3com 3C15100E User Guide

3Com® Network Supervisor v5.0 User Guide

3C15100E

http://www.3com.com/

Part No. DUA15100-EAAA01

Published September 2004

3Com Corporation
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CONTENTS

ABOUT THIS GUIDE

Conventions 12
Feedback about this User Guide 13
Related Documentation 13

1 GETTING STARTED

Introduction 15

What is 3Com Network Supervisor 15
Installation 16
Activation 16

Getting Started 17

Creating a New Network Map 18
Coexistence with other Network Management Applications 19
Upgrading from earlier versions of 3Com Network Supervisor 19

Main Features 21

Main Window 21
Network Discovery 21
Network Monitoring 21
The Event System 22
Traffic Prioritization 22
Reporting 22
Live Update 22

2 PRODUCT ACTIVATION

Introduction 23
Key Concepts 23
Components 24

About Dialog 24
Activate Now dialog 24

Examples 25

Useful Information and References 26
Key Considerations 26

3 MAIN WINDOW

Overview 29
Key Concepts 29

Map Files 29

Components 30

Map 30
Tree 30
Toolbar 30
Status Bar 30
Main Menu 31
File 31
Edit 32
View 33
Device 35
Monitoring 36
Alerts/Events 36
To ol s 37
Help 37
File > Exit Menu Option 38
Tools > Options Menu Option 38
Help > Contents and Index Menu Option 42
Help > Launch User Guide 42
Help > About 3Com Network Supervisor Menu Option 42

Examples 42

Finding the Product Version 42
Finding the Serial Number and Activation Key 43

4 DISCOVERING THE NETWORK

Overview 45
Key Concepts 46

The Discovery Process – Detecting Devices 46
The Discovery Process – Determining Topology 51
The Discovery Process – Rediscovery 58

Components 59

Launching a discovery 60
The Network Discovery Wizard 63
The Network Discovery Progress Dialog Box 75
The Discovery Report 78
The Misconfigurations and Optimizations Report 79
The Changes Report 80
The Displayed Map 80

Examples 81

I have four separate subnets - how do I specify them? 81
I am using different SNMP community strings for different devices on my

network - how do I specify this? 82

Useful Information and References 83

Why the discovered map may not exactly reflect the network 83
Support for 3Com devices 84
Support for third party devices 85

Key Considerations 86

Discovery Report Errors and Warnings 86

5 WORKING WITH THE MAP

Overview 93
Key Concepts 94

The Map 94
The Tree 96

Components 98

Map Structure 98
The Grouped Network View 98
The Ungrouped Network View 100
Clouds 108
Navigation 123
Modifying the Map Layout 141
Saving and Opening Maps 145
Printing the Map 148

Examples 149

Selecting all of the SuperStack 3 Switch 4400 Devices in the
Network 149

Viewing all of the Physical Connections for a Router 152
Focusing in on a Set of Devices in the Map 154
Adding a Link between Map Items from Different Submaps 157

Adding a New Device on Your Network Into the Map 158

Useful Information and References 162

Graphical Support for Specific Device Types 162

6 VIEWING DEVICE DETAILS

Overview 165
Key Concepts 166

Items Supported by the Properties Dialog Box 166

Components 166

Launching the Properties Dialog Box 166
Structure of the Properties Dialog Box 167
Properties Dialog Box for a Node 171
Properties Dialog Box for a Supported Device 172
Supported Device (Stack or Chassis) 173
Supported Device (Single Unit) 174
Properties Dialog Box for an Unsupported Device 174
Properties Dialog Box for an End station 175
Properties Dialog Box for a Phone 176
Properties Dialog Box for a Subnet 178
Properties Dialog Box for a Device Group 178
Properties Dialog Box for a Cloud 179
Properties Dialog Box for a Link 180
Properties Dialog Box for a Layer-3 Connection 182
Properties Dialog Box for a Multiple Selection 183
Applying Changes to Devices Using the Properties Dialog Box 185

Changing the Community Strings for a Device 189
Examples 193
Key Considerations 196

Troubleshooting 196

7 MONITORING THE NETWORK

Overview 199
Key Concepts 199

Monitor 199

Monitoring and Event Generation 200

Monitoring State 200

Monitoring Techniques 202

Monitor-able Items 205
Link Monitoring 205

Components 206

Live Graphs Window 206
Live Graphs Tree 207
Live Graphs Display 208
Live Graphs Menu 210
More Detail Dialog Box 211

Configuration 213

Starting and Stopping Monitoring 213
Controlling Event Generation from Monitors 215
Registering 3Com Network Supervisor as an SNMP Trap

Destination 215

Examples 216

Enabling Monitoring on the Core Devices in the Map 216
Disabling Monitoring on the Whole Network 217

Key Considerations 217

Text Displayed in Graphs 217
Problems Starting Monitoring for a Device or Link 218

8 THE EVENT LOG

Overview 221
Key Concepts 221

Events 221
Event Severities 223
Event Resolution 224
Alerts 226

Events List Components 227

Launching the Events Window 227
Events Main Window 228
Working With Events 234
Refreshing the Events List 237
Exporting the Events List to a CSV Format File 238
Printing the Events List 239
Find Dialog Box 239
Filter Dialog Box 240
More Detail Dialog Box 245

Event System Configuration 247

Disabling and Enabling Events 247

Controlling How Events are Logged 250

Setting Thresholds for Monitor-Based Events 250

Managing Event Ageing 254
Alert System Components 257

Alerts System Overview 257

Attach Alerts Dialog Box 257
Examples 263

Viewing the Unresolved Events for a Subnet 263

Exporting High Severity Events Generated in the Last Week 264

Undeleting an Event 266

Receiving Notification When A Server Farm Is Unreachable 269
Key Considerations 273

No Events in the Events List 273

9 CREATING REPORTS

Overviews 275
Key Concepts 276

Selection-sensitive 276

Feature Reports Types 276

Device Report History - Restriction 276

Custom Report Types 277

Reports History 277

Export to CSV 277
Components 277

Inventory Report 278

Capacity Report 278

Topology Report 278

Free ports Report 279

Reports Dialog Box 279

Custom Report Types Dialog Box 283

Add/Edit Report Type Wizard 284
Examples 289

Assessing Network Expansion Capability 289

Ensuring Stacks are Running the Same Agent Version 290
Key Considerations 291

Report Information Out-of-Date 291
Disk Usage 291
Generate Report not Working 292

10 CONFIGURING SINGLE DEVICES

Overview 293
Key Concepts 294

Web Management 294
Telnet Management 294
SSH Management 294
Administration Menu 294
Properties Dialog Box 295
Registering Devices for Warranty 297

Components 298

Device Warranty Dialog Box 298
Device Warranty Wizard 299
Connection to the 3Com Server 305
What Data is Sent to the 3Com server 305
Reports 306

Examples 308

Renaming a Switch 4007 using Telnet 308
Disabling a Port on a Switch 4400 using the Web Interface 308
Registering 3Com Devices for Warranty 308

Key Considerations 310

Troubleshooting 310
Frequently Asked Questions 311

11 PRIORITIZING NETWORK TRAFFIC

Overview 313
Key Concepts 314

Classification 314
Marking 315
Queuing 317
Dropping 319
Service Levels 319
Configuring the Network for End-to-end Traffic Prioritization 320

Components 321

Prioritize Network Traffic Wizard 321

Prioritization Reports 328
Examples 330

Applying an Existing Configuration to New Devices 330

Prioritizing NBX Voice Traffic 331

Prioritizing Traffic To and From a SAP Server 332

Blocking Access to a Streaming Audio Server 334

Prioritizing a Video Conferencing Application 335

Restricting Access to SNMP 338
Useful Information and References 342

User Priority Field 342

DiffServ Codepoint Field 343

Determining Field Values for Applications 344

3Com Network Supervisor Classifier Rules for NBX Phone Traffic 344

3Com Network Supervisor Service Levels 345

Configuration Levels for Supported 3Com Devices 345
Key Considerations 347

Resource Warnings 347

Why Errors Can Occur When Adding a Server 349

Potential Hazards When Blocking Traffic To and From Servers 349

Servers That Cannot be Selected for Blocking 350

Potential Hazards of Blocking Application Traffic 351

Potential Hazards of Blocking SNMP, HTTP and Telnet 352

12 NBX SUPPORT

Overview 353
Key Concepts 353

How 3Com Network Supervisor Discovers the Phone Network 354

How 3Com Network Supervisor Represents the Phone Network

Icons 354

How 3Com Network Supervisor Monitors the Phone Network 356
Components 357

Discovering the NBX Voice Network 357

Properties dialog box 360

Monitoring the Phone Network 361

Understanding Voice-related 3Com Network Supervisor Events 362
Examples 363

Discovering Several NBX Call Processors Simultaneously 363
Receiving an Alert when my Phones Stop Working 364

Useful Information and References 365

NBX system 365
NBX Call Processor 365
NBX NetSet 365

Key Considerations 366

Troubleshooting 366
Frequently Asked Questions 369

13 LIVE UPDATE

Overview 373
Key Concepts 374

Connection Type 374
Service Packs 374
Live Update Engine 374

Components 375

Live Update Setup Wizard 375
Live Update Select File Groups Dialog Box 379
Select File Group - Group Name 382
Download Progress 383
Changing the Download Settings 384
Live Update Activity Report 387

Examples 388

Ensuring 3Com Devices are Supported 388
Updating the Connection Information 389

Useful Information and References 392

Proxy Server 392

Key Considerations 392

The Proxy Settings are not Retrieved 392
Not Enough Space on the Disk 393

A OBTAINING SUPPORT FOR YOUR PRODUCT

Register Your Product to Gain Service Benefits 395
Purchase Value-Added Services 395
Troubleshoot Online 395
Access Software Downloads 396

Contact Us 396
Telephone Technical Support and Repair 396

B SYSTEM REQUIREMENTS

Operating System 399
Web Browser 399
Additional Software Required 399
Hardware 400

C REPORT EXAMPLES

Overview 401
Discovery Report 401

Discovery Report Example 401

Discovery Report Example Content 402
Misconfigurations and Optimizations Report 404

Spanning Tree Fast Start 404

XRN Fabric 404

Limitations 413

D ADDING TRAP DECODES

E ADDING MAC ADDRESS VENDOR TRANSLATIONS

F INTEGRATING AN SSH CLIENT

INDEX

3COM END USER SOFTWARE LICENSE AGREEMENT

ABOUT THIS GUIDE

This guide is intended for use by those responsible for installing, setting
up and managing a network; consequently, it assumes a working
knowledge of networks and network management systems.

