CCENT/CCNA ICND1 100-101 Official Cert Guide

Rules for IP Addresses

If a device wants to communicate using TCP/IP, it needs an IP address. When the device has an IP address and the appropriate software and hardware, it can send and receive IP packets. Any device that has at least one interface with an IP address can send and receive IP packets and is called an IP host.

IP addresses consist of a 32-bit number, usually written in dotted-decimal notation (DDN). The “decimal” part of the term comes from the fact that each byte (8 bits) of the 32-bit IP address is shown as its decimal equivalent. The four resulting decimal numbers are written in sequence, with “dots,” or decimal points, separating the numbers—hence the name dotted-decimal. For example, 168.1.1.1 is an IP address written in dotted-decimal ...