Internet principles of operation Flashcards
Syllabus: 1.2.3
Define
network
A computer network is a number of computers linked together and able to communicate using certain protocols. Networked computers can share resources including hardware, software and data.
Most computer networks have at least one server.
List some advantages of using networks
Advantages:
- Easy, efficient communication by emails, instant messaging, telephony, video conferencing, chat rooms, etc.
- Ability to share files, data and information (beneficial for large organizations to organise data and allow certain people access to data)
- Saves costs by sharing hardware (e.g. printer) and software (site licences are likely to be cheaper than buying several standalone licences)
- Sensitive files and programs on a network can be password protected.
- Rapid sharing and transferring of files, saves time while maintaining the integrity of files
List some disadvantages of using networks
Disadvantages:
- Possibility of breakdowns and loss of resources
- Expensive to build
- Managing a large network is complicated, requires training and a network manager usually needs to be employed
- Viruses can spread to other computers in the network
- Danger of hacking, particularly with wide area networks. Security procedures are needed to prevent such abuse, e.g. a firewall.
Define
protocol
Pre-agreed signals, codes and rules that are used between two or more computer systems to exchange data and information
Define
internet
The internet is a global computer network providing a variety of information and communication facilities, consisting of interconnected networks using standardized communication protocols.
It is a network of networks that consists of millions of private, public, academic, business, and government networks, of local to global scope, that are linked by a broad array of electronic, wireless and optical networking technologies.
The Internet carries an extensive range of information resources and services, such as the inter-linked hypertext documents of the World Wide Web (WWW) and the infrastructure to support email.
Define
web browser
A piece of software used to view and download web pages and various types of files such as text, graphics, sound and video.
List the typical functions offered by web browers
- Displaying web pages
- Browsing back and forward between web pages
- Customisation of basic options such as your homepage, content censorship and security preferences
- Bookmarking
- History
- Offline browsing
- Downloading
- Search engines
Define
server
A combination of computer and software that provides a service to other client computers or application programs.
What is an Internet server?
This is a computer with specific web server software that provides clients with access to web pages
Define
client
Client devices send requests for services, e.g. printing or retrieval of data to specific server devices that perform the requested processing
What is an Internet Service Provider (ISP)?
A company that provides you with access to the Internet, usually for a fee. The most common ways to connect to an ISP are by using a phone line (dial-up) or broadband connection (cable or DSL).
Examples : STC, Mobily, Zain, etc.
What is http?
Hypertext transfer protocol (http) is the underlying protocol used by the World Wide Web which defines (1) how messages are formatted and transmitted, and (2) what actions Web servers and browsers should take in response to various commands.
For example, when you enter a URL in your browser, this actually sends an HTTP command to the Web server directing it to fetch and transmit the requested Web page.
What is https?
Hypertext transfer protocol over secure (https) is a secure method of accessing or sending information across a web page. All data is encrypted before it is sent, preventing anyone from understanding that information if intercepted.
Because data is encrypted over https, it is slower than http, which is why https is only used when requiring login information or with pages that contain sensitive information such as an online bank web page.
What is HTML?
HyperText Markup Language (HTML) is the markup language used in creating web pages on the World Wide Web.
A document Markup Language is a modern system for annotating a document in a way that is clearly distinguishable from the text.
Distinguish between HTML structure and presentation
Structure consists of the mandatory parts of an HTML document plus the semantic and structured markup of its contents.
Presentation is the style you give the content. In most cases presentation is about the way a document looks, but it can also affect how a document sounds – not everybody uses a graphical web browser.
Separate structure from presentation as much as possible. Ideally you should end up with an HTML document which contains the structure and content, and a separate CSS file which contains everything that controls presentation.
What is the format of an IPv4 address?
- Four numbers separated by periods (in the form w.x.y.z.)
- Each number is an 8-bit binary number between 0 and 255, making up a 32-bit address
- Each number group in the address sub-divides the network to which the computer is connected with the final number being the actual computer.
What is the format of a MAC address?
Six pairs of hexadecimal digits (48 bits in length), usually separated by colons or dashes
