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Chapter 5
Introduction to the Internet
What is the Internet ?
•Internet is a network of networks.
•It is the largest ever known system of interconnected networks, carries a vast amount of information resources, and services.
• Accessible by billions of people over the world.
Internet Protocol Suite (TCP/IP)
•All communications are governed by
predefined rules called Protocols.
•TCP/IP is the set of communication protocols
used for the internet and other similar
networks.
•The name is driven from two of the most
important protocols
•1. Transmission Control Protocol(TCP)
•2. Internet Protocol(IP)
• which were the first two networking
protocols defined in this standard.
The Internet and WWW
• The terms Internet and World Wide Web(WWW) are not same.
• The Internet is a global data communication system.
• It is a hardware and software infrastructure that provides connectivity between computers.
• The web is one of the services that use the internet such as e-mail, instant messaging, videoconferencing and more.
Internet Services and Protocols
1. WWW(World Wide Web):
• Is a collection of connected web pages, documents and multimedia information linked by hyperlinks.
• Each web page or file in the web has its own URL(Uniform Resource Locator), which is the complete address for this page on a web server.
• Hyperlinks are special items- regularly text- in web pages that are associated with specific URLs, when clicked; it opens another web page
Protocols Used in WWW:
HTTP(Hyper Text Transfer Protocol):
• is the protocol used with the WWW to
transfer the web pages between web
servers and clients through internet.
• Web page is nothing but a Hyper Text that
is written using the HTML(Hyper Text
Markup Language).
2. E-mail(Electronic Mail):
• is used to send electronic messages from one mailbox to another.
• Every mail box has a unique name referred to as email account.
• E-mail address are written as
Email_Account@Domain_Name
The most popular domains that provide email service are Yahoo, Gmail and Hotmail
Protocols used in e-mail communication:
SMTP(Simple Mail Transfer Protocols)
POP(Post Office Protocol)
3. Downloading and Uploading Files:
• Is to collect or send files from or to the
internet.
• It is an important characteristics of the
internet.
• When we browse the web or when we
attach a file through an Email.
Protocols Used:HTTP: (Hyper Text Transfer Protocol)
FTP: File Transfer Protocol
BitTorrent Protocol:
One of the most common protocols for transferring large files.
This protocol downloads pieces of the file in a random approach while the previous protocols downloads them sequently.
This protocol makes many connections to different machines, while classic downloading makes only one connection to a single machine
4. Instant Messaging(IM) or Chatting:
• is a real-time system that allows two or more
people to use their personal computers to
communicate with each other by sending and
receiving text messages
• real-time means, when you send the
message it should appear immediately to the
other side computer.
• More advanced instant messaging software
allows enhanced communication, such as
voice chatting, file sharing and video calling.
Protocols used in Instant Messaging: IRC (Internet Relay Chat): used with mIRC
MSNP:(Microsoft Notification Protocol): used with Windows Live Messenger.
Skype Protocol: used with Skype
YMSG(Yahoo Messenger): used in Yahoo Messenger
OSCAR:(Open System for Communication in Real –Time) used with AIM(AOL Instant Messaging) and ICQ.
XMPP: (Extensible Messaging and Presence Protocol) used with Google-talk and Facebook chat
Web Addresses
Domain Names or Web Site addresses are composed of the following parts:
1- The Protocol: e.g. http followed by (:) and (//).
2- WWW: This means that this address is a World Wide Web address.
3- Domain Name: the name or the abbreviation of the registered Organization or, may be, the person who are registered to get a web address.
4- Top-Level Domains (TLDs)
TLD Purpose
.biz Businesses
.com Unrestricted, but intended for commercial
entities
.edu Educational institutions
.gov Government agencies
.info Unrestricted use
.mil Military
.net Unrestricted use, Group or network in a
specified field.
.org Unrestricted use, but intended for nonprofit
organizations and organizations that don't fit
elsewhere
5-Two letters (Usually) representing the
Home Country of the domain.
Abbreviation Country
ae Arab Emirates
jo jordan
sa Saudi Arabia
qa Qatar
bh Bahrain
eg Egypt
lb Lebanon
om Oman
Abbreviation Country
sy Syria
ku Kuwait
uk United Kingdom
au Australia
in India
Web Technologies
1. Search Engines
• Programs that are used to search for
information on the world wide web.
• Search results are presented in a list, and
it may contain web pages, images and
other types of files
Example: Google, Yahoo, Bing, AOL
Narrowing the Search Results
• A group of words with double quotes tells the search engine to only retrieve documents in those words appear side-by-side.
• Phrase Searching is a powerful search technique for narrowing the search results.
Examples: Google Advanced Search Page used to choose more options like exact wording or phrase, file type, language and a specific domain.
2. Video Sharing Websites
• Allows millions of people to watch and share originally created videos.
Features
• Video Embedding : where users can insert a video into Facebook, blogs or other web sites where anyone can watch them.
• Users can also add comments and rate any shared videos.
Example: You Tube
3.Blogs(Forums)
• Blog is a word made up from web log.
• Initially they began as online journals with
frequent comments on a few topics of
interest to the bloggers.
• Users can participate in many forums
according to their interests.
• Users can create new posts or respond to
any previously shared posts.
Example: Omani Sabla Forum
4.Social Networking
• Are websites that allow people to connect and build online communities that share common interests or activities.
• Users may use various ways to interact such as chatting, messaging and video sharing.
• Users can upload pictures and can be “friends” with other users.
• Users also have the ability to create groups that share the common interests.
• Examples: Facebook, Twitter, LinkedIn, MySpace and Hi5
5. E-Learning:
• Many specialized high school courses and some complete college programs are offered entirely on the web.
• Refers to the usage of electronic applications and process to learn, including web-based learning, computer based learning and virtual classrooms.
• Course content are delivered via the Internet, audio or video tapes and DVDs.
Examples: University of Nizwa EDUWAVE E-Learning System, University of Nizwa MOODLE E-Learning System, Arab Open University E-Learning System.
6. E-Commerce
• Refers to buying and selling items online.
• Most of the traditional companies established we sites for online business.
• Usually payments via those websites are handled by trusted intermediary companies such as PayPal.
Benefits:
• Considering more products and sellers
• Reaching a huge number of costumers and buying from different countries without moving a step
Example: eBay.com
7. E-Government
• Is the delivery of government services
through the Internet.
• Helps to simplify processes and enable
access to government information through
easier methods for public sector agencies
and citizens.
Example: Royal Oman Police Website
8. Wikipedia
• Is a free, online, collaborative encyclopedia
• Is an excellent example of collaborative projects among large numbers of strangers worldwide that produce extremely valuable product for public.
• Is one of the Internet’s most used reference sites, even so, some articles may contain errors.
• Thousands of volunteers write and continually edit and update Wikipedia.
• Anyone who chooses to participate can do so.
Web Browsing Application
Web Browser:
• is the application program used to open
any website.
• All web browsers are available free and
can be downloaded and updated
immediately from their websites.
Examples: Microsoft Internet Explorer,
Google Chrome, Mozilla Firefox, Opera,
Apple Safari.
Common features of most of the Web browsers
1. History: recently visited web pages, collectively known as “history” are stored so that you can review them later.
2. Bookmarks: a personal list of interesting web sites. Bookmarks make it quick and easy to get favorite places on WWW.
3. Add-ons (or) plug-ins (or) widgets: are set of software that adds specific capabilities to a larger software application.
4. Embedded Search: Using a search engine immediately from the tool-bar of the web browser.
5. Tabbed browsing: a tabbed document interface(TDI) is one that allows multiple documents to be contained within a single window.
What are the criteria we have to
consider to choose the perfect
browser?
