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| Question | Answer |
| What is the internet? | A collection of inter-connected computer networks. |
| What is the world wide web? | A part of the internet that contains webpages and websites. |
| How many networks were connected to the internet in 1969? | Four Networks |
| How many networks were connected to the internet in 1989? | 100,000 Networks |
| And 2012? | 2.1 Billion Networks |
| Which two devices are needed to connect to the internet? | Modem - Connects you to your ISP Router - Provides access to a LaN |
| What is the modem needed for? | It is needed to convert the digital signal from the computer to an analogue signal used by telephone lines and the modem at the receiving end converts the signal back to digital. |
| What is the router used and needed for? | Allows you to connect several computers and other devices to a single Internet connection, in a home network. Most routers allow you to easily created a wireless network. It also manages the direction of packets on there way to their destination. |
| What must all transmissions follow in order for the transmission to be successful? | A set of rules. |
| What are these rules called? | The set of rules is called a Protocol. |
| What does a TCP do? | Breaks up messages sent over the internet into small chunks called packets, Reassembles packets at the other end, Detects Errors and resends lost messages |
| What does TCP stand for? | Transmission Control Protocol. |
| What is Packet Switching? | Suppose you want to send a file of 3Mb across the Internet, The file is broken up into data “packets” of 512 bytes. |
| What does the packet have written on it? | IP Address of Recipient. IP Address of Sender. How to put the packets together. The number of packets in the whole communication. |
| What is an IP Address? | A unique set of numbers with dots to identify a computer of device. |
| What does a DNS do? | Translates a web address into an IP address for the web browser. |
| What does DNS stand for? | Domain Name System |
| What is a Mac Address? | An address that identifies the network card. |
| What is the difference between a Mac address and an IP Address? | Mac Addresses are fixed IP Addresses change depending where you are. |
| How can my IP Address Change? | If you use a device at home, its IP address is the one belonging to the router at home but if you take the laptop on holiday and use it, your IP address doesn’t go with you so it will change each time you move to a different place. |
| What two IP Addresses does each device have? | Public IP Address Private IP Address |
| Whats the difference? | The Public one belongs to the router on your LaN and the private one is only accessible within the LaN. |
| Why do we need a private IP Address for each device? | Once a message arrives at the router of your LaN, it will use the private IP address to identify which machine requested information from the internet and the router sends it to that device. |
| Whats the role of the Mac address? | Each router has its own Mac Address so when a router requests something off the internet, it asks another router to get it by using its Mac Address to send the packet to the next leg of journey. |
| What does HTTP stand for? | Hypertext transfer protocol |
| What does HTTPS stand for? | Hypertext transfer protocol secure |
| Whats HTTP? | HTTP is used for accessing and receiving web pages in the form of HTML files on the Internet, The protocol requests the web server to upload the requested web page to the user’s browser for viewing. |
| Whats the difference between HTTP and HTTPS? | HTTPS encrypts the information so it cannot be hacked. |
| What is a WaN and a LaN? | WaN - Wide area network (internet) LaN - Local area network (school) |
| What does a WaN use to connect? | A WAN uses cables, telephone lines, satellites and radio waves to connect |
| What does a LaN use to connect? | All the devices on the network are connected by cables or by wireless – no third party carrier such as BT is involved |
| Whats the purpose of a LaN and a WaN? | For computers to connect so they can share files. |
| Benefits of LaN? | Sharing resources such as printers saves money You can access your files from any computer in the network Data is easy to back up as it is stored centrally on the server |
| Disadvantages of a LaN? | Purchasing the network hardware is expensive Managing a large network is complicated Viruses may be able to infiltrate the network and infect every computer |
| Whats a network topology? | The pattern that devices are connected in the network. |
| What are the 3 basic typologies? | Bus Star Ring |
| Whats a node? | Any device with an IP Address Eg. Phone, Ipad, laptop or TV |
| What are the advantages of a Bus Topology? | Cheap Easy to Install New nodes can be easily added without disrupting the network |
| What are the disadvantages of a Bus Network? | If the bus fails the whole network fails When more workstations brings performance degrades as all data travels down the same bus. |
| What are the advantages of a Ring Network? | Data is transferred quickly as it flows in one direction Heavy traffic has no effect More workstations can be added with no performance issues |
| What are the disadvantages of a Ring Network? | If a cable fails the whole network fails Workstations can see data thats not for them, Security issue Hard to identify issues |
| What are the advantages of a star network? | Fast data transfer as no theres no data collisions If a cable fails other workstations aren't affected |
| What are the disadvantages of a star network? | Expensive to install If central device fails the whole network goes down |
| What does a router do in the network? | Sends packets on their way in the best direction |
| What does a hub do in the network? | Broadcasts packets for the whole network when it receives it Adapter for all computers and printers on the network |
| What does a switch do in the network? | Sends packets to the intended recipient Reduces network traffic and increases speed |
| What's a WaP? | A device that allows wireless devices to connect to a wired network using Wi-Fi |
| Where is it in the network? | Its can stand by itself but normally its part of the router, its integrated in the router itself |
| What's a server? | A powerful computer which provides services required by any of the clients |
| What's the role of the server? | It waits for requests from the clients and it passes requests from clients to another server so it becomes a client to that server. |
| Role of a client? | Sends requests to the server Waits for reply Receives the reply from the server |
| What are the different types of servers? | Servers are often dedicated computers, meaning each one performs no other tasks beside its server tasks However, on a multiprocessing operating system, a single computer can perform the tasks of several servers |
| What is client server networking? | Where the server is in the center a lots of less powerful workstations connect to the server. |
| What are the advantages of Client Server Networking? | All data can be backed up centrally rather than on each individual computer Security is better because data is held in one location rather than all over the organisation Users can log in from any computer on the network and access their data |
