease of installation and troubleshooting but has the disadvantage of being disrupted if one device fails or there is a break in the cable.

💡Bus Topology

Bus topology is an older network setup where all devices connect to a single cable or backbone, typically a coaxial cable. The script describes the use of special connectors called BNC or T-connectors for this topology. It is noted for its cost-effectiveness and simplicity but has the drawback of requiring terminators at both ends to prevent signal reflection, which can disrupt data flow.

💡Mesh Topology

Mesh topology is characterized by each device being connected to every other device in the network, providing multiple paths for data to travel. The script illustrates this with an example of four computers, each with three connections, resulting in a total of twelve connections. It is advantageous for its high redundancy but can be expensive due to the extensive cabling and network cards required.

💡Infrastructure Wireless Topology

Infrastructure wireless topology combines wired and wireless devices, similar to a star topology, with wired devices connected to a switch and a wireless access point also connected to the same switch. The script explains that the wireless access point acts as a bridge for wireless devices to connect to the network, and it can be scaled with multiple access points as needed.

💡Ad hoc Topology

Ad hoc topology is a simple wireless network setup that does not rely on any infrastructure such as cables, routers, or access points. The script describes it as a peer-to-peer network where devices connect directly to each other without a centralized device. It is useful for quickly setting up a wireless network without the need for existing infrastructure.

💡Wireless Mesh Topology

Wireless mesh topology is similar to wired mesh but with devices interconnected wirelessly. The script provides an example of deploying multiple wireless access points throughout a building, where each access point communicates with others to provide a seamless internet connection. It is highlighted for its redundancy and ability to reroute data if one or more access points fail.

💡Single Point of Failure

Single point of failure refers to a critical component in a system whose failure can cause the entire system to fail. In the context of the video, it is mentioned in relation to star and ring topologies, where the central hub or switch, or a single break in the ring, can cause the entire network to go down.

💡Redundancy

Redundancy in network topology refers to the presence of backup connections or paths that ensure the network can continue to operate even if one or more components fail. The script discusses this in the context of mesh topology, where multiple connections prevent a single failure from disrupting the entire network, and in wireless mesh, where access points reroute data to maintain connectivity.

💡Signal Reflection

Signal reflection is a phenomenon that occurs in certain network topologies, such as bus topology, when a signal encounters an impedance mismatch, causing it to bounce back. The script explains that in bus topology, if terminators are missing or loose, the cable would be open, and the signal would reflect, disrupting data flow.

Highlights

Network topologies are the layout of how a network communicates with different devices.

There are wired and wireless topologies.

Star topology is the most common wired topology, with all computers connected to a central point like a hub or switch.

In a star topology, if one computer fails or a cable breaks, other computers are unaffected due to individual cable connections.

Star topology has a single point of failure with the central hub or switch. If it fails, the entire network goes down.

Ring topology connects each computer to two neighbors in a closed loop, but is rarely used today.

Ring topology is easy to install and troubleshoot, but if one computer fails or a cable breaks, data flow is disrupted.

Bus topology is an old technology where computers connect to a single cable backbone using BNC connectors.

Bus topology is cheap and easy to implement, but requires cable termination at both ends to prevent signal reflection.

Mesh topology connects each computer to every other computer, providing high redundancy and handling failures well.

Mesh topology is expensive due to the amount of cabling and network cards required, and is mainly used in wide area networks like the internet.

The internet is an example of a mesh topology with numerous interconnected routers routing data to their intended destination.

Infrastructure wireless topology combines wired and wireless devices, similar to a star topology with a wireless access point.

Ad hoc wireless topology is a simple, peer-to-peer network without relying on infrastructure like routers or access points.

Ad hoc networks are useful for quickly setting up a wireless network where devices can share data without an existing network.

Wireless mesh topology is similar to wired mesh, with devices interconnected wirelessly, providing redundancy and seamless internet access.

In a wireless mesh, each access point communicates with others to relay connections, allowing internet access no matter which point is connected.

A wireless mesh is very redundant as the internet connection is spread over many access points, and can reroute data if some points fail.

Transcripts

What are network topologies?

So that's what we re going to discuss in this video.

Now a topology is the layout of how a network communicates with different devices.

And there are a couple of different categories of topologies There's wired and wireless.

So we're first going to talk about the most common wired topologies.

And the most common wired topology that's used is the star topology.

In a star topology, all computers are connected to a central wiring

point, such as a hub or a switch.

All data on a star network passes through this central point before continuing

to its destination.

One of the major benefits of this topology is

that if one computer failed or if there was a break in the cable

the other computers would not be affected because each computer has their own cable connection.

