Binary exponential backoff

The binary exponential backoff is a congestion resolution mechanism in Ethernet according to IEEE 802.3. If a collision is detected by stations in the Ethernet, these stations end their transmission and try immediately or after a slot time of 51.2 µs (corresponds to 512 bits, only applies to 10/100 Mbit / s Ethernet, 4.096 µs and 4096 bits for 1 GBit / s) to retransmit their broadcast over the Ethernet. A collision can occur again if both stations happen to make the same choice. In the next attempt, each of the two stations will now again randomly choose a new start date, but this time from four options: 0, 1, 2 or 3 slot times, i.e. 2 ² . If there is another collision, there are then 2 ³ = 8 possibilities, then 16, 32, 64, 128, 256, 512 and finally 1024. 1024 (2 ¹⁰ ) also represents the maximum limit of the possibilities (truncated). After a total of 16 unsuccessful transmission attempts with a collision, the Ethernet controller aborts with an error message.

literature

• PRAKASH C. GUPTA: DATA COMMUNICATIONS AND COMPUTER NETWORKS. Prentience-Hall of India Private Limitad, New Delhi 2006, ISBN 81-203-2846-9 .
• Charles E. Spurgeon: Ethernet. The Definitive Guide, O'Reilly Media Inc, Sebastopol 2000, ISBN 1-56592-660-9 .
• Martin Bossert, M. Breitbach: Digital networks. Function groups of digital networks and system examples, BG Teubner Verlag, Stuttgart 1999, ISBN 3-519-06191-0 .
• Rolf Herheuser: Planning of switching networks: An introduction , vdf Hochschulverlag AG, Zurich 2008, ISBN 978-3-7281-3698-5 .

See also

• The backoff procedure for Ethernet

Web links

• Link Layer - Ethernet (accessed July 27, 2017)
• Modified Binary Exponential Backoff Algorithm to Minimize Mobiles Communication Time (accessed July 27, 2017)
• MINIMIZING MOBILES COMMUNICATION TIME USING MODIFIED BINARY EXPONENTIAL BACKOFF ALGORITHM (accessed July 27, 2017)