Wireless Mobile Internet Security, 2nd Edition

Chapter 2

TCP/IP Suite and Internet Stack Protocols

The Internet protocols consist of a suite of communication protocols, of which the two best known are the Transmission Control Protocol (TCP) and the Internet Protocol (IP). The TCP/IP suite includes not only lower-layer protocols (TCP, UDP, IP, ARP (Address Resolution Protocol), RARP (Reverse Address Resolution Protocol), ICMP, and IGMP (Internet Group Management Protocol)), but also specifies common applications such as the World Wide Web, e-mail, domain naming service, login, and file transfer. Figure 1.3 depicts many of the protocols of the TCP/IP suite and their corresponding OSI layer.

It may not be important for the novice to understand the details of all protocols, but it is important to know which protocols exist, how they can be used, and where they belong in the TCP/IP suite.

This chapter addresses various layered protocols in relation to Internet security, and shows which are available for use with which applications.

2.1 Network Layer Protocols

At the network layer in the OSI model, TCP/IP supports the IP. IP contains four supporting protocols: ARP, RARP, ICMP, and IGMP. Each of these protocols is described below.

2.1.1 Internet Protocol (IP)

The IP is a network layer (layer 3 in the OSI model or the Internet layer in the TCP/IP model) protocol which contains addressing information and some control information to enable packets to be controlled. IP is well documented in RFC 791 and is the basic communication protocol ...