1. Features: (Discussed in the previous
slides)
2. Ease of Use: User friendly ?
3. Security: browsers should protect their
users against hazards, such as viruses?
4. Speed: browsers should help the users
to surf fastly and efficiently.
Internet Service Provider(ISP)
• ISP is a company that provides access to the internet.
• Users can connect to the Internet Immediately by connecting with the ISP.
• ISP can provide different methods for Internet connections with different characteristics and different costs.
• ISP gives you a software, username, password and access phone number. Equipped with a modem, you can then log on to the internet.
Internet Connection Types
• There are two categories of Internet connections: 1. Normal(dial-up)
2. Fast(broadband).
• The choice will depend on a number of factors, the most important one is the speed and other factors are availability and cost.
1. Dial-up connection
• slow and most inexpensive(cheap)
To connect using dial up,
• First your PC must have a standard
modem and it should be connected with
the telephone line.
• Then you can use a dial up connection
software with the account and phone
number given to you by the ISP.
• Your PC dials a phone number and
connects to the ISP and, therefore, the
Internet.
2. ADSL Connections: stands for
• Asymmetric Digital Subscribers Line
• Offers incredible performance compared with dial-up.
• Becoming the first choice of broadband for most Internet subscribers.
• ADSL connections are not available every-where.
• Needs a special ADSL modem and ADSL filters.
• Quite expensive compared with dial-up
• It splits the phone line into two separate
channels: one for data (Internet) one for
voice (phone calls).
• So users can talk on the phone and be
connected to the Internet at the same
time.
• Depending on the ISP, ADSL have
different speed specifications such as
512Kbps, 1Mbps, 2Mbps, 4Mbps and
8Mbps
Internet Ethics
• Internet Architecture Board (IAB) issued a
statement of policy concerning Internet ethics.
Unethical and Unacceptable statements are:
• Seek to gain unauthorized access to the resources
of the Internet
• Disrupt (Disturb) the intended use of the Internet.
• Waste resources (people, capacity, computer)
through such actions
• Destroy the integrity of computer-based information.
• Compromise the privacy of users.
Internet Privacy
• Is the ability to control what information you would accept to be revealed about yourself over the Internet, and control who can access that information.
Example Problems
1. Your personal email can be used by third parties without your knowledge.
2. Without you knowledge, third parties can track the websites you have visited or whether web sites you visit can collect and store information about you.
Ways to Protect your Privacy on the
Internet :
1. E-mails can be encrypted
2. Proxies can be used to prevent the ISPs
from knowing which sites you visit and
with whom you communicate.
Internet Security
• The Internet represents an insecure channel for exchanging information, leading to a high risk of Intrusion or Phishing.
• Intrusion: is breaking into computers and computer networks, either for profit or just a challenge.
• Phishing: is the criminally fraudulent process of attempting to acquire sensitive information, such as username, passwords and credit card details.
Methods to Protect the Transfer of Data
1. Encryption:
• is the process of transforming original
information into unreadable data before
sending through the Internet.
• Usually encrypted web pages are
identified by “https” instead of “http” for
the protocol in their web address starter.
2. Antivirus Programs and Internet Security Programs: are also useful in protecting your computer from:
Viruses: are small pieces of software that attach themselves to a real program.
Worms: are self-replicating computer programs.
Trojan horses: are harmful piece of software that look legitimate.
Spyware: is software that collects information about users without their knowledge and send them to a third party.
Adware: is a software package, which automatically plays, or displays advertisements to a computer
Popular Anti-virus and Internet Security
Softwares are
1. Norton Internet Security
2. Kaspersky Internet Security
3. Webroot Internet Security
4. Panda Internet Security
5. BitDefender Total Security
6. McAfee Total Protection.
3. Firewall:
• It is hardware or software that controls the
access between networks.
• It is usually used as a shield between
private networks and the Internet.
• All the messages whether incoming or
outgoing must pass through the firewall,
and only authorized traffic is allowed.