OPNET WAN Assignment1 We are now familiar with the use of network simulation software in general and OPNET as a specific example. To complete the basic network models that may be created in OPNET, this assignment goes over the creation of a wide area network. We use an IP cloud as the example of a WAN in this example, because it is relatively easy to set up and configure, compared to other WAN models such as frame relay, ATM and MPLS. To make the exercise interesting we examine the improvements that may be achieved by replacing 56Kbps lines with DS-1 and DS-3 lines for network connectivity. OPNET started out as software to model protocols and network devices. The original product was called Modeler and it allowed detailed internal specifications of network devices. IT guru is an offshoot of Modeler and only allows user views of devices. However, many modules related to network management work with IT Guru. Start OPNET IT Guru (Start Programs OPNET IT Guru 8.1 OPNET IT Guru) 1) Create an IT Guru project with an empty scenario. To see how some of the other built-in maps may be

used, select Choose From Maps in the Choose Network Scale dialog box. Check or uncheck the Metric Units box as you like and then Click Next

2) Select USA from the Choose Map dialog box and Click Next 3) The default Object Palette that opens up is the internet_toolbox palette. We need to add one more

object to the palette. Add a CS3640_Router by clicking Configure Palette and in the dialog box, clicking Node Models. Include the CS3640_Router entry and Click OK. Click OK to close the Configure Palette dialog box

4) Click the Zoom action button 5) Select the center of the area and zoom in on and drag a rectangle to the bottom right corner. Make sure

that Minneapolis, Dallas, Atlanta and Detroit are all included in the zoomed view (Note: If you are not happy with your first zoom, you can click the Unzoom action button next to the Zoom action button, and then zoom in again).

6) Unlike the LAN exercise where our entire model was a single network, we now have 4 networks connected by long-haul links. To make it easy to represent these networks for the overall model while simultaneously allowing details within each network, we can create an “envelope” around them. These envelopes are called a subnets.

7) Place a subnet over Minneapolis a) Click the subnet icon in the Object Palette and place it on the workspace corresponding to

Minneapolis. b) Right-Click when finished placing the subnet. Name the subnet Minneapolis by right-clicking and

selecting Set Name 8) Enter the Minneapolis subnet by double-clicking on it. We

can now create the Minneapolis network in every detail as we did in the LAN assignment. a) Choose Topology Rapid Configuration; change

“Bus” to “Star”. b) Set Center Node Model as

“eth16_ethch16_fddi16_tr16_switch” c) Set Periphery Node Model as “ethernet_wkstn” d) Set Link Model as “100BaseT” e) Set Number as “28” Click OK to close the Rapid

Configuration dialog box. 9) Each subnet is connected to the network through a router. Place the CS3640_Router object into the

workspace. Set the name of the router as Minneapolis_cisco_router. 1 Special thanks to Sri Subramanian, Graduate assistant for ISM 6225 in Fall 2002 for creating the project specifications and detailed instructions

ISM 6225: OPNET WAN instructions

a) Create a “100BaseT” link between the Router and the switch. Your subnet should look like the above figure.

10) Go back to the WAN view of the network by right-clicking on a blank part of the subnet and selecting “Go to Parent Subnet”. This is the fundamental mechanism to move between parents and subnets. Note that you may nest subnets, meaning that as the departments grew bigger, we could have subnets for each department in the Minneapolis office.

11) Since we are just creating a usable network, we can simplify our design of the overall network by using some simple copying and pasting. Copy the Minneapolis LAN subnet to Detroit, and Atlanta: a) Select the Minneapolis subnet; copy it using Edit Copy or Ctrl-C b) Choose Edit Paste or Ctrl-V; left-click on Detroit c) Repeat on Atlanta

12) Make appropriate changes to the 2 newly created subnets a) Name the subnets “Detroit” and “Atlanta”. These labels vastly simplify understanding the network

later. b) Enter the subnets, name the routers in each respective city, “Detroit_cisco_router” and

“Atlanta_cisco_router”. 13) To further simplify the design of the network in this assignment, we decided to place all the servers in

one single subnet. This corresponds to a centralized IT infrastructure. Since the machines here are different from the machines in the other 3 “client” subnets, we need to create it from scratch like Minneapolis. We will create the “server” subnet in Dallas. a) Place a subnet over Dallas from the Object Palette. Set the name as Dallas. Enter the Dallas subnet b) Select the ethernet_server from the Palette c) Place 6 servers in the subnet d) Place a eth16_ethch16_fddi16_tr16_switch and a CS3640_Router in the subnet e) Connect all servers to the switch using 100BaseT links f) Connect the router to the switch also using 100BaseT link.. g) Return to the parent subnet

