Components of a Computer Network

Summary

This computer networks course segment introduces the three core components: nodes, media, and services. Nodes include end devices like computers and smartphones, and intermediary devices such as routers and switches. Media refers to wired (e.g., Ethernet, fiber optic) and wireless (e.g., microwaves, radio waves) links for data transmission. Services cover a range of functionalities like email, file sharing, and web access, highlighting the network's role in facilitating communication and data exchange.

Takeaways

• 💻 A computer network consists of three main components: nodes, media, and services.
• 🌐 Nodes can be either end nodes, which initiate or terminate communication, or intermediary nodes that facilitate data transfer.
• 🖨️ Examples of end devices include computers, printers, and smartphones, while intermediary devices include switches, routers, and cell phone towers.
• 📡 Intermediary nodes forward data from one node to another without modifying the data.
• 📡 Media, also known as links, can be either wired (like Ethernet or fiber optic cables) or wireless (like radio waves or microwaves).
• 🔌 Wired media use physical cables to connect devices, while wireless media use air as the medium for data transmission.
• 🌐 Different types of wired media include Ethernet, fiber optic, coaxial, and USB cables, each with specific uses and characteristics.
• 📶 Wireless media use various types of waves such as infrared, radio, microwaves, and satellite waves for communication.
• 🌐 Services provided by computer networks include email, file sharing, instant messaging, voice-over IP, video calls, and internet access.
• 🌐 The script provides a comprehensive overview of computer network components, emphasizing the importance of each in facilitating communication and data transfer.

Q & A

What are the three main components of a computer network?

The three main components of a computer network are Nodes, Media, and Services.

What is a node in a computer network?

A node in a computer network is any device that can send, receive, or both send and receive data. Nodes can be categorized as end devices or intermediary devices.

Can you give examples of end devices in a computer network?

Examples of end devices include computers, network printers, Voice-over IP (VoIP) phones, telepresence endpoints, security cameras, smartphones, tablets, personal digital assistants, wireless debit/credit card readers, and barcode scanners.

What are intermediary devices, and can you provide examples?

Intermediary devices forward data from one node to another and are placed between end devices. Examples include switches, wireless access points, routers, firewalls, bridges, hubs, repeaters, and cell phone towers.

What is the role of media in a computer network?

Media, also known as the link, carries data from one node to another. It can be either a wired medium (cable) or a wireless medium (air).

What are the differences between wired and wireless media?

Wired media involves cables (guided medium), while wireless media does not use cables and transfers data through waves (unguided medium). Wired media includes Ethernet cables, fiber optic cables, coaxial cables, and USB cables. Wireless media includes infrared, radio waves, microwaves, and satellite communication.

What is an Ethernet cable, and how is it used?

An Ethernet cable is a twisted-pair cable used to connect devices in a wired network. There are two types: straight-through cables for connecting different devices (e.g., a computer to a switch) and crossover cables for connecting devices of the same type (e.g., two routers).

How does fiber optic cable differ from other wired media?

Fiber optic cables transmit data as light waves, making them much faster than other types of cables like Ethernet or coaxial, which use electrical signals. Fiber optic cables are the fastest form of wired communication.

What are the four types of wireless media mentioned in the transcript?

The four types of wireless media mentioned are infrared waves, radio waves, microwaves, and satellite communication. Infrared is used for short-range communication (e.g., TV remote), radio waves for medium-range (e.g., Wi-Fi, Bluetooth), microwaves for long-range (e.g., cellular systems), and satellite communication for very long-range communication (e.g., GPS).

What services can be provided by a computer network?

Computer networks provide services such as email, file sharing, instant messaging, online gaming, voice-over IP (VoIP), video calls, and web browsing (accessing websites).

Outlines

00:00

🖥️ Introduction to Computer Network Components

This segment introduces the fundamental components of a computer network, which include nodes, media, and services. Nodes are devices that can send, receive, or both send and receive data, and they can be either end nodes or intermediary nodes. End nodes initiate or terminate communication, such as computers, printers, and mobile devices, while intermediary nodes, like switches and routers, facilitate data transfer between end nodes. The lecture also covers various end and intermediary devices, emphasizing their roles in network communication.

05:02

🌐 Exploring Wired and Wireless Media in Networks

This section delves into the concept of media, also known as links, which are responsible for carrying data between nodes. Media can be either wired or wireless. Wired media, such as Ethernet, fiber optic, coaxial cables, and USB, use physical connections to transmit data in the form of electrical or light signals. The segment explains the differences between straight-through and crossover Ethernet cables and their applications. Wireless media, conversely, uses air as a medium for data transmission without physical cables. It discusses various types of wireless media, including infrared, radio waves, microwaves, and satellite waves, each with different communication ranges and applications, such as Wi-Fi, Bluetooth, and GPS.

Keywords

💡Nodes

Nodes are integral components of a computer network that can either send, receive, or both send and receive data. In the context of the video, nodes are categorized into end nodes and intermediary nodes. End nodes are the starting or ending points of communication, such as computers, smartphones, and printers, while intermediary nodes facilitate data transfer between end nodes, including devices like routers, switches, and cell phone towers. The script uses these examples to illustrate how nodes function within network communication.

💡Media

Media, also referred to as the link in the video, is the pathway that carries data across a network. It is categorized into wired and wireless media. Wired media, such as Ethernet cables and fiber optic cables, physically connect devices through cables, whereas wireless media uses air as the medium for data transmission, as seen with technologies like Wi-Fi and cellular networks. The video script explains that media is essential for transmitting data from one node to another in a network.

💡Services

Services in the context of computer networks refer to the various functions and utilities provided by the network to users. The video outlines services such as email, file sharing, instant messaging, and internet access. These services are made possible by the underlying network infrastructure and are central to how users interact with and benefit from computer networks. The script emphasizes the diversity of services, highlighting their significance in daily digital activities.

💡End Nodes

End nodes are the devices that initiate or terminate communication within a network. Examples given in the script include computers, network printers, and smartphones. These nodes are crucial as they are the direct interaction points for users, representing the source and destination of data transmission in a network.

💡Intermediary Nodes

Intermediary nodes are devices that assist in the transfer of data between end nodes without being the origin or destination of the data. As explained in the script, examples include switches, routers, and wireless access points. These nodes play a critical role in routing and managing the flow of data across a network.

💡Ethernet Cable

An Ethernet cable is a type of wired medium used to connect devices within a network. The video script distinguishes between two types of Ethernet cables: straight-through and crossover. Straight-through cables are used to connect different devices, while crossover cables are used for connecting similar devices, such as two computers or two routers.

💡Fiber Optic Cable

Fiber optic cables are a high-speed wired medium that transmit data using light waves. The video script highlights their speed advantage over other wired media, making them ideal for high-bandwidth applications. They are typically used in scenarios requiring fast data transfer over long distances.

💡Coaxial Cable

Coaxial cables, as mentioned in the script, are commonly used for audio and video communication, such as connecting a television to a cable box. They carry data as electrical signals and are a type of wired medium, though they are not as fast as fiber optic cables.

💡Wireless Media

Wireless media refers to the transmission of data without the need for physical cables. The script explains that wireless communication can occur through various means, including infrared, radio waves, microwaves, and satellite waves. Each method has its use cases, ranging from short-range communication like infrared to long-range communication like satellite waves.

💡Guided Medium

A guided medium, as the term is used in the script, refers to wired media that uses physical cables to direct the flow of data. This is in contrast to unguided media, which pertains to wireless media. The video emphasizes that guided media, such as Ethernet and coaxial cables, provide a direct and often reliable means of data transmission.

💡Unguided Medium

Unguided medium, as explained in the script, is a term used to describe wireless media where data is transmitted through air or space without the use of physical cables. Examples include Wi-Fi and cellular networks, which use radio waves to transmit data over distances without the need for a direct physical connection.

