Problem 21
Describe two major differences between the ECN method and the RED method of congestion avoidance.
Problem 22
A token bucket scheme is used for traffic shaping. A new token is put into the bucket every \(5 \mu \mathrm{sec}\). Each token is good for one short packet, which contains 48 bytes of data. What is the maximum sustainable data rate?
Problem 23
Explain how large file transfers could degrade the latency observed by both a gaming application and small file transfers.
Problem 26
A computer on a 6-Mbps network is regulated by a token bucket. The token bucket is filled at a rate of 1 Mbps. It is initially filled to capacity with 8 megabits. How long can the computer transmit at the full \(6 \mathrm{Mbps}\) ?
Problem 30
A router can process 2 million packets/sec. The load offered to it is \(1.5\) million packets/sec on average. If a route from source to destination contains 10 routers, how much time is spent being queued and serviced by the router?
Problem 31
Consider the user of differentiated services with expedited forwarding. Is there a guarantee that expedited packets experience a shorter delay than regular packets? Why or why not?
Problem 34
Suppose that instead of using 16 bits for the network part of a class B address originally, 20 bits had been used. How many class B networks would there have been?
Problem 35
Two IPv6-enabled devices wish to communicate across the Internet. Unfortunately, the path between these two devices includes a network that has not yet deployed IPv6. Design a way for the two devices to communicate.
Problem 37
A network on the Internet has a subnet mask of \(255.255 .240 .0\). What is the maximum number of hosts it can handle?
Problem 39
A router has just received the following new IP addresses: \(57.6 .96 .0 / 21,57.6 .104 .0 / 21\), \(57.6 .112 .0 / 21\), and \(57.6 .120 .0 / 21\). If all of them use the same outgoing line, can they be aggregated? If so, to what? If not, why not?
