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CHAPTER

INTERNET-BASED APPLICATIONS

7.1 Electronic Mail and SMTP Single-Computer versus Multiple-Computer Electronic Mail Simple Mail Transfer Protocol Multipurpose Internet Mail Extensions (MIME) Web Access and HTTP HTTP Overview Messages Web Security Web Traffic Security Approaches Secure Sockets Layer HTTPS Internet Telephony and SIP SIP Components and Protocols SIP Uniform Resource Identifier Examples of Operation SIP Messages Session Description Protocol Summary Recommended Reading and Web Sites Key Terms, Review Questions, and Problems 7.2

7.3

7.4

7.5 7.6 7.7

ISBN 0-558-69515-9

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Business Data Communications, Sixth Edition, by William Stallings. Published by Prentice Hall. Copyright © 2009 by Pearson Education, Inc.

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CHAPTER 7 / INTERNET-BASED APPLICATIONS

Chapter Objectives After reading this chapter, you should be able to ♦ Discuss the applications for electronic mail. ♦ Explain that basic functionality of SMTP. ♦ Explain the need for MIME as an enhancement to ordinary e-mail. ♦ Describe the key elements of MIME. ♦ Explain the role of HTTP in the operation of the Web. ♦ Describe the functions of proxies, gateways, and tunnels in HTTP. ♦ Explain Web caching. ♦ Discuss the role of SIP. ♦ Explain the relationship between SIP and SDP.

As we discussed in Chapters 2 and 3, distributed information processing is essential in virtually all businesses. Much of the distributed processing is tailored to specific types of data and is supported by proprietary vendor software. However, there is a growing use of distributed applications for both intracompany and intercompany exchange that are general purpose in nature and that are defined by international standards or by industry de facto standards. These applications can have a direct impact on the efficiency and competitiveness of a business. In this chapter, we look at three of the most important and widespread of these distributed applications: electronic mail (e-mail), Web access,...