Chapter 19 discusses logical or IP addressing. We first discuss the historical classful addressing. We then describe the new classless addressing designed to alleviate some problems inherent in classful addressing. The completely new addressing system, IPv6, which may become prevalent in the near future, is also discussed. | Chapter 19 Network Layer: Logical Addressing Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 19. 19-1 IPv4 ADDRESSES An IPv4 address is a 32-bit address that uniquely and universally defines the connection of a device (for example, a computer or a router) to the Internet. Address Space Notations Classful Addressing Classless Addressing Network Address Translation (NAT) Topics discussed in this section: 19. An IPv4 address is 32 bits long. Note 19. The IPv4 addresses are unique and universal. Note 19. The address space of IPv4 is 232 or 4,294,967,296. Note 19. Figure Dotted-decimal notation and binary notation for an IPv4 address 19. Numbering systems are reviewed in Appendix B. Note 19. Change the following IPv4 addresses from binary notation to dotted-decimal notation. Example Solution We replace each group of 8 bits with its equivalent decimal number (see Appendix B) and add dots for separation. 19. Change the following IPv4 addresses from dotted-decimal notation to binary notation. Example Solution We replace each decimal number with its binary equivalent (see Appendix B). 19. Find the error, if any, in the following IPv4 addresses. Example Solution a. There must be no leading zero (045). b. There can be no more than four numbers. c. Each number needs to be less than or equal to 255. d. A mixture of binary notation and dotted-decimal notation is not allowed. 19. In classful addressing, the address space is divided into five classes: A, B, C, D, and E. Note 19. Figure Finding the classes in binary and dotted-decimal notation 19. Find the class of each address. a. 00000001 00001011 00001011 11101111 b. 11000001 10000011 00011011 11111111 c. d. Example Solution a. The first bit is 0. This is a class A address. b. The first 2 bits are 1; the third bit is 0. This is a class C address. c. The first byte is 14; the . | Chapter 19 Network Layer: Logical Addressing Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 19. 19-1 IPv4 ADDRESSES An IPv4 address is a 32-bit address that uniquely and universally defines the connection of a device (for example, a computer or a router) to the Internet. Address Space Notations Classful Addressing Classless Addressing Network Address Translation (NAT) Topics discussed in this section: 19. An IPv4 address is 32 bits long. Note 19. The IPv4 addresses are unique and universal. Note 19. The address space of IPv4 is 232 or 4,294,967,296. Note 19. Figure Dotted-decimal notation and binary notation for an IPv4 address 19. Numbering systems are reviewed in Appendix B. Note 19. Change the following IPv4 addresses from binary notation to dotted-decimal notation. Example Solution We replace each group of 8 bits with its equivalent decimal number (see Appendix B) and add dots for separation.
