|  | 2.1 | General Model of Communication
| 2.1.4 | Protocol
In order for data packets to travel from a source to a destination on a network, it is important that all the devices on the network speak the same language or protocol. A Protocol is a set of rules that make communication on a network more efficient. Some common examples are as follows: In congress, a form of Roberts Rules of Order makes it possible for hundreds of representatives, who all like to talk, to take turns, and to communicate their ideas in an orderly manner. While driving a car, other cars (should!) signal when they wish to make a turn; if they did not, then the roads would be chaos. While flying an airplane, pilots obey very specific rules for communication with other airplanes and with air traffic control. When answering the telephone, someone says, "Hello," then the person calling says, "Hello. This is.... "; and so it goes back and forth. One technical definition of a data communications protocol is: a set of rules, or an agreement, that determines the format and transmission of data. Layer n on one computer communicates with layer n on another computer. The rules and conventions used in this communication are collectively known as the Layer n protocol.
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