4. a) Consider designing an ATM network with a leaky-bucket policer that ensures a virtual circuit does not send more cells than expected. Suppose a link has a first-in-first-out (FIFO) queue and carries traffic for two virtual circuits. The traffic on the first virtual circuit follows a leaky- bucket policer (with a bucket depth of 9 cells and a token rate of 100 cells/second) and can settle for best-effort service. The traffic on the second virtual circuit follows a leaky-bucket policer (with a bucket depth of one cell and a token rate of 100 cells/second) that cannot tolerate more than 100 milliseconds of delay in delivering each cell. Suppose the propagation delay on the link is 50 milliseconds. Analyse the smallest transmission rate R, in cells per second, that can satisfy the delay constraint, given that the link serves cells in FIFO order. 4. a) Consider designing an ATM network with a leaky-bucket policer that ensures a virtual circuit does not send more cells than expected. Suppose a link has a first-in-first-out (FIFO) queue and carries traffic for two virtual circuits. The traffic on the first virtual circuit follows a leaky- bucket policer (with a bucket depth of 9 cells and a token rate of 100 cells/second) and can settle for best-effort service. The traffic on the second virtual circuit follows a leaky-bucket policer (with a bucket depth of one cell and a token rate of 100 cells/second) that cannot tolerate more than 100 milliseconds of delay in delivering each cell. Suppose the propagation delay on the link is 50 milliseconds. Analyse the smallest transmission rate R, in cells per second, that can satisfy the delay constraint, given that the link serves cells in FIFO order