Lab 1: ns Basics

Exercise I

Run lab1c.tcl.
Now change size of buffer to 10 and see animation in nam. (Uncomment the two lines).What do you see?
Change TCP window size to 10. Do you see drops anymore?

Exercise II

By now you should know basic commands for creating simple networks. Create lab1d.tcl.

  1. Set up below network topology. Links 0-2 and 1-2 have bandwidth 5Mb and 2ms delay. Link 2-3 has bandwidth 1.5Mb and 10ms delay. 
    			
         0
          \
           \
            2------3
           /
          /
         1

  2. Set up TCP connection from node 0 to node 3, add FTP traffic (start at time 0.5);
  3. Generate nam trace and show animation;
  4. Show TCP sequence plot with nam graph;
  5. Change the size of buffer on link 2-3 to 10, repeat step 2 and 3. What do you observe? Is that what you expect?
  6. Re-run simulation with different types of TCP (TCP/Reno and TCP/NewReno), repeat step 3. What do you observe? Is that what you expect?
  7. Set up UDP connection from node 1 to node 3, add CBR traffic (packet size: 1000B, inter-arrival time: 8ms, start at time 1.0), repeat step 3. What do you observe? Is that what you expect?
  8. Re-run simulation with different types of TCP, repeat step 3. What do you observe? Is that what you expect?

Optional task:
  1. Insert error module on link 2-3, with packet drop rate 1%. Re-run simulations and show animation.
  2. Redo the simulation in nam editor.

References: