OPNET Simulation Project: Summer Internship 2006/2007

Project Description

In a previous project Evaluation of Core-Edge Storage Area Network Designs using Simulation we investigated the suitability of Rockwell's Arena simulation package for simulating computer networks. In this project we trialled OPNET's IT Guru and Modeler as a alternative software package for computer network simulation. This project was intended as an initial discovery phase for our ongoing Network Simulation research.

Project Diary

This is (an edited version of) the project diary of Bill (Xinsheng) Qu, an Honours Year Engineering Science undergraduate student.

Last edited by Mike O'Sullivan and Cameron Walker on Jun 14, 2007.

Week 1

16 November 2006: My First Day

Today is the first day of my studentship. It is a reading day. I am reading a paper called Evaluation of Core-Edge Storage Area Network Designs using Simulation, written by Cameron G.Walker, Michael J. O'Sullivan and Mihiriyani Elangasinghe.

In this paper, they used a commercial simulation package called Arena simulation package to simulate the Cecil network and compare the performance of a core-edge network design to the current network used by Cecil.

Cecil is the learning content management system at The University of Auckland and they only consider the back-end of the Cecil network.

Their paper showed that Arena is not a good tool for simulating this as it may take a day just to simulate several minutes of the network.

My responsibility this summer is to learn another well-known simulation software package IT Guru from OPNET, use it to simulate a similar network, and analyse the performance of a core-edge design.

17 November 2006

I am still reading the paper (see 16 November 2006).

I have also got a picture of the Cecil network structure. This really helps me to better understand the paper.

20 November 2006

I have been told that I can use an academic version of OPNET's IT Guru starting next week. Therefore, the rest of this week I will study the paper with the help from the network diagram (see 16 and 17 November 2006).

This is really the first time I need to understand terms such as "Switch", "Servers" and "SAN". I will research those terminologies this week.

Week 2

This week is gonna be an IT Guru week for me!

I have got OPNET's IT Guru Academic Edition 9.1 today which means the actual project is really starting now.

My objective for this and next week is to get familiar with the software and learn as much as possible.

I will be continuously posting my learning onto the lovely wiki.

27 November 2006: Project and Scenarios

All network models are built in IT Guru using a Project and Scenarios.

Each Project is a collection of different Scenarios for a modeled network. Each new network always needs a new Project to be built and each Project must contain at least one Scenario.

Each scenario represents a unique configuration with changes to one or more of the topology, protocols, applications and profiles, or traffic.

28 November 2006: Workflow of Constructing a New Model

To create a new network, a Project needs to be created first. After that, create a basic Scenario and define the topology and traffic. The user could construct other Scenarios in the Project with their own configurations (i.e., topology, protocols, traffic, etc).

The user then needs to choose which statistics and results will be reported then run the simulation for the configured time and conditions.

After running the simulation, the user could analyse the results and make corresponding modifications to their Scenario(s).

29 November 2006: Problems with Switches

After some practice with IT Guru, I have started the construction of the Cecil back-end network topology. Unfortunately, the palette of network switches does not include either the Cisco 3550-12T or the Cisco 3750G-24FS, both of which are required for Cecil back-end network.

One possible way to overcome this limitation is to derive a new switch based on the current resources available in the IT Guru Academic Edition palette.

30 November 2006: Device Creator

IT Guru provides users with a powerful tool called Device Creator to create user-defined devices if the desired type is not included in the standard palette of the software. Users need to specify the device configuration and then the device can be automatically created.

Typically, the types of device that Device Creator can create include: Router, Bridge, Hub, Switch, Multi-homed Host, Vendor Device, LAN Model, Cloud, Firewall, and Multi-Service Device.

Here is a screen shot of the device types available in Device Creator:

Device Creator is under the Topology pull-down menu.

After selecting all the options and basic parameters for a new device, the user needs to locate this device in the specified model list. Once the user finishes the creation process, the device is available under the selected model list and ready for use.

Another way of customising a model is by Deriving New Models (see below).

1 December 2006: Switch Parameters

Up until now, I have understood the process of creating a new vendor device or deriving one based on the palette items.

However, I have run into problems because I don't know any of the parameters of the switch attributes within OPNET's IT Guru. This is difficult. I have searched other links, e.g., the Cisco website, but there is no valuable information about switch parameters. Therefore, we need to consult a network engineer about finding these parameters.

My superviser Dr. Michael O'Sullivan has contacted a network engineer Warwick Dixon from ITSS (Information Technology Systems and Services). We will have a meeting with him (Monday at 1pm) next week to discuss the problems we are facing now.

Hopefully I can understand a "Switch" better by Monday.

1 December 2006: Deriving New Models

IT Guru allows users to derive a new model based on a parent model's specification.

First, the user needs to select and place an existing standard or vendor model on to the Project Editor, then right click the model and alter the attributes to obtain the desired device for use in the network simulation.

Another way of obtaining a new device is by using Device Creator (see above).

Applications and Profiles

Profile and Application definition nodes will always be added to created networks to generate traffic.

The Application node defines the types of standard network applications available for use in the constructed topology.

The user also creates new Profiles. In each new Profile, the user defines the Name, Start Time, Duration and Repeatability of the traffic. All the profiles which will be applied to the network topology need to be configured in the Profile configuration.

After that, the user could apply those defined Profiles to any of the workstations of the network.

Using Applications and Profiles a user can build a complex traffic patterns within a network without repeating too much of their work.

Week 3

4 December 2006: Meeting

Today, we had a meeting with Warwick Dixon, a network engineer from ITSS.

The main output from the meeting is that he suggested we simulate an easier network than the Cecil back-end network first. This is because the Cecil back-end network has changed dramatically from the network diagram we have (from 2 years ago). We all agreed to simulate the Engineering Science network first, which is easier to simulate than the Cecil back-end network, but has all the devices we want to gain experience simulating. If our simulation gets convincing results, we will then move on to simulate another, larger network.

Mr. Mark Bradly will help us to further develop the Engineering Science network simulation.

6 December 2006: My Opinion of OPNET

I have been going through two tutorials from OPNET's IT Guru Academic Edition 9.1. These tutorials are included in the Academic Edition, which helps users become familiar with the IT Guru software.

The first tutorial is about the basics of using IT Guru, several common protocols and vendor devices are discussed. The Project Editor is the main area of modelling and simulation in IT Guru. In the Project Editor, we create the network model, collect statistics, execute simulations and analyze the results. In the Project Editor window, there are five sections:

1. Menu Bar
2. Tool Button
3. The Workspace
4. The Message Area
5. Tooltips

Refer to the Tutorial 1: Introduction in the Academic Edition for a more detailed description.

In Tutorial 2 the user builds a small network to simulate a small company's intranet. A project in IT Guru is built whenever we want to create a new network model. Each project contains several related scenarios. The Startup Wizard is used to configure the network environment of the new project and scenario. It defines the initial topology, size and the background of the network. Also, the user needs to choose the objects included in the object palette for each scenario. The Object palette should include all the nodes and links needed to create a network. Three methods could be used to create a new network topology:

1. Import a topology
2. Create a network by placing nodes and links
3. Use a Rapid Configuration

This tutorial utilised a rapid configuration where the user needs to specify the network configuration and types of nodes and links. A generic network topology is created. Finally, Application and Profile nodes need to be added to generate traffic. Specifying the traffic using Applications and Profiles could be a difficult job. In Week 2 I wrote my understanding of Applications and Profiles. Anyone is welcome to comment on the contents of my wiki.

Before simulation, the user should specify the statistics they want to collect. There are mainly two types: Global statistics, which apply to the whole network; and Object statistics for individual nodes.

The user can then run the simulation and view the results, IT Guru offers many different kinds of graphs and tables for analysing individual objects or comparing multiple objects and/or scenarios.

In my opinion, OPNET's IT Guru has a very wide application range and is a very user-friendly network simulation software.

Afterthoughts

I have been waiting for the Engineering Science network diagram. Meanwhile, I am still learning about OPNET's IT Guru.

There are several useful documents and websites available on the internet:

• OPNET Lab Manual
• OPNET Training Manual
• OPNET IT Guru: A Tool For Network Education

Week 4

11 December 2006

Today, I received the description of the Engineering Science network from Mark Bradley.

The network looks simpler than then original Cecil back-end network, this is a good news.

Project Introduction

We have decided to simulate Engineering Science departmental network.

The Department of Engineering Science (DES) is located on the 2^nd, 3^rd and 4^th floor of Uniservices House, 70 Symonds Street.

Here is the description of the DES network on levels 2, 3, and 4. The information is provided by:

• Mark Bradley (ITS staff)
• Rao Cherukuri (DES IT staff)
• Percy Barboza (DES IT staff)

Switches

The building switch is a Cisco 4506 ethernet switch, in slot 3 of this switch is a WS-X4424-GB-RJ45 card and in slot 4 there is a WS-X4448-GB-RJ45 card. All the edge switches are connected to the card in slot 3 and all the servers are connected to the card in slot 4. All the edge switches are Cisco 2950 ethernet switches. There are 2 switches on level 2, 2 on 3 and 3 on 4.

Servers

For the Department of Engineering Science, there are three groups of servers: Esc-Staff, Esclab and Esc-Linux. There are 4 ethernet servers for Esc-Staff group, 4 for Esclab and 6 for Esc-Linux.

Links

Connections between workstations and edge switches in each floor are 100Mbps. Connections between edge switches and the building switch are 1Gbps. Connections between the building switch and servers are 1Gbps.

Topology

We have decided to model traffic from other systems in 70 Symonds St as clouds. This is the due to the difficulty of obtaining the necessary information.

The topology of the network described above is:

Enlarged Network Topology

Three subnets represent three groups of servers. Here is a screen shot of this part of the network:

Week 5

11 January 2007

Some Switch Information

From the description of the network (see the Project Introduction) we know the building switch has two slots.

Here is the information for the building switch and the associated slot cards:

• Building Switch: Catalyst 2950T-48-SI 48 10/100 and 2 10/100/1000BASE-T ports
• Slot cards:
  1. WS-X4424-GB-RJ45: Catalyst 4000 24-port 10/100/1000 Module (RJ45)
  2. WS-X4448-GB-RJ45: Catalyst 4000 48-port 10/100/1000 Module (RJ45)

One difficulty I am facing now is to model these two slots in OPNET's IT Guru. Currently, I have modeled the two slots card as two separate switches.

Finally, the full edition of OPNET's IT Guru is coming soon. Hopefully I can find the devices I need in the full edition.

12 January 2007: Some Problems

My superviser, Michael, is gonna be away next week. Before he left, he gave me some information from Multi Router Traffic Grapher (MRTG).

MRTG is a tool to monitor the traffic load on network-links. From the information we extracted from MRTG, we can probably get some traffic information for our constructed network topology.

From the information I have now, and because of the help I received from Rao and Percy, our dedicated IT staff, I can identify the appropriate devices for the Department of Engineering Science.

But there are some things I can't figure out from MRTG's Information, e.g.

• 2/1 -- 70-Sym-St-Bx-bx-sym-st.net.auckland.ac.nz_2_1 Max 1 Gbps

I think bx stands for building switch and the maximum speed is 1 Gigabyte per second.

I need to ask someone...

15 January 2007

Today, I asked Rao and Percy some questions about MRTG (thanks for your time guys). I have got some useful information. The next thing I need to do is try to contact Mark Bradley, who knows some more information and I could learn more about MRTG and the network topology.

Rao said all the servers for Engineering Science are located on Level 4, there are 16 altogether, 14 servers in the building and 2 outside. This matches with the information provided from MRTG. However, they can't identify the servers from the names listed on MRTG. They suggested it may be better to talk to Mark Bradley about this. However, I found from the previous email Mark wrote that it is better to contact Tiong Lim or Andrew Cantell regarding the server information. I am not sure if it is Ok to contact them straight away by myself. Anyway, the names are not important at this stage for constructing the topology.

Rao also suggests that it is actually better to analyse the ports instead of servers because the servers are being updated but the ports are not. I don't understand this part at all.

Apart from that, he said the Engineering Science servers are updating this month and information such as the speed and name of the servers may change (there will still be 16). Next week I need to ask them again about those servers.

I have constructed the updated network topology on IT Guru. I still can't figure out how to model the slot cards on the building switch, there is not much help on the internet either.

Another major problem is that the IT staff don't know anything about 2/1, 2/2, etc. They said it would definitely be better to ask Mark about this. Probably I will contact Mark sooner or later.

I have sent an email to Michael and told him what has happened, he is away this week.

16 January 2007

Rao told me today that the Engineering Science servers are still updating, so we need to wait until they finish and then get the new information from MRTG.

I have got the email from my superviser Michael today, which means I have more work to do now. I am still learning from the information Michael gave me from MRTG. In the "Device Information" sheet, it appears "Max 1 Gbps" means the maximum speed of 1 Gbps (obvious?). However, this means that the 16 servers in the Department of Engineering Science each have a different connection to the edge switch. This is different to the information I obtained from Rao.

I have sent a email to Mark asking about this. I am looking forward to his reply.

17 January 2007: A Big, Big Mistake

What a big mistake I made!

I just realised today that I treated a router as a switch for our project!

The building switch for 70 Symonds Street is WS-4506. This switch is not available in OPNET's IT Guru Academic Edition, so I thought I could use a 4500 instead (for now). However, I forgot to read the "node description" for this switch. This is actually a Router!

Routers in IT Guru have a lot more attributes than Switches. There are far less Switch attributes…

How did I make such a stupid mistake!

Week 6

h3 22 January 2007

I got the updated version of OPNET Modeler 12.0. However, I have encountered difficulties with "License Management" in Modeler. The error is "You have either "Student" or "Standard" Extranet privileges to access the OPNET Website". Probably I need ask Rao for help.

Mark emailed me about back the question I have asked, and I know 2/1 means the 2nd port of the 1st edge switch.

Also, from tomorrow on, I need to work on the MRTG information to understand more about the edge switches, e.g., the number and location of the workstations connected to a specific edge switch.

h3 23 January 2007

Today, Michael assigned some tasks to me for figuring out the edge switches.

I need to identify specific edge switches from MRTG and their connections to different workstations.

We are planned to finish constructing the topology within approximately 2 weeks.

h3 More about MRTG

I have spent the rest of the day trying to figure out information about the edge switches from MRTG.

Here is a summary\: Level 2

* ex-439-fd212-1.net.auckland.ac.nz is the edge switch C2950-Lev2, there are 47 FastEthernet connections (are these to workstations?) + 1 wap-439-209 * ex-439-fd212-2.net.auckland.ac.nz is the edge switch C2950-Lev2, there are 48 FastEthernet connections (again, are these workstations)

Level 3

* ex-439-fd312-1.net.auckland.ac.nz is the edge switch C2950-Lev3, there are 48 FastEthernet connections * ex-439-fd312-2.net.auckland.ac.nz is the edge switch C2950-Lev3, there are 47 FastEthernet connections + 1 wap-439-329a

Level 4

* ex-439-fd412-1.net.auckland.ac.nz is the edge switch C2950-Lev4, there are 48 FastEthernet connections * ex-439-fd412-2.net.auckland.ac.nz is the edge switch C2950-Lev4, there are 48 FastEthernet connections * ex-439-fd412-3.net.auckland.ac.nz is the edge switch C2950-Lev4, there are 48 FastEthernet connections

The connections to the building switch in MRTG must be GigabitEthernet0/1, because the maximum speed is 1 Gbps. I don't know what GigabitEthernet0/2 is, maybe it is irrelevant to our project.

h3 24 January 2007

I got the updated OPNET Modeler 12.0 today and I was trying to get the license via Internet.

Problems occurred when getting the license\:

"Operation did not go through. The username, password and group ID yo entered are not authorized to access licenses for this group. Please make sure that you have entered the correct username and password for the group that you are working with. (error - 16148)"

I emailed the problem to support@opnet.com and they replied saying that\:

"students are not allowed to administer licenses. You will need to have your professor, or an administrator add these licenses for you."

