7. Connection-Oriented Protocols for Clients
You'll recall from the last chapter that there are two basic modes of communication for sockets. They are connection and connectionless modes of communication. In the last chapter, you also saw how the UDP protocol could be used to communicate in a connectionless fashion. In this chapter, you'll put the TCP/IP protocol to use, using a connection-oriented form of communication.
This chapter will introduce you to
The advantages of connection-oriented protocols
The /etc/services file and its support routines
The /etc/protocols file and its support routines
The connect(2) function
How to write a TCP/IP client program
Before you jump in and write your first client program, however, a quick review and an introduction to connection-oriented communications is in order. Additionally, you'll learn about some of the support functions that are often used by TCP/IP programs that locate service and protocol information.