Interactive end-of-chapter exercises


Supplement to Computer Networking: A Top Down Approach 8th Edition


"Tell me and I forget. Show me and I remember. Involve me and I understand." Chinese proverb

Textbook Cover

IPv6 Tunneling and Encapsulation

Consider the network shown below which contains four IPv6 subnets, connected by a mix of IPv6-only routers(shaded blue), IPv4-only routers (shaded red) and dual-capable IPv6/IPv4 routers (shaded blue with red interfaces to IPv4 routers). You might want to review Section 4.3.4 in the textbook before doing this problem.


Suppose that a host of subnet F wants to send an IPv6 datagram to a host on subnet A. Assume that the forwarding between these two hosts goes along the path: F --> b --> a --> c --> B --> A



Question List


1. Is the datagram being forwarded from F to b an IPv4 or IPv6 datagram?

2. What is the source address of this F to b datagram?

3. What is the destination address of this F to b datagram?

4. Is this F to b datagram encapsulating another datagram? Yes or No.

5. What is the source address of this encapsulated datagram?

6. What is the destination address of this encapsulated datagram?

7. Is the datagram being forwarded from b to a an IPv4 or IPv6 datagram?

8. What is the source address of this b to a datagram?

9. What is the destination address of this b to a datagram?

10. Is this b to a datagram encapsulating another datagram? Yes or No.

11. What is the source address of this encapsulated datagram?

12. What is the destination address of this encapsulated datagram?

13. Is the datagram being forwarded from a to c an IPv4 or IPv6 datagram?

14. What is the source address of this a to c datagram?

15. What is the destination address of this a to c datagram?

16. Is this a to c datagram encapsulating another datagram? Yes or No.

17. What is the source address of this encapsulated datagram?

18. What is the destination address of this encapsulated datagram?

19. Is the datagram being forwarded from c to B an IPv4 or IPv6 datagram?

20. What is the source address of this c to B datagram?

21. What is the destination address of this c to B datagram?

22. Is this c to B datagram encapsulating another datagram? Yes or No.

23. What is the source address of this encapsulated datagram?

24. What is the destination address of this encapsulated datagram?

25. Is the datagram being forwarded from B to A an IPv4 or IPv6 datagram?

26. What is the source address of this B to A datagram?

27. What is the destination address of this B to A datagram?

28. Is this B to A datagram encapsulating another datagram? Yes or No.

29. What router is the 'tunnel entrance'? Give the router's letter

30. What router is the 'tunnel exit'? Give the router's letter

31. Which protocol encapsulates the other, IPv4 or IPv6?




Solution


1. The datagram is an IPv4 datagram.

2. The source IP address is 94.151.135.135

3. The destination IP address is 176.71.38.30

4. Yes, the datagram is encapsulated.

5. The source address of this encapsulated datagram is CBB2:93C1:E149:E31C:2F5E:35EF:3285:A7AB

6. The destination address of this encapsulated datagram is C55B:C337:74F2:3385:3DAB:1C7A:94ED:D8B8

7. The datagram is an IPv4 datagram.

8. The source IP address is 94.151.135.135

9. The destination IP address is 176.71.38.30

10. Yes, the datagram is encapsulated.

11. The source address of this encapsulated datagram is CBB2:93C1:E149:E31C:2F5E:35EF:3285:A7AB

12. The destination address of this encapsulated datagram is C55B:C337:74F2:3385:3DAB:1C7A:94ED:D8B8

13. The datagram is an IPv4 datagram.

14. The source IP address is 94.151.135.135

15. The destination IP address is 176.71.38.30

16. Yes, the datagram is encapsulated.

17. The source address of this encapsulated datagram is CBB2:93C1:E149:E31C:2F5E:35EF:3285:A7AB

18. The destination address of this encapsulated datagram is C55B:C337:74F2:3385:3DAB:1C7A:94ED:D8B8

19. The datagram is an IPv4 datagram.

20. The source IP address is 94.151.135.135

21. The destination IP address is 176.71.38.30

22. Yes, the datagram is encapsulated.

23. The source address of this encapsulated datagram is CBB2:93C1:E149:E31C:2F5E:35EF:3285:A7AB

24. The destination address of this encapsulated datagram is C55B:C337:74F2:3385:3DAB:1C7A:94ED:D8B8

25. The datagram is an IPv6 datagram.

26. The source IP address is CBB2:93C1:E149:E31C:2F5E:35EF:3285:A7AB

27. The destination IP address is C55B:C337:74F2:3385:3DAB:1C7A:94ED:D8B8

28. No, the datagram is NOT encapsulated.

29. The tunnel entrance is router F

30. The tunnel exit is router B

31. IPv4, in order to maintain compatibility with existing IPv4 infrastructure, IPv6 datagrams are put in the payload of an IPv4 datagram. These IPv4 datagrams are passed on until it reaches a router which supports IPv6, where the IPv6 datagram is decapsulated and passed on.



That's incorrect

That's correct

The answer was: IPv4

Question 1 of 31

The answer was: 94.151.135.135

Question 2 of 31

The answer was: 176.71.38.30

Question 3 of 31

The answer was: Yes

Question 4 of 31

The answer was: CBB2:93C1:E149:E31C:2F5E:35EF:3285:A7AB

Question 5 of 31

The answer was: C55B:C337:74F2:3385:3DAB:1C7A:94ED:D8B8

Question 6 of 31

The answer was: IPv4

Question 7 of 31

The answer was: 94.151.135.135

Question 8 of 31

The answer was: 176.71.38.30

Question 9 of 31

The answer was: Yes

Question 10 of 31

The answer was: CBB2:93C1:E149:E31C:2F5E:35EF:3285:A7AB

Question 11 of 31

The answer was: C55B:C337:74F2:3385:3DAB:1C7A:94ED:D8B8

Question 12 of 31

The answer was: IPv4

Question 13 of 31

The answer was: 94.151.135.135

Question 14 of 31

The answer was: 176.71.38.30

Question 15 of 31

The answer was: Yes

Question 16 of 31

The answer was: CBB2:93C1:E149:E31C:2F5E:35EF:3285:A7AB

Question 17 of 31

The answer was: C55B:C337:74F2:3385:3DAB:1C7A:94ED:D8B8

Question 18 of 31

The answer was: IPv4

Question 19 of 31

The answer was: 94.151.135.135

Question 20 of 31

The answer was: 176.71.38.30

Question 21 of 31

The answer was: Yes

Question 22 of 31

The answer was: CBB2:93C1:E149:E31C:2F5E:35EF:3285:A7AB

Question 23 of 31

The answer was: C55B:C337:74F2:3385:3DAB:1C7A:94ED:D8B8

Question 24 of 31

The answer was: IPv6

Question 25 of 31

The answer was: CBB2:93C1:E149:E31C:2F5E:35EF:3285:A7AB

Question 26 of 31

The answer was: C55B:C337:74F2:3385:3DAB:1C7A:94ED:D8B8

Question 27 of 31

The answer was: No

Question 28 of 31

The answer was: F

Question 29 of 31

The answer was: B

Question 30 of 31

The answer was: IPv4

Question 31 of 31

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 © 2010-2021 J.F. Kurose, K.W. Ross
Comments welcome and appreciated: kurose@cs.umass.edu