Figure12.4 Procedure for pure ALOHA protocol纯ALOHA协议的流 Station has K:Number of attempts Start a frame to send Tp:Maximum propagation time Tr:Average transmission time for a frame Tg:Back-off time K=0 Wait Tg time (TB=R×Tpor RXT) Send the frame Choose a random number R between Wait time-out time 0and 2K-1 (2×Tp) No Kmax is K=K+1 No ACK a normally 15 received? Yes Yes Abort Success 12.6 12.6 Figure 12.4 Procedure for pure ALOHA protocol 纯ALOHA协议的流程图