CHAPTER 0
INTRODUCTION TO TCP/IP
This chapter gives an overview of TCP/IP networking principles that form the basis of
discussion for many of the laboratories that are covered in this text. Using the example of a
web access, the chapter gives some insight into the intricacies and complexities of TCP/IP
networking. The chapter also provides an in-depth discussion of IP addresses and other
addressing schemes used in the Internet.
TABLE OF CONTENTS
1. A TCP/IP NETWORKING EXAMPLE
1
2. THE TCP/IP PROTOCOL SUITE
8
2.1. AN OVERVIEW OF THE TCP/IP PROTOCOL SUITE
9
2.2. ENCAPSULATION AND DEMULTIPLEXING
12
2.3. DIFFERENT VIEWS OF A NETWORK
17
3. THE INTERNET
20
3.1. A BRIEF HISTORY
20
3.2. INFRASTRUCTURE OF THE INTERNET
21
3.3. ADMINISTRATION AND STANDARD BODIES OF THE INTERNET
24
4. ADDRESSES AND NUMBERS
26
4.1. MEDIA ACCESS CONTROL (MAC) ADDRESSES
26
4.2. PORT NUMBERS
28
4.3. IP ADDRESSES
28
4.3.1. SUBNETTING
30
4.3.2. CLASSFUL ADDRESSES
33
4.3.3. CLASSLESS INTER DOMAIN ROUTING (CIDR)
36
4.3.4. THE FUTURE OF IP ADDRESSES
38
5. APPLICATION LAYER PROTOCOLS
38
5.1. FILE TRANSFER
39
ii
5.2. REMOTE LOGIN
42
5.3. ELECTRONIC MAIL
44
5.4. THE WEB
47
5.5. RECENT APPLICATIONS
52
1. A TCP/IP Networking Example
Consider a web browser (a web client) at a host with name Argon.cerf.edu (“Argon”) that makes
a web access to a web server on a host with name Neon.cerf.edu (“Neon”).1 The web access is
illustrated in Figure 0.1. Both hosts are connected to the Internet. The web access is a request
for the home page of the web server with URL http://Neon.cerf.edu/index.html.
argon.cerf.edu
("Argon")
neon.cerf.edu
("Neon")
Web request
Web page
Web client
Web server
Figure 0.1. A simple web request.
We will explore what happens in the network when the web request is issued. We proceed, by
following the steps that are performed by network protocols until the first packet from Argon
reaches the web server at Neon. An outline of the steps involved is given in