If the Release Notes provided with this 3Com Network Supervisor User
Guide contain details that differ from the information in this guide,
follow the information in the release notes.

Most 3Com user guides are available in Adobe Acrobat Reader Portable
Document Format (PDF) or HTML on the 3Com World Wide Web site:

http://www.3com.com/

12 ABOUT THIS GUIDE

Conventions Ta bl e 1 and Tab l e 2 list conventions that are used throughout this guide.

Tab le 1 Notice Icons

Icon Notice Type Description

Information note Information that describes important features or

instructions.

Caution Information that alerts you to potential loss of data or

potential damage to an application, system, or device.

Warning Information that alerts you to potential personal

injury.

Tab le 2 Text Conventions

Convention Description

Screen displays This typeface represents information as it appears on the

Syntax The word “syntax” means that you must

Commands The word “command” means that you must enter the

The words “enter”
and “type”

Keyboard key names If you must press two or more keys simultaneously, the key

screen.

evaluate the syntax provided and then supply
the appropriate values for the placeholders
that appear in angle brackets. Example:

To change your password, use the following syntax:

system password <password>

In this example, you must supply a password for <password>.

command exactly as shown and then press Return or Enter.
Commands appear in bold. Example:

To display port information, enter the following command:

bridge port detail

When you see the word “enter” in this guide, you must type
something, and then press Return or Enter. Do not press
Return or Enter when an instruction simply says “type.”

names are linked with a plus sign (+). Example:

Press Ctrl+Alt+Del

Tab le 2 Text Conventions (continued)

Convention Description

Words in italics Italics are used to:

■ Emphasize a point.

■ Denote a new term at the place where it is defined in the

text.

■ Identify menu names, menu commands, and software

button names. Examples:

From the Help menu, select Contents.

Click OK.

Feedback about this User Guide 13

Feedback about this User Guide

Related Documentation

Your suggestions are very important to us. They will help make our
documentation more useful to you. Please e-mail comments about this
document to 3Com at:

[e-mail]

Please include the following information when commenting:

■ Document title

■ Part number

■ Page number (if appropriate)

Example:

■ 3Com Network Supervisor User Guide

■ Part No. DUA15100-EAAA01

■ Page 21

Do not use this email address for technical support questions. For
information about contacting Technical Support, please refer to

Appendix A

on page 395.

In addition to this guide, 3Com Network Supervisor provides on-line help
which can be accessed through the application.

14 ABOUT THIS GUIDE

GETTING STARTED

1

Introduction This chapter contains introductory information about 3Com Network

Supervisor, how to install and activate the application and a brief
summary of all its major features.

What is 3Com

Network Supervisor

3Com Network Supervisor is an easy-to-use application that allows you to
manage and monitor your network. With 3Com Network Supervisor, you
can:

■ Discover all devices on your network

■ View the network topology to show exactly how the network is

configured

■ Monitor all devices on the network, including 3Com NBX

and end stations

■ Be alerted wherever you are (for example by pager or SMS), if any

problems occur

■ Pin-point the source of network problems through a powerful

fault-correlation event engine

■ Automatically register all your 3Com devices for warranty in a single

operation

3Com Network Supervisor also provides:

■ Powerful reporting capability for network asset auditing and

identifying potential misconfigurations

You can view supported devices from the following option on the Start
menu: Start>Programs>3Com Network Supervisor>Supported Devices

®

telephones

16 CHAPTER 1: GETTING STARTED

Installation Double-click your downloaded 3com_network_supervisor_v5_0.exe file

to begin the installation process. Once the installation has started (as
shown in Figure 1

Figure 1 InstallShield Wizard

), please follow the steps in the installation wizard.

Activation Once you have installed 3Com Network Supervisor, you will have a

60-day evaluation period within which to activate your software. When
you launch 3Com Network Supervisor for the first time the Activate Now
dialog will be displayed as shown in Figure 2

:

Figure 2 Activate Now Dialog

Getting Started 17

To activate your software:

1 Click Get Activation Key. 3Com Network Supervisor will direct you to a

3Com activation website to retrieve your activation key.

2 Once you have your activation key, enter it into the Activation Key text

box and click OK to complete the activation process.

For more information, please refer to “

Product Activation” on page 23.

Getting Started This section details the operations you need to perform before you can

start using 3Com Network Supervisor with your 3Com devices.

When you first run 3Com Network Supervisor, a Welcome dialog is
displayed which enables you to:

■ Create a new network map

■ Open an existing map

■ Open the last map you were using

18 CHAPTER 1: GETTING STARTED

Creating a New

Network Map

To create a new map, select Create a new network map and click OK to
launch the Network Discovery wizard. Follow the steps in the wizard to
initiate discovery of your network as follows:

Discovery Type Step

You can choose whether you want to:

■ Discover your local IP subnet

■ Discover all subnets connected to your default router

■ Discover one or more specific routers

Specify Subnets Step

If you have chosen to discover specific subnets, enter their details here.

Monitor Core Devices and Links Step

You can choose whether you want 3Com Network Supervisor to monitor
the status of your network after it has been discovered. If you select No,
you can enable monitoring at any time after discovery is complete.

Community Strings Step

You can enter any non-default SNMP community strings used by your
network devices. 3Com Network Supervisor needs to read SNMP
information from your network devices in order to successfully create
your network map. 3Com Network Supervisor also needs to write to
some devices in order to determine network topology accurately.

NBX Voice Network Step

Select Yes, if you have a 3Com NBX voice solution on your network.

NBX Call Processors Step

Enter the details for any NBX Call Processors on your network. 3Com
Network Supervisor needs to read HTML information from your NBX Call
Processors in order to accurately discover and represent telephony
equipment on your network.

Summary Step

Use this step to check that all the options you have selected are correct.

For detailed help in stepping through the wizard, see “

The Network

Discovery Wizard” on page 63.

Getting Started 19

Click Finish to initiate your network discovery. For detailed help in
understanding the steps that 3Com Network Supervisor goes through to
discover your network see “
on page 75

.

The Network Discovery Progress Dialog Box”

The Network Discovery Summary dialog box is automatically displayed
when the discovery process is complete. Click OK to view your network
map or any of the four View Report... buttons for more information on
the network discovery operation.

The Network Changes Report button is only displayed when it is
applicable, so often there will only be three buttons visible.

Network Discovery Summary dialog box” on page 76 for more

See “
information on the reports that 3Com Network Supervisor generates on a
network discovery.

Now that you have discovered your network, you can use 3Com Network
Supervisor to monitor and manage your network devices.

Coexistence with

other Network

Management

Applications

Upgrading from

earlier versions of

3Com Network

Supervisor

You cannot install 3Com Network Supervisor on a PC which has 3Com
Network Director or 3Com Network Administrator installed. If you
already have either of these applications installed on your PC, please
uninstall them before installing 3Com Network Supervisor, or install
3Com Network Supervisor on a different PC.

3Com Network Supervisor v5.0 can be installed over earlier versions of
3Com Network Supervisor, and all files will be upgraded for use with
3Com Network Supervisor v5.0.

However, note the following restrictions:

■ All stress monitoring will initially be disabled

■ Any manually disabled stress monitors will be re-enabled

■ Any manually adjusted thresholds will be reset to default values

■ All alert attachments will be removed from devices and links (the alert

templates themselves will be preserved)

■ Information shown in the Properties dialog against a device or link

may be incomplete

20 CHAPTER 1: GETTING STARTED

■ Saved event logs from earlier versions of 3Com Network Supervisor

To avoid these problems, it is strongly recommended that you rediscover
your network using 3Com Network Supervisor v5.0.

If you save an upgraded map from within 3Com Network Supervisor
v5.0, you will be unable to subsequently load it back into an older version
of 3Com Network Supervisor.

3Com Network Supervisor v5.0 can be used to upgrade from:

■ 3Com Network Supervisor v4.0 (any Service Pack level)

■ 3Com Network Supervisor v3.5 (any Service Pack level)

Older versions of 3Com Network Supervisor are not supported.

("<Mapname Events>.mdb" files) are not compatible with 3Com

Network Supervisor v5.0. 3Com Network Supervisor v5.0 uses a new

event log file format and file extension ("<Mapname> Events.edb").

When you load maps saved using earlier versions of 3Com Network

Supervisor into z v5.0, the event log will initially be empty.

After you upgrade to 3Com Network Supervisor v5.0, do not attempt to
reinstall any Service Packs that you may have downloaded for your older
version of 3Com Network Supervisor. 3Com Network Supervisor v5.0
includes all functionality and bugfixes present in Service Packs for older
versions of 3Com Network Supervisor.

Advanced Package compatibility

3Com Network Supervisor v5.0 is not compatible with Advanced Package
v1.0 or Advanced Package v2.0. If you upgrade from an installed
Advanced Package to 3Com Network Supervisor v5.0, you will lose your
Advanced Package features.

If you have Advanced Package v1.0 or v2.0, 3Com strongly recommends
that you upgrade to 3Com Network Director, which offers all the features
contained in your Advanced Package, and much more. A discount is
available for registered owners of Advanced Package v2.0 who wish to
upgrade to 3Com Network Director. For more information please visit

http://www.3Com.com/3ndupgrade.

Main Features 21

Main Features This section outlines the main features in 3Com Network Supervisor, with

references to the relevant chapters where each feature is described in
more detail.

Main Window The map and tree within the Main Window provide the main interface for

viewing and managing your network. You can choose to view your
network in several different ways, show the current health of monitored
devices and links within your network and act as a launching point for
many of the tools available within 3Com Network Supervisor. The Main
Window also contains the main menu, toolbar and status bar of 3Com
Network Supervisor.

For more information, see “

Main Window” on page 29.

Network Discovery The Network Discovery process allows 3Com Network Supervisor to

discover, topologise and map all devices in your network. Using the
Network Discovery wizard, you can specify exactly which parts of your
network you want to discover.

For more information, see “

Discovering the Network” on page 45.

Network Monitoring 3Com Network Supervisor can actively or passively monitor your network

for abnormal conditions which may indicate problems and will alert you
when a problem is detected.

You can also provide control over exactly how 3Com Network Supervisor
monitors your network and over what conditions should cause an event
to be logged.

For more information, see “

Monitoring the Network” on page 199.

22 CHAPTER 1: GETTING STARTED

The Event System The 3Com Network Supervisor Event System provides a constantly

updated log of activity on your network and can be used to view and
take action on abnormal network conditions before they cause problems.
The event system offers filtering tools to allow you to view only events of
interest.

For more information, see “

The Event Log” on page 221.

Traffic Prioritization Many 3Com devices have traffic prioritization (or quality of service)

features. 3Com Network Supervisor provides the Prioritize Network Traffic
Wizard to simplify the configuration of these devices. Using the wizard,
you can choose to prioritize or block specific servers or traffic types. To
provide an end-to-end quality of service, your configuration can be
applied to all supported 3Com devices.

For more information, see “

Prioritizing Network Traffic” on page 313.

Reporting The Reporting facility enables you to retrieve stored information about

your 3Com devices. Many of the features in 3Com Network Supervisor
have their own reports but there are other, general purpose reports which
give you different views of your 3Com devices. You can also create your
own reports using the Custom Report facility.

For more information, see “

Creating Reports” on page 275.

Live Update The Live Update feature keeps your copy of 3Com Network Supervisor

up-to-date with the latest device support and fixes. You can view and
download updates specifically for your copy of 3Com Network
Supervisor. In addition, 3Com Product News is also available from Live
Update to keep you informed with what is happening at 3Com.

For more information, see “

Live Update” on page 373.

PRODUCT ACTIVATION

2

Introduction 3Com Network Supervisor uses an activation system which allows you to

use your copy of the software beyond the evaluation period. This chapter
describes how to activate 3Com Network Supervisor.

Once you have installed 3Com Network Supervisor, you can use it for an
evaluation period of up to 60 days without activating it. During this time,
you have the opportunity to activate the product each time you launch it.

It is important that you activate 3Com Network Supervisor, this removes
the evaluation period and allows you unrestricted access to the product.
Activation also starts the product’s warranty period, entitling you to
customer support for 3Com Network Supervisor for the duration of the
warranty. You can also decide to receive important update information
relating to both this and other associated products.

This chapter covers the following topics:

■ Key Concepts

■ Components

■ Examples

■ Useful Information and References

■ Key Considerations

Key Concepts 3Com Network Supervisor uses the following information in the

activation process:

■ The Serial Number — 3Com Network Supervisor automatically

generates this number when it is first installed.

24 CHAPTER 2: PRODUCT ACTIVATION

■ The Product Number — the part number of your software, which

starts with ‘3C’.

The part number for 3Com Network Supervisor is 3C15100E.

■ The Activation Key — the key returned from the 3Com registration

site. Type this key into the Activate Now dialog to complete the

activation process.

3Com Network Supervisor provides an Activate Now dialog which allows
you to activate the product.

Components The following section describes how to activate 3Com Network

Supervisor.

About Dialog 3Com Network Supervisor’s About dialog is used to display general

information relating to the product, such as the name, product number,
serial number and activation state.

You can launch the About dialog by selecting the menu option Help >
About 3Com Network Supervisor.

Activate Now dialog The Activate Now dialog allows you to activate 3Com Network

Supervisor. The dialog can be launched by clicking Help > Activate Now
from the top level menu.

When the evaluation period has expired, most menu options are
disabled. However, you can still activate the product using the Help >
Activate Now menu option.

The dialog already knows the product number and serial number so you
do not need to type them in.

To obtain the activation key for this copy of 3Com Network Supervisor,
click Get Activation Key. This launches your default web browser, which
displays the 3Com registration web site.

3Com Network Supervisor sends the serial number and product number
for you. Follow the instructions on the web site to complete the product
registration process.

Examples 25

Once registration is complete, the web site displays your activation key.
You will also be sent a copy of this key via e-mail.

If you prefer, you can register your product manually at:

http://www.3com.com/register

However, 3Com recommends that you use the Activate Now dialog.

Enter the activation key you receive from the 3Com web site by typing or
copying it in to the Activation Key text box and clicking OK in the Activate
Now dialog as shown in Figure 3

Figure 3 Activate Now dialog

:

Examples The following section provides an example of how you might use the

Activation process.

26 CHAPTER 2: PRODUCT ACTIVATION

Activating 3Com Network Supervisor

You have installed 3Com Network Supervisor on your computer and you
want to activate it.

1 Start 3Com Network Supervisor. The Activate Now dialog will appear,

showing the number of days remaining in the evaluation period.

2 Click Get Activation Key. Your default web browser is launched which

automatically directs you to the 3Com registration site.

If the wizard fails to launch your web browser, you can go directly to
3Com’s registration system by opening your preferred web browser and
entering the following URL into the browser’s address bar:

http://www.3com.com/register

3 Follow the instructions on the registration site to complete the

registration of the product and obtain the activation key. 3Com will also
send you a copy of your activation key via e-mail.

4 Enter the activation key in the Activation Key text box to activate the

product.

Useful Information and References

The following section provides useful information and references when
activating 3Com Network Supervisor.

Where can I find the product number for 3Com Network
Supervisor?

The product number for 3Com Network Supervisor is found on the
product’s packaging and is also displayed in the About 3Com Network

Supervisor dialog. To launch the About dialog, select Help > About 3Com
Network Supervisor from the menu on the main window. Refer to Finding

the Product Version on page 42 for more information.

Where can I find the serial number for 3Com Network Supervisor?

The serial number for your copy of 3Com Network Supervisor is displayed
in the About 3Com Network Supervisor dialog. Refer to F

inding the Serial

Number and Activation Key on page 43 for more information.

Key Considerations The following section contains troubleshooting information when

activating 3Com Network Supervisor.

Key Considerations 27

What if I lose my Activation Key after registration?

You can re-register your copy of 3Com Network Supervisor to obtain your
activation key again. You will also receive an e-mail confirmation of your
activation key.

When you are re-registering the product, it is very important to enter
exactly the same user and product information during the original
registration. This includes the username, product number and serial
number. Entering different information may result in the registration
begin rejected.

If I re-install the product after it has been activated, do I need to
activate it again?

No - the product activation information is stored on your computer and
will remain intact following de-installation and re-installation.

Why can’t I log in to the 3Com support web site?

If you experience difficulties logging in to the 3Com support web site,
please check your web browser settings to ensure that cookies are
enabled. You may also want to check with your system administrator that
your site’s firewall settings permit web site cookies.

28 CHAPTER 2: PRODUCT ACTIVATION

MAIN WINDOW

3

Overview This chapter describes the 3Com Network Supervisor main window. The

main window provides access to all of the features in 3Com Network
Supervisor.

This chapter covers the following topics:

■ Key Concepts

■ Components

■ Examples

Key Concepts This section describes some 3Com Network Supervisor key concepts

relating to the main window.

Map Files 3Com Network Supervisor stores device and topology information in map

files. Map files have the file extension

Only one map file may be open at any one time. Opening a new map file
will close the current map file.

Two other types of files are saved alongside map files. These files use the
same name as the map file but have
extensions. These files are used internally by 3Com Network Supervisor.
Although the presence of these files is not required to successfully load a
map file, previously logged event information will not be available if the
former is not present and some user-defined options may not be set if the
latter is not present.

.map.

Events.mdb and .properties file

30 CHAPTER 3: MAIN WINDOW

Components The following section describes the features of the main window and

describes the operations you can perform from this window.

Map The map provides a graphical representation of the topology of your

network. The map is covered in more detail in “
on page 93

.

Tree The tree displays the devices within your network grouped by subnet and

device group. The tree, subnets and device groups are covered in more
detail in “

Working with the Map” on page 93.

Toolbar The toolbar provides access to the most commonly used map navigation

and administration tools.

Some items in the toolbar are not always applicable. When this is the
case, the toolbar button is grayed out.

Hovering the mouse cursor over a button in the toolbar causes a tooltip
for that button to be displayed. The tooltip describes the operation
associated with the button.

Working with the Map”

The operations provided by the toolbar buttons are equivalent to their
corresponding menu items. For more information see “

page 31

.

Main Menu” on

Status Bar The status bar provides detailed information about items within the map

and tree, as well as providing a location for minimized progress dialog
boxes, such as the Network Discovery Progress dialog box.

The status bar provides information on the current selection as follows:

■ For a selected map item the text displayed is:

Selected <map item type> “<map item label>”

For example, if you were to select a router that had the label test, the
text displayed would be:

Selected Router “test”

■ For a selected link the text displayed is:

Selected Link from <map item type> ”<map item label>” to

<map item type> ”<map item label>”

Components 31

For example, if you were to select a link that connected a router with
the label test to a router with the label test2, the text displayed would
be:

Selected Link from Router ”test” to Router ”test2”

■ For multiple selections in the map or tree the text displayed is:

Selected Multiple Items

The status bar also provides detailed information about a menu item
when it is highlighted.

Main Menu The following tables list each menu item for a given main menu and the

associated operation invoked by selecting it.

File Ta bl e 3 lists each menu item for the File menu and the associated

operation invoked by selecting it.