Highlights

Introduction to the components of a computer network.

Understanding of nodes, media, and services in computer networks.

Definition and role of nodes in computer networks.

Explanation of end nodes and intermediary nodes.

Examples of end devices in a computer network.

Examples of intermediary devices and their functions.

Introduction to media in computer networks.

Difference between wired and wireless media.

Types and examples of wired media.

Detailed explanation of Ethernet cables and their variations.

Description of fiber optic cables and their speed advantage.

Use cases and characteristics of coaxial cables.

Functionality and applications of USB cables.

Introduction to wireless media and communication methods.

Examples of wireless communication technologies and their ranges.

Practical scenario involving both wired and wireless media.

Introduction to the services offered by computer networks.

Examples of services like email, file sharing, and internet access.

Summary of the session covering nodes, media, and services.

Transcripts

Hello everyone,

welcome back to the computer networks course.

And today we will see the various components of a computer network.

Upon the completion of this session,

we will be able to understand nodes,

we will also understand

what are the different media in computer network,

and what are the various services offered by computer network.

Any computer network has three components

Nodes, Media and Services.

Firstly we will deal with nodes.

We have already seen nodes in detail in the previous lectures.

A node can send or receive or both send and receive the data.

And these nodes can be an end node or an intermediary node.

We can call end nodes as end devices

and intermediary nodes as intermediary devices.

We will first see end nodes.

End nodes are the nodes that is going to be the

starting point in the communication

or the end point in the communication.

If two devices wants to communicate with each other,

the device which initiates this communication

is an end device and the device which accepts the communication

at the final stage is an end device.

And these two end devices are going to communicate

with each other with the help of some intermediary devices.

Let's first see some examples for end devices.

A computer is an end device, network printers,

voice-over IP Phones, telepresence endpoint

(this is mainly for video conferencing), security cameras

and many mobile handheld devices like

smart-phones, tablets, personal digital assistants,

wireless debit or credit card reader,

bar-code scanner and many more.

We are done with end nodes.

Now we will see some examples for intermediary nodes.

Intermediary nodes are nodes that just forwards the data

from one node to another.

In other words, they are going to be placed in between end nodes.

switches, wireless access points,

routers, security devices like firewall,

bridges, hubs, repeaters, cell phone tower, etc.

If you feel any of these terms are new, no worries

we are going to deal elaborately

about all the terms in detail in the upcoming lectures.

There are lot of end devices

and intermediary devices involved in the scenario.

These devices: smart phone, Voice-over IP phone, printers,

these desktop computers, tablet and web servers --

these are all end devices.

Switches, cell phone towers, this wireless router,

these routers and this switch, they are intermediary devices.

We are done with nodes. Now we will move on to the media.

Media -- It is also called as the link.

We know very well that, link is going to carry

the data from one side to the other.

This link or this media can be

a wired medium or a wireless medium.

Some authors refer wired medium as guided medium

and wireless medium as unguided medium.

In wired medium, there will be a cable that connects two nodes

whereas in a wireless medium, cable will not be present.

Since cables are used to guide the data flow,

we call wired medium as guided medium

whereas there is no cable in a wireless medium

and that is why we call wireless medium to be unguided medium.

We will see some examples for

wired medium and wireless medium.

The examples for wired medium are ethernet cables,

fiber optic cable, coaxial cable and USB cable.

We will see each of these cables in detail now.

Firstly, ethernet cable.

This is an example of an ethernet cable.

Ethernet cable is an example of a twisted-pair cable.

I will talk about twisted-pair cable in the upcoming lectures.

For time bring, you just know this is an ethernet cable

and this ethernet cable comes in two variations:

one is ethernet straight-through cable

and ethernet crossover table.

We will see the difference between this

ethernet straight-through cable and ethernet crossover cable.

If we want to connect different devices,

we have to go for ethernet straight-through cable.

In case if we want to connect two devices of same kind,

say two switches or two routers,

or two computers wants to be connected to each other,

then we have to go for ethernet cross-over.

