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(Note: Please click on Run to view Animation directly)
TitleCSMA/CA Demo Applet
LevelUnder Graduate
Summary:The 802.11 standard specifies a carrier sense multiple access with collision avoidance (CSMA/CA) protocol. In this protocol, when a node receives a packet to be transmitted, it first listens to ensure no other node is transmitting. If the channel is clear, it then transmits the packet. Otherwise, it chooses a random "backoff factor" which determines the amount of time the node must wait until it is allowed to transmit its packet. During periods in which the channel is clear, the transmitting node decrements its backoff counter. (When the channel is busy it does not decrement its backoff counter.) When the backoff counter reaches zero, the node transmits the packet. Since the probability that two nodes will choose the same backoff factor is small, collisions between packets are minimized. Collision detection, as is employed in Ethernet, cannot be used for the radio frequency transmissions of IEEE 802.11. The reason for this is that when a node is transmitting it cannot hear any other node in the system which may be transmitting, since its own signal will drown out any others arriving at the node.
Language: English
IDD writer:V V Raja Rao, V Sreenivasulu and Tanmay Kumar Pradhan
Mentor:Prof. Sridhar Iyer
Developer:V V Raja Rao, V Sreenivasulu and Tanmay Kumar Pradhan
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