A link with data rate R bps is shared by N users. Each user is only active 10% of the time, and a user requires 100kbps when active. a. If circuit switching is used and N=100, find the minimum R that can support all the users. b. For the remainder of the problem, we let R equal to the value of R obtained in (a). Suppose that packet switching is adopted. Find the maximum number of users the link can support if it is required that the probability of having no link congestion is at least 0.95. (Hint: Use the Central Limit Theorem for approximation.) c. If the users are active with probability of 0.9, repeat (b). d. Based on the results of (a), (b) and (c), discuss the advantages/disadvantages of circuit switching and packet switching.