epl324 lab 2 delays - university of cyprus · lab 2: looking into delays objectives 1. to learn how...

DELAYS

OPNET LAB MANUAL

Yiannos Mylonas

Yiannos Mylonas 9/16/2013

Lab 2: Looking into Delays

Objectives

1. To learn how to use work with palette

2. To learn how to add nodes in your network

3. To learn how to choose statistics

4. To lean about end-to-delay, possessing delay, transmission delay, propagation delay, queuing delay

5. View Results

6. Compare Results

Overview

Figures 1-3 show the network topology that we use in this lab which is consisted from two subnets (local area networks) one located in Cyprus and the other one in USA. Each subnet has its own network.

Figure 1: USA-Cyprus Network Topology


Figure 2: USA Network Topology

Figure 3: Cyprus Network Topology

Instructions


1. Opening an existing Project in OPNET

a. Start OPNET Modeler

b. You need to download the lab_2_dist_2011.rar file from the website.

i. Go to the lab website (http://www.cs.ucy.ac.cy/courses/EPL324/laboratory.htm)

ii. Click on the link saying OPNET Files: lab_2_dist_2013.rar

iii. Saved this file under the o:/op_models directory

iv. Extract the lab_2_dist_2013.rar file in your op_models directory

v. From the OPNET application click on File/ Model Files/ Add Model Directory find the new directory that has been created under the op_models and click OK.

vi. Then check the option to include all sub-directories and click OK.

c. To open an existing project click on File/ Open.

d. From the Open dialog box click on the project you want to open lab_2_dist_2011_delays and then click Open.

e. Make sure you are in the baseline scenario. Scenarios-Switch to Scenarios-baseline. Start building the above network in figures 1, 2, and 3.

i. To connect the wan link between the two subnets you need to be on the top level and seeing the two subnets click on the one subnets and then to the next one. A new window will pop up where you can choose how to connect your wan link; you need to choose the two routers of each site.

f. After finishing placing and connecting all the network components make sure all the links are connected correctly. You can check this by click on the verify links icon.

g. Add the applications and profiles for this network. The applications and the profiles have being pre-configured but have not being assigned on the server or on the workstation.

h. Double click on the USA subnet and right click on the USA FTP Server and choose Edit Attributes. Double click on none value next to Applications- Application: Supported Services. On the new window you need add to a new row. To do that click next to the Rows on the left and type 1.


Figure 1: Node Attributes

i. On the new row that has being appeared click under the name and choose FTP_Apps. Click OK and again OK.


Figure 2: Application: Supported Services

j. Now return back to the top level by clicking on the . At the top level double click on the Cyprus Subnet. Right click on the Cyprus User 1 and choose Edit Attributes. Double click on none value next to Applications- Application: Supported Profiles. A new window will appear click to add a new row to 1 and then click on the name of the new line that has appeared. Choose FTP_Profile. Click OK and again OK.

k. Return to the top level.

l. At this point you need to choose the statistics that you want to investigate. Choose DES- Choose Individual Statistics or right click with your mouse on an empty space and click on the - Choose Individual Statistics

i. FTP: Download File Size (as is)

ii. FTP: Download Response Time (as is)

iii. IP: Processing Delay (as is)

iv. Wan Link: queuing delay (average)

v. Wan Link: queuing delay (average)

vi. Wan Link: Throughput bits/sec (average)

vii. Wan Link: Utilization bits/sec (as is)


Running Simulation

a. You are ready to run your simulation and obtain some results. Click on DES/

Run Discrete Event Simulation or click on the icon . A hot key short cut is CTRL+SHIFT+R.

b. From the Configure / Run DES dialog box just make sure the Duration is set to 20 minutes and Click Run.

NOTE: Duration time is real network time. It means that the 20 minutes that you will be monitoring your network for 20 minutes. It does not mean that it would take 20 minutes for the simulator to produce results. It could take much less than or more than 20 minutes. It depends on how large is your network and on your processor speed, memory and etc.

c. Click Close.

d. To open the DES Log, click on DES/ Open DES Log. Examine the DES Log and if there no any errors move to the next step.


2. View Results

a. There are two ways to access your results:

i. Click on DES/Results or Right click on an empty workspace in your Project Editor and click on View Results

Figure 4: View Results

Figure 3: View Results

b. From the dialog box click View Results.


3. Propagation Delay

a. Switch to Scenario: Baseline_Cyprus

i. Click Scenarios-> Switch to Scenarios -> Baseline_Cyprus

b. The Baseline_Cyprus scenario has the same characteristics as the baseline with the only difference that the distance between of the two subnets is different. We will use the Baseline_Cyprus as our baseline scenario to perform various comparisons among other scenarios.

c. Make sure that the following statistics have being selected. Choose DES- Choose Individual Statistics:

i. FTP: Download File Size (as is)

ii. FTP: Download Response Time (as is)

iii. IP: Processing Delay

iv. Wan Link: queuing delay (average)

v. Wan Link: queuing delay (average)

vi. Wan Link: Throughput bits/sec (average)

vii. Wan Link: Utilization bits/sec (as is)

d. Switch to Scenario: USA_Propagation_Delay This scenario has the same characteristics as the scenario we have build and it is the same with Baseline_Cyprus with a minor difference the distance between the two sites.

i. Make sure that the following statistics have being selected. Choose DES- Choose Individual Statistics:

1. FTP: Download File Size (as is)

2. FTP: Download Response Time (as is)

3. IP: Processing Delay

4. Wan Link: queuing delay (average)

5. Wan Link: queuing delay (average)

6. ink: Throughput bits/sec (average)

7. Wan Link: Utilization bits/sec (as is)

e. Click on Scenarios and Manage Scenarios. Run the Baseline_Cyprus and the USA_Propagation scenarios.

f. Check the results that you have got from this scenario. Do you notice any differences? (Compare Results)

i. To be able to understand what is happening in these two scenarios you need to have some more information regarding this networks.


Follow the steps below to obtain some more information about this network.

ii. Go to the top level of the project and right click on Applications and Edit Attributes.

iii. Double-click on …. It is next to the Applications Definitions. You will get a new window double-click on the …. Find the row of the Ftp and double click on the …..

iv. Figure x shows the parameters that are related with the Ftp application.

Figure 4: Application Attributes

v. Find the file Size and write it down.

vi. File Size (Bytes):____________

vii. Click cancel in all windows and return back to the top level.


viii. Click on the wan link and right click- edit attributes. Click on Advanced more parameters will appear in the window. Find the Data Rate, and Propagation Speed, and write it down.

ix. Check the value of the delay. Here you can define the delay of the link to be computed by OPNET based on distance or you can set your own fix delay.

x. Click cancel.

Propagation Delay

Scenario File Size(bytes)

Data Rate(b/sec) Speed of the Medium

Distance(m)

Baseline_Cyprus

USA_Propagation Delay

Write the Definition for the Propagation Delay and the formula that we use to calculate the Propagation delay:

_____________________________________________________________________

Propagation Delay =


4. Transmission Delay

a. Switch to Scenario: USA_Transmission_Delay

b. The USA_Transmission_Delay scenario has the same characteristics as the USA_Propagation_Delay baseline with the only difference that the link between USA and Cyprus has being upgraded to 1,545,000 bits/sec.


viii. FTP: Download File Size (as is)

ix. FTP: Download Response Time (as is)

x. IP: Processing Delay

xi. Wan Link: queuing delay (average)

xii. Wan Link: queuing delay (average)

xiii. Wan Link: Throughput bits/sec (average)

xiv. Wan Link: Utilization bits/sec (as is)

d. Click on DES/ Run Discrete Event Simulation or click on the icon . A hot key short cut is CTRL+SHIFT+R.

e. Compare the USA_Propagation_Delay with the USA_Transsmisison_Delay.


Fill in the table:

Transmission Delay

Scenario File Size(bytes) Data Rate(b/sec)

USA_Propagation_Delay

USA_Transmission Delay

Write the Definition for the Transmission Delay and the formula that we use to calculate the Propagation delay:

_____________________________________________________________________

Transmission Delay =


Queuing Delay

g. Switch to Scenario: USA_Queuing_Delay

h. The USA_ Queuing _Delay scenario has the same characteristics as the USA_Propagation_Delay with the only difference that we have added more traffic at the link USA to Cyprus to demonstrate the Queuing Delay.

i. Make sure that the following statistics have being selected. Choose DES- Choose Individual Statistics:

xv. FTP: Download File Size (as is)

xvi. FTP: Download Response Time (as is)

xvii. IP: Processing Delay

xviii. Wan Link: queuing delay (average)

xix. Wan Link: queuing delay (average)

xx. Wan Link: Throughput bits/sec (average)

xxi. Wan Link: Utilization bits/sec (as is)

j. Click on DES/ Run Discrete Event Simulation or click on the icon . A hot key short cut is CTRL+SHIFT+R.

k. Compare the USA_Propagation_Delay with the USA_Queueing_Delay.

l. Check the results that you have got from this scenario. Do you notice any differences? (Compare Results)

Write the definition for the Queuing Delay:

_____________________________________________________________________


5. Processing Delay

a. Switch to Scenario: USA_Processing_Delay

b. The USA_ Processing_Delay scenario has the same characteristics as the USA_Propagation_Delay with the only difference that we have configured the routers of the scenario USA_Processing_Delay to forward 1000 packets per second and on the USA_Propagation_Delay to 50000. The value of this metric is dependent on the performance of the router. To investigate this metric right click on router, Edit Attributes, click on IP, IP Processing Information and find the attribute Datagram Forwarding Rate.

Figure 5: Datagram Forwarding Rate


xxii. FTP: Download File Size (as is)


xxiii. FTP: Download Response Time (as is)

xxiv. IP: Processing Delay

xxv. Wan Link: queuing delay (average)

xxvi. Wan Link: queuing delay (average)

xxvii. Wan Link: Throughput bits/sec (average)

xxviii. Wan Link: Utilization bits/sec (as is)

d. Click on DES/ Run Discrete Event Simulation or click on the icon . A hot key short cut is CTRL+SHIFT+R.

e. Compare the USA_Propagation_Delay with the USA_Processing_Delay.


Write the definition for the Processing Delay:

_____________________________________________________________________


Analytic Approach on delays

Processing Delay

The time required to examine the packet’s header and determine where to direct the packet. Usually is in the order of microseconds or less in high speed routers.

Queuing Delay

It is the time the packet waits in the queue of the router until is being transmitted on the link.

Transmission Delay

The amount of time is needed to push all of the packet’s bits into the link. Transmission delays are typically on the order of microseconds to milliseconds.

Transmission Delay = L (size of the packet in bits) / R (transmission rate)

Propagation Delay

Once a bit is pushed onto the link, it needs to propagate to router. The time required to propagate from the beginning of the link to the next router is the propagation delay.

Propagation Delay = d (distance between two router) / s (propagation speed)

Propagation speed depends on the physical medium of the link.

epl324 lab 2 delays - university of cyprus · lab 2: looking into delays objectives 1. to learn how...

Documents