Homework #6
  Homework #6.
Due 11:45PM, Jun.8 2016 Wednesday.
Please answer the following problems for the chapter 6 of the textbook:
  1. What is the function of the Transport Layer in the OSI Reference Model?
  2. Some protocols are said to provide a "reliable" service. What guarantees must a reliable protocol offer?
  3. To a certain extent, the transport service is similar to the network service, why are there two distinct layers? Why is one layer not adequate? What are the important differences between them.
  4. In some ways, transport protocols resemble the data link protocols we studied in detail in Chap. 3. Both have to deal with error control, sequencing, and flow control, among other issues. However, significant differences between the two also exist. Please explain these differences between the environments in which the two protocols operate.
  5. Explain what is meant by the term Service Access Point
  6. Using suitable diagrams, explain the purpose of the Ethernet Frame Type Field. Provide two examples of protocols whose operation relies on the presence of the Ethernet Frame Type Field.
  7. Draw diagrams to show UDP header format and TCP header format. You are supposed to draw them by yourself (don't copy from the Internet or the powerpoint slides). 
  8. Why does UDP exist? Would it not have been enough to just let user processes send raw IP packets?
  9. A session uses the User Datagram Protocol (UDP). It sends a series of packets over an Ethernet LAN. The payload of each UDP packet has a size of 690 bytes. Determine the total size of each Ethernet frame.
  10. Describe the operation of the "traceroute" program.
  11. 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 those two ports at the same time?
  12. What is the total size of the minimum TCP/IP MTU, including TCP and IP overhead but not including dad link layer overhead.
  13. In the TCP header (Fig.6-36 in the text), we saw that in addition to the 32-bit acknowledgement field, there is an ACK bit in the fourth word. Does this really add anything? Why or why not.
  14. Can both UDP and TCP deal with data on same port simultaneously?
  15. The maximum payload of a TCP segment is 65,495 bytes. Why was such a strange number chosen?
  16. Explain the TCP congestion Control mechanism in detail.
  17. Consider the effect of using slow start on a line with a 10 ms round-trip time and no congestion. The receive window is 24KB and the maximum segment size is 2 KB How long does it take before the first full window can be sent?
  18. Suppose that the TCP congestion window is set to 18KB and timeout occurs. How big will the window be if the next four transmission bursts are all successful? Assume that the maximum segment size is ../homework.html1KB.


  Notes for Submission  
  You may submit  follow the Electronic Submission Guidelines to submit HW6.
You can create your submission by doing the following for e-submission:
  • 1. Create a file containing your answers
  • 2. mail this file to class mail address, name the mail subject according to the Guidelines