Written Exercise #1

Due by 5:00pm, Monday, October 15.

This assignment is meant to help you review materials that we have learned so far. Although it also helps you to prepare for the midterm exam, note that it does not contain all materials that you need to review for the midterm. In particular, it does not contain any questions concerning the transport layer. Also note that we will not discuss written exercises with you over emails (which often add more confusions than doing the opposite). Please arrange to meet the TA or the instructor in person if you need help. Finally, for issues related to your grades, please speak to the TA only.

This assignment includes a number of end-of-chapter problems in the textbook by Kurose and Ross (third or fourth edition). Note that we are talking about end-of-chapter Problems, not Review Questions. If you do not own a copy of this textbook, you can come to us to make a copy of the problems.

  1. Chapter 5 Problem 5 (in fourth edition); or Chapter 5 Problem 4 (in third edition).
  2. Chapter 5 Problem 7 (in fourth edition); or Chapter 5 Problem 5 (in third edition).
  3. Chapter 5 Problem 11 (in fourth edition); or Chapter 5 Problem 8 (in third edition).
  4. Chapter 5 Problem 17 (in fourth edition); or Chapter 5 Problem 13 (in third edition). In this problem, we assume the signal propagates in the physical wire at the speed of 1.8 * 10^8 meters/second.
  5. List at least two practical scenarios in which link-layer broadcast (e.g., Ethernet broadcast) is needed.
  6. Chapter 4 Problem 22 (in fourth edition); or Chapter 4 Problem 21 (in third edition).
  7. Chapter 4 Problem 24 (in fourth edition); or Chapter 4 Problem 23 (in third edition).
  8. Chapter 4 Problem 25 (in fourth edition); or Chapter 4 Problem 24 (in third edition).
  9. Network latency triangular inequality.
    1. Consider a network that employs shortest-path routing (e.g., the routing path between two nodes is the shortest-latency path between them). For three machines A, B, and C, let lAB be the network latency between A and B; let lBC be the network latency between B and C; let lAC be the network latency between A and C. Is it possible for lAB + lBC < lAC? Explain your answer.
    2. Consider the practical wide-area Internet routing. lAB, lBC, and lAC are defined as in (a). Is it possible for lAB + lBC < lAC? Explain your answer.

Turn-in:
You have three ways to turn in your solution to this written exercise. First, you can turn in a hard copy of your solution to the TA in person anytime before the due time. The TA will be in his office during scheduled office hours. He may also be in office at other time but there is no guarantee. Second, you can turn in a hard copy of your solution at the class on Monday, October 15. Finally, you can email the TA an electronic copy of your solution (PDF format only) anytime before the due time.

Late turn-in policy:
No late turn-ins will be accepted. We enforce this policy because we want to hand back graded exercises before the midterm exam.