Chapter 28. Introduction to the TCPIP Protocol | HP Certified: HP-UX System Administration

Chapter 28. Introduction to the TCP/IP Protocol

Chapter Syllabus

28.1 Introduction to TCP/IP

28.2 Building an IP Network

28.3 TCP and UDP Protocols

28.4 Ports and Sockets

Transmission Control Protocol/Internet Protocol (TCP/IP) is the most widely used protocol in computer networks in the world. All modern network operating systems support TCP/IP. It is a five-layer protocol where the lower four layers have the same functionality as the lower four layers of the OSI model. The fifth layer in the TCP/IP protocol is the application layer, which covers the upper three layers of the OSI model. All hosts in a TCP/IP network are assigned a unique address called an IP address. It is a 32-bit long number divided into four parts of 8 bits each. Each of these parts is called an octet. An octet is written as a decimal number ranging from 0 to 255. An IP address is written as a combination of the four octets separated by dot characters . IP addresses are divided into two parts for routing purposes. One of these parts is called the network part, which is common to all hosts on a network, and the other one is the host part. IP networks are classified depending on the length of the network part into A, B, and C classes. Class A addresses are used for very large networks, class B addresses are used for medium- size networks, and class C is reserved for small networks.

TCP and User Datagram Protocol (UDP) are used in the transport layer of the protocol stack. The TCP protocol provides connection-oriented and reliable data delivery. The UDP protocol, on the other hand, is an unreliable protocol used for connection-less data transfer. The UDP protocol has less communication overhead compared with TCP and is used for faster but noncritical data transfer, where loss of some data can be tolerated. Examples of the use of the UDP protocol are voice and video communication over IP networks.

In this chapter, we will start with an introduction to the TCP/IP protocol stack and will discuss IP address classes. When building an IP network, you have to assign IP addresses to participating hosts in an orderly fashion, and you will learn how to obtain IP addresses and how to assign these to hosts in a network. Netmasks will be used for different network classes to divide larger networks into smaller ones and for routing purposes. You will find a brief introduction to the Address Resolution Protocol (ARP) and the Reverse Address Resolution Protocol (RARP). A short comparison of TCP and UDP protocols will be presented. In the last part of the chapter, you will find an introduction to sockets and ports.

Top