3. (30 points) A random access LAN with 50 computers employs a CSMA protocol with collision detection. Consider the following parameters: maximum bus propagation delay=r=10 sec one packet transmission time P= 100 sec average collision detection delay To'=P, thus To=P+ (TB=0) Link rate R-1 Mbps Average network load G = 0.5 All stations are evenly placed on the bus All destinations are equally likely, i.e., average propagation delay 1, 1/3. For b and c, assume S-G 1+(1+a)G a. (10 points) Determine the probability a transmitted packet results in collision. b. (10 points) Determine the average number of retransmissions needed to transmit a packet successfully. c. (10 points) Determine the average transfer delay of a packet.