Tab le 3 File Menu

Menu Item Hot Key Operation

File > New Ctrl+N Creates a new empty map file and

File > Open

File > Save

File > Save As Saves the current map file using a

File > Print Ctrl+P Prints the current contents of the

Ctrl+O

Ctrl+S

launches the Network Discovery
wizard. Prompts for a save if the
current map has changed. For more
information see “Saving and Opening

Maps” on page 145.

Opens an existing map file. Prompts
for a save if the current map has
changed. See “Saving and Opening

Maps” on page 145 for more

information.

Saves the current map file. Prompts
for a filename if the map has not been
saved previously. See “Saving and

Opening Maps” on page 145 for

more information.

specified name. See “

Opening Maps” on page 145 for

more information.

map. See on
on

page 148 for more information.

“Printing the Map”

Saving and

32 CHAPTER 3: MAIN WINDOW

Edit Ta bl e 4 lists each menu item for the Edit menu and the associated

Menu Item Hot Key Operation

File > Most Recently Used File
List

File > Exit Exits 3Com Network Supervisor.

Opens the map selected from the
Most Recently Used File List.

See “Saving and Opening Maps” on

page 145

Prompts for a save if the current map
has changed. For more information
see “

page 38

for more information.

File > Exit Menu Option” on

.

operation invoked by selecting it.

Tab le 4 Edit Menu

Menu Item Hot Key Operation

Edit > Add Map Item Launches the Add Map Item dialog

Edit > Add Link Links the two map items currently

Edit > Delete Ctrl+Delete Deletes the selected map item or link.

Edit > Grouping > Group
Devices

Edit > Grouping > Move
Devices to Group

Edit > Grouping > Ungroup
Devices

Ctrl+G Groups the selected devices together

Ctrl+M

box. This dialog box allows you to add
new devices and clouds to the map.
See “

Manually Modifying the Map
Contents” on page 142 for more

information.

selected. See “

Map” on page 144 for more

information.

See “

Deleting Items from the Map”

on page 144

into a single logical device group. See

“

Device Groups” on page 111 for

more information.

Moves the selected devices to an
existing device group. See “

Groups” on page 111 for more

information.

Ungroups the selected device group.
See “

Device Groups” on page 111 for

more information.

Linking Items in the

for more information.

Device

Components 33

Menu Item Hot Key Operation

Edit > Find Ctrl+F Launches the Find dialog box. This

dialog box allows you to find items in
the map by various attributes, such as
Name, IP or MAC address. See

“

Finding Items on Your Network”on

page 133

Edit > Select All Ctrl+A Selects all map items in the currently

viewed submap. See “

in the Map and Tree” on page 121 for

more information.

Edit > Select All Core Devices Selects all core infrastructure devices

in the map. See “

the Map and Tree” on page 121 for

more information.

for more information.

Selecting Items

Selecting Items in

View Ta bl e 5 lists each menu item for the View menu and the associated

operation invoked by selecting it.

Tab le 5 View Menu

Menu Item Hot Key Operation

View > Show End Stations Toggles whether end stations are

displayed in the map or not. See

“

Devices” on page 100 for more

information.

View > Show Undiscovered
Subnets

View > Annotate Aggregated
Links

View > Annotate Duplex
Mode

View > Annotate Resilient
Links

Toggles whether undiscovered
subnets are displayed in the map or
not. See “

page 110

Toggles whether the link annotations
for aggregated links are displayed in
the map or not. See “

Annotations” on page 105 for more

information.

Toggles whether the link annotations
for link duplex modes are displayed in
the map or not. See “Physical Link

Annotations” on page 105 for more

information.

Toggles whether the link annotations
for resilient links are displayed in the
map or not. See “Physical Link

Annotations” on page 105 for more

information.

Undiscovered Subnets” on

for more information.

Physical Link

34 CHAPTER 3: MAIN WINDOW

Menu Item Hot Key Operation

View > Group Map by Subnet Toggles whether devices in the map

are grouped by subnet or not. See

“

The Grouped Network View ” on
page 98
Network View ” on page 100 for

more information.

View > Labels > Custom
Name

View > Labels > User Name Selects the display of the User Name

View > Labels > DNS Name Selects the display of the DNS Name

View > Labels > System Name Selects the display of the System

View > Labels > IP Address Selects the display of the IP Address

View > Labels > MAC
Address

View > Relayout Map Performs an automatic relayout of the

View > Go Up Ctrl+Up Navigates to the parent submap of the

Selects the display of the Custom
Name label for map items in the tree
and map. See “Map Item Labels and

Address Translation” on page 116 for

more information.

label for map items in the tree and
map. See “Map Item Labels and

Address Translation” on page 116 for

more information.

label for map items in the tree and
map. See “

Address Translation” on page 116 for

more information.

Name label for map items in the tree
and map. See “Map Item Labels and

Address Translation” on page 116 for

more information.

label for map items in the tree and
map. See “Map Item Labels and

Address Translation” on page 116 for

more information.

Selects the display of the MAC
Address label for map items in the
tree and map. See “

and Address Translation” on
page 116

map items in the currently viewed
submap. See “Automatic Relayout of

Maps” on page 141 for more

information.

currently visible submap when you are
viewing the devices in your network
grouped by subnet. See “
on page 123

and “The Ungrouped

Map Item Labels and

Map Item Labels

for more information.

Navigation”

for more information.

Components 35

Menu Item Hot Key Operation

View > Enter Submap Ctrl+Down Navigates to the submap associated

with the currently selected subnet or
device group. See “

page 123

View > Zoom > Zoom in Ctrl+Page

Down

View > Zoom > Zoom out Ctrl+Page UpZooms out from the map. See

View > Zoom > Fit to page Centers the map on the display and

Zooms in towards the map, centering
the current selection in the display if
applicable. See “Navigation” on

page 123

Navigation” on page 123 for more

“

information.

zooms in or out as necessary so that
the entire map is visible in the display.
See “
more information.

for more information.

for more information.

Navigation” on page 123 for

Navigation” on

Device Ta bl e 6 lists each menu item for the Device menu and the associated

operation invoked by selecting it.

Tab le 6 Device Menu

Menu Item Hot Key Operation

Device > Web Management Launches the web interface for the

selected device. See

“Web

Management” on page 294 for

more information.

Device > Telnet Management Launches the Telnet management

Device > Administration >

Network Jack Configuration

Device > Properties Launches the Properties dialog box for

interface for the selected device. See

“Telnet Management”on page 294

for more information.

Launches 3Com Network Jack
Configuration Manager for the
selected device. See “Network Jack

Configuration Manager” on page 294

for more information.

the selected items. See “

Device Details” on page 165 for more

information.

Viewing

36 CHAPTER 3: MAIN WINDOW

Monitoring Ta bl e 7 lists each menu item for the Monitoring menu and the associated

operation invoked by selecting it.

Tab le 7 Monitoring Menu

Menu Item Hot Key Operation

Monitoring > Start
Monitoring

Monitoring > Stop
Monitoring

Monitoring > What’s Wrong Launches, or brings to the front, an

Monitoring > Live Graphs Launches the Live Graphs window for

Starts the monitoring of the selected
items by 3Com Network Supervisor.
See “Starting and Stopping

Monitoring” on page 213 for more

information.

Stops the monitoring of the selected
items by 3Com Network Supervisor.
See “

Starting and Stopping
Monitoring” on page 213 for more

information.

instance of the Events window filtered
to show unresolved events for the
selected items only. See “

Unresolved Events for a Selection:” on
page 228

the selected item. See “

Menu” on page 210 for more

information.

for more information.

Viewing

Live Graphs

Alerts/Events Ta bl e 8 lists each menu item for the Alerts/Events menu and the

associated operation invoked by selecting it.

Tab le 8 Alerts/Events Menu

Menu Item Hot Key Operation

Alerts/Events > Attach Alerts Launches the Attach Alerts dialog box

for the selected items. See “

Alerts Dialog Box”on page 257 for

more information.

Alerts/Events > View Filtered
Events

Alerts/Events > All Events Launches, or brings to the front, an

Launches, or brings to the front, an
instance of the Events window,
filtered to show events for the
selected items only. See “

Components” on page 227 for more

information.

unfiltered instance of the Events
window. See “Events List

Components” on page 227 for more

information.

Events List

Attach

Components 37

Tools Ta bl e 9 lists each menu item for the Tools menu and the associated

operation invoked by selecting it.

Tab le 9 Tools Menu

Menu Item Hot Key Operation

Tools > Reports Launches the Reports dialog box. See

Tools > Network Discovery Launches the Network Discovery

Tools > Trace Path Ctrl+T Launches the Trace Path toolbar to

Tools > Prioritize Network
Traffic

Tools > Live Update Launches the Live Update wizard. See

Tools > Device Warranty Ctrl+W Launches the Device Warranty wizard.

Tools > Options Launches the Options dialog box. See

Reports Dialog Box” on page 279 for

“

more information.

wizard for the selected subnets. See

“The Network Discovery Wizard” on
page 63

show the possible physical paths
between the two selected devices, or
launches the Trace Path wizard if two
devices are not selected. See “

Path” on page 129 for more

information.

Launches the Prioritize Network Traffic
wizard for the selected devices. See

“Prioritize Network Traffic Wizard” on
page 321

“
page 375

See “

page 299

“
page 38

for more information.

for more information.

Live Update Setup Wizard” on

for more information.

Device Warranty Wizard” on

for more information.

Tools > Options Menu Option” on

for more information.

Trace

Help Ta bl e 10 lists each menu item for the Help menu and the associated

operation invoked by selecting it.

Table 10 Help Menu

Menu Item Hot Key Operation

Help > Contents and Index Launches the online help. For more

information see “

Index Menu Option” on page 42.

Help > Launch User Guide Launches the user guide. For more

information see

Help > Contents and

“Help > Launch

User Guide” on page 42

38 CHAPTER 3: MAIN WINDOW

Menu Item Hot Key Operation

Help > Activate Now Launches the Activation dialog box.

