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Layer 3 of 3: In layer 2, one can convert the address to binary. Layer 3 of 3: In layer 3, an example of dotted-decimal format and binary are displayed. Emphasize: IP address format is dotted-decimal. Dotted-decimal makes it easy to work with IP addresses. However, in this course we will work with the addresses on the bit level, so we will convert these addresses into binary, make changes to them, and convert them back. The central authority for addresses is the Internet Assigned Numbers Authority. Note: This most common form of addressing reflects the widely used IP version 4. Faced with the problem of depleting available addresses, Internet Engineering Task Force (IETF) work is under way for a backward-compatible next generation of IP (IPng, also called IP 6). IP 6 will offer expanded routing and addressing capabilities with 128-bit addresses rather than the 32-bit addressing shown on the graphic. Addresses from both IP versions will coexist. Initial occurrences will probably be at locations with address translator software and firewalls. Purpose: This graphic describes the three most common classes of IP address. Emphasize: Discuss classes of addresses. Each address contains information about the network number and the host number of the device. Class A addresses are for very large organizations. Class B addresses are for smaller organizations, and Class C addresses for even smaller ones. As the number of networks grows, classes may eventually be replaced by another addressing mechanism, such as classless interdomain routing (CIDR). RFC 1467, Status of CIDR Deployment in the Internet, presents information about CIDR. RFC 1817, CIDR and Classful Routing, also presents CIDR information. Emphasize: Highlight the fixed values that start each class address. The first octet rule states that when an address falls into a specified range, it belongs to a certain class. Students should soon be able to recognize the address class of any IP address on sight. Note: I