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Chapter 13 - The internet. In this chapter we first give a brief history of the Internet. We formally introduce the TCP/IP protocol suite (Internet model) that we used as a networking model throughout the book. We then discuss briefly the next generation protocol. Access to the Internet, both residential and organizational, is also discussed. Finally we introduce private networks, intranets, and extranets. | Chapter 13 The Internet Know how the Internet began. Understand the architecture of today’s Internet and its relation- ship with ISPs. Understand the importance of the TCP/IP protocol suite. After reading this chapter, the reader should be able to: OBJECTIVES Understand the role of IP, UDP, and TCP in the Internet. Understand the difference between the Internet, an intranet, and an extranet. HISTORY AND ADMINISTRATION 13.1 RFCs can be found at http://www.rfc-editor.org Note: Figure 13-1 Internet today Technical Focus: Maturity Levels of an RFC An RFC, during its lifetime, falls into one of six maturity levels: proposed standard, draft standard, Internet standard, historic, experimental, and informational. Figure 13-2 Internet administration TCP/IP PROTOCOL SUITE 13.2 Figure 13-3 TCP/IP protocol suite Figure 13-4 IP datagram Technical Focus: Inside the Header of an IP Datagram An IP datagram contains several fields. The most important are the source and destination addresses of the | Chapter 13 The Internet Know how the Internet began. Understand the architecture of today’s Internet and its relation- ship with ISPs. Understand the importance of the TCP/IP protocol suite. After reading this chapter, the reader should be able to: OBJECTIVES Understand the role of IP, UDP, and TCP in the Internet. Understand the difference between the Internet, an intranet, and an extranet. HISTORY AND ADMINISTRATION 13.1 RFCs can be found at http://www.rfc-editor.org Note: Figure 13-1 Internet today Technical Focus: Maturity Levels of an RFC An RFC, during its lifetime, falls into one of six maturity levels: proposed standard, draft standard, Internet standard, historic, experimental, and informational. Figure 13-2 Internet administration TCP/IP PROTOCOL SUITE 13.2 Figure 13-3 TCP/IP protocol suite Figure 13-4 IP datagram Technical Focus: Inside the Header of an IP Datagram An IP datagram contains several fields. The most important are the source and destination addresses of the datagram (IP addresses). The header also contains fields related to fragmentation. The size of a datagram may be too large for some LAN or WAN protocols. In this case, the datagram is divided into fragments; each fragment carries the same identification number as well as other information to help the receiver assemble the datagram. The header also has two length fields; one defines the length of the header, the other defines the length of the entire packet. One field that can decrease traffic on the Internet holds the number of routers a packet can visit before it is discarded. The header also contains a checksum field to determine the validity of the packet. Figure 13-5 Internet address Technical Focus: Classful versus Classless Addressing With more and more organizations wanting to use the Internet, the Internet authorities are running out of IP addresses. Internet addresses were originally designed as classful addresses. By this, we mean that the total number of 32-bit addresses .