Help > About 3Com Network
Supervisor

For more information see “

Now dialog” on page 24.

Launches the About 3Com Network
Supervisor dialog box. For more
information see “Help > About 3Com

Network Supervisor Menu Option” on

Activate

page 42.

File > Exit Menu

Option

Tools > Options Menu

Option

This operation closes 3Com Network Supervisor. The following message
will be displayed if there are outstanding changes to the map that need
to be saved:

Figure 4 Exit Before Save Dialog Box

This menu item launches the Options dialog box, which is used to
configure the default behavior of 3Com Network Supervisor. The Options
dialog box consists of the following tabs:

■ General — default file locations and how the application should

behave.

■ Device Management — options for managing devices in your map.

■ Internet — how 3Com Network Supervisor should connect to the

Internet.

Any option set in the Options dialog box applies to all maps opened
within 3Com Network Supervisor, not just the map that was open when
the option was set. All options are automatically saved, and are retained
for future use in 3Com Network Supervisor.

Components 39

General

This tab, as shown in Figure 5

■ Default File Location — change the default location where map files

, displays the following:

are saved to a different location. Click Browse to choose the directory
you want. If the path you enter does not exist, you are warned of this
when you click OK.

The default directory is:

dir>\maps\my_maps

Saving and Opening Maps” on page 145 for more information.

See “

Figure 5 General Tab

< 3Com Network Supervisor install

.

■ MAC Addresses — for any MAC address displayed, you can append

the manufacturer’s name to the start by enabling the Translate MACs
option. For example, 08-00-8F-xx-xx-xx becomes 3Com-xx-xx-xx. This
option is disabled by default. See “

Vendor Translation of MAC

Addresses” on page 118 for more information.

■ Show the Live Update Setup Wizard next time — this option is

enabled by default, See “

Live Update Setup Wizard” on page 375 for

more information.

40 CHAPTER 3: MAIN WINDOW

■ Show the Device Warranty dialog box after a refresh operation

— this is enabled by default. See “

page 298

■ Auto-expand product information banner on toolbar - this is

for more information.

Device Warranty Dialog Box” on

enabled by default. Unchecking this option will prevent the product
information banner on the toolbar from expanding when you hover
the mouse over it.

Device Management

This tab allows you to change the management application that is
launched when a device is double clicked in the list as shown in Figure 6

Figure 6 Device Management Tab

.

Choose from Web Management, which is the default, Telne t
Management or Administration Application. If a device does not support
the preferred Web Management application, Tel n et is launched instead.

For further information on the Device Management options see

Configuring Single Devices” on page 293.

“

Components 41

Internet

This tab, as shown in Figure 7

■ Use Web browser settings — this is the default option. If your web

, allows you to set the following options:

browser uses a proxy server to access the Internet, 3Com Network
Supervisor will use the same system.

Figure 7 Internet Tab

■ Direct connection to the Internet — use this option if your

management station connects to the Internet directly through a Local
Area Network, without using a proxy server.

■ Custom proxy settings — specify the address of the proxy server

followed by the proxy port number. If your proxy server requires
authentication click the My proxy server requires authentication
checkbox and enter the username and password.

Live Update” on page 373 for more information.

See “

42 CHAPTER 3: MAIN WINDOW

Help > Contents and

Index Menu Option

Help > Launch User

Guide

Help > About 3Com

Network Supervisor

Menu Option

Examples

Finding the Product

Version

This launches the Contents and Index pages of the online help.

The 3Com Network Supervisor online help system is a browser-based
help system, and uses the default browser for displaying help. If you do
not have a default browser configured on your system then 3Com

Network Supervisor will be unable to launch the online help system.

This launches the 3Com Network Supervisor User Guide.

You must have a suitable PDF reader correctly installed on your PC in
order to launch the user guide.

When you launch 3Com Network Supervisor for the first time, the About
dialog box is displayed.

The dialog box shows the product name, product number, serial number
and the major version number. Any service packs installed are also listed.

You have a query about an aspect of 3Com Network Supervisor
functionality and want to contact 3Com support. The support engineer
asks you for your 3Com Network Supervisor product version.

®

1 Launch the About dialog box using Help > About 3Com

Network

Supervisor:

Figure 8 About Dialog Box

Examples 43

2 The product version number and service pack level are listed in the first

line of the dialog box.

Finding the Serial

Number and

Activation Key

You have a query about an aspect of 3Com Network Supervisor
functionality and contact 3Com support. The support engineer asks you
for your 3Com Network Supervisor serial number and activation key.

®

1 Launch the About dialog box using Help > About 3Com

Network

Supervisor:

2 The serial number is located on the second line of the dialog box.

3 The activation key is located on the third line of the dialog box.

If you have not yet entered the activation key then the About dialog box
will not display them, but will instead show the remaining evaluation
period.

44 CHAPTER 3: MAIN WINDOW

DISCOVERING THE NETWORK

4

Overview This chapter describes how 3Com Network Supervisor discovers

information about your network.

Before you can use 3Com Network Supervisor to manage your network
you must instruct it to perform a network discovery. This chapter explains
the discovery process, and how to tailor it to work best on your network.
It also describes any problems you may encounter with the discovery
process and the steps you can take to overcome them.

This chapter covers the following topics:

■ Key Concepts

■ Components

■ Examples

■ Useful Information and References

■ Discovery Report Errors and Warnings

46 CHAPTER 4: DISCOVERING THE NETWORK

Key Concepts The discovery process can be initiated in a number of ways detailed later

in this chapter. This section explains the key concepts behind the
discovery process itself.

The process is divided into two distinct operations – detecting the devices
that exist on the network (discovering devices), and subsequently
establishing how they are physically connected together (determining
topology). Both of these operations are divided further into several
stages. The main concepts associated with these operations and
associated stages are outlined in this section as follows:

■ How 3Com Network Supervisor discovers devices on the network

■ How 3Com Network Supervisor determines the network topology

■ How 3Com Network Supervisor re-discovers information about a

network it already knows about

The Discovery Process

– Detecting Devices

This operation determines which devices exist on one or more IP subnets.
It also finds out more about each discovered device, such as its type and
capabilities. The operation is initiated with a list of subnets to discover.
Within each subnet 3Com Network Supervisor attempts to locate devices
across one or more specific IP ranges. You can control the ranges of
devices to be detected within each subnet, but the default behavior is to
attempt the full range for each subnet. Fine-tuning the discovery process,
including specifying subnet ranges, is described later in this chapter.

The detecting devices part of the discovery process consists of a number
of discrete stages:

P Ping

1 I

evice Capability Detection

2 D

3 SNMP Type Detection

4 IP to MAC Resolution

5 End Station Type Recognition

6 Web Type Recognition

7 DNS Name Resolution

BX Phone Detection

8 N

9 Device Sizing

Key Concepts 47

With the exception of the sizing stage (explained below), each of the
stages runs sequentially, and the sequence is repeated for each subnet
that is being discovered. The sizing stage runs once only, when all the
other stages have been executed for all of the subnets being discovered.

The purpose of each stage is described below:

IP Ping

In order to detect which IP nodes exist, this stage performs an IP Ping over
the specified ranges of addresses for the subnet. If no ranges are
specified, a default range is deduced from the subnet address and subnet
mask of the subnet being discovered. This range excludes the subnet
address itself (lowest address value) and the subnet broadcast address
(highest address value).

Device Capability Detection

This stage is applied to each device that responded to a ping in the
previous stage. Its purpose is to determine if a device supports certain
network protocols. Specifically, these are:

■ SNMP

■ HTTP

■ Tel ne t

The most detailed information is generally obtained from devices that
support SNMP. For these devices 3Com Network Supervisor initially starts
the communication using the read community string as originally
specified in the Network Discovery wizard. Having successfully
communicated using the read community string it then attempts
communication using the write community string(s), again obtained from
the Network Discovery wizard. While the write community string is not
heavily used by the discovery process (except a small part of topology), it
is used extensively by other features of 3Com Network Supervisor.
Consequently, if the write community cannot be successfully determined,
discovery will continue, but add a warning to the report provided at the
end of discovery.

48 CHAPTER 4: DISCOVERING THE NETWORK

3Com Network Supervisor detects HTTP and Telnet capabilities by
attempting to open a TCP connection to the device using ports 80 and 23
respectively. The purpose of this detection is to decide whether to enable
the Web and Telnet menu options on the right-click menu. For certain
3Com devices additional information can be obtained using HTTP – see

Web Type Recognition” and “NBX Phone Detection” on page 49

“

SNMP Type Detection

This stage only applies to devices that were found to support SNMP
during the Device Capability Stage. 3Com Network Supervisor reads
standard SNMP MIBs in order to determine additional information about
each SNMP node, in particular the type of the device (based on MIB-II
sysObjectID), its IP addresses and its MAC addresses. Where a device has
multiple IP addresses that respond with the same information, e.g. list of
MAC addresses, 3Com Network Supervisor ensures that it is represented
as a single device on the map. Certain devices which have multiple IP
addresses respond with different information. Initially they are detected
as separate nodes, which 3Com Network Supervisor attempts to resolve
in the sizing stage.

If a router is detected when discovering a given subnet, that router
information will be made available to any subsequent subnets included as
part of the whole discovery operation. This ensures that the router is not
interrogated more than once for the same information by several stages.

IP to MAC Resolution

This stage is responsible for obtaining the MAC addresses of non-SNMP
nodes. For the local subnet, i.e. the one to which the 3Com Network
Supervisor PC is attached, this is achieved by reading the ARP cache of
the 3Com Network Supervisor PC. For remote subnets this is achieved by
querying any routers that have been discovered on these subnets. This
stage is not normally required for determining the MAC addresses of
SNMP nodes, since that can be achieved in the SNMP type detection
stage.

It is important for 3Com Network Supervisor to determine the MAC
addresses of nodes in order to be able to subsequently determine their
position in the network topology.

