For each user, when active, needs 400Kbps bandwidth. There are total 30 such users wanting to get connected, where each user will be active with probability 0.2, all going through a link of 6Mbps. (a) Under circuit switching, up to how many users can be supported on this link? (b) Under packet switching, write down the probability that there are k active users out of 30, k = 0, 1, 30. What is the average number of active users? What is the probability that the link is actually overloaded, when all the 30 users are in the network