|  | 6.5 | Media Access Control (MAC)
| 6.5.2 | Three analogies for MAC
Tollbooth Analogy Consider how a tollbooth controls multiple lanes of vehicles crossing a bridge. Vehicles gain access to the bridge by paying a toll. In this analogy, the vehicle is the frame, the bridge is the shared medium, and paying the fee at the tollbooth is the protocol that allows access to the bridge. Ticket Line Analogy Picture yourself waiting in line to ride a roller coaster at an amusement park. The line is necessary to ensure order; there are a specified maximum number of people that can fit into the roller coaster car at one time. Eventually, as the line moves, you pay for your ticket, and sit in the car. In this analogy, the people are the data, the cars are the frames, the roller coaster tracks are the shared medium, and the protocol is the waiting in line and presentation of the ticket. Meeting Analogy Imagine yourself at a meeting table, along with the other members of a large talkative group. There is one shared medium - the space above the meeting table (air)- through which signals (spoken words) are communicated. The protocol for determining access to the medium is that the first person that speaks, when everyone quiets down, can talk as long as he/she wishes, until finished. In this analogy, the words of the individual members are the packets; the air above the meeting table is the medium; and the first person to speak in the meeting is the protocol.