End Station Type Recognition

This stage is responsible for attempting to determine the operating
system type for devices that are IP-only or unrecognized (generic) SNMP.

Key Concepts 49

The end station stage attempts to determine an end station’s type by
performing the following steps:

1 Attempting to start a Telnet session with the device and subsequently

parse the Login banner if the Telnet service is supported.

2 Determining if the node is operating as a file server. This is achieved by

attempting to connect to the device via TCP port 2049.

3 Determining if the node is operating as a print server. This is achieved by

attempting to connect to the device via TCP port 515.

4 Using Microsoft Windows API calls to obtain the Windows operating

system information, provided the node is a member of
domain/workgroup.

Web Type Recognition

Certain 3Com devices have Web (HTTP) management interfaces but do
not support SNMP. Some of these devices identify their type using a
hidden tag in their home page. For devices that have been recognized as
supporting HTTP but not supporting SNMP, 3Com Network Supervisor
looks for this tag in order to recognize the device.

DNS Name Resolution

During this stage 3Com Network Supervisor attempts to retrieve a DNS
name for each IP address that has been detected. 3Com Network
Supervisor uses information from the Windows registry in order to
establish potential DNS servers that exist. It then communicates with
them directly making DNS queries using UDP.

NBX Phone Detection

This stage obtains detailed information about any Network Branch
eXchange (NBX) devices that were discovered as part of the Web Type
Recognition Stage.

The Network Discovery wizard allows you to specify the IP addresses of
individual NBX call processors (NCPs) on the network, and a separate
username/password for each.

This stage is required because the NBX chassis and phones do not support
SNMP. Many of the phones will not have IP addresses and consequently
will not respond to a ping. The NBX chassis contains a non-visible Web
page which 3Com Network Supervisor downloads using HTTP. The page
provides 3Com Network Supervisor with a list of phones that are

50 CHAPTER 4: DISCOVERING THE NETWORK

associated with that NBX chassis. This allows 3Com Network Supervisor
to identify the existence of phones which would not normally be
detected.

NBX phones can be configured to work with or without an IP address.
Those with just a MAC address will be added to the 3Com Network
Supervisor map in the same subnet as the NBX chassis, i.e. the subnet
currently being discovered. Those phones that additionally have an IP
address are only added to the map if the subnet they belong to is
discovered as part of the current discovery operation.

Device Sizing

During this final discovery stage further details are obtained about
individual SNMP devices that have been discovered. This is done for
devices which 3Com Network Supervisor knows how to interrogate
further, often using proprietary MIBs. Sizing basically means obtaining
detailed configuration information. Normally this includes determining:
the number of units in a stack or number of modules in a chassis, their
type and software version, the number and type of ports on each unit or
module and their link status, the VLANs configured on the device.

This stage is executed once only when all the other stages have been run
on all of the desired subnets. The reason for this is that during the other
discovery stages some IP addresses may have been discovered as separate
devices, but it is desirable for 3Com Network Supervisor to display them
as a single device on the map. Typically this applies to devices, with their
own IP addresses, that can contain intelligent modules, also with their
own IP addresses. In particular this applies to routing modules, since they
tend to have IP addresses on subnets not known to the host device
chassis or stack. By communicating with the chassis and its intelligent
modules, 3Com Network Supervisor can deduce that they are physically
part of the same chassis, and consequently merge them into a single
device on the map.

Key Concepts 51

The Discovery Process

– Determining

Topology

The second part of the discovery process is to determine the topology of
a network, by establishing what links exist between the different devices
that have been discovered. The operation determines how the devices
discovered by the previous detecting devices operation are physically
connected together.

The topology process starts when all discovery operations have
completed. The topology process is applied to one subnet (or more
specifically multinet) at a time.

3Com Network Supervisor uses the term multinet to describe a situation
where more than one subnet is attached to a single router port. This can
result in devices on different subnets sharing the same switched
infrastructure. Consequently, although devices may logically be on
different subnets they may learn the MAC addresses of the devices on the
other subnet(s) in their bridge tables. Switches learning the MAC
addresses of other switches is an important concept in determining the
network topology.

The topology algorithm uses Bridge Forwarding Database (FDB) tables to
determine on which ports a switch has learned the MAC addresses of
other switches in the network. It uses the information of switch ports that
have learned the addresses of other switches in order to build a tree of
network devices representing the physical connectivity. In reality, each
subnet/multinet may not physically appear to be a tree, for instance if
spanning tree is used to employ resilient paths. The algorithm used to
deduce the topology takes such scenarios into consideration.

Before the tree-building process can take place 3Com Network Supervisor
needs to obtain the list of learned addresses for each switch. In practice
this involves more than just reading the FDB tables, as different device
types have different port and unit numbering schemes. For efficiency
purposes an initial attempt is made to determine the positions of most of
the end stations. This is done by checking for ports that have only learned
the address of a single device that is not a switch. Because the positions
of many end stations are resolved here, the amount of information
required to be read from the switches is reduced. A summary of the main
topology stages is given below.

Unlike the discovery stages described in the previous section these stages
are all represented on a single progress bar in the Network Discovery
Progress dialog box.

52 CHAPTER 4: DISCOVERING THE NETWORK

Sizing stage

This stage determines the units and ports that belong to each switch. It
establishes which ports have a link present so that it knows which ports
to consider during topology. Since the detecting devices operation has
already sized each device, it does not need to communicate with the
devices again.

Information obtained from the devices is also used to establish whether
they are supported by 3Com Network Supervisor. For instance, it checks
the agent version along with other parameters. Warnings are logged in
the Discovery report. For non-3Com devices an attempt is made to use
standard MIBs when considering them as part of the topology process.
Since different devices use differing numbering schemes for units and
ports and often use proprietary MIBs, the information displayed about
the topology of third party devices will not be as detailed as that of 3Com
ones, and sometimes may not be as accurate.

Spanning Tree stage

Having obtained a list of supported switches,
determine those whose spanning tree links are blocked. This information
is generally provided by standard bridge MIBs. This is an extension of the
Device Sizing stage, but the information obtained is only required for
topology.

this stage attempts to

The ports participating in such links are eliminated from the remainder of
the topology process until the tree-building stage.

Remote Poll Stage (broadcast ARP)

The purpose of this stage is to attempt to force each switch to learn the
addresses of other switches on the same subnet/multinet. It uses remote
poll to instruct each switch to ping an unused address on the subnet,
thus forcing it to transmit a broadcast ARP. This causes other switches on
the subnet to learn the addresses of the source switch.

Remote Poll, sometimes called Remote Ping, is a mechanism, using SNMP,

to instruct a device to ping another IP address. This requires an SNMP set
instruction to be sent to the device, which relies on 3Com Network
Supervisor having correctly determined the SNMP write community string
during the Device Capabilities Detection stage. If the write community
string has not been correctly established or the device does not support
the remote poll feature (e.g. third party devices) then the accuracy of the
deduced topology may be reduced.

Key Concepts 53

Initial Endstation stage

During this stage an attempt is made to identify the ports that have only
learned a single address. This is done by reading bridge address tables.
The purpose of this stage is two-fold:

■ to eliminate the need for many end station addresses having to be

considered in the rest of the topology, which can reduce the amount
of processing and network traffic generated in the remainder of the
topology process;

■ to detect the existence of non-IP (MAC-only) nodes. If a port has a

functioning link and has learned exactly one MAC address then that
address is assumed to be a single node attached to that port. If no IP
address was found to map to this MAC address during the IP to MAC
Resolution stage then 3Com Network Supervisor will assume that this
MAC address belongs to a new node. Consequently 3Com Network
Supervisor will show the MAC-only node on the map.

You may have deliberately instructed the discovery operation to only
detect IP ranges relevant to your switches which are outside the ranges of
your endstations. Consequently the depiction of MAC-only nodes may
not be required.

Device Resolution Stage

During this stage 3Com Network Supervisor attempts to establish which
switches have learned the addresses of other switches, and on which
ports. Since some addresses have already been read from the bridge
tables in the previous stage, 3Com Network Supervisor may not need to
communicate with all switches during this stage.

At the end of this stage, 3Com Network Supervisor analyses whether it
has enough information to determine the network topology.

Remote Poll Stage (directed pings)

If insufficient information was obtained from the Device Resolution stage,
then an attempt is made to force devices to learn the addresses of others
by instructing them to ping each other (remote poll).

As with the previous remote poll stage the write community string of the
relevant switches is required. Also, as with the previous stage some
devices may not support remote poll. If either the write community string
is not known for a device or it does not support remote poll then the
accuracy of the deduced topology may be reduced.

54 CHAPTER 4: DISCOVERING THE NETWORK

Outstanding end station stage

Not all end stations will be resolved by the Initial Endstation stage. For
instance, some ports may have multiple addresses in their bridge tables
even though only a single device is attached (if, for example, older
addresses not have aged out). Therefore a similar process to the Device
Resolution stage is used to locate the switches that have learned the
addresses of known end stations. As with the Device Resolution stage it
may not be necessary to communicate with all switches since their
address tables will have been cached from the previous stages.

Tree Building Stage

This does not require any device access. It is the point at which 3Com
Network Supervisor analyzes all the information it has obtained from the
previous stages. It builds a tree view of the subnet/multinet, placing end
station devices appropriately. It also adds back in any blocked spanning
tree links.

Clouds – Unknown Topology

When 3Com Network Supervisor builds the network tree, there may be
certain parts where it is unable to exactly determine the network
topology. In such cases you will see clouds on your map depicting the
areas of uncertainty. Typically these tend to be ports that have seen the
addresses of multiple devices, but those learned devices do not provide
any further topology information about the network.

For example, there may be a case where a switch port is connected to an
unmanaged hub, and that unmanaged hub is directly connected to two
end stations (e.g. PCs). The port on the first switch will learn the
addresses of the two end stations. It will not learn the address of the hub
(because it does not have one) and 3Com Network Supervisor will not
detect the existence of the unmanaged hub because it won’t respond to
a ping. 3Com Network Supervisor depicts this scenario as follows:

Key Concepts 55

Figure 9 Clouds – Unknown Topology

The switch port cannot be physically connected to two end stations, and
as such 3Com Network Supervisor inserts the cloud to indicate that there
is something missing. In this case the cloud is where the unmanaged hub
should be.

A similar situation can also occur when insufficient topology information
has been obtained from one or more switches, possibly because 3Com
Network Supervisor lost communication with that switch during the
topology process. If the problem device were an edge switch that is
actually connected to many end stations, 3Com Network Supervisor
would show this as below:

56 CHAPTER 4: DISCOVERING THE NETWORK

Figure 10 Edge Switch – Unknown Topology

You can identify which switch is the problem device here by checking if
unit and port information has been successfully retrieved for each link to
each switch. Hover the mouse over the end of the link nearest each
switch to show tooltip information on the link. The switch with missing
unit and port information is probably the cause of the problem. In the
situation above, it is clear that the bottom switch is at fault.

If information was available, the problem switch would be positioned
where the cloud is, and the cloud would not be shown. The above
situation occurs because the switch to the left of the diagram has learned
the addresses of all the end stations, and also the bottom switch.
However, because 3Com Network Supervisor lost communication with
the bottom switch, it also gets treated as if it were an end station (since
topology information could not be read from it).

Key Concepts 57

If a problem was encountered when communicating with the switch you
should see an error in the Discovery report produced by 3Com Network

Supervisor at the end of the discovery process. Always check the
Discovery report first when your discovered network map appears to be

incorrect.

Sometimes clouds appear in the core of the network when a key, core
device has not been discovered properly:

Figure 11 Clouds – Core Device Failed to be Fully Discovered

Hover the mouse over the links to each of the Switches. If one of them
shows no unit or port details, it is likely that this switch should have been
positioned where the cloud is. If all the switches give unit and port
details, it is likely that there is another device that should be positioned
where the cloud is, but that was not detected by 3Com Network
Supervisor.

58 CHAPTER 4: DISCOVERING THE NETWORK

Wireless Clients Clouds

Wireless client clouds are shown directly connected to a Wireless access
point on your map. They are used to indicate the number of wireless
clients connected to the access point.

The Discovery Process

– Rediscovery

When the first discovery operation is fully complete the information
3Com Network Supervisor has obtained will be displayed on the map.
You can then instruct 3Com Network Supervisor to perform additional
discoveries (rediscoveries). You may wish to do this because:

■ There are some additional subnets that you wish to see on your map

that either weren’t specified in the original discovery or didn’t exist on
your network at the time you performed the initial discovery.

■ Some new devices have been added to your existing subnets or some

of the existing devices have changed configuration.

When you perform a rediscovery on existing subnets 3Com Network
Supervisor will remember and reuse some of the options you specified on

the previous discovery, including additional community strings that you
specified and the NCPs in your network.

When 3Com Network Supervisor performs a second or additional
discovery it does not update your map as it progresses. It adds all the
information it acquires to a temporary database. This means that you can
continue to work with your current map until the new discovery
completes, though certain tasks are restricted. Although 3Com Network
Supervisor is populating the temporary database with the new
information, it does obtain some parameters from the main, working
database, for example any community strings that were successfully
determined for devices that are subsequently being rediscovered.

Once 3Com Network Supervisor completes its additional discovery it then
updates the main database (and subsequently the map) with the newly
discovered information. It does this by comparing the information that
exists in the main database with that in the new, temporary database.
The basic rules it applies, when updating the main database, are as
follows:

■ Any new subnets are simply added to the new database as they would

be on an initial discovery

■ Any new devices are simply added to the appropriate subnets (either

existing or new).

Components 59

■ Any devices that have changed (e.g. unit added/removed) are updated

– you can view their new details using the Properties dialog box.

■ Devices that exist in the main database but have been removed from

the network and/or simply did not respond in the second discovery
will not be deleted from the database or the map. The exception to
this is if a device’s IP address now belongs to another device. For
example: device A initially has address x, device B has address y. On a
subsequent discovery device A now has both addresses x and y. In this
scenario device A’s information will be updated to reflect its new
addresses and device B will be deleted.

■ Any new links (that is, connections between devices and/or device’s

ports) detected by the topology process will be added to the relevant
devices on the map.

■ If a port previously had a link to a device and that port is subsequently

detected as being connected to a different device, the old link will be
deleted and the new one created. A port can only be connected to
one other node.

■ If a port previously had a link and the second discovery could not

successfully establish that the same port was connected (for example,
3Com Network Supervisor lost communication part way through)
then that link will not be deleted. Instead it will be marked as
unconfirmed and as a result will appear as a dashed line on the map.

Any changes detected as a result of additional discoveries are fully
described in the Changes report, automatically generated by 3Com
Network Supervisor at the end of a rediscovery operation. See “

The

Changes Report” on page 80.

Components The following section describes the features of the discovery tool and

how you can use them to tailor the discovery process to your needs. It
includes the dialogs and wizards that you can use to control the
discovery, and any appropriate reports that may be generated as a result
of a discovery operation.

You cannot launch the Network Discovery wizard while an existing
discovery operation is in progress. Instead, 3Com Network Supervisor will
simply display the Progress dialog box for that discovery.

60 CHAPTER 4: DISCOVERING THE NETWORK

Launching a

discovery

This section describes how your instruct 3Com Network Supervisor to
start the discovery process. You can initiate network discovery from a
number of places:

■ The Welcome dialog box

■ File > New menu option

■ Too ls > Network Discovery menu option with nothing selected

■ Too ls > Network Discovery menu option with a discovered subnet

selected

■ Too ls > Network Discovery menu option with an undiscovered subnet

selected

The Welcome dialog box

When 3Com Network Supervisor is opened it displays the Welcome
dialog box:

Figure 12 Welcome Dialog Box

Components 61

If you have not yet registered 3Com Network Supervisor and it is still in
the evaluation period, the first dialog box you see when launching the
application is the About dialog box. Closing this takes you to the

Welcome dialog box.

When you select the Create a new network map option and click OK, the
Network Discovery wizard is launched.

File > New

From the main menu, when you select the New option from the File
menu the Network Discovery wizard is launched. This is identical to
choosing Create a new network map from the Welcome dialog box.

Tools > Network Discovery with nothing selected

With no subnets selected in the tree or map, select Network Discovery
from the tools menu. The Network Discovery wizard will be launched at
the first pane Discovery Type.

Tools > Network Discovery with a discovered subnet selected

If you select one or more discovered subnets in the map or the tree and
select Network Discovery from the tools menu, the Network Discovery
wizard will be launched at the Specify Subnets pane. (See Specify Subnets

Pane on page 65.) The subnets you selected will be included in the list on

this pane:

Figure 13 Specify Subnets Pane

62 CHAPTER 4: DISCOVERING THE NETWORK

The subnet mask and range information are also filled out. You can
modify the range information by selecting the appropriate subnet in the
list and clicking Edit. If you choose not to modify the range information
then the discovery operation will include all ranges that have currently
been added to that subnet. If you do modify the range then only the
ranges you specify will be used in the discovery operation. However, old
ranges will not be discarded, and you can still view them by launching the
properties dialog box against the subnet.

You can also start a Network Discovery by right-clicking on a discovered
subnet, and selecting Network Discovery. This has the same effect as
selecting Network Discovery from the Tools menu.

Tools > Network Discovery with an undiscovered subnet selected

If you have already performed a discovery operation, and a router was
detected during that discovery, then it is likely that you will have some
undiscovered subnets on your map. These subnets will be those to which
the router is directly attached and were not specified in the original
discovery.

Figure 14 Undiscovered Subnet

If you select one or more of these subnets in the map or the tree and
select Network Discovery from the To ol s menu, the Network Discovery
wizard will be launched at the Specify Subnets pane. As with selecting an
existing subnet, the subnet information will be included in the list. The
range information will always default to All, although you can change
this if you wish by selecting the desired subnet in the list and clicking the

Edit button.

As with selecting discovered subnets, if you select an undiscovered
subnet in the tree or the map the right-click menu contains the Network

Discovery option. Selecting this has the same effect as selecting Network
Discovery from the tools menu.

Components 63

You can also launch the Network Discovery wizard for an undiscovered
subnet by double-clicking on its icon in the map or tree. This has the
same effect as selecting Network Discovery from the tools menu.

The Network

Discovery Wizard

This step-by-step guide takes you through the Network Discovery wizard
in order to customize the discovery process. When you complete the
wizard the discovery process will be started.

If you have previously created a network map, you can use this wizard to
rediscover all of your network, part of it, or discover a completely new
part. The discovery process verifies the devices and links on the network
map and incorporates any changes. To do this, you must open the map
before starting the wizard.

Discovery Type Pane

This is the first pane of the wizard:

Figure 15 Discovery Type Pane

64 CHAPTER 4: DISCOVERING THE NETWORK

It allows you to specify how the list of subnets to discover is determined:

■ Local subnet – Select this radio button and click Next to discover only

the subnet to which the 3Com Network Supervisor PC is attached.
The discovery process queries the operating system to determine the
subnet mask for the local subnet. The wizard moves onto the Monitor
Core Devices and Links pane. (See M

Pane on page 70.) This means that you cannot specify IP ranges when

using this option. If you wish to specify ranges for the local subnet
discovery you will need to use the Specify Subnets option and add the
details of the local subnet to the list of subnets to discover.

■ LAN subnets connected to the default router or gateway - Select

this radio button and click Next to discover all devices on the local
subnet (to which the 3Com Network Supervisor PC is attached) and
any additional subnets that are one router hop away (but only via LAN
connections). 3Com Network Supervisor establishes which subnets are
one hop away by querying the default router. As with the Local
Subnet option it is not possible to specify the IP address ranges for the
subnets to be discovered.

