Interactive end-of-chapter exercises


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



Question List


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

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

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

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

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

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

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

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

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

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

11. Is the datagram being forwarded from b to d an IPv4 or IPv6 datagram?

12. What is the source address of this b to d datagram?

13. What is the destination address of this b to d datagram?

14. Is this b to d datagram encapsulating another datagram? Yes or No.

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

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

17. Is the datagram being forwarded from d to c an IPv4 or IPv6 datagram?

18. What is the source address of this d to c datagram?

19. What is the destination address of this d to c datagram?

20. Is this d to c datagram encapsulating another datagram? Yes or No.

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

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

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

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

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

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

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

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

29. Is the datagram being forwarded from a to C an IPv4 or IPv6 datagram?

30. What is the source address of this a to C datagram?

31. What is the destination address of this a to C datagram?

32. Is this a to C datagram encapsulating another datagram? Yes or No.

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

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

35. Is the datagram being forwarded from C to A an IPv4 or IPv6 datagram?

36. What is the source address of this C to A datagram?

37. What is the destination address of this C to A datagram?

38. Is this C to A datagram encapsulating another datagram? Yes or No.

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

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

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




Solution


1. The datagram is an IPv6 datagram.

2. The source IP address is BFA6:7112:67B5:5A6C:15BB:F46A:9C78:8F16

3. The destination IP address is B664:A49E:FD15:F6E3:359A:9177:C6F7:69A1

4. No, the datagram is NOT encapsulated.

5. The datagram is an IPv4 datagram.

6. The source IP address is 29.5.180.249

7. The destination IP address is 187.23.39.235

8. Yes, the datagram is encapsulated.

9. The source address of this encapsulated datagram is BFA6:7112:67B5:5A6C:15BB:F46A:9C78:8F16

10. The destination address of this encapsulated datagram is B664:A49E:FD15:F6E3:359A:9177:C6F7:69A1

11. The datagram is an IPv4 datagram.

12. The source IP address is 29.5.180.249

13. The destination IP address is 187.23.39.235

14. Yes, the datagram is encapsulated.

15. The source address of this encapsulated datagram is BFA6:7112:67B5:5A6C:15BB:F46A:9C78:8F16

16. The destination address of this encapsulated datagram is B664:A49E:FD15:F6E3:359A:9177:C6F7:69A1

17. The datagram is an IPv4 datagram.

18. The source IP address is 29.5.180.249

19. The destination IP address is 187.23.39.235

20. Yes, the datagram is encapsulated.

21. The source address of this encapsulated datagram is BFA6:7112:67B5:5A6C:15BB:F46A:9C78:8F16

22. The destination address of this encapsulated datagram is B664:A49E:FD15:F6E3:359A:9177:C6F7:69A1

23. The datagram is an IPv4 datagram.

24. The source IP address is 29.5.180.249

25. The destination IP address is 187.23.39.235

26. Yes, the datagram is encapsulated.

27. The source address of this encapsulated datagram is BFA6:7112:67B5:5A6C:15BB:F46A:9C78:8F16

28. The destination address of this encapsulated datagram is B664:A49E:FD15:F6E3:359A:9177:C6F7:69A1

29. The datagram is an IPv4 datagram.

30. The source IP address is 29.5.180.249

31. The destination IP address is 187.23.39.235

32. Yes, the datagram is encapsulated.

33. The source address of this encapsulated datagram is BFA6:7112:67B5:5A6C:15BB:F46A:9C78:8F16

34. The destination address of this encapsulated datagram is B664:A49E:FD15:F6E3:359A:9177:C6F7:69A1

35. The datagram is an IPv6 datagram.

36. The source IP address is BFA6:7112:67B5:5A6C:15BB:F46A:9C78:8F16

37. The destination IP address is B664:A49E:FD15:F6E3:359A:9177:C6F7:69A1

38. No, the datagram is NOT encapsulated.

39. The tunnel entrance is router F

40. The tunnel exit is router C

41. 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: IPv6

Question 1 of 41

The answer was: BFA6:7112:67B5:5A6C:15BB:F46A:9C78:8F16

Question 2 of 41

The answer was: B664:A49E:FD15:F6E3:359A:9177:C6F7:69A1

Question 3 of 41

The answer was: No

Question 4 of 41

The answer was: IPv4

Question 5 of 41

The answer was: 29.5.180.249

Question 6 of 41

The answer was: 187.23.39.235

Question 7 of 41

The answer was: Yes

Question 8 of 41

The answer was: BFA6:7112:67B5:5A6C:15BB:F46A:9C78:8F16

Question 9 of 41

The answer was: B664:A49E:FD15:F6E3:359A:9177:C6F7:69A1

Question 10 of 41

The answer was: IPv4

Question 11 of 41

The answer was: 29.5.180.249

Question 12 of 41

The answer was: 187.23.39.235

Question 13 of 41

The answer was: Yes

Question 14 of 41

The answer was: BFA6:7112:67B5:5A6C:15BB:F46A:9C78:8F16

Question 15 of 41

The answer was: B664:A49E:FD15:F6E3:359A:9177:C6F7:69A1

Question 16 of 41

The answer was: IPv4

Question 17 of 41

The answer was: 29.5.180.249

Question 18 of 41

The answer was: 187.23.39.235

Question 19 of 41

The answer was: Yes

Question 20 of 41

The answer was: BFA6:7112:67B5:5A6C:15BB:F46A:9C78:8F16

Question 21 of 41

The answer was: B664:A49E:FD15:F6E3:359A:9177:C6F7:69A1

Question 22 of 41

The answer was: IPv4

Question 23 of 41

The answer was: 29.5.180.249

Question 24 of 41

The answer was: 187.23.39.235

Question 25 of 41

The answer was: Yes

Question 26 of 41

The answer was: BFA6:7112:67B5:5A6C:15BB:F46A:9C78:8F16

Question 27 of 41

The answer was: B664:A49E:FD15:F6E3:359A:9177:C6F7:69A1

Question 28 of 41

The answer was: IPv4

Question 29 of 41

The answer was: 29.5.180.249

Question 30 of 41

The answer was: 187.23.39.235

Question 31 of 41

The answer was: Yes

Question 32 of 41

The answer was: BFA6:7112:67B5:5A6C:15BB:F46A:9C78:8F16

Question 33 of 41

The answer was: B664:A49E:FD15:F6E3:359A:9177:C6F7:69A1

Question 34 of 41

The answer was: IPv6

Question 35 of 41

The answer was: BFA6:7112:67B5:5A6C:15BB:F46A:9C78:8F16

Question 36 of 41

The answer was: B664:A49E:FD15:F6E3:359A:9177:C6F7:69A1

Question 37 of 41

The answer was: No

Question 38 of 41

The answer was: F

Question 39 of 41

The answer was: C

Question 40 of 41

The answer was: IPv4

Question 41 of 41

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We greatly appreciate the work of John Broderick (UMass '21) in helping to develop these interactive problems.

Copyright © 2010-2025 J.F. Kurose, K.W. Ross
Comments welcome and appreciated: kurose@cs.umass.edu