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INTERNET AND THE WORLD WIDE WEB
The Internet is a worldwide collection of networks that connects millions of businesses, government agencies, educational institutions and individuals.
INTERNET SERVICES
The followings are examples of internet services;-
i. The web.
ii. Email.
iii. VoIP.
iv. Instant messaging.
v. Chat rooms.
vi. (^) Discussions.
vii. Forums and
viii. FTP.
EVOLUTION OF THE INTERNET
The internet has its roots in a networking project started by the Pentagon’s Advanced Research Agency (ARPA), an emergency of the US defense.
ARPA’s goal was to build a network that (1) allowed scientists at different physical locations to share information and work together on military and scientific projects and (2) could function even if part of the network were disabled or destroyed by a disaster such as nuclear attack.
That network called ARPANET became functional in September 1969 linking scientific and academic researchers across the United States.
A hosts, more commonly known today as a server is any computer that provides services and connections to other computers on a network. Hosts often use high- speed communications to transfer data and messages over a network.
By 1984, ARPANET had more than 1,000 individual computers linked as hosts. Today, Millions of hosts connect to this network, which is now known as Internet.
The internet consists of many local, regional, national and international networks. Both public and private organizations own the internet. These networks, along with phone companies, cable and satellite companies, and the government, all contribute toward the internal structure of internet.
CONNECTING TO THE INTERNET
Users can connect their computers to the Internet through;-
i. Wired technology or
ii. (^) Wireless technology and then access its services free or for a fee.
Wired Technology; With wired technology, a computer or device physically attaches via a cable or wire to a communication devices such as a moderm, that transmit data and other items over the transmission media to the internet.
Wireless Technology
For wireless connections, many computers include the necessary built in technology so that they can transmit data and other items wirelessly. Computers without this capability can use a wireless modem or any other communication devices that enables wireless connectivity.
A wireless moderm for example uses cellular radio network to provide internet connections. The wireless modems is known as a dongle. Which is a small device that connects to a computer.
Today, Users connects to the internet via broadband internet service because of its fasts data transfer speeds and its always on connection. Through broadband internet services, users can download webpages quickly, play online games, communicate in real time with others and more.
DOMAIN NAMES AND IP ADDRESSES
Take a look at these;-
IPv4 address 71.14.207.
IPv6 address 2001:4860:4860::
Domain name: google.com
An IP address, short for Internet protocol address, is a sequence of numbers that uniquely identifies the location of each computer or device connected to the Internet.
The Internet uses two IP addressing Schemes: IPv4 and IPv6. Due to the growth of the internet, the original scheme, IPv4, began dwindling in availability. To rectify the problem, the IPv6 scheme lengthened the address, which increased the available number of IP addresses exponentially. Because all-numeric IP addresses are difficult to remember and use, the internet supports domain names.
Domain Name
A domain name is a text based name that correspond to the IP address of a server that hosts a website. A domain name is part of the web address that you type in a browser’s address bar to access a website.
The suffix of the domain name, called the top-level domain (TLD), identifies the type of organization associated with the domain.
Table showing Popular TLDs
TLD INTENDED PURPOSE
.Com Commercial organization, businesses and companies.
.edu Educational Institution
.gov Government agencies
.mil Military organisations
.net Network providers or commercial companies
.org Non-profit organisation
The domains name system (DNS) is the method that the Internet uses to store domain names and their corresponding IP addresses. When you enter a domain name (i.e. google.com) in a browser, a DNS server translates the domain name to its associated IP address so that the requests can be routed to the correct computer.
THE WORLD WIDE WEB
While the internet was developed in the late 1960’s, the world wide web emerged in the early 1990s. since then, it has grown phenomenally to become one or more widely used services on the internet.
The world wide web (WWW), or the web is a world wide collection of electronic documents.
Each electronic document on the wb is called a webpage, which can contain text, graphics, audio, animation, and vide.
Some web pages are static (fixed); others are dynamic (changing). Visitors to a statics webpage all see the same content. With a dynamic webpage, by contrasts, Visitors can customize some or all of the viewd contents, such as desired stock quotes, weather for a region or ticket availability for flights.
A website is a collection of related webpages and associated items, such as documents and pictures, stored on a web server.
A web server is a computer that delivers requested webpages to your computer or mobile devices. The same web servers can store multiple websites.
As web technologies maturedin the mid 2000s, industry experts introduced the term web 2.0 to refer to websites that provides a mean for users to share personal information (such as online social networks), allow users to modify website contents (such as wikis) and provide application through a browser (such as web apps).
BROWSING AND NAVIGATING THE WEB
- Opera; This second oldest browser is free, fast and small. It began as a research project in Norway in 1994 and introduced several features found on most of today’s browsers.
Web addresses
A web page has a unique address, called a web address or URL (Uniform Resource Locator). A browser retrieves a webpage using its web address.
A web address consists of protocol, domain name and sometimes the host name, path to a specific webpage, or file name of the webpage.
The http, which stands for Hypertext Transfer protocol, is a set of rules that defines how web pages transfer on the internet.
Many web pages begins with http:// as the protocol. The text between the protocol and the domain name, called the host name, identifies the types of internet server.
The www, for example indicates a web server.
http://www.nps.gov/history/places.htm
TYPES OF WEBSITES
- Search engine; A search engine is a software that finds websites, webpages, images, videos, news, maps and other information related to a specific topic.
Thousands of search engine are available. Some search engines, such as Bing, Google, and yahoo!.
- Online social networks; An online social network or social networking site, is a website that encourages members in its online community to share their interests, ideas, stories, photos, musics and videos with other registered users. Some social networking sites also enables users to communicate through text, voice and video chat, and play games together online. Examples of social networking sites include;-
- Facebook
- Watsapp
- LinkedIn, Google +, Twitter, Instagram.
- (^) Informational websites; an informational websites contains factual information. Examples includes libraries, encyclopedias, dictionaries, directories, guides), and other types of reference.
- Media sharing and bookmarking sites; A media sharing site is a website that enables members to manage and share media such photos, videos and music. These websites are sometimes called photo sharing sites, video sharing sites and music sharing sites, respectively.
- News, Weather, Sports and other Mass Media; News, Weather, sports and other mass media websites contains news worthy material, including stories and articles relating to current events, life, money, politics, weather and sports.
- Educational; An educational websites offers exciting, challenging avenues for formal and informal teaching and learning.
- Business, Governmental, Organizational; A business websites contains content that increases brand awareness, provides company background or other information, and/or promotes or sells products or services.
- Blogs; A blog short for weblog) is an informal websites consisting of time stamped articles, or posts in a diary or journal format, usually listed in reverse chronological orders.
- Wikis; A wiki is a collaborative websites that allows users to create, add, modify or delete the websites content via a browser.
- Portal; a portal is a website that offers a variety of internet services from a single, convenient location. Most portals offer these free services; Search engine; news, sports, and weather; web publishing; reference tools such as yellow pages, stock quotes, and maps; shopping and email and other communications services.
An email address is a combination of a user name and domain name that identifies a user so that he or she can retrieve internet email. A user name is a unique combinations of characters, such as letters of the alphabet and/or numbers that identifies a specific user.
ii. Email Lists; An email lists, or electronic mailing lists are a group of email addresses used for mass distribution of a message. When a message is sent to an email lists, each person on the lists receives a copy of the message in his or her mailbox
iii. Instant Messaging; Instant messaging (IM) is a real time internet communications services that notifies you when one or more of your established contacts are online and then allows you to exchange messages or files or joins a private chat room with them.
iv. Chat rooms; A chat is a real time typed conversation that takes place on a computer with many other online users. A chat room is a website or application that permits users to chat with others who are online at the same time.
v. Discussion forums; A discussion forum, or message board, is an online area in which users have a written discussions about a particular subject. To participate in a discussion, a user posts a message, called an article, to the news group, other users in the news group read and reply to the messages.
vi. VoIP (VoIP, short for Voice over IP(internet protocol), enables users to speak to other users via their internet connections. That is, VoIP uses the internet (instead of the public switched telephone network) to connect a calling party to one or more local or long distance called parties. To place an internet telephone call, you need a broadband internet connections, a microphone and speaker, both of which are included with a standard computer or mobile devices, and VoIP software such as skype.
vii. FTP (File transfer protocol); is an internet standard that permits file uploading and downloading to and from other computers on the internet.
