Binary Exponential Backoff Algorithm

• Binary Exponential Backoff Algorithm

When there is a collision, the stations involved in the collision will execute the binary exponential backoff algorithm to reduce the possibility of futher collisions.

When a collision is detected, the sender generates a noise burst to insure that all stations recognize the condition and aborts the transmission.
Wait 0 or 1 contention period (2  tex2html_wrap_inline740 , i.e. 2 end-to-end propagation time) before attempting transmission again.
If another collision is detected, wait 0, 1, 2, or 3 contention period. And repeat the protocol.
In general, wait between 0 and  tex2html_wrap_inline770 contention periods, where r is the number of collisions encountered.
Finally, freeze interval at 1023 contention periods after 10 attempts, and give up (report failure) after 16 attempts.

http://kevscode.com/csnotes/utpa/6345meng/notes/chpt-3/node18.html

• In a variety of computer networks, binary exponential backoff or truncated binary exponential backoff refers to an algorithm used to space out repeated retransmissions of the same block of data, often as part of network congestion avoidance.

Binary exponential backoff refers to a collision resolution mechanism used in random access MAC protocols.
This algorithm is used in Ethernet (IEEE 802.3) wired LANs. In Ethernet networks, this algorithm is commonly used to schedule retransmissions after collisions.

http://en.wikipedia.org/wiki/Exponential_backoff