| What is a Peer-to-Peer Network? | There is no central server. Each computer holds its own applications and data All computers have equal status |
| What are the advantages of a P2P Network? | Easier to set up – computers can simply be cabled together No special software is required to run the network Individual computers can share a printer, router, modem and other hardware Users can communicate directly with each other and share each others’ files |
| What are the disadvantages of a P2P network? | Viruses and malware are easily transferred over this type of network Data recovery and backup is not done centrally, so each computer has to have its own backup system Files aren't centrallty organised so its hard to locate files |
| Can you name any examples of a P2P Network? | BBC iPlayer Illegal Music and MOvie sites |
| Why are P2P networks used for illegal music and films download sites? | They're hard to close down |
| What is cloud computing? | The practice of using a network of remote servers hosted on the Internet to store, manage, and process data, rather than a local server or a personal computer. |
| Can you name any clouds? | Dropbox Google Drives icloud |
| What are the three types of computer security? | Preventive Security Corrective Detective |
| What is involved in Preventive security? | Access rights Firewalls Physical security Passwords Encryption Acceptable use policies |
| What is involved in Corrective security? | Backup and restore procedures Redundant hardware Disaster recovery procedures |
| What is involved in Detective security? | Virus checking software Firewall software Fire alarms Audit trails |
| What is an acceptable use policy? | A document you sign before using the computers on a network that says you will not hack or tamper with documents etc. |
| What is Redundant Hardware? | Extra hardware in case the original is damaged. |
| What is audit trails? | They're logs that say who logged onto which computer and where abouts the computer is and what time. Its is used to find out who vandalized or hacked something. |
| What are access rights? | A set of things that say who can access which drives, files or folders on the network. |
| What is a firewall? | Acts as a filter or barrier between your network and another. It stops other networks accessing your network. It can also stop certain packets coming into your network. |
| What is physical security? | Locks on doors and security guards Fingerprint recognition Retina scanners Iris recognition Voice recognition |
| How do you make the perfect password? | Include numbers, upper and lowercase letters, symbols and no personal details. Swap numbers for letters and use memorable phrases. |
| What does http stand for? | Hypertext transfer protocol |
| whats does https stand for? | Hypertext transfer protocol secure |
| Whats the difference between http and https? | Http isnt encrypted where as https is. Banks and paypal and websites that hold personal information use https so people cannot view your information. |
| What is plaintext? | the original message to be encrypted |
| What is ciphertext? | the encrypted message |
| What is encryption? | The process of turning plaintext to cyphertext. |
| What is a key? | A sequence of numbers used to encrypt or decrypt data using a mathematical formula |
| What is a Encryption algorithm? | the formula for encrypting the plaintext |
| What does encryption do? | Makes a piece of text that regular people can understand into a piece of text that only the people who know the formula can understand |
| What are the two encryption techniques? | Private Key Public Key |
| Whats a private key? | A single key used to encrypt and decrypt, it is given to the recipient to decypher the message. |
| Whats a public key? | Two keys are used - one to encrypt and the other to decrypt data and this is more secure as it means that you never have to send or reveal your decryption key |
| What is the purpose of anti-virus software? | Is updated with known code patterns found in viruses Checks programs and files for matching patterns Quarantines anything with matching sections for deletion |
| What is backup and archiving? | A backup is a copy for using and editing again if your system fails An archive is a copy of a file that is kept for historic reference and is not meant to be edited again |
| Where are backups kept? | Really far away from the original data store encase the original is compromised. |
| Whats the role of redundant hardware? | Companies have spare hardware systems ready in case their primary hardware fails, in the event of failure the system switches over to the spare hardware and data can be edited at both places. |
| What is compression? | If you compress something you make it smaller. In computing we compress files to make them smaller. |
| What are the two types of compression? | Lossy Compression Lossless Compression |
| What is lossy compression? | Permanently removes some data Recreates the file using the remaining data and uses algorithms to guess the removed content This cannot be used for computer programs. |
| What is lossless compression? | Finds patterns in the original text Encodes each pattern in a dictionary. So repetition of words or phrases aren't duplicated inside the table for words and the number equivalent. |
| Why use compression? | Download speeds are increased Data allowances are reduced Voice can be transmitted fast enough to keep up with speech |
| What are the advantages of compression? | Faster Download/Upload speeds Faster transmission due to fewer packets Reduces space on disk Enables better streaming |
| What is buffering? | Video or music streaming causes buffering if the download speed is slower than the playback speed |
| How do you fix buffering? | Compress the video or file so people don't need to download as much. |
| What is the link between file formats and compression? | JPG – Lossy compressed files commonly used for website images GIF – Lossy compressed images using only 256 colours, used for simple web graphics |
| What is the purpose of having HTTP? | HTTP is a language and if we want to view a webpage in brazil and were in the UK we need a standard that all browsers undertsand. This standard is HTTP. |
| What is HTML? | Hypertext markup language its the code for webpages and websites |
| Where is HTML for websites kept? | It resides in a text file containing the content of the website to be displayed by the browser |
| What does it do? | Stores the locations of images that are to be displayed Governs how to present sections of content Stores the locations of other websites using hyperlinks |
| What is CSS? | Cascading Style Sheets (CSS) control the style and appearance |
| Whats the difference between CSS and HTML? | HTML code controls the content and function of a web page Cascading Style Sheets (CSS) controls the style and appearance |
| What are websites made up of when you strip it down to basics? | Websites are made up of a Head and a Body |
| Whats the head? | The head is the titles and the top bar of the webpage |
| Whats the body? | The body is where most of the text and images are kept for displaying |
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