The Illustrated Network- P60:In this chapter, you will learn about the protocol stack used on the global public Internet and how these protocols have been evolving in today’s world. We’ll review some key basic defi nitions and see the network used to illustrate all of the examples in this book, as well as the packet content, the role that hosts and routers play on the network, and how graphic user and command line interfaces (GUI and CLI, respectively) both are used to interact with devices. | CHAPTER Hypertext Transfer Protocol 22 What You Will Learn In this chapter you will learn about the HTTP protocol used on the Web including the major message types and HTTP methods. We ll also discuss the status codes and headers used in HTTP. You will learn how URLs are structured and how to decipher them. We ll also take a brief look at the use of cookies and how they apply to the Web. After email the World Wide Web is probably the most common TCP IP application general users are familiar with. In fact many users access their email through their Web browser which is a tribute to the versatility of the protocols used to make the Web such a vital part of the Internet experience. There is no need to repeat the history of the Web and browser which are covered in other places. It is enough to note here that the Web browser is a type of universal client that can be used to access almost any type of server from email to the file transfer protocal FTP and beyond. The unique addressing and location scheme employed with a browser along with several related protocols combine to make surfing the Web it s really more like fishing or trawling an essential part of many people s lives around the world. The protocol used to convey formatted Web pages to the browser is the Hypertext Transfer Protocol HTTP . Often confused with the Web page formatting standard the Hypertext Markup Language HTML it is HTTP we will investigate in this chapter. The more one learns about how the Hypertext Transfer Protocol and the browser interact with the Web site and TCP IP the more impressed people tend to become with the system as a whole. The wonder is not that browsers sometimes freeze or open unwanted windows or let worms wiggle into the host but that it works effectively and efficiently at all. 560 PART IV Application Level bsdclient winclil winsvrl Inxserver Ethernet LAN Switch with Twisted-Pair Wiring AS 65459 the last two octets are shown. FIGURE The Web servers on the .
