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The TCP/IP Guide  9  TCP/IP Lower-Layer (Interface, Internet and Transport) Protocols (OSI Layers 2, 3 and 4)       9  TCP/IP Internet Layer (OSI Network Layer) Protocols            9  Internet Protocol (IP/IPv4, IPng/IPv6) and IP-Related Protocols (IP NAT, IPSec, Mobile IP)                 9  Internet Protocol Version 4 (IP, IPv4)

Internet Protocol Version 4 (IP, IPv4) 1 IP Addressing Concepts and Issues

The primary job of IP is delivering messages between devices, and like any good delivery service, it can't do its job too well if it doesn't know where the recipients are located. Obviously then, one of the most important functions of the Internet Protocol is addressing. IP addresses are used not only to uniquely identify IP addresses but to facilitate the routing of IP datagrams over internetworks. They are used and referred to extensively in TCP/IP networking.

In this section I provide a comprehensive explanation of the issues and techniques associated with IP addressing. There are five subsections. The first provides an overview of IP addressing concepts and issues. The second discusses the original class-based (“classful”) IP addressing scheme and how the different classes work. The third and fourth subsections are devoted to IP subnets and subnet addressing. This includes a discussion of subnetting concepts and also a thorough illustration of practical step-by-step subnetting. The last subsection describes the new classless addressing system, also sometimes called “supernetting”.

Internet Protocol Version 4 (IP, IPv4) 1 IP Addressing Concepts and Issues