Uploading is the process of transferring file from your computer to a server on the internet.
Downloading is the process of transferring files from as server on the internet to your computer.
Webpage developers, for example often use FTP to upload their webpages to a web server.
NOTE
Netiquettes, which is short for Internet etiquette, is the code of acceptable behaviours users should follow while on the internet; that is, it is the conduct expected for individuals while online.
Nettiquettes includes rules for all aspects of the internet, including the web web, social media, instant messaging, chat rooms, discussion forums, and FTP.
Question on internet;
- A. Distinguish between the folloing terms used in internet (2 marks @)
a. Network and Internet
b. IP address and domain name.
c. (^) Www and search engine
b) With the help of diagrams, describe any three types of network topologies you know.
c) What are some of the advantages of using internet today in your village?
d) Explain any three disadvantages of using internet (3 marks)
e) Describe three types of network you know.
f) Discuss any two types of Internet connection (2 marks)
PAST PAPERS (2000)
- A) What is meant by the following terms?
i. E-Mail.
ii. Internet
b) Explain briefly how the internet can be used as a learning tool
c) i) Mention four advantages of the internet
ii) Mention four disadvantages of the internet
- A. What is meant by the following terms
The internet is a network of computers spanning the globe. The followings are the merits of internet;-
b. Information; The internet provides a wide range of information ranging from government law and services, trade fairs and conference, market information, new ideas etc. Any kind of information under the sun is available on the internet.
c. Research; Internet offers computer users the ability to gather resources and research on different topics with ease.
d. Public services; Internet provides many services such as online banking, online job seeking and applications, hotel reservations amongst others.
e. Communities; Internet provides a great way for people with similar interest to meet and discuss common issues online.
f. Communication; Internet enables computer users to send and receive messages on line. This method of sending messages is faster and less costly compared to the post office method of sending mails.
g. Entertainment; Internet enables computer users to play game, watch movies and read stories, poems and novels on line.
h. E-Commerce; Internet enables buying and selling on line without the buyer and seller meeting in person. For example, a person can order for a product e.g. vehicle from America and have it delivered up to Kitgum without having to travel up to America.
i. Advertisements; Internet helps the business communities to advertise their products on line so as to easily reach the public, public can in turn place orders through the internet.
DEMERITS/DISADVANTAGES OF INTERNET
a. Theft of personal information; Using internet can expose the user to grace danger as the person’s names, address, credit card number etc can be accessed by wrong people.
b. Information overload; The internet provides a lot of information which may be fake and authentic in nature. These information sometimes tends to mislead a computer user.
c. Spamming; This referes to sending an unwanted email in bulk, which provides no purpose and needlessly obstruct the entire system.
d. Virus attack; Computers connected to the internet are more prone to virus attack which at times end up crushing the computers hard disk.
e. Moral degredation; There are a lot of information on the internet that degrades the moral values of children like for example pornography.
NETWORKS
A network is a collection of computers and devices connected together via a communication devices and transmission medias.
A network may be internal to an organization or span the world by connecting to the internet. Many homes and Business usres create a network to;-
- Facilitate communication; Using network, people communicate efficiently and easily via email, instant messaging, chatrooms, blogs, Wikis, wikis, online social networks, video calls, online meetings, video conferencing, VoIP, wireless messaging services and more. Some of these communications occur within an internal network. Other times, they occur globally over the internet.
- Share hardware; Each computer or device on a network can be provided access to hardware on the network. For example, each computer and mobile device users can access a printer on the network, as they need it. Thus, home and business users create networks to save money on hardware expenses.
- Share data and information; Any authorized user can access data and information stored on a network. A large company, for example, might have a database of customer information.
- Share software; Users connected to a network have access to software on the network. To support multiple user’s software access, vendors often sell versions of their software designed to run on a network.
- Transfer funds; Electronic funds transfer (EFT), allows users connected on a network to exchange money from one account to another via transmission media. Both business and consumers uses EFT. Examples include wire transfers, use of credit cards and debit cards, direct deposits of funds into banks accounts, online banking, and online bill payment.
A wide area network (WAN) is a network that covers a large geographic areas such as a city, country or the world) using a variety of wired and wireless transmission media.
