3. Suppose users share a 1 Mbps link. Also suppose each user requires 100kbps when transmitting, but each user transmits only 10 percent of the time. a. When circuit switching is used, how many users can be supported? b. For the remainder of this problem, suppose packet switching is used. Find the probability that a given user is transmitting. c. Suppose there are 40 users. Find the probability that at any given time, exactly n users are transmitting simultaneously. 4. List five access technologies. Classify each one as residential access, company access or mobile access.

Fig: 1