COSC 450: Computer Networks

Homework Assignment #2

Due: 2/19/2009

  1. Consider the following routing table:
    MaskNetwork addressNext-hop addressFlagsInterface

    /7 6.0.0.0 162.25.1.1 UG m1
    /8 17.0.0.0 162.25.1.2 UG m1
    /8 56.0.0.0 56.0.1.1 UG m2
    /24 165.190.114.0 165.190.114.1 UG m3
    /26 140.24.7.0 ----
    		m4
    /26 140.24.7.64 ---- U m4
    /26 140.24.7.128 ---- U m4
    /22 140.24.0.0 140.24.0.1 U m4
    /0 0.0.0.0 140.24.7.1 UG m5

    Describe the process and the result of routing a packet addressed to:

    1. 7.5.1.100
    2. 165.190.114.2
    3. 140.12.0.1
    4. 140.24.0.9
    5. 140.24.7.3

  2. A router could be a dedicated device or could be software running on a host machine. If the router is a host on the network, are there any additional requirements for the host? What are the disadvantages of using a host as a router (as opposed to a dedicated device)? What are the advantages?

  3. Why are BOOTP and DHCP favored over ARP?

  4. Do Exercises 1, 2, and 3 from Practice Set 9.10

  5. List three significant differences between the UDP and IP protocols.

  6. Write an insult server program and an insult client program that communicate via UDP. The client program should prompt the user for a name of a person. The client should send a user datagram to the server with that name and receive back a user datagram containing an insult about that person, i.e., the returned insult should involve the name of the person. The client should then print the message to the screen of the user. The server should cycle through a list of insults. For example, the output from the client might look like: 

    Enter person's name> Sam
Sam is an idiot.

    Make sure that the programs run properly. E-mail me the source code for both the server and the client.

  7. Bonus Trivia Question: Describe what MBONE is and what it does. Find the closest MBONE router to Duquesne.
    Last modified: Feb. 11, 2009
    Dr. Donald L. Simon, simon@mathcs.duq.edu