The Internet has changed our world. Communications and commerce move instantaneously across borders and around the world. Anyone can publish their wares, ideas, or desires. Chapter 3 will present a brief introduction to the origin of the Internet, its structure, and how it is used.
The Internet was created for two purposes: to establish a safe form of military communications and to create a means by which all computers could communicate. Scientists were asked to come up with a solution to secure communications between large computer centers in case of a nuclear attack. They responded by inventing packet-switching and routers. By taking data messages and breaking them into small packets, each packet could be addressed and sent individually to a destination through a series of routers. The routers would send each packet along the optimum path to the next router, depending on traffic and availability. This development also gave birth to a network that could be scaled up infinitely. It could be argued that the scientists who quietly built the first packet-switched network in 1969 were more important to the future than the NASA scientists who landed a man on the moon in the same year.
What distinguishes the Web from the rest of the Internet is its use of: Common communication protocols enabling different computers to talk to teach other and display information. Special links (called hyperlinks ) enabling users to jump from one place to another on the Web. The Web was invented long after the Internet, in 1989 by Tim Berners-Lee at CERN in Switzerland. In 1993, the National Center for Supercomputing Applications (NCSA) released the Mosaic browser. Netscape heralded the beginning of the Web’s monumental growth.
Forms of Internet-based communication include: Instant messaging Podcasts Blogs Vlogs Webcasts Wikis Voice over Internet (VoIP) E-mail
Instant messaging (IM) uses real-time text-based conversations, similar to chat rooms. Users set up a list of contacts, often called a buddy list. Contacts must be online to participate. IM software detects the presence of members who are online. Examples include: AOL Instant Messenger Yahoo! Messenger
Podcasts use compressed audio and video files distributed on the Internet using RSS technology. RSS (Really Simple Syndication) technology allows for constant, automatic updates of Web pages. Podcasts are found all over the Web. They require aggregator and media player software to listen to them. Podcast creation is an easy process, including attaching the RSS files.
Weblogs, or blogs, are a way for anyone to post their thoughts for public viewing. Of course, posting a blog doesn’t guarantee that anyone will read it. Blogging is easy and free. Reading blogs can be very interesting, as they plug into the unsolicited viewpoints of people who believe they have something to say. Video blog (vlog): Entries are video clips recorded digitally and playable on standard media player software.
Webcasts broadcast audio/visual files, but unlike podcasts, they are not automatically updated. Webcasts use streaming media technology to facilitate the viewing and downloading processes of large audio and video files. A wiki is a type of Web site that allows anyone visiting the site to change its content by adding, removing, or editing the content. Wikis provide an excellent source for collaborative writing.
VoIP turns the Internet into a means for placing phone calls. VoIP uses a protocol similar to e-mail to send voice data. Voice is digitized as an alternative to analog phone lines. VoIP minimally requires Speakers A microphone An Internet connection A VoIP provider VoIP services differ. Free services like Skype require an account on both ends. Paid services like Vonage connect your regular phone to your computer through a special adapter. Cable and DSL providers offer telephone service through their existing broadband account. WiFi IP phones allow calls through Internet hotspots and wireless networks.
VoIP has become very popular due to its affordability, portability, and convenience. However, it does have some disadvantages compared to traditional phone lines. Sound quality varies based on available bandwidth. The very nature of Internet transmission can cause reliability problems during a call. When the power (electricity) is out, service is lost and calls cannot be placed. If proper security and encryption are not used in the transmission process, calls can easily be monitored.
E-mail has quickly caught on as the primary method of electronic communication because it’s fast and convenient and it reduces the costs of postage and long-distance phone calls. Some e-mail accounts are client-based. These programs require a computer with the correct e-mail client. Client-based systems are normally tied to a local ISP and use that domain for an address. If a user changes ISPs, their e-mail address changes. Web-based e-mail, on the other hand, finds the messages at a host site received by and stored on a mail server and can be accessed from anywhere. A Web-based e-mail address will stay the same no matter what ISP is used. Free e-mail accounts such as Yahoo! or Hotmail use Web-based e-mail clients.
There are many ways you can interact with a wide variety of people online. Internet social networks Multiplayer online game services Chat rooms Newsgroups Listservs
Social networking sites like MySpace.com have become immensely popular. These sites are easy places for members to hang out, meet new people, and share common interests. They provide a way for members to communicate with their friends by voice, chat, IM, videoconference, and blogs. Members of these sites can create personalized profiles. Growth of participation in these sites has been explosive. Risks must be recognized and reduced. Avoid interactions with cyberbullies, con artists, and other predators.
There are many multiplayer online games in which play occurs among hundreds or thousands of other players, over the Internet, in a persistent or ever-on game environment. In some games, you can interact with other players around the world in a meaningful context by trading, chatting, or playing cooperative or combative mini-games.
A chat room is an area on the Web where many people come together to communicate online. The conversations are in real time and are visible to everyone in the chat room. Chat rooms are sometimes theme oriented and sometimes not. There is no chance for editing out outlandish or offensive opinions or language. People in chat rooms choose an identity and therefore are anonymous. General rules of etiquette (netiquette) include introducing yourself when you enter the room; specifically addressing the person you are talking to; and refraining from swearing, name calling, and using explicit or prejudiced language. Users cannot repeatedly post the same text and should not type in all capital letters.
Newsgroups are sometimes called threaded discussions or discussion groups . Built around topics or interests, participants read entries from other participants and respond, each respondent adding something new to the discussion, creating a thread. A participant can also start a new thread. Unlike chat rooms, threaded discussions don’t rely on instant response but on a more thought-out written response. In distance education classes, threaded discussions are often required and serve as the class participation component of a course. Listservs are similar to newsgroups except that the threads are sent out as e-mails, with each participant in the thread receiving each new posting. They are less public than newsgroups.
Multimedia is anything that involves one or more forms of media in addition to text. All kinds of multimedia are available on the Web. One can download music files, video files, and even movies. Streaming audio and video can deliver on-demand pictures and sounds. Sites like CNN.com offer clips from their broadcasts. Some files require a plug-in program like RealPlayer. In recent versions of Windows, Microsoft’s MediaPlayer is built in and automatically loads when a music file is selected. The speed and quality of audio and video on the Web is dependent on the speed of the Internet connection.
E-commerce grows in importance every day, with billions of dollars worth of transactions. In business-to-consumer or B2C transactions, such as Amazon.com, the end buyer purchases goods or services over the Internet. In business-to-business or B2B transactions, businesses sell to one another. In consumer-to-consumer or C2C transactions, like Ebay.com, consumers sell to one another.
Businesses hire security companies such as VeriSign to certify that their online transactions are secure. Thus, if a Web site displays the VeriSign seal, you can usually trust that the information you submit to the site is protected. Another indication that a Web site is secure is the appearance of a small icon of a closed padlock (IE) or key (Netscape) on the status bar at the bottom of the screen. Additionally, the beginning of the URL of the site changes from http:// to https://, the s standing for “secure.”
To shop safely online, follow these guidelines: Shopping at well-known, reputable sites helps ensure a safe shopping experience. If you are not familiar with a site, check it out with the Better Business Bureau, and also make sure that the company has a phone number and street address before ordering from it. Debit cards do not have the same level of protection as credit cards under U.S. federal consumer credit card protection laws. Use a card with a small limit, or consider using a pre-paid credit card. Check and print out the return policy. You may need it when filing a complaint to prove what the policy showed at the time of your order. Web sites can be changed easily and rapidly and can also be shut down overnight.
As the Internet has grown, so have the annoying things on it. Some of these are dangerous, and some are merely annoying. Like heavy traffic on the roads, air pollution, or any number of annoyances in life, the Internet reflects the public that uses it. The next few slides will discuss each of these annoyances in more detail.
Spam is a particularly difficult problem because there is little that can be done to control the people who send it. All one needs is a list and a message. Lists with millions of e-mail addresses can be purchased. Laws have been passed that make sending spam illegal, but they are difficult to enforce. One way to avoid spam in your primary account is to create a special e-mail address that you use when you fill out forms on the Web. A spam filter is an option you can select in your e-mail account that places known spam messages into a folder other than your inbox . Ninety-five percent of spam can be filtered, never reaching your inbox. You can also avoid spam by reading privacy practices carefully before registering your name on Web sites, by not replying to spam, and by reporting spam to agencies that filter and fight spam.
Cookies are a necessary annoyance because they enhance the Web experience and speed up Web page loading. When you go to a Web page for the first time, the Web document drops a small text file in a folder. This text file saves information about the user and assigns an identification code so that when the user returns, the same preferences are loaded and the Web site may be more geared to the user. This is critical on sites where the content is somewhat chosen to meet the user’s wishes, like in My Yahoo! or other personalized sites. The identification codes can also be used to track a person’s browsing habits. Although cookies are generally not privacy risks, there have been cases in which the information has been collected and sold to advertisers.
Software that has a malicious intent is called malware . I t can cause serious damage to a computer system. There are three primary types of malware: adware, spyware, and viruses/worms. Malware is designed to render a computer useless or to penetrate it completely.
Adware is software programs that download on your computer when you install or use other software, such as a freeware program, game, or utility. Adware is considered a legitimate means of generating revenue for those developers who do not charge for their software. Generally, adware enables sponsored advertisements to appear in a section of your browser window or as a pop-up ad box. Pop-up windows are the billboards of the Internet. Some sites use pop-ups to increase the functionality of their site (your account balance may pop up at your bank’s Web site, for example). There are ways to reduce or eliminate pop-ups. Firefox and Safari have built-in pop-up blockers. Windows includes a Pop-Up Manager in Internet Explorer that allows you to selectively block pop-ups. If you feel you need more protection, you can install anti-pop-up software such as Pop-Up Stopper and Pop-Up Defender.
Often, companies offer something for free, like a screensaver or a game. Piggybacked with the program is a hidden spyware program that monitors your browsing habits and sends this information back to a server. Some spyware programs, known as keyloggers, record every keystroke you type and forward the keystrokes on, with the intent of stealing passwords, logins, and other personal information. Spyware removal software is available from many sources, often for free, and can effectively find and destroy these annoyances.
If you receive an official looking e-mail from your bank saying that there has been a software security breach and that to help regain control you need to confirm your username and password, don’t do it. This is one of the most common scams, called phishing . The e-mail is made to look very official, with logos and signatures, and many unsuspecting customers have entered their passwords into the return email. Internet hoaxes contain information that is untrue. Hoax e-mail messages may request that you send money to cover medical costs for an impoverished and sick child or may ask you to pass on bogus information, such as how to avoid a virus. It is always best to know who is sending a message before responding to it.
A Web browser is software installed on your computer system that allows you to locate, view, and navigate the Web. Web browsers are graphical, meaning they can display pictures (graphics) in addition to text, as well as other forms of multimedia, such as sound and video. Although Microsoft Internet Explorer is the most used Web browser, there are other browsers available. All of them have similar tools. Because Microsoft products are the main targets for virus writers, an alternative browser may be less vulnerable than Internet Explorer. Camino is a new browser developed by Mozilla for the Mac OS X platform.
The latest version of Internet Explorer, IE7, has a much more streamlined approach than its predecessors. The browser’s toolbars provide convenient navigation and Web page management tools. Quick tabs show thumbnail images of all open Web pages in open tabs. The browser also includes a built-in search box in which you can designate your preferred default search engine. Tools for printing, page formatting, and security settings are allocated to a special toolbar. With tabbed browsing, Web pages are loaded in “tabs” within the same browser window. Rather than having to switch between Web pages on several open windows, you can flip between the tabs in one window.
The World Wide Web is simple to navigate once you understand a few important fundamentals. The next few slides will introduce those fundamentals.
The first page in a Web site is called the home page. If you type the domain name into the browser window, the server will find the site and look for a file called index.htm, the standard name for the home page. Every Web page has a unique URL and is an HTML document. It may or may not have links to other pages or other Web sites.
A URL is a Web site’s address. It is composed of several parts that help identify the Web document it stands for. The first part of the URL indicates the set of rules (or the protocol ) used to retrieve the specified document. HTTP is most common. Another popular protocol is FTP. The protocol is generally followed by a colon, two forward slashes, www (indicating World Wide Web), and then the domain name. The domain name is also referred to as the host name . At times, a forward slash and additional text follow the domain name . The information after the slash indicates a particular file or path (or subdirectory ) within the Web site.
The three-letter suffix in the domain name (such as .com or .edu) is called the top-level domain (TLD). This suffix indicates the kind of organization the host is. The most used is the .com or commercial domain, which can be used by anyone. There are also domains for countries outside the United States. For instance, a Web site in Germany has the extension .de, and in Britain it is .uk. Unsponsored top-level domains were developed by ICAAN, a nonprofit corporation responsible for IP address allocation.
Sponsored top-level domains support a narrower community and include: .asia, .cat, .coop, .jobs, .mobi, .museum, .pro, .tel, .travel, and .arpa. .cat = Catalan, group of languages from Spain—Catalonia (Barcelona)
Once you’ve reached a Web site, you can jump from one Web page to another within the Web site or to another Web site altogether by clicking on specially coded text called hyperlinks. When programming HTML, the Web page author can code any word or image to be a hyperlink. Generally, text that operates as a hyperlink appears in a different color (often blue) and/or is underlined. Sometimes images also act as hyperlinks. When you pass your cursor over a hyperlink, the pointer turns from an arrow into a hand. To retrace your steps, some sites also provide a breadcrumb list — a list of pages within a Web site you’ve visited that usually appears at the top of a page.
While browsing the Web, you may want to remember a site for future reference. Using the Favorites or Bookmark feature, you can store the site’s URL in a special folder. To add a Web page to your Favorites list in IE, from within the site you wish to mark, click on the Favorites menu and select Add to Favorites. You can modify the name of the Web page on your Favorites list to make it more meaningful. You can also add subfolders that categorize the favorites. Live bookmarks add the technology of RSS (Really Simple Syndication) feeds to bookmarking, allowing updates to be delivered to you as soon as they are available. Web sites such as del.icio.us and digg.com provide proprietary toolbars and tagging tools that incorporate into your web browser and that allow you to tag and organize Web sites using your own keywords.
A search engine is a set of programs that searches the Web for specific keywords you wish to query and then returns a list of the Web sites on which those keywords are found. Search engines have three parts. The first part is a program called a spider , which collects data on the Web. An indexer program organizes the data into a large database. The search engine software searches the indexed data, pulling out relevant information according to your search. Using search engines like Google, users can scan millions of Web sites in seconds, with the search page returning thousands of relevant Web pages. Revenue is generated by offering a side column of paid links that are ties to certain search requests. For instance, if you enter “cat food” in the search box, Google returns many related sites. Businesses that have their link appear when someone requests “cat food” pay a small amount every time their ad link appears.
A subject directory is a guide to the Internet organized by topics and subtopics. Examples include Yahoo! or the Librarians’ Index. With a subject directory, you do not use keywords to search the Web. Instead, after selecting the main subject from the directory, you narrow your search by successively clicking on subfolders that match your search until you have reached the appropriate information. For example, to find previews on newly released movies in Yahoo’s subject directory, you would click on the main category of Entertainment, select the subcategory Movies and Films, select the further subcategory Preview, and then open one of the listed Web sites.
Boolean operators are words you can use to refine your searches, making them more effective. These words—AND, NOT, and OR—describe the relationships between keywords in a search. Some search engines let you use an asterisk (*) to replace a series of letters and a percent sign (%) to replace a single letter in a word. These symbols, called wildcards , are helpful when you’re searching for a keyword but are unsure of its spelling, or if a word can be spelled in different ways or may contain different endings.
Evaluating the content of a Web site is important. Before you believe what the site says or take action based on the information presented, several questions need to be answered. Who exactly owns and operates the Web site? Are the opinions expressed on the site objective, or are they slanted toward one position or another? If it is slanted, why is it slanted? Is the information up to date? How often is the site updated? Who is the site trying to reach with its message? Do the hyperlinks all work, or are some dead ends? Are the links appropriate? Like anything else, how well maintained a site is helps determine its believability.
Basic information about the Internet includes the origin of the Internet, how the Web relates to the Internet, how the Internet is based on clients and servers, and how to best connect to the Internet.
The Internet is a huge client/server network. Thus, a computer connected to the Internet acts in one of two ways: it is either a client , a computer that asks for data, or a server , a computer that receives the request and returns the data to the client. IP addresses are the means by which all computers connected to the Internet identify each other.
To take advantage of the resources the Internet offers, you need a means to connect your computer to it. Home users have several connection options. Originally, the only means to connect to the Internet was with a dial-up connection . With dial-up connections, you connect to the Internet using a standard telephone line. However, other connection options, collectively called broadband connections , offer faster means to connect to the Internet. Broadband connections include cable, satellite, and DSL.
One type of broadband connection is cable Internet. Cable Internet uses coaxial cable and a cable modem. This always-on connection can be slowed by the number of users connected at any one time, and it is not available in all areas.
