Interactive end-of-chapter exercises


Link Layer (and network layer) addressing and forwarding

Consider the figure below. The IP and MAC addresses are shown for nodes A, B, C and D, as well as for the router's interfaces.


Consider an IP datagram being sent from node B to node A.



Question List


1. What is the source mac address at point 3?

2. What is the destination mac address at point 3?

3. What is the source IP address at point 3?

4. What is the destination IP address at point 3?

5. Do the source and destinaton mac addresses change at point 2? Answer with yes or no.

6. What is the source mac address at point 2?

7. What is the destination mac address at point 2?

8. Do the source and destinaton mac addresses change at point 1? Answer with yes or no.




Solution


1. The source mac address at point 3 is 21-5B-63-01-DB-AB

2. The destination mac address at point 3 is E0-BA-EE-85-F8-BE

3. The source IP address at point 3 is 128.119.244.62

4. The destination IP address at point 3 is 128.119.105.55

5. Yes, the datagram is being passed through a router, which causes a subnet change.

6. The source mac address at point 2 is E6-D3-45-2A-E7-EA

7. The destination mac address at point 2 is 79-F2-84-53-ED-93

8. No, datagrams can be sent across the subnet via the link layer in one go.



That's incorrect

That's correct

The answer was: 21-5B-63-01-DB-AB

Question 1 of 8

The answer was: E0-BA-EE-85-F8-BE

Question 2 of 8

The answer was: 128.119.244.62

Question 3 of 8

The answer was: 128.119.105.55

Question 4 of 8

The answer was: Yes

Question 5 of 8

The answer was: E6-D3-45-2A-E7-EA

Question 6 of 8

The answer was: 79-F2-84-53-ED-93

Question 7 of 8

The answer was: No

Question 8 of 8

Try Another Problem

We gratefully acknowledge the programming and problem design work of John Broderick (UMass '21), which has really helped to substantially improve this site.

Copyright © 2010-2022 J.F. Kurose, K.W. Ross
Comments welcome and appreciated: kurose@cs.umass.edu