Networking

Question 1

Define Topology

Answer 1

Different arrangements of computer connections and devices

Question 2

Describe a bus topology

Answer 2

A central cable is used to connect all the devices with terminators at the end of the cable so the signal doesn’t bounce back

Question 3

What is a backbone?

Answer 3

The central cable in a bus topology

Question 4

How does a bus topology send signals?

Answer 4

A signal is sent via the main cable which reaches all the the connected devices

The signal contains a destination address to identify the recipient and a source address to identify the sender

MAC address are hardcoded in the Network Interface Controller of each device

Devices must detect if they are transmitting at the same time so they can stop to avoid collision

Question 5

What is the disadvantages of bus topology?

Answer 5

A bus setup doesn’t allow 2 computers to transmit at the same time as it causes collisions

When network is in heavy use, the overall performance decreases as collisions increase

If the main cable breaks it brings the whole network to a stop

Devices can eavesdrop on each other

Question 6

Define Mac address

Answer 6

Media Access Control address- An address given to a network interface controller used to uniquely identify devices on a local network

Question 7

Define NIC

Answer 7

Network Interface Controller- A component that allows a device to connect to a network

Question 8

What’s Ethernet?

Answer 8

A bus topology with a coaxial cable as the backbone
All the computers are connected by a special interface cable which plugged into a NIC connecting the computer and the cable

Question 9

The ethernet protocol

Answer 9

Includes the CSMA/CD rules and the need to send destination and recipient MAC addresses
Specifies the structure of the data sent via hardware

Question 10

What’s an ethernet frame?

Answer 10

A blue print for the structure of data, it has 5 different fields for the pieces of information needed for transmission

Question 11

What are the 5 fields of an ethernet frame?

Answer 11

Data transmitted
Destination address
Source address
Type field
FCS (Frame check sequence)

Question 12

What is the FCS?

Answer 12

Frame Check Sequence- Used to detect whether errors have occurred during transmission

Question 13

What is a UTP (ethernet) cable?

Answer 13

Unshielded Twisted Pair cable, a type of cable where two conductors are twisted together to reduce interference

Question 14

Explain a Star topology if the central device is a hub

Answer 14

A UTP cable connects each computer to a central device (e.g. a hub) which sends signals to all the computers

Each cable acts like a bus network as the hub has no understanding of what the signals mean

Question 15

What’s a Switch?

Answer 15

A network computer that is used to connect devices on a LAN, it learns which device is connected to each port so it can direct traffic

Question 16

Explain a Star topology if the central device is a switch

Answer 16

A UTP cable connects each computer to a central device (e.g. a switch) which sends signals to all the computers

The switch learns the address of each device connected to its ports by looking at source MAC addresses.
It builds a table mapping each port-device connection so it can direct incoming data to a specific device
If an unknow destination address is sent it defaults to hub behaviour

Question 17

What’s needed for a client- server network

Answer 17

A central powerful computer (server)

Client computers

Question 18

Define server

Answer 18

A computer on a network that provides resources to be used by authorised clients

Access level granted by the server is controlled by the handler

Question 19

Explain Web servers

Answer 19

The most common type of server

Store and provide webpages

Question 20

What’s a client?

Answer 20

A computer or computer controlled device that provides user access to a network

They run software to make requests to servers then interpret/display the response

They send requests to the server which processes it and returns it

Question 21

What is client-sever networking used for?

Answer 21

Web services, game hosting and private networks

Question 22

How does peer-peer networking work?

Answer 22

No central server

All computers have equal roles & access rights

They share portions of their resources

Network security & resource management is not controlled centrally so backs have to occur locally

Question 23

What is peer-peer networking used for?

Answer 23

LANs, file sharing networks

Question 24

What is a wireless security protocol?

Answer 24

A set of rules specific to wireless communication

Question 25

WEP
how it works
pros
cons

Answer 25

Wired Equivalent Privacy
Designed to have the same security as a wired network
Uses symmetric encryption (same key to en and de -crypt)
Sufficient for first line of defence
WEP keys are too short & used for too long
Keys are easy to decipher

Question 26

WPA
how it works
pros
cons

Answer 26

WiFi Protected Access

Temporary improvement to WEP

Introduced key management
Generates a new encryption key for each packet
Keys are larger

Question 27

WPA2
how it works
pros
cons

Answer 27

WiFi Protected Access 2

An improvement on WPA that provides a stronger encryption algorithm

Question 28

What is an SSID

Answer 28

Service Set Identifier

A string of alphanumeric characters specified during the setup of wireless devices

Question 29

How do SSIDs work?

Answer 29

Broadcast for all to see

Passwords are often used to allow devices to connect

Question 30

What are the 2 most common frequencies for WiFi?

Answer 30

2.4GHz

5GHz