Probably I need to ask Michael tomorrow.

h3 25 January 2007

Michael told me today that he needs to install the software on a server. I have to uninstall it on my own computer. Sajy, the computer system officer helped me for doing this.

Michael is gonna be away until next Wednesday. During this time, I will play around with the latest version of OPNET Modeler 12.0.

h3 26 January 2007

With the help from Sajy, the Computer Systems Officer in the Department of Engineering Science, I have installed OPNET Modeler 12.0 successfully.

It is pretty much the same as the IT Guru Academic Edition 9.1. From next week on, my new task is gonna be constructing the topology using this new edition.

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h2 {anchor:|week7}{anchor}Week 7

h3 29 January 2007 Michael will be back this Wednesday, so I was playing with Modeler 12.0 the whole day.

The good news about Modeler 12.0 is that it has a Help section and there are more and better tutorials than in IT Guru 9.1.

I sent an email to support@opnet.com to ask about the difficulty I have on modeling the slots of the building switch. The reply said that I have to create the custom device for each slot.

The {link:Cisco Website|https://www.cisco.com/en/US/products/hw/switches/ps663/products_configuration_guide_chapter09186a00801762ec}, from my best understanding, says I should just model each slot as a multi-port hub. I posted this question onto the Forum (Mike\: Bill, I'm not sure what forum this is!), I hope someone will reply to me soon.

h3 31 January 2007 I have got the updated MRTG information and I can start to construct the topology now.

Michael told me it is better to draw the diagram by hand first to get a clear picture of the structure in my mind.

I drew 4 diagrams today. Diagrams 1 and 2 are for the spare ports of the building switch, we may not model that in our project, but maybe it is worth drawing it for future use. Diagram 3 is for the edge switches and Diagram 4 is for all the servers.

Here are the diagrams I have drawn today\:

* [Diagram 1] * [Diagram 2] * [Diagram 3] * [Diagram 4 (front)] * [Diagram 4 (back)]

In each diagram, I have put all the relevant information from MRTG into the diagram.

Tomorrow, I may start to build the topology on OPNET Modeler 12.0.

h3 1 February 2007 I have tried to construct the topology today but there are still some difficulties that I can't get around.

h4 The Building Switch

The true building switch is a WS-C4506 switch which is not included in Modeler 12.0. I am using a CS_5000_3s_e24_fe2_fe12 instead for now.

~~Naming~~\: _<Chassis/Make>_ From my own opinion, I think CS_5000_3s_e24_fe2_fe12_adv means Cisco Switch 5000 with three slots (3s), 24 Ethernet ports. The detailed description can be found in OPNET Modeler 12.0.

h4 The Edge Switches

All the edge switches described in the project should be WS-C2950T-48-SI, but I am using Cisco WS-3200 instead.

h4 The Slot Cards

I have created 2 Ethernet hubs to represent the 2 cards on Slot 3 and Slot 4. Here is the description I got from the {link:Cisco Website|https://www.cisco.com/en/US/products/ps5931/prod_release_note09186a008065ca3c.html}.

The description of each slot\:

* WS-X4424-GB-RJ45\: 24-port 10/100/1000 with RJ-45 connectors

* WS-X4448-GB-RJ45\: 48-port Ethernet 10/100/1000 with RJ-45 connectors

The connection I have used for joining the building switch and the slot card is 10Gbps. (I randomly picked that). (Mike\: Bill, there should be some information on what link is used, if not then 1Gbps is sufficient because of how hub technology works).

h4 Servers

I have used Ethernet servers to represent those.

The detailed description of each node is included in the documentation section. It can be viewed by clicking "Edit Documentation" for each node and link.

h3 2 February 2007 Today, I studied more about using Applications and how to generate traffic. Here are some thoughts\:

h4 More on Application and Traffic Generation

There are three main types of traffic in Modeler 12.0\:

# Explicitly generated traffic The user needs to specify the size of the transaction and the the distribution of the "number of transactions per time unit". The traffic could be created by configuring the Application Definition and Profile Definition. # Traffic flows "are special objects that specify end-to-end traffic between source and destination nodes". (Retrieved from "Importing Traffic" in "Product Documentation"). The traffic flow could be created either manually using a Demand object or imported from an external source. # Link Baseline Load Traffic This specifies the background traffic of a particular link in bits per second by either configuring the Background Load of a link or by importing from an external source.

