Networks

Question 1

What is the computer network?

Answer 1

Two or more computer devices linked together to communicate and share resources and data. A network can be wired or wireless

Question 2

What are the ways a device/network connects to other networks?

Answer 2

• Routers and switches • Network interface cards • MAC address • Ethernet • Packet

Question 3

What does a router do?

Answer 3

It is used to route data between two distinct networks. Usually between LAN and WAN

Question 4

What does a switch do?

Answer 4

Used to connect devices on the same LAN together. Knows MAC address of each device on the LAN and only sends packets to the intended recipient

Question 5

What do Network Interface Cards do?

Answer 5

They are required to connect a device to a network. Can be wired or wireless. Includes a MAC address built in

Question 6

What does MAC stand for?

Answer 6

Media Access Control

Question 7

What does the MAC address do?

Answer 7

Unique address for each network interface card. Set at the factory. Made up of 48 bits, shown as 12 hexadecimal characters - each pair is separated by a colon. First 6 characters identify the manufacturer. Next 6 characters identify the unique device

Question 8

What is the difference between the internet and the world wide web?

Answer 8

The world wide web is web pages - it is a subset of the internet

Question 9

What is the internet?

Answer 9

A universe-wide system of computer networks. A network of networks. A wide area network

Question 10

What is the world wide web?

Answer 10

It is a combination of all resources and users on the internet that are using the Hypertext Transfer Protocol (Secure) HTTP/HTTPS. This includes all webpages you visit via a web browser

Question 11

What is a star network?

Answer 11

A network where all computers have their own cable to a network switch. If a link fails, all other computers are not affected. It has consistent performance. Good for security. Expensive to implement. Single point of failure (switch)

Question 12

What is a bus network?

Answer 12

All computers connected to a single cable. Very cheap to implement. More computers mean slower performance

Question 13

What is ethernet?

Answer 13

A family of protocols for computers to transmit between each other on the same LAN. Nodes wait until the network is quiet, then transmit. If a conflict occurs, try again in a random amount of time. Transmits data in small chunks called frames - similar to packets

Question 14

What is packet switching?

Answer 14

Packet switching involves splitting up data into small packets. These are sent from A to B via the best route, which isn’t necessarily the same route

Question 15

What is a network protocol?

Answer 15

A set of rules that allows computers to communicate and exchange information over a network

Question 16

What is internet protocol (IP)?

Answer 16

IP identifies the location (the internet location, not the geographical location) of a device on the internet. IP then can be used to route from A to B via a router. IP addresses are 32 bits long. It is 4 numbers from 000-255 separated by dots

Question 17

What is TCP?

Answer 17

Transmission Control Protocol. It is used when data is required to make it to the recipient. TCP splits data up into packets and reassembles them at the other end. If any packet goes missing with TCP, it will be resent

Question 18

What is UDP?

Answer 18

User Datagram Protocol. It is much simpler than TCP, as it is a send and forget approach - No error checking or checking the datagram was received. Used for video calls and gaming

Question 19

What is HTTPS?

Answer 19

HyperText Transfer Protocol Secure. Used to transfer HTML web pages on the world wide web. It transfers from a web server to a web browser. HTTPS uses encryption to secure the connection

Question 20

What is FTP?

Answer 20

File Transfer Protocol. A simple protocol for transferring files from an FTP server to a computer. Not used anymore. Uses 2 connections - control connection is used to send the instructions, data connection is used to send the requested file data

Question 21

What are the two protocols in email?

Answer 21

SMTP - sending emails. IMAP - retrieving email from mail server to client

Question 22

How does email work?

Answer 22

Email is sent between email servers, with email clients then requesting these emails from the email server

Question 23

What is SMTP?

Answer 23

Simple Mail Transfer Protocol. It is used only for sending emails. It is also used to relay mails between different mail servers

Question 24

What is IMAP?

Answer 24

Internet Message Access Protocol. It is used to access emails stored on a mail server. Emails remain on the server until deleted so multiple devices can use a single email account. It replaces the POP3 protocol

Question 25

What is the application layer?

Answer 25

It contains application protocol information. This includes HTTP/S for web browsers, FTP for file transfer and SMTP/IMAP for email. The application layer directly interacts with the user software like a web browser or email client

Question 26

What is the transport layer?

Answer 26

It is the TCP/UDP layer. It is the layer involved with breaking up the data into packets/datagrams. It adds packet sequence numbers. It establishes configuration such as language and packet sizes. It sets up the communication between the devices

Question 27

What is the internet layer?

Answer 27

Responsible for addressing and routing information to get the packet across the internet. It adds IP addresses to the packets, and routes the packets across the internet/network

Question 28

What is the link layer?

Answer 28

It is physical network hardware like NICs. It adds MAC addresses. It is where operating device drivers operate

Question 29

What are network security goals?

Answer 29

To keep unauthorized users out of a system and ensure authorized users can only access the required resources that they need

Question 30

What are network security methods?

Answer 30

Authentication, Encryption, MAC Address filtering, Firewall

Question 31

What is authentication?

Answer 31

The need to confirm a user is who they say they are. It is often something you know, something you have or something you are

Question 32

What are 2 methods of authentication?

Answer 32

Password protection and user access levels

Question 33

What is password protection and why do we use it?

Answer 33

In a networked environment, computers can be used by multiple people, so a username and strong password (with numbers, symbols, and at least 8 characters) is used

Question 34

What are user access levels?

Answer 34

User access levels involve locking down files so only some users can access them. They can also involve making folders read-only. If a user account is breached, the attack surface is minimized

Question 35

What is encryption?

Answer 35

Scrambling "plain text" data so unreadable without the required key if intercepted

Question 36

What is a firewall?

Answer 36

A network security device that monitors incoming and outgoing traffic and regulates it based on a defined set of security rules e.g. Blocking certain IP addresses

Question 37

What is MAC address filtering?

Answer 37

Using MAC addresses to "ban" certain devices from a wireless network.

Question 38

What are the 4 network layers

Answer 38

ATIL

Question 39

What are the 2 advantages and 3 disadvantages of copper cables?

Answer 39

Uses electrical signals + Cables cheap to buy + NICs are cheap to produce (E10) - Reasonable maximum bandwidth (10gbit/s) - Max length around 90m - Can be affected by electrical interference

Question 40

What are the 2 advantages and 3 disadvantages of fibre-optic cables?

Answer 40

Uses light pulses - Cables expensive to buy - NICs are expensive to produce (£150+) + Very high maximum bandwidth (1tbit/s+) + Max length around 100km + Can't be affected by interference