TCP and TCP/IP Commands

TCP, ICMP and IP are extremely important protocols as they allow hosts to communicate over the Internet in a reliable way. The TCP layer is defined by RFC793 and RFC1122, ICMP by RFC792 and the IP layer by RFC791. TCP provides a connection between two hosts and supports error handling. This chapter discusses TCP in more detail and shows how a connection is established and then maintained. An important concept of TCP/IP communications is the usage of ports and sockets. A port identifies the process type (such as FTP, TELNET, and so on) and the socket identifies a unique connection number. In this way, TCP/IP can support multiple simultaneous connections of applications over a network.