Look at the following figure where N users share a 1 Mbps link. Each user alternates between periods of activity, when a user generates data at a constant rate of 100 kbps, and periods of inactivity, when a user generates no data. Suppose that a user is active only 50 percent of the time and is idle during the remaining 50 percent of the time.

If the maximum number of simultaneous users that circuit-switching can support is k, then determine the probability that at most k users will be active when we use packet switching to support 20 users. What happens when the number of users increases beyond 20 in packet switching?