However a disadvantage of the star topology is that if

the central hub or switch fails, then all the computers on

that central point would be affected.

This is called a single point of failure.

If this happens the entire network goes down.

Another type of topology is called ring.

The ring topology is a type of network configuration where each computer is connected to each other

in the shape of a closed loop or ring.

So every computer on this ring has exactly two neighbors for communication purposes. purposes.

Each data packet is sent around the ring until it reaches its final destination.

This kind of topology is rarely used today.

The advantage of a ring topology is that they are easy to install and easy to

troubleshoot.

However, the disadvantage would be, that if just one of

these computers goes down or if there was a single

break in the cable, then all data flow would be disrupted.

And the next on is the bus topology

The bus topology is very old technology and like the ring topology, it not used today that much.

This is the kind of network setup where each of the computers and network devices,

are connected to a single cable or backbone.

and this backbone is a coaxial cable.

The computers connect to this cable using special

connectors called BNC, which are also known as T connectors.

One of the advantages of the bus topology is that it is also fairly cheap and easy to implement.

However, a disadvantage of the bus topology is that it

requires that the cable is terminated at both ends using terminators.

In order for this setup to remain operational, there must not be any open connections,

including the ends that attach to the computers.

So if a computer is removed or if the terminators

are loose or missing, then the cable would be

open and data would bounce back.

This bounce is known as signal reflection, and if this happens data

flow would be disrupted.

There is also the mesh topology.

In a mesh topology, each computer on the network is connected

to every other computer on the network.

So by having so many connections it handles failure very well.

In this illustration there are 4 computers

with 3 connections on each computer, which makes

a total of 12 connections for this network.

The advantage of a mesh topology is that it creates a high redundancy level.

Because if one or more connections fail, the computers would

still be able to communicate with each other.

But because of the amount of cabling and network cards that have

to be used, mesh topologies can be expensive, so

they are rarely used on local area networks or LANs.

They are mainly used on wide area networks, like the internet.

In fact, the internet is a good example of a mesh topology.

Because the internet is made up of numerous routers, all over the world that are

Connected to each other to route data to their intended desintation.

So even if a few routers go down, the data will get rerouted using a different path to

ultimately reach their destination.

So the internet is very redundant because it s using a mesh topology.

So now we re going to talk about wireless topologies.

So let s start with infrastructure wireless topology.

This topology uses a combination of wired and wireless devices.

This is very similar to a star topology, where you have wired devices, such as these

computers here, physically connected to a switch. And you also have a wireless access

point that's also connected by a cable to same switch.

The wireless access point is here so that wireless devices, such as laptops, tablets,

cell phones, etc, can connect wirelessly to the network.

So the wireless access point acts like a bridge between the wireless network and the wired

network.

Now the infrastructre topology is not limited to a single wireless access point..in fact

you can have multiple wireless access points if you want .it just depends on the needs

of the network.

The next wireless topology is Ad hoc.

Ad hoc is a very simple wireless topgology.

It s simple because it doesn t rely on any infrascture, such as cables, routers, servers,

or wireless access points.

All the devices in an ad hoc network, wirelessly connect to other devices in a simple peer

to peer network.

They directly connect to each other without using a centralized device, such as a wifi

router or access point.

And because they directly access each other without a server or router in between, each

device is responsible for its own security and permissions.

Ad hocs are useful for setting up a quick wireless network on the fly, where devices

can share data without the need of an existing wireless network.

And the last wireless topology is called a wireless mesh.

Wireless mesh topologies are similiar to wired mesh topologies, where devices are interconnected

with each other, but with the exception that they are wirelessly interconnected.

So for example, let's say you wanted to deploy multiple wireless access points all throughout

a building so that wireless devices that are in different areas are able to access the

internet.

So normally you would have a modem that brings in the internet to the building, and then

you would have a switch that's connected to the modem.

And then you would connect each wireless access point with a cable to the switch.

So by doing it this way, this requires extra cabling and it would also require extra time

running the cables through the building.

So this is more expensive and more time consuming.

Now a wireless mesh topology would be similiar to this setup, but without the need of these

extra cables.

In a wireless mesh, each wireless access point with talk to other wireless access points

to create a seamless internet connection for wireless devices to connect to. So if this

laptop over here wanted to access the internet, it would connect to the nearest wireless access

point and then this access point will would relay the connection to the next access point

and then the next one and eventually find its way back to the modem.

So no matter which access point that you re connected to, you will have internet access

because all the access points are in constant communication with each other and the modem.

And even if one or more access points were to fail, it wouldn t matter, because the other

access points will reroute the data.

So a wireless mesh topology is very redundant...because the internet connection is spread out over

many wireless access points.