In ethernet cable the data is going to be carried

in terms of electrical signals.

So far we have seen ethernet straight-through cable

and ethernet crossover cable.

Now we will move onto fiber optic cable.

In fiber optic cable, the data is going

to be carried in the form of light waves.

We know very well that light is the fastest one in the world.

Since this cable takes the data in the form of light waves,

this is the fastest mode of wired communication.

Now we will see coaxial cable.

This is an example coaxial cable.

This cable is mainly used for audio or video communication.

We can see this cable in our home.

If you have a set-top box, just go and see this coaxial cable

which connects the dish antenna and the set-top box.

This cable also carries the data in the form of electrical signals.

And coming to USB cable, USB stands for Universal Serial Bus.

This cable is used to connect a computer and a smart phone.

We know very well if we want to connect our computer

to a smart phone, most of us will prefer this cable only.

And we are done with wired medium.

Now we will move onto wireless media.

In wireless media, two or more devices are going to communicate

with each other but without the help of a cable.

Here, air is the medium that carries the data from one node to other.

In wired networks, the data are converted into signals,

maybe electrical signals or light signals.

Whereas in wireless network data are converted into waves.

Coming to the wireless media, we have infrared waves,

radio waves, microwaves and Satellite waves.

Infrared waves are mainly used for short range of communication.

Example: TV remote control.

The wave between the remote control

and the television is an infrared wave.

And if the distance between the TV and the remote control increases,

this communication cannot happen.

Because infrared are used for short range communication.

Coming to the radio wave, the range of this radio wave

is higher than infrared. Bluetooth and Wi-Fi uses radio waves.

The next one is the microwaves. Example: Cellular system.

Our cell phone technology uses microwaves.

Microwaves are used for long distance communication

when compared to radio waves or infrared waves.

And finally, the satellite communication.

And this is ultimately the long distance communication.

Our GPS enabled cell phone gives signal to the satellite

and the location of this device is identified with the help of this signal.

So far we have seen, nodes and media.

Two types of media are addressed:

wired media and wireless media.

This scenario involves both wired media and wireless media.

This straight lines represents ethernet straight-through.

Just recall what are ethernet straight-through cables.

Say a computer with a switch, a switch with a printer,

a switch with a router or wireless router.

But ethernet crossover cables are used

to connect devices of similar type.

Between routers we use only straight-through cables.

Straight lines are ethernet straight-through cables,

and dashed lines are crossover cables.

So this is an example for a wired media.

At the same time our example also uses wireless media.

In this case, between smart phone and cell phone tower

wireless technology is used,

between smart phone and wireless router,

between tablet and wireless router we have wireless technologies.

To be specific, here microwaves are used

because this is a long distance communication.

And here radio waves are used,

because this is a Wi-Fi router and smart device.

So this is a longer distance communication

when compared to this communication.

We will now see the third component of a computer network, services.

We use computer network for sending mails or receiving mails,

storing our data in a remote computer.

Google Drive is an example for storage.

We can share files using computer network,

we can send instant messages like whats-app using computer network,

we can play online games using computer networks,

we can make voice calls using voice-over IP,

we can also do video calls or video conferencing using video telephony,

and we can also use computer network for surfing internet

that is accessing websites.

We have already seen about nodes and media

and the last part here is the services.

This scenario involves many kinds of services.

Suppose if this guy is sending some message

to his friend through whatsapp. So it uses instant messaging.

And two people are talking over voice-over phone,

so here voice communication is happening.

So,voice communication is one of the services of computer network.

If somebody is accessing amazon.com,

so he using www that is the world wide web services.

And there is a file here, if this computer wants this file,

it uses this computer network for getting that file.

So, file sharing is another service depicted in this scenario.

And that's it guys.

We have seen nodes, media and services.

I hope now you are clear with nodes,

different media -- wired media and wireless media

and various services like E-mail, instant messaging,

file sharing, world wide web, voice-over IP etc.

I hope the session is informative.

Thank you for watching.