Select File Save to save the project 14) Having created the 4 subnets, we are now ready to add the WAN object to connect the 4 networks. We

will do this by placing an IP cloud in the middle of the 4 subnets: a) Open the Object Palette. Drag the icon labeled

ip32_cloud onto the workspace. Set the name of the cloud as IP Cloud

b) Connect the Dallas subnet to the cloud with a PPP_DS1 link

c) When prompted for which node within the subnet to connect the link to, choose the node name ending in “Dallas_cisco_router”

d) Right-click in the workspace to stop placing DS1 links e) Connect the cloud to the other 3 subnets using a

PPP_56K link (These are slow links and will help us see the improvements by upgrading links) f) Again when prompted for which node within the subnet to connect the link to, choose the node

name ending in “cityname_cisco_router”. Verify that your network topology looks as shown Choose File Save

ISM 6225: OPNET WAN instructions

15) Find the Application Config object in the palette. Select and drop it into the workspace. Right-click to indicate you are finished placing this kind of object. We have to now set the attributes for the Application Config object to create some applications a) Select this object and right-click on it. b) Select Edit Attributes. Change the name attribute to Application Configuration Utility. c) Select Edit from the Value column corresponding to the Applications Definitions attribute =>The

(Application Definitions) Table dialog box appears. d) Change the number of rows to 1. Enter the Application name as DB User. e) In the Description column, select Edit.

=>The (Description) Table dialog box appears. f) Select High Load from the Value column for the Database attribute. Click OK to close the

Description dialog box. g) Click OK to close the Application Definitions dialog box. Click OK to close the Attributes dialog

box.

16) Find the Profile Config object on the Palette. Select and drop it into the workspace. Now we have to set the attributes of this object. To simplify things, assume that there is only one kind of user on the network so that the profile configuration only has one row. Right-click the profile configuration utility. Select Edit Attributes. Change the name attribute to Profile Configuration Utility. Change the Profile Configuration attribute by clicking in its Value column and selecting Edit from the pop-up list =>The (Profile Configuration) Table dialog box appears. a) Change the number of rows to 1 b) Enter the profile name as DB Client. c) Change the supported Application by selecting the Edit from the pop-up list in the Applications

column =>The (Applications) Table dialog box appears d) Select DB User from the pop-up list in the Name column. Click OK to close the Applications Table

dialog box e) Click OK to close the Profile Configuration dialog box. f) Click OK to close the Attributes dialog box.

17) We need to Configure the Workstations by assigning them the profile just created

a) Double-click on the Atlanta subnet and right-click a workstation b) Choose “Select Similar Nodes” c) Right-click on the workstation again and select Edit Attributes d) First, check the box at the bottom of the window for “Apply Changes to Selected Objects” e) Next, change the value of the Application: Supported Profiles attribute to “Edit” f) Change the number of rows to 1 g) Choose “DB Client” from the popup in the Profile name column h) Click OK to close the Application: Supported Profiles dialog box. i) Click OK to close the Attributes dialog box. j) Note status bar (in lower left corner) showing 84 objects changed

18) We need to now Configure the Servers in the Dallas subnet by assigning them the application we created.

Effectively, our network has one category of users accessing one application. a) Double-click on the Dallas subnet and right-click a server b) Choose “Select Similar Nodes” c) Right-click on the server again and select Edit Attributes d) Check the box at the bottom of the window for “Apply Changes to Selected Objects” e) Change the value of the Application: Supported Services attribute to “Edit” f) Change the number of rows to 1 g) Choose “DB User” from the pop-up for the Name column h) Click OK to close the Application: Supported Services dialog box

ISM 6225: OPNET WAN instructions

i) Click OK to close the Attributes dialog box j) Save your Project

19) Now we need to Choose Statistics and Run the simulation

a) From the Simulation menu, select Choose Individual Statistics b) Click on the plus signs next to the categories and expand them c) Choose the following statistics by clicking on the gray box next to the statistic:

o Global Statistics/DB query/Response Time (sec) o Node Statistics/Server DB Query/Task Processing time o Link statistics/point-to-point/utilization o Link statistics/point-to-point/utilization

d) Click OK to close the Choose Results dialog box 20) Next, we must configure and run the simulation to run for half-an hour

a) Choose Simulation Configure Simulation b) Set the duration to 0.5 hours. c) Press “Run”

21) We need to now View the Results of our simulation

a) Choose Results View Results b) Check the box next to Global Statistics/DB

Query/Response Time (sec) c) Press “Show” d) In the View Results dialog box, change the filter from “As Is”

to “average” e) Press “Add” and click on the graph that was just created f) Verify that your graphs look similar to the one below- you may

have peaks and valleys in different places, but the range should be similar

g) Save the project Note: Results may differ slightly based on the location of your subnets, clouds and nodes 22) As is obvious, this Database application is taking some time to deliver a user response. Certainly, our

example is highly stylized but it gives you the general idea. Let us try to discover what is causing the slow response times. First, look at the server utilization to see if that is the culprit. a) Choose Results Find Top Results b) Select Node Statistics/Server DB Query/Task Processing

time, click “Find Top Results” c) Change “Graphs Stacked” to “Graphs Overlaid” d) Click the Graph button and view the graph e) Notice that the processing time is quite low, meaning that the

servers are not overloaded. The Graph may look somewhat similar to that shown 23) If the servers are not causing the bottleneck, perhaps the links are

overutilized. Let us check the most utilized links for bottlenecks a) Choose Results Find Top Results b) Select Link Statistics/point-to-point/utilization, click “Find

Top Results” c) Change “Graphs Stacked” to “Graphs Overlaid” d) Click on the Graph button and view the graph

ISM 6225: OPNET WAN instructions

e) Notice which of the links have 100% utilization for part of the simulation.

f) Save the project The Graph may look somewhat similar to that shown In this section, we diagnosed the slow response times---- more bandwidth is needed on the long-distance links. Let us see if fixing this helps. We know that we can examine this relatively easily by creating a scenario with the upgraded links. Creating Additional Scenarios 1) We need to fix the network bottleneck. Since the links are overutilized, try

upgrading all the 56K links to DS1 links. First, we would want to create a duplicate scenario in which to make this change a) Choose Scenarios Duplicate Scenario b) Name the new Scenario “DS1” c) Right-click on the link connecting the Detroit subnet to the IP Cloud and “Select Similar Links” d) Right-click on this link again and select “Edit Attributes” e) Change the Model attribute from “PPP_56K” to “PPP_DS1” f) Check the box that says “Apply Changes to Selected Objects” and press “OK” g) Run the simulation. The simulation run will take quite some time to complete since there are more

number of events being processed. 2) Create a panel containing DB Query Response times

a) Choose Results View Results b) Check the box next to Global Statistics/DB

Query/Response Time (sec) c) Press “Show” d) In the View Results dialog box, change the filter from

“As Is” to “average” e) Press “Add” and click on the graph that was just

created f) Verify that your graphs look similar to the one below-

you may have peaks and valleys in different places, but the range should be similar

g) Save the project

The Graph may look somewhat similar to the following 3) At a glance we can see that there is a significant reduction in response time, however, the response time is

increasing with time. Let’s see if we can get a further improvement by upgrading to DS3 links a) Choose Scenarios Duplicate Scenario b) Name the new Scenario “DS3” c) Right-click on the link connecting the Detroit subnet to the IP Cloud and “Select Similar Links” d) Right-click on this link again and select “Edit Attributes” e) Change the Model attribute from “PPP_DS1” to “PPP_DS3” f) Check the box that says “Apply Changes to Selected Objects” and press “OK” g) Run the simulation. Once again it may take a few minutes for the simulation run to complete.

4) Create a panel containing DB Query Response times

ISM 6225: OPNET WAN instructions

a) Choose Results View Results b) Check the box next to Global Statistics/DB

Query/Response Time (sec) c) Press “Show” d) In the View Results dialog box, change the filter from “As Is”

to “average” e) Press “Add” and click on the graph that was just created f) Verify that your graphs look similar to the one below- you may

have peaks and valleys in different places, but the range should be similar

g) Save the project The Graph may look somewhat similar to the following 5) Now let us compare the DB Query Response Times for all scenarios in a single graph to show us a better

picture a) Choose Results Compare Results b) Check the box next to Global Statistics/DB query/Response

Time (sec) c) Change the filter to “average” d) Click “Show”

The Graph may look somewhat similar to the following. From the graph, we can see that there is a great reduction in response time when DS3 links were used. 6) Generate a Web report for the “DS3” scenario, and then launch it:

a) Choose Results Statistic Report Generate Web Report and press “OK” in the dialog box that appears.

b) Choose Results Statistic Report Launch Last Report 7) View DB Query Response Time:

a) If you have more than one Web report, you will start at your Simulation Reports Home Page and would have to select the simulation report you wish to view

b) If this is the first report ever generated, you will bypass this home page

c) Find and view the results for Report: User Selected/Global Statistics/DB query/DB Query Response Time (sec)

d) Exit the browser e) Save the Project

The web report looks similar to the following 8) Turn in a printout of the web report and

comparative results from (5) above.