Assignment 5 


**** Do the following two activities at OnlineTextbookLearningCenter of only related materials 

(1) Take online quizzes of multiple choices.

(2) Try the multiple choices at the end of each chapter of textbook.  Selected solutions are founded at the site.

 

0. Draw a diagram showing the connection establishment, flow of TCP segments, and connection setup and termination during a TCP session involving the transfer of 20-byte request from client followed by the transfer of 3000 bytes from the server (transferred 1000 bytes at a time).  The server closes the connection after the last segment is acknowledged.  Assume the ISNs for client and server are 100 and 200, respectively.

1. Are there any circumstances when a virtual circuit (e.g., connection oriented) service will (or at least should) deliver packets out of order?  Explain.

2. Give three examples of protocol parameters that might be negotiated when a connection is set up.

3. Assuming that all routers and hosts are working properly and that all software in both is free of all errors, is there any chance, however small, that a packet will be delivered to the wrong destination?

4.  If delays are recorded as 8-bit numbers in a 50-router network, and delay vectors are exchanged twice a second, how much bandwidth per (full-duplex) line is chewed up by the distributed routing algorithm?  Assume that each router has three lines to other routers.

5. An IP datagram using the strict source routing option has to be fragmented.  Do you think the option is copied into each fragment, or is it sufficient to just put it in the first fragment?  Explain your answer.

6. A class B network on the Internet has a subnet mask of 255.255.240.0.  What is the maximum number of hosts per subnet?

7. ARP and RARP both map addresses from one space to another.  In this respect, they are similar.  However, their implementations are fundamentally different.  In what major way do they differ?

8.  Most IP datagram reassembly algorithms have a timer to avoid having a lost fragment tie up reassembly buffers forever.  Suppose a datagram is fragmented into four fragments.  The first threee fragments arrive, but the last one is delayed.  Eventually the timer goes off and the three fragments in the receiver's memory are discarded.  A little later, the last fragment stumbles in.  What should be done with it? 

9.  The Protocol  field used in the IPv4 header is not present in the fixed IPv6 header. Why not?

10. When the IPv6 protocol is introduced, does the ARP protocol have to be changed?  If so, are the changes conceptual or technical?

11. Discuss the advantages and disadvantages of credits vs. sliding window protocols.

12. Datagram fragmentation and reassembly are handled by IP and are invisible to TCP.  Does this mean that TCP does not have to worry about data arriving out of order?

13. A process on host 1 has been assigned port p and a process on host 2 has been assigned port q.  Is it possible for there to be two or more TCP connections between these two ports at the same time?

14. The maximum payload of a TCP segment is 65,495 bytes.  Why was such a strange number chosen?

15. Consider the effect of using slow start on a line with a 10-msec round-trip time and no congestion.  The receive window is 24 KB and theMSS is 2 KB.  How long does it take before the first full window can be sent?

16. Suppose that TCP congestion window is set to 18K bytes and a timeout occurs.  How big will the window be if the next four transmission bursts are all successful?  Assume that  the MSS is 1 KB. 

 17.  If the TCP round-trip time, RTT, is currently 30 msec and the following acknowledgements come in after 26, 32, and 24 msec, respectively, what is the new RTT estimate?  Use a=0.9.

18. A TCP machine is sending windows of 65,535 bytes over a 1-Gbps channel that has a 10-msec one-way delay.  What is the maximum throughput achievable?  What is the line efficiency?

19. Why does UDP exist?  Would it not have been enought to just let user processes send raw IP packets?

20. A router using distance vector routing has the following routing table:

Net2 6 A
Net3 4 E
Net4 3 A
Net6 2 D
Net7 1 B

The router receives the following packet from router C:

Net2 4
Net3 5
Net4 2
Net6 3
Net7 2

Show the updated routing table for the router.

 

21. The value of the HLEN in an IP datagram is seven.  How many option bytes are present?

22. When I checked the TCP segment format,  I did not find any field in the header to indicate the segment length. And the question is: - How does the IP protocol in the same host know the length of the segment?

23 - Also, how does the TCP protocol in the other side know the length of the segment?

24 - How is MTU Discovery in IPv6 is different than that of IPv4?