medium access control
	collision - 2+ stations xmit simultaneously
	each active station will transmit with prob p
	2 machines, p^2 = 1-((1-p)^2 + 2p(1-p))
	3 machines, 3p^2(1-p)+p^3
	4 machines, 6p^(2)*(1-p)^2+4p^(3)*(1-p)+p^4 = 1-((1-p)^4 + 4p(1-p)^3)
	n machines, 1-((1-p)^n + np(1-p)^(n-1))

i'm bored as fuck
if you need guarantee on delay, look at something other than ethernet, like token ring or real-time
csma/cd (carrier sense multiple access/collision detection aka ethernet)
csma/ca (carrier sense multiple access/collision avoidance aka ethernet)
2d is round trip propagation delay

jamming sequence sent out when a collision occurs to alert other stations, backoff timer enabled