What is Media Access Control?

Media Access Control is the set of mechanisms and protocols through which various devices on a computing and telecommunications network agree to share a media, the frequency range assigned to the system). Is the same concept as the multiplexing although this is a technique that can use different mechanisms. We talked about multiplexing in the article on Synchronous Optical Network.

Basics of Media Access Control

Theoretically, in the OSI model of computer networking, media access control is a data communication protocol in the sublayer of the data link layer. Media Access Control is abbreviated as MAC. Now recall the phrase MAC Address – this media access control is the MAC part.

One of the problems to be solved in a communication system is how to share data among multiple users using a single channel of communication or transmission medium, that can manage several messages simultaneously. Without a method of organization, interference that may well be annoying or directly impede communication. This concept is called multiplexing or media access control, depending on the context. A possible analogy to the problem of multiple access would be a room (which represent the channel) in which several people wish to speak at once. If several people talking at once, there will be interference and it will be difficult to understand individual’s words. To avoid or reduce the problem, they could take turns and speak (time division strategy), speak in sharper and more serious tones ( frequency division ), directing their voices in different directions in the room (spatial division) or speak in different languages ??(code division, as in CDMA), only people who know the code (ie, the “language”) can understand it.

Usage communication networks and media access control

More specifically, in computer networks; the acronym MAC is used in the family of IEEE 802 standards to define the sublayer of media access control. The MAC sublayer is located in the bottom of the data link layer. The exact implementation of this sublayer may vary depending upon the requirements of the physical layer (e.g. Ethernet, Token, WLAN ).

Some functions of the MAC sublayer includes :

1. Access Control to the physical transmission medium by devices that share the same communication channel.
2. Add the MAC address of the source node and the destination node in each of the frames those are transmitted.
3. When transmitting at source, delineate frames by adding flags, so that the receiver can recognize the beginning and end of each frame upon receipt at the destination to determine the start and end of a data frame within a bit stream received by the physical layer.
4. Perform screening and, if necessary, correction of errors of transmission.
5. Discard duplicate or erroneous frames.