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 --> E --> d --> c --> B --> A



Question List


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

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

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

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

5. Is the datagram being forwarded from E to d an IPv4 or IPv6 datagram?

6. What is the source address of this E to d datagram?

7. What is the destination address of this E to d datagram?

8. Is this E to d 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 d to c an IPv4 or IPv6 datagram?

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

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

14. Is this d to c 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 c to B an IPv4 or IPv6 datagram?

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

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

20. Is this c to B 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 B to A an IPv4 or IPv6 datagram?

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

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

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

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

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

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




Solution


1. The datagram is an IPv6 datagram.

2. The source IP address is 5828:36C1:DB22:A744:41C4:CCC2:9383:8A2F

3. The destination IP address is DBF4:FD5C:993C:76E9:428C:2998:22C9:4B72

4. No, the datagram is NOT encapsulated.

5. The datagram is an IPv4 datagram.

6. The source IP address is 119.91.2.39

7. The destination IP address is 182.110.207.85

8. Yes, the datagram is encapsulated.

9. The source address of this encapsulated datagram is 5828:36C1:DB22:A744:41C4:CCC2:9383:8A2F

10. The destination address of this encapsulated datagram is DBF4:FD5C:993C:76E9:428C:2998:22C9:4B72

11. The datagram is an IPv4 datagram.

12. The source IP address is 119.91.2.39

13. The destination IP address is 182.110.207.85

14. Yes, the datagram is encapsulated.

15. The source address of this encapsulated datagram is 5828:36C1:DB22:A744:41C4:CCC2:9383:8A2F

16. The destination address of this encapsulated datagram is DBF4:FD5C:993C:76E9:428C:2998:22C9:4B72

17. The datagram is an IPv4 datagram.

18. The source IP address is 119.91.2.39

19. The destination IP address is 182.110.207.85

20. Yes, the datagram is encapsulated.

21. The source address of this encapsulated datagram is 5828:36C1:DB22:A744:41C4:CCC2:9383:8A2F

22. The destination address of this encapsulated datagram is DBF4:FD5C:993C:76E9:428C:2998:22C9:4B72

23. The datagram is an IPv6 datagram.

24. The source IP address is 5828:36C1:DB22:A744:41C4:CCC2:9383:8A2F

25. The destination IP address is DBF4:FD5C:993C:76E9:428C:2998:22C9:4B72

26. No, the datagram is NOT encapsulated.

27. The tunnel entrance is router E

28. The tunnel exit is router B

29. 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 29

The answer was: 5828:36C1:DB22:A744:41C4:CCC2:9383:8A2F

Question 2 of 29

The answer was: DBF4:FD5C:993C:76E9:428C:2998:22C9:4B72

Question 3 of 29

The answer was: No

Question 4 of 29

The answer was: IPv4

Question 5 of 29

The answer was: 119.91.2.39

Question 6 of 29

The answer was: 182.110.207.85

Question 7 of 29

The answer was: Yes

Question 8 of 29

The answer was: 5828:36C1:DB22:A744:41C4:CCC2:9383:8A2F

Question 9 of 29

The answer was: DBF4:FD5C:993C:76E9:428C:2998:22C9:4B72

Question 10 of 29

The answer was: IPv4

Question 11 of 29

The answer was: 119.91.2.39

Question 12 of 29

The answer was: 182.110.207.85

Question 13 of 29

The answer was: Yes

Question 14 of 29

The answer was: 5828:36C1:DB22:A744:41C4:CCC2:9383:8A2F

Question 15 of 29

The answer was: DBF4:FD5C:993C:76E9:428C:2998:22C9:4B72

Question 16 of 29

The answer was: IPv4

Question 17 of 29

The answer was: 119.91.2.39

Question 18 of 29

The answer was: 182.110.207.85

Question 19 of 29

The answer was: Yes

Question 20 of 29

The answer was: 5828:36C1:DB22:A744:41C4:CCC2:9383:8A2F

Question 21 of 29

The answer was: DBF4:FD5C:993C:76E9:428C:2998:22C9:4B72

Question 22 of 29

The answer was: IPv6

Question 23 of 29

The answer was: 5828:36C1:DB22:A744:41C4:CCC2:9383:8A2F

Question 24 of 29

The answer was: DBF4:FD5C:993C:76E9:428C:2998:22C9:4B72

Question 25 of 29

The answer was: No

Question 26 of 29

The answer was: E

Question 27 of 29

The answer was: B

Question 28 of 29

The answer was: IPv4

Question 29 of 29

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