TDC 562
Spring 2009

Computer Network Design and Analysis (Internet Engineering)

Assignment # 2: Network Simulation-I

Due: 5:45pm, May 12, 2009

Part I: Network Simulation and Analysis (80%)

 In this assignment you will do network simulation experiments using ns to study the Internet fairness when different multiple TCP streams (bulk and interactive) coexist. In addition, you will investigate the impact of UDP streams on the bandwidth fairness in Internet.

Network Topology and Infrastructure

Create two source hosts (n1 and n2) connected to router E1 with two links. Each link has 1 Mbps and 2 ms delay. The sources are connected to two destination hosts (h1 and h2 respectively) that are connected to router E2 through two links respectively. Each link has of 1 Mbps and 2 ms delay. The routers E1 and E2 are connected with each other over the Internet /WAN thru link of 1 Mbps, 15ms delay and Drop Tail for packet dropping. The topology is sketched as follows:

FTP n1 h1

\ /

1Mb\ 1Mb, 15ms /1Mb

E1--------------E2

1Mb/ \1Mb

/ \

CBR n2 h2

Initiate FTP traffic from n1 to h1 that uses packet size of 1024 bytes and window size 4Kbyte. The FTP traffic runs for 20 seconds. At time 4, initiate an audio traffic using UDP from n2 to h2 such that the audio packet size 1000 bytes and the rate is 0.5 Mbps. At time 10, the UDP traffic rate is increased to 1 Mbps. The UDP traffic stops at time 18 of the simulation and FTP stops at time 20.

(A) Plot in two graphs the throughput in Mbps for FTP, and UDP streams every 1 sec till the end of the simulation. (1 graphs – 20%)

(B) Plot in two graphs the number of packet dropped for FTP, and UDP streams every 1 sec till the end of the simulation. (1 graphs – 20%)

(C): After analyzing the results, state your observations and conclusion of the experiment above. Suggest solutions for any foreseen problems (10%)?

Send your solution in one file that includes all the graphs. Indicate clearly the parts and your conclusion. For plotting you can use Excel or any other tool. For analysis you can use awk, grep and wc –l in order to process the trace files in the UNIX environment. Feel free to use any other text processor program such as Excel. 

Part II: Fair Queuing

Re-do part#1 using FQ, instead of drop tail, such that each one will take equal share of the bandwidth. Run the simulation such that FTP starts from the beginning but CBR starts at the 5^th second and ends at 15^th second. Simulation ends after 18 seconds. (Use the same simulation configuration of ass#2 except the scenario and CBR start from the beginning as 1 Mbps). Show the throughput of both FTP and CBR streams at the receiver for each second.

Resources:

• You do not need to study ns Manual
• Use the nsBench software developed by the Multimedia Networking Research Laboratory to design and generate the TCL script of this project. You can find nsBench at www.mnlab.cs.depaul.edu/projects/nsbench/
• You can analyze the trace file using grep and Awk or any other text processing tool to extract the desired data. Look at the “Resources” link to download the “ns” and “nam” for Windows, and to get Awk tutorial/introduction.
• Download ns (and optionally nam) from www.mnlab.cs.depaul.edu/~ehab/Courses/resources
• To know how to trace the, look at this link: http://www.mnlab.cs.depaul.edu/~ehab/Courses/TDC562/resources/trace.readme and you may also look at NS Manual for more clarification.

Submission Procedure:

Use Word and Excel to write and plot graphs. For the simulation part, you MUST submit your solution electronically. Your submission of this project must include the following files:

(1) A DOC file that includes all the graphs, Awk/grep scripts used to extract the data, and the calculation of your answers

(2) The NS GUI source file

(3) The TCL script

DO NOT SEND TRACE FILE. They will not be used for grading your project. Use word processor and plotting programs to answer this assignment. You can either send your answers as ONE document. PLEASE SUBMIT USING DLWEB (do not send email).

Grading Policy:

Late penalty is 15% per day. Your solution must be concise and follow the number of pages and layout described in here and in the class.