Section 1: Overview of Networks (10.2.1)

What is a network?

A group of two or more connected devices/nodes that can communicate and share resources.

Node

A node is any device that is connected to a network and can:

Send

Receive

Or Process data

Client

A client is a computer or device that requests and receives resources or services from a server.

Workstation

A workstation is a computer used by a person to perform tasks on a network

Can the same computer be both a client and a server?

Yes. A device’s role depends on whether it is requesting or providing a service.

Server

A server is a computer or device that provides services or resources to clients on a network

Give examples of services a server can provide

1. File Sharing ( provides access to files)

2. Authentication (verifies user’s identities)

3. Email services (manages email services)

4. Web hosting (provides websites to users)

Switch

A switch is a networking device that:

1. Connects devices within the same network

2. And forwards data to the intended device.

What type of address does a switch primarily use to identify devices?

A MAC address

Router

A router is a networking device that

1. connects different networks and

2. forwards data packets between them.

What type of address does a router use to determine where packets should be sent?

An IP adress.

What is a firewall?

A firewall is a security system the monitors and filters network traffic according to predefined rules

What is the purpose of a firewall?

To help protect a network by:

Blocking unauthorised or potentially harmful traffic whil

Allowing legitimate traffic

What is a NIC?

A NIC is a hardware component that allows a device to connect to a network

What is a Bridge?

A bridge is a networking device that connects two or more network segments and forwards data between them

What is Bounded Media?

Bounded media is a method of transmitting data where:

The signal travels through a physical cable or wire between devices.

What does UTP stand for?

Unshielded twisted pair

What is UTP?

UTP is a network cable consisting of pairs of insulated copper wires that are twisted AROUND each other to reduce interference.

Why are the wires in UTP twisted?

To reduce interference such as crosstalk and EMI

Advantages of UTP

1. Relatively inexpensive

2. Easy to install

3. Flexible

4. Widely used in LANS

Disadvantages of UTP

1. More susceptible to interference such as EMI and crosstalk than fibre

2. Has a more limited transmission distance (100m)

3. Generally has a lower bandwidth than than fibre

What is fibre optic cable

Fibre optic cable is a network cable that transmits data as pulses of light through thin stands of glass and plastic fibre

What type of signal does fibre-optic cable use?

Light signals/pulses

Advantages of fibre

1. Higher bandwidth than UTP

2. High data-transfer speeds

3. Can transmit signals over long distances

4. Less susceptible to EMI

5. More difficult to intercept than copper cables

Disadvantages of fibre-optic cable

1. More expensive than UTP

2. More difficult to install and repair

3. Fibre is less flexible/ more fragile than copper cabling

What is unbounded media

Unbounded media is a method of transmitting data where signals travel through air or space, often over long distances

What are microwaves

Microwaves are high-frequency electromagnetic waves that can transmit data WIRELESSLY over long distances

Advantages of microwaves

1. Can transmit over long distances

2. Does not require physical cables

3. Can provide relatively high data rates

Disadvantages of microwaves

1. There needs to be line of sight between the transmitting and receiving antennas

2. Buildings, terrain and other obstacles can interfere with the signal

3. Weather can affect some microwave link

What is a PAN ?

A personal area network is a network that connects devices within a very small area around an individual, typically within a few metres.

Give examples of a PAN

1. A phone connected to wireless buds

2. A phone connected to a smartwatch

3. A laptop connected to a Bluetooth mouse

What is a LAN ?

A local area network is a network that connects devices within a limited geographical area, such as a home,school,office or building.

Give examples of a LAN

1. School network

2. Home network

3. Office network

What is a WAN?

A Wide area network is a network that connects multiple networks across a large geographical area, such as:

• cities

• countries

• Or continents

How can a WAN relate to LANS?

A WAN can connect multiple LANs over a large geographical area

What is a GAN?

A Global area network is a network that connects networks across the entire world.

Examples of a GAN

1. A multinational company can use a GAN to connect its offices around the world

2. The Internet