■ Specify subnets – Select this radio button and click Next to specify

exactly which subnets you wish to discover and also limit the ranges of
IP addresses to discover on each subnet. Use the Specify Subnets pane
to enter the subnets you want to discover.

onitor Core Devices and Links

Components 65

Specify Subnets Pane

This pane is shown if you chose the Specify Subnets option on the first
pane of the wizard.

Figure 16 Specify Subnets Pane

If you select one or more subnets in the tree or map view prior to
launching the Network Discovery wizard then you will be immediately
taken to this step, with the details of the subnets you selected added to
the list box.

Once you are happy with the list of subnets you have configured in the
list in the Specify Subnets pane of the wizard, and with the address
ranges associated with each, click Next to move to the next step of the
wizard.

Adding subnets to the list

To add a new subnet to the list you wish to discover, use the Add button.
This will launch the Add Subnet dialog box below:

66 CHAPTER 4: DISCOVERING THE NETWORK

Figure 17 Add Subnet Dialog Box

You must enter at least the IP address and subnet mask into the
appropriate fields for the subnet you wish to specify.

You can use the dot ‘.’ key to move to the next segment of an address
field.

If you wish to limit the ranges of addresses that 3Com Network
Supervisor will detect for your specified subnet, you must first select the
Discover custom ranges radio button and the ranges table and Add
button will become enabled.

The Discover full range and Discover custom ranges radio buttons are
only enabled if you have entered a valid Address and Mask pair.

The ranges table lists the ranges of IP addresses that 3Com Network
Supervisor will detect for your specified subnet. To add a range to the list
of ranges to detect, use the Add button. This will launch the Add Range
dialog box below:

Components 67

Figure 18 Add Range Dialog Box

This allows you to enter the start and end IP addresses of the range to
detect.

To discover a single IP address on a subnet, add a range with the same
start and end IP address.

An existing range can be modified by selecting the range and clicking
Edit. This will display the same dialog box as for adding subnets,
described above, with the Start and End fields completed with the
information you originally supplied. Modify the fields as necessary and
select OK to update the range.

To remove ranges from being detected, select the ranges and click Delete.

Removing discovered ranges from the list, or modifying discovered ranges
so that previously detected IP addresses will not be detected, does not
remove them from the map, but simply removes them from the list of
ranges to rediscover when the Network Discovery is started. The ranges
will remain in the map but will be unchanged by the Network Discovery
process. See “

Deleting Items from the Map” on page 144 for details of

how to remove devices permanently from the map.

Click OK to return to the Specify Subnets pane of the wizard. The subnet
you have just specified has been added to the list box. Note that if you
enter information that conflicts with a subnet already in the list, the
dialog box will report an error and will not be dismissed. For example, the
two subnets 1.2.3.0 / 255.255.255.0 and 1.2.3.192 / 255.255.255.192
cannot both exist – one is a superset of the other.

68 CHAPTER 4: DISCOVERING THE NETWORK

Editing subnets in the list

You can modify the details of any of the subnets in the list by selecting
the item and clicking Edit. This will display the same dialog box as for
adding subnets, described above, with each of the fields completed with
the information you originally supplied. Modify the fields as necessary
and select OK to return to the wizard. 3Com Network Supervisor will not
allow you to modify the subnet if it conflicts with another one in the list.

Removing subnets from the list

Select a subnet and click Remove to remove a subnet from the list.

Removing discovered subnets from the list does not remove them from
the map, but simply removes them from the list of subnets to rediscover
when the Network Discovery is started. The subnet will remain in the map
but will be unchanged by the Network Discovery process. See “Deleting

Items from the Map” on page 144 for details of how to remove subnets

permanently from the map.

Choosing from a list of known subnets

The Find Subnets button instructs 3Com Network Supervisor to attempt
to locate the subnets immediately neighboring your local subnet. The
located subnets are displayed in the Find Subnets pane.

Figure 19 Find Subnets List

Components 69

Select one or more subnets from the list, and click s to add them to the
list of subnets to be rediscovered. You can then edit their range as
normal.

3Com Network Supervisor communicates with the routers on your local
subnet in order to populate the above dialog box. It uses SNMP to
communicate with the routers and consequently requires their read
community strings in order to query them. By default, it uses public. If
that is not the correct read community for any of the routers, the query
will fail and the following dialog box displays:

70 CHAPTER 4: DISCOVERING THE NETWORK

Figure 20 Query Failure Dialog Box

If you want 3Com Network Supervisor to continue searching for subnets
using the router highlighted in this dialog box, enter the correct read
community for the router and select OK. Click Cancel to move onto the
next router.

Monitor Core Devices and Links Pane

The next step of the wizard allows you to configure how core devices will
be monitored for stress when the discovery process is complete.

The Monitor Core Devices and Links pane is displayed as follows:

Figure 21 Monitor Core Devices and Links Pane

Components 71

If you choose the Yes radio button then monitoring of the discovered
devices will be started when discovery is complete. By selecting the No
radio button no monitoring on the new devices will start at the end of
discovery. However, you can subsequently enable monitoring on selected
devices from the updated map.

Community Strings Pane

This step of the wizard allows you to specify the SNMP community strings
to use for devices while attempting to discover them.

Figure 22 Community Strings Pane

Typically, for security reasons, you will modify the community strings on
your SNMP devices from their factory default settings. In this case, you
will need to specify the modified community strings in this pane,
otherwise 3Com Network Supervisor will not be able to access them
using SNMP.

3Com Network Supervisor attempts to use different community strings in
the following order:

1 If a device already exists on your map, it will attempt to use the

community strings already stored against it in the database

2 It will then attempt to use the community strings you provide in this pane

of the wizard

72 CHAPTER 4: DISCOVERING THE NETWORK

3 Finally, it will attempt the default community strings. The default read

community for all devices is public, and the default write community
string depends upon the device type. If 3Com Network Supervisor
successfully establishes the read community string then it will be able to
deduce the type of device and consequently know what the default write
community is for that device (assuming it is a 3Com device).

If you are discovering the subnet for the first time (that is, not a
re-discovery), and you have changed the community strings on your
devices from the factory defaults, then you will need to add the strings to
the Read and Write list boxes. If you have assigned different community
strings to some of your devices (for instance you may have assigned
different strings to your routers and switches) then you should add all the
entries to the list boxes.

If you are rediscovering an existing subnet and haven’t changed the
community strings on the devices it contains then there should be no
need to specify any additional community strings here.

NBX Voice Network Pane

This step of the wizard asks you to indicate whether you have a NBX
voice system on your network, or specifically, on the subnets you are
about to discover.

Figure 23 NBX Voice Network Pane

Components 73

By choosing Yes the next step of the wizard will ask you for username
and password details. By specifying No this step of the wizard will be
bypassed.

NBX Call Processors Pane

This step of the wizard will only be shown if you selected the Yes option
button on the NBX Voice Network pane, indicating that you have an NBX
voice system on your network.

The step asks you to provide the access passwords for your NBX Call
Processor (NCP) devices. The NCP devices support Web management
(HTTP) only – they do not support the SNMP protocol. When you access
an NCP device with you Web browser you will be asked for a username
and password. 3Com Network Supervisor uses the same username and
password to obtain information from NCP devices. See “
on page 46

. It is likely that you will have modified the username and/or

Key Concepts”

password from the defaults. Therefore, you will need to specify the new
values here. If you have not modified the username and password, then
leave the default option Use factory defaults selected and click Next to
move to the next step of the wizard.

■ If you only have one NCP on your subnet(s) or you have modified all

NCP devices to use the same username and password, specify the
values by selecting the Custom option and entering the Username and
Password into the fields on this pane.

■ If you have multiple NCP devices and have modified them to use

different usernames and passwords then you will need to add each
one individually to the list of NCPs using the Add button. You need to
provide the IP address of each one individually specified along with the
Username and Password. You can still use the Custom settings to
cover any NCPs which use common settings.

74 CHAPTER 4: DISCOVERING THE NETWORK

Figure 24 NBX Call Processors Pane

Summary Pane

This is the final pane of the wizard. It summarizes the options you
selected throughout the course of the wizard.

Figure 25 Network Discovery Wizard - Summary Pane

Components 75

When you click Finish on this, or any other step of the wizard, 3Com
Network Supervisor attempts to start the discovery process, using the
options you have specified.

If there is a conflicting task currently running, the standard Tas k I n
Progress dialog box will be displayed, giving you the option of:

■ Allowing the current task to run to completion.

■ Cancel the current task and start the discovery.

■ Discard the discovery request completely.

The Network

Discovery Progress

Dialog Box

The Network Discovery Progress dialog box is displayed while the
discovery process is running. The process starts when you click Finish on
the Network Discovery wizard.

Figure 26 Network Discovery Progress Dialog Box

Figure 27 Network Discovery Progress Dialog Box - Minimized

76 CHAPTER 4: DISCOVERING THE NETWORK

You can use the Stop button on the status bar to cancel the discovery
operation, and the Restore button to restore the full Network Discovery
Progress dialog box.

The Network Discovery Progress dialog box shows how complete each
stage of the discovery is. The top two progress bars relate to the discovery
process.

■ The upper of these shows progress through the various discovery

stages on the current subnet. See “

Devices” on page 46 for details of the stages involved in discovering

each subnet. This will reset each time the discovery process moves
onto a new subnet.

■ The lower of these indicates progress on the current discovery stage.

This will reset each time the discovery process moves onto a new stage
within the current subnet. After completing discovery of all specified
subnets, this progress bar is used to indicate progress of the sizing
stage.

The table in the center of the dialog box periodically displays the devices
that have been detected. This is updated each time the discovery process
establishes the exact type of a device it has discovered.

The Discovery Process – Detecting

When the sizing stage is complete the discovery process moves on to
topology (discovering links). The bottom progress bar on the dialog box is
used to show the progress of each multinet. See “

The Discovery Process –

Determining Topology” on page 51 for more information

Click the Cancel button to abort the discovery process.

Click the Minimