Online Fundamentals of Data Communication
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Online Fundamentals of Data Communication
This document covers data from Chapters 11 through 14. The data from those chapters is condensed in this document so that you do not have to read every page in your book. When time permits, I highly recommend that you read those chapters. There are questions to answer at the end of each Chapter in this document. Some of these are not directly addressed in the information in this document and many pertain to Chapters 1 – 10. You will need to research using the Internet (or your friends in the IS field) to find some of the answers. Using Word, Notepad, or Wordpad, enter your answers. When you have answered ALL of the items, submit them to the link associated with the Assignment for Chapters 11 – 14. Print this out BEFORE you begin working on it so that you will not miss any items. As you go, it would be a good idea to mark off what you have completed.
There is a total of 23 items and each item counts 4.34 points. Be sure to answer them all.
Chapter 11
The Internet is so much more than just the service that allows a person to browse Web pages and click links. One of the first services, and still one of the more popular offered on the Internet, is the File Transfer Protocol (FTP), which allows a user to upload or download files. Other services offered by the Internet include remote login, Internet telephony, electronic mail, listservs, Usenet, and streaming audio and video. To support the Internet, a host of protocols are necessary. Two of the most common protocols are the Internet Protocol (IP) and the Transmission Control Protocol (TCP). These protocols are supported by a host of secondary protocols, which include Internet Control Message Protocol (ICMP), User Datagram Protocol (UDP), and Address Recognition Protocol (ARP).
Internet Protocols
Although many protocols are necessary to support the operation of the Internet, several stand out as the most common: Internet Protocol (IP), Transmission Control Protocol (TCP), User Datagram Protocol (UDP), Internet Control Message Protocol (ICMP), and Address Resolution Protocol (ARP). The reliable transport service, provided by software called Transmission Control Protocol (TCP), turns an unreliable sub-network into a reliable network, free from lost and duplicate packets. If an application did not need to create a connection to transfer data, the User Datagram Protocol (UDP) could be used instead of TCP. UDP supports a connectionless application in which a connection-oriented stream of packets is not necessary. The connectionless packet delivery service provides an unreliable, connectionless network service in which packets may be lost, duplicated, delayed, or delivered out of order. Even worse, the sender and receiver of these packets may not be informed that these problems have occurred. This connectionless packet delivery service is called Internet Protocol (IP). Because the connectionless packet delivery service doesnt inform users that problems may have occurred, a reliable transport service is needed “above” the connectionless packet delivery service to cover for its possible shortcomings.
The World Wide Web
Although the Internet still offers tried-and-true services, such as file transfer, electronic mail, and remote login, a relatively new service has grown dramatically since its introduction in 1992: the World Wide Web (WWW). Using a Web browser such as Netscape Navigator or Microsoft Internet Explorer, you can download and view Web pages on a personal computer. Of all the Internet services, the World Wide Web has probably had the most profound impact on business. Web pages are created using HyperText Markup Language (HTML) generated manually with a text-based editor such as Notepad or by using a Web page authoring tool. Once a Web page is created, it is stored on a computer that contains Web server software and has a connection to the Internet. The Web server software accepts Hypertext Transport Protocol (HTTP) requests from Web browsers connected to the Internet, retrieves the requested Web page from storage, and returns that Web page to the requesting computer via the Internet. Although HTML was the original and still most commonly used method for controlling the display of Web pages, two new forms of HTML have emerged that offer more power and flexibility in Web page creation–Dynamic HTML and eXtensible Markup Language.
Internet Services
When the Internet came into existence as the Arpanet, most people used the Internet for e-mail, file transfers, and remote logins. To appreciate the many capabilities of the Internet, lets examine several of the more popular services that the Internet provides today, starting with File Transfer Protocol for downloading and uploading files and continuing with remote login, Internet telephony, e-mail, listservs, Usenets, and streaming audio and video.
The Internet and Business
An intranet is a TCP/IP network inside a company that allows employees to access the companys information resources through an Internet-like interface. Using a Web browser on a workstation, an employee can perform browsing operations, but the applications that can be accessed through the browser are available only to employees within the company. When an intranet is extended outside the corporate walls to include suppliers, customers, or other external agents, the intranet becomes an extranet. Since an extranet allows external agents to have access to corporate computing resources, a much higher level of security is usually established.
The Future of the Internet
The Internet is not a static entity, but continues to grow by adding new networks and new users every day. People are constantly working on updating and revising the Internets myriad pieces. One of the biggest changes, however, to affect the Internet will be the adoption of a new version of the Internet Protocol, IPv6. Currently, most of the Internet is using IPv4, which was the version presented earlier in the chapter. If changes to the IP protocol are not enough, work is progressing on a new, very high-speed network that will cover the U.S., interconnecting universities and research centers at transmission rates up to a gigabit per second (1000 Mbps). The new high-speed network is called Internet2, and its links are currently being built and tested on top of existing Internet links.
The Internet In Action: A Company Creates a VPN
The In Action example for this chapter shows how a company can support its external and mobile employees