A Wan can be one large network or can consist of multiple LANs connected together. The internet is one of the world’s biggest WAN. A wide area network is said to exists when the computer networks exceeds 100 meters.
iv. PAN
A personal area network (PAN) is a network that connects computers and devices in an individual work space using wired or wireless technology.
A PAN may connect devices through a router using network cables or directly using special USB cables. PANs also may use Bluetooth or Wi-Fi technology.
iv) A campus Area Network (CAN) is a computer network made up of an interconnection of local area networks (LANs) within a limited geographical area. It can be considered one form of a metropolitan area network, specific to an academic setting.
In case of a university based campus area network, the network is likely to link a variety of campus buildings including; academic departments, the University library and students residence halls. A CAN is larger than local area network but smaller than a WAN.
NETWORK ARCHITECTURES/NETWORK STRUCTURAL MODELS
The configuration of computers, devices and media in a network, sometimes called the network architecture is categorized as;-
a. Client/server or
b. Peer-to-peer.
CLIENT/SERVER; On a client/server network, one or more computers acts as server, and the other computers on the network requests services from the server.
A server, sometimes called a host computer, controls access to hardware, software and other resources on the network and provides a centralized storage area for programs, and information.
The clients are other computers on the network that rely on the server for its resources. For example, a server might store an organization’s email messages. Clients on the network, which include any user’s connected computers, access email messages on the server.
PEER-TO-PEER network (P2P) is a simple, inexpensive network that typically connects fewer than 10 computers. Each computer, called a peer, has equal responsibilities and capabilities, sharing hardware (such as a printer), data, or information with other computers on the peer-to-peer network. Each computer stores files on its own storage devices.
Here, a group of computers is connected together so that the users can share resources and information. There is no central location for authenticating users, sharing files or accessing resources.
NETWORK TOPOLOGIES
A network topology refers to the layout of the computers and devices in a communication network.
Alternatively; It can be defined as “The layout of the interconnections of the nodes of a computer network" The most common network topologies are;-
i) A bus network topology.
ii) A star network.
iii) A mesh network
iv) A ring network
v) Overlay network.
vi) Tree network Structure.
If a computer or device on a ring network fails, the entire network potentially could stop functioning.
A ring network could span a larger distance than a bus networks, but it is more difficult to install.
The ring topology primarily is used for LANS, but it also used in WANS.
Advantages of Ring Topology
- They are very easy to troubleshoot because each device incorporates a repeater.
- A special internal feature called beaconing allows troubled workstations to identify themselves quickly.
- (^) There is no master computer on controller. Every computer has equal chance to place the data and access the token.
- There are no collisions.
- Data Packet travels at greater speeds.
- It is easier to locate the problem with the device and cable. I.e. faulty isolation is simplified. If one device does not receive a signal within a specified time, it can issue an alarm. This alarm alerts the network operator to the problem and its location.
Disadvantages of Ring Topology
i. A ring requires more cable than a bus network.
ii. A break in cable ring brings down entire network (in case of single ring).
iii. Adding or removing the nodes disturbs the network activity.
iv. In ring network, communication delay is directly proportional to the number of nodes in the network. Hence addition of new nodes in the network also increases communication delay.
v. It is considerably difficult to install and reconfigure ring topology.
vi. Media failure on a single loop cause complete network failure.
Ring Topology
Ring topology, lso known as Ring Network, is a type of network topology where each node is exactly connected to two other nodes, forward and backward, thus forming a single continuous path for single transmission.
Token Passing
Token contains a piece of information which is sent along with data by the source computer. In easier term, a token is like a permission packet which allows a particular node the permission to release information over the network.
A token is regularly passed from one node to another. An if a node has some information to pass on the network, the node releases the information. If the node does not have any data to release on the network, then it transfers the token to the next node. The nodes with token are the only ones allowed to send data. Other nodes have to wait for an empty token to reach them.
ADVantAgES of ring TOPOLOGY
j. Reduced chances of data collision as each node releases adata packet after receiving the token.
k. Token passing makes ring topology perform better than Bus topology uner heavy traffic.
l. No need of server to control connectivity amongs nodes.
m. Equal access to resources.
