Ch. Yoon et Ck. Un, UNSLOTTED 1-PERSISTENT AND PI-PERSISTENT CSMA-CD PROTOCOLS FOR FIBER OPTIC BUS NETWORKS, IEEE transactions on communications, 42(2-4), 1994, pp. 458-465
We analyze the performance of the unslotted 1-persistent carrier sense
multiple access with collision detection (CSMA-CD) protocol for fiber
optic bus networks with a finite number of stations M, each of which
has an infinite storage buffer for storing packets with its length fix
ed or exponentially distributed. Treating the bus network as an M-clas
s priority queueing system with apreemptive-repeat-identical retransmi
ssion strategy, we show numerically that this 1-persistent retransmiss
ion strategy provides better delay-throughput performance than the non
-persistent one. To satisfy the fairness of equal delays among station
s in the bus network, we next present the unslotted p(i)-persistent CS
MA-CD protocol. Under this protocol, the first packet arriving at stat
ion i is forced to enter into the backoff procedure with the probabili
ty of (1 - p(i)). After backoffs, transmission begins until the statio
n becomes empty. We determine the persistent probability p(i) and show
that the delay-throughput performance of the p(i)-persistent strategy
is better than that of the 1-persistent one. and further it is robust
for any packet lengths. Simulation results are presented to verify th
e analytical results.