CSMA Back-Off Algorithm

[Matthew MacKenzie <mattm@adobe.com>]

On the topic of improving our retry algorithm, I think a variant of the
Back-Off algorithm used in Carrier Sense Multiple Access may be suitable.
Me may want to specify a "reset interval", so that the delay does not built
up to such a high number that the message is never transmitted after an
extended loss of connectivity.



http://www2.rad.com/networks/2001/ethernet/backof.htm

"Each sender will delay after a collision before attempting to retransmit.
If they will delay for the same time, another collision will occur. Thatıs
why each sender chooses a random delay between 0 and d (d is some standard
delay value). If, nevertheless, another collision occurs, each computer
doubles the range from which the delay is chosen,  that means, the random
delay will now be between 0 and 2d. If another collision occurs the range
will be between 0 and 4d and so onŠ After each collision the range of the
random delay increases exponentially, therefore the probability of collision
rapidly decreases and after few iterations becomes negligible."
___________________________
Matthew MacKenzie
Senior Architect
IDBU Server Solutions
Adobe Systems Canada Inc.
http://www.adobe.com/products/server/
mattm@adobe.com
+1 (506) 871.5409