J. Blustein

Network Computing

Assignment 1

Dates

Assigned

16 May

Due

26 May

Description

1. Answer the following four problems from Kurose & Ross (second edition) Chapter 1 (pp.68-73):
   1. Problem #2 (pp.68-69),
   2. Problem #3 (p.69 and Figure 1-5 on p.16),
   3. Problem #5 (p.69),
   4. Problem #9 (p.70) and

   Notes

   1. Note that some of the questions may be ambigous. You must state any assumptions you make in your answer.

      For instance, for problem #3 you might assume that all connections are between nodes in the network, or you might assume that the network is a subnet that might also have a connection to a larger network (such as the Internet).

      Furthmore, you might assume that time-division multiplexing or frequency-division multiplexing is being used. Your must state your assumption as part of your answer.

   2. Problem #3 refers to Figure 1-5 which is not in the first edition of the textbook. You can view that Figure here.

   3. You may use the following conversions without stating them as assumptions:

      1 byte =

      8 bits

      1 K =

      1000 (base 10, not base 2)

2. Consider the frosting-and-conveyor-belt analogy for a sender, a single link, and a receiver, as introduced in class today. Suppose that the sender outputs 3 bits per second, and that the conveyor belt is 4 meters long and moves at 10 cm/sec. Suppose that packets are 40 bits long.

   1. What is the propagation delay for this link?
   2. What is the transmission delay for one packet?
   3. How long will it take from the time the first bit is sent until the last bit arrives at the destination?
   4. What is the physical length of a bit on the conveyor belt?

   5. Add a router and a second link identical to the first, so that there are two 4-meter conveyor belts in succession. Suppose that there is a processing delay of 8 seconds to begin retransmitting a packet at the router.

      Calculate how long it would take to transfer a file consisting of 15 packets across the two links. (You can think of the file as a message in the terminology we've been using in class.)

Submission Instructions

1. You will be submitting an entire directory electronically, even if there is only one file in the directory.
2. The files you submit must all be in a directory named A1.
3. Be sure that your name and student number are in all of the files you submit.
4. turn in all the files in your A1 directory using the submit program on borg (or torch).