DSL uses a standard phone line to connect to the Internet . However, the line is split between digital and voice, meaning that the digital signal does not have to be converted into sounds, and greater speeds can be realized. DSL requires a special DSL modem. Although the monthly fee is higher than that for dial-up, there is no need for a second phone line. Often the end price is comparable, but the Internet speed is at least double. Not all areas of the United States have DSL. Also, to use DSL, your telephone connection must be within fairly close proximity of a switching station. DSL provider Web sites include interactive tools you can use to determine whether your phone line is capable of including a DSL connection. The more typical DSL transmissions download data from the Internet faster than they can upload data. Such transmissions are referred to as Asymmetrical Digital Subscriber Line (ADSL). Other DSL transmissions, called Symmetrical Digital Subscriber Line (SDSL), upload and download data at the same speed.
Fiber-optic Internet transmits data by sending light through optical fibers. Because light travels so quickly, this technology can bring an enormous amount of data to your home at super fast speeds. When the data reaches your house, it’s converted to electrical pulses that transmit digital signals your computer can read. The biggest advantage to fiber-optic Internet is its speed. Cost might be the main disadvantage. Also, because fiber-optic lines must be laid in place before service is available, the service is available only in select areas.
Connecting wirelessly increases mobility and productivity, as the user can access networks and resources from more locations without having to have a cabled connection. To connect wirelessly, a WiFi (wireless fidelity) hotspot must be within range and the device (i.e., laptop, PDA, or cell phone) must have either an internal or an external WiFi access card. Another expensive option available and usually used when a WiFi hotspot is not in range is an aircard. Aircards provide access through cell phone towers and generally require a separate service plan. Costs can be very expensive and range from provider to provider.
A dial-up connection needs only a standard phone line and a modem. A modem is a device that converts ( mod ulates) the digital signals the computer understands to the analog signals that can travel over phone lines. In turn, the computer on the other end must also have a modem to translate ( dem odulate) the received analog signal back to a digital signal for the receiving computer to understand. Modern desktop computers generally come with internal modems. Laptops use either internal modems or PC cards that are inserted into a special slot on the laptop. Current modems have a maximum data transfer rate that is generally five times slower than a broadband connection.
Internet connection costs vary widely, as does performance. One factor to consider in choosing the right Internet connection is speed. The data transfer rate , also informally referred to as the connection speed , is the measurement of how fast data travels between computers.
Internet service providers (ISPs) are national, regional, or local companies that connect individuals, groups, and other companies to the Internet. EarthLink, for example, is a well-known national ISP. The Internet backbone is the main pathway of high-speed communications lines through which all Internet traffic flows. Large communications companies, such as AT&T, Qwest, and Sprint, are backbone providers that control access to the main lines of the Internet backbone. If you have a broadband connection, your broadband provider is your ISP. If you're accessing the Internet from a dial-up connection, you need to determine which ISPs are available in your area.
The Internet will continue to have great influence in the future. Greater bandwidth; wireless access; and the amalgamation of telephone, TV, and Internet technologies will bring change and spur new, unforeseen developments. The U.S. government sponsors research called the Large Scale Networking (LSN) program, which funds cutting-edge research in wireless and networking technologies. Another major effort is Internet2 , a cooperative research project of over 200 universities. A major thrust of their research is increased bandwidth for the whole Internet.
Make & RECEIVE CALLS THROUGH SECURE WIRELESS NETWORKS The Wi-Fi Phone is a standalone device that does not require a computer to use. All you need is an 802.11g or 802.11b wireless network with high-speed Internet access to make and receive calls1. Use it at home, hotels, offices, airports, Internet cafes, school campuses, or just about anywhere there is a wireless connection available . In addition, with a growing number of Wi-Fi hotspots and metropolitan areas deploying low-cost or free high-speed wireless Internet connection, you have more places available to make and receive VoIP calls. This Wi-Fi Phone uses Session Initiation Protocol (SIP) and is ready to be used with an Internet (VoIP) phone service plan. For accessing secure wireless networks, the Wi-Fi Phone supports WEP, WPA, and WPA2 encryption. With features like echo cancellation, packet delay compensation, and lost packet recovery, you can expect the voice quality from the Wi-Fi phone to be similar to traditional phones calls.