1.3 - wired and wireless networks

Question 1

pros of wired networks

Answer 1

reliable
faster
not subject to interface
more secure

Question 2

cons of wired networks

Answer 2

not portable
more expensive
installation requires technical knowledge

Question 3

Pros of wireless network

Answer 3

cheap and easy to install

Question 4

Cons of wireless network

Answer 4

Limited in range
Subject to magnetic interference
Walls block them

Question 5

What is bluetooth

Answer 5

Form of wireless communication that enables different devices to connect. It works like a small private network between two devices, allowing them to share data and documents.

Question 6

Bluetooth vs WiFi

Answer 6

Wifi uses a WAP to connect to a network to communicate with other devices. Multiple devices access the one point.
Bluetooth uses a direct network connection to another device e.g. headphones, speakers, printer. It has shorter range than WiFi
Similarities – both use radio waves

Question 7

What is encryption

Answer 7

The process of disguising a message so that it cannot be understood by anyone but its intended recipient. Encryption requires the use of a key. The key is secret as to how the message has been disguised.

Question 8

What are encrypted and unencrypted data known as

Answer 8

Cipher text and plaintext

Question 9

How does Caesar cipher work

Answer 9

The cipher works by giving a number value to a key. Each plaintext letter is replaced by a new letter, the one found at the original letter’s position in the alphabet plus the value of the key.

Question 10

Public and private keys

Answer 10

A public key can be given to anyone. Anyone can then use this key to encrypt a message. However, the public key cannot decrypt a message - only the second key (the private key) can do that. So long as the private key is never given out, messages will stay safely encrypted.

Question 11

What is IP addressing

Answer 11

When connected to a network each device is given a unique IP address. This address consists of four sets of up to three digits, each with a maximum value of 255, which are separated by dots. When a node wants to send a message to another node, it uses the recipient node’s address as the destination. A switch on the network knows where the node with this address is and routes the message to it accordingly.

Question 12

Static vs dynamic IP addresses

Answer 12

A node with a static address always remains the same. A node with a dynamic address has a new one assigned each time it connects to the network

Question 13

What is MAC addressing

Answer 13

A unique serial number assigned to each
network interface controller (NIC). This allows a network to uniquely identify any device. A MAC address consists of a string of hexadecimal numbers and it can not be changed

Question 14

What is TCP/IP

Answer 14

Transmission Control Protocol/Internet Protocol - enables communication over the internet.

Question 15

What is HTTP and HTTPs

Answer 15

Hypertext Transfer Protocol - governs communication between a webserver and a client. HTTPS (secure) includes secure encryption to allow transactions to be made over the internet.

Question 16

What is FTP

Answer 16

File Transfer Protocol - governs the transmission of files across a network and the internet.

Question 17

What is SMTP

Answer 17

Simple Mail Transfer Protocol - governs the sending of email over a network to a mail server.

Question 18

What is POP and IMAP

Answer 18

Post Office Protocol and Internet Message Access Protocol - govern retrieving emails from email servers. POP is an older implementation, largely replaced by IMAP.

Question 19

Encryption in use

Answer 19

• purchases made online are encrypted to try to prevent theft of credit card details
• tools enable a user to encrypt a document, such as a spreadsheet, before sending it to a colleague via the internet
• satellite TV transmissions are encrypted to prevent users who are not subscribed from watching TV shows

Question 20

What is network layering

Answer 20

Breaking up the sending of messages into separate components and activities. Each component handles a different part of the communication.

Question 21

4 networking layers

Answer 21

Application layer
Transport layer
Network layer
Link layer

Question 22

What is the application layer

Answer 22

encodes/decodes the message in a form that is understood by the sender and the recipient

Question 23

What is the transport layers

Answer 23

breaks down the message into small chunks (packets). Each packet is given a packet number and the total number of packets. The recipient uses this information to assemble the packets together in the correct order. It also allows the recipient to see if there are any missing packets.

Question 24

What is the network layer

Answer 24

adds the sender’s IP address and that of the recipient. The network then knows where to send the message, and where it came from.

Question 25

What is the link layer

Answer 25

enables the transfer of packets between nodes on a network, and between one network and another.

Question 26

What does layering allow

Answer 26

standards to be developed, but also to be adapted to new hardware and software over time.

Question 27

Drawbacks of bluetooth

Answer 27

is limited in transmission speed and range