To understand how the token bucket algorithm can give credit to the sender that does not use its rate allocation for a while but wants to use it later, let's repeat the previous problem with r = 3 and c =10, but assume that the sender uses a variable rate, as shown in Figure 30.15. The sender sends only three packets per second for the first two seconds, sends no packets for the next two seconds, and sends seven packets for the next three seconds. The sender is allowed to send five packets per second, but, since it does not use this right fully during the first four seconds, it can send more in the next three seconds. Show the contents of the token bucket and the buffer for each second to prove this fact.