To use explicitly generated traffic, the user needs to add and configure the Application Definition and Profile Definition. The user should define different Profiles in the Profile Definition object and Applications in the Application Definition object.

A Profile could be applied to any workstation, LAN or server. The profile specifies the applications used by that user or users. Different groups should use different Profiles for different purpose.

An Application could be any common applications (such as email or file transfer), or some applications defined by the users.

There are eight common Applications defined in Modeler 12.0\: Database Access, Email, File Transfer, File Print, Telnet Session, Video conferencing, Voice over IP Call, and Web Browsing. Each application has two sub-applications.

h3 {anchor:|traffic}{anchor}Steps to Create Explicit Traffic

# Configuring the Application Configuration object \\ \\ The user needs to add the Application node onto the project workspace. \\ \\ In Edit Attributes, under Application Configuration, the user could choose which application should be included. Choosing Default will include all the pre-configured applications. \\ \# Configuring the Profile Configuration object \\ \\ Similarly, in Edit Attributes, under Profile Configuration, click in its Value column and select Edit… from the drop-down list. Then the user could define the profile under the new Profile Configuration dialog box. In the Profile Configuration dialog box, the user could add more profiles by adding more rows. There are several places in order to define a new profile\: Name of the new Profile, Operation Mode, the distribution of the Start Time, etc. \\ \\ Also, under Profile Configuration dialog box, we need to specify the application which would be used for this just-defined profile. Click in the Applications column and choose Edit... from the pop-up menu to get the Applications dialog box. The user then could specify the Name of the application, the Start Time Offset, Duration and Repeatablity. \\ \# _ Applying Profiles_ \\ \\ After defining all the Applications and Profiles which will be used for the project, they could be applied to any workstation, server or LAN. This could be done by right clicking Edit attributes, then under Supported Profiles, the user could apply the profiles that have been created earlier.

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h2 {anchor:|week8}{anchor}Week 8

h3 6 February 2007

We need to access to MRTG to get the information for each edge switch, but unfortunately the system is not working today, so we have to wait. Michael has contacted Mark, hopefully we can get access to MRTG by Monday.

h3 7 February 2007

MRTG is working TODAY and we have got our information. The information we are trying to retrieve from MRTG are the temporary names, and I need to match these names with the actual edge switches.

Here is what I have found\:

True Name

# C2950-Lev2(223.18) is ex-439-fd212-1.net # C2950-Lev2(223.19) is ex-439-fd212-2.net # C2950-Lev3(223.16) is ex-439-fd312-1.net # C2950-Lev3(223.16) is ex-439-fd312-2.net # C2950-Lev4(223.18) is ex-439-fd412-1.net # C2950-Lev4(223.18) is ex-439-fd412-2.net # C2950-Lev4(223.22) is ex-439-fd412-3.net

h3 8 Febuary 2007

I am trying to model the "Clouds" today. Each "Cloud" represents one particular group of users. We don't know how many workstations are in each group, so we are going to model each group as a Cloud.

The questions I have are\:

# How many clouds are there in each floor? # There are more than 1 edge switches in each floor, how are they connected with the "Clouds"?

h3 9 Febuary 2007

I spent the whole day trying to model the groups of users today. Initially we considered to model those groups as "Clouds", but the main disadvantage is that "Application" and 'Profile" can't applied to those and therefore no traffic would be generated.

We decided to put subnets in to represent each group. In each subnet, there is one edge switch, each edge switch controls one particular group of users.

Here are the edge switches and their corresponding groups\:

Level 2\: # Master Room\: C2950-Lev2(223.18) # Staff\: C2950-Lev2(233.19)

Level 3\: # Staff\: C2950-Lev3(223.16) # PhD and Project Room\: C2950-Lev2(223.16)

Level 4\: # Staff\: C2950-Lev4(223.18) # BME Lab\: C2950-Lev4(223.18) # EngSci Lab\: C2950-Lev(223.22)

Note this is randomly assigned, the actual groups and their corresponding edge switch is unknown at the moment.

Subnet Structure

In each subnet, there is a edge switch and 48 workstations. The number 48 is obtained from MRTG, because each edge switch has 48 ports, so I decided to put 48 workstations. The connection speed is different for each workstation, this also could be obtained from MRTG.

I will try to finish this part by Monday, and then I could apply some traffic to my network.

{link:Return to Contents|#contents}

h2 {anchor:|week9}{anchor}Week 9

h3 12 February 2007

Unfortunately I haven't finished modeling the groups of users. Since the network is large, the computer is getting very slow. In the future, the file should be backed up regularly.

h3 13 February 2007

I have finished constructing the topology network. The next task I will do is applying "Application" and "Profile" to generate some traffic.

Here is a summary for the topology I have built\:

# Building Switch \\ \\ The building switch should be the type of WS-4506, but because this type is not available in the OPNET edition I have got, I have used a WS-C5000 instead. \\ \# Slot Card \\ \\ There are two slot cards connected to the building switch\: WS-C2950T-48-SI and WS-X4424-GB-RJ45, but a major problem is that I don't know how to model the slot using OPNET, so I used two hubs, each with 48 ports instead. \\ \# Server \\ \\ There are 17 servers for the Engineering Science Department. All the information is retrieved from MRTG. The "Documentation" part in each "server" describes all the information about that server. \\ \# Subnet \\ \\ Each subnet includes one edge switch and 48 workstations. Each subnet represents one particular group of users. \\ \# Edge Switch \\ \\ The switches used in the topology are not the appropriate ones. For the same reason as for the building switch, I used Cisco WS-C3200 instead of WS-C2950. \\ \# Workstation \\ \\ There are 48 workstations in each subnet connecting to the edge switch. The connections are found from MRTG.

Here is the screen shot of my constructed topology\: {image:sakai:/~1f4cb7d1-c12f-4a51-0007-f57aa698ef2b/Updated_EngSci.bmp|Updated_EngSci.bmp}

h3 14 February 2007 I am trying to apply "Application" and "Profile" to the network topology now. Because we can't obtain the actual data and traffic, I will apply some artificial data.

Generating Traffic Each subnet represents a particular group of users. Each group shares the same applications and profiles. For example, in my model, the users in level 2 master room mainly use web browsing and File Transfer.

To define those applications and profiles, first follow Steps to Create Explicit Traffic to configure the application and profile nodes, then for all the workstations in each subnet, apply the profiles; Also, in each server, select the supported applications and profiles which are used by the workstations.

Run the Simulation After defining the applications and profiles, the topology could be run to generate traffic. Run Setup could be defined under DES. The user could define the simulation length and other parameters.

I have encountered two major problems for my particular case\:

First, I have used a hub to represent the slot. The problem is that for every node that each hub connects to, the connection speed must be the same. In my topology, the connection speed to each server is different. So what I did is use the same connection speed (10Mbps) for all the connections. The reason I am using 10 Mbps is that Michael said the hub should work under the speed of the slowest connection. All the information for the connection speeds could be obtained from MRTG.

Another problem I had before is that the edge switch I previously used (Cisco WS-C3200) has only 12 ports. But in each subnet which is connecting to the edge switch, there are 48 workstations plus a connection to the slot, so we need a Cisco Switch which has at least 49 ports. Therefore, I used a Cisco WS-C6250 instead, because it has got 66 ports.

After fixing those two problems, I ran my network and it seems like everything works ok. The simulation speed is very fast - it takes about 2-5 minutes to simulate 1 hour, which is awesome.

By now, my studentship is pretty much finished and I am really glad. I am very proud that I could work with Dr. Michael O'Sullivan and Dr. Cameron Walker.

Thank you very much.

-- MichaelOSullivan - 16 Dec 2010

• Updated_EngSci.bmp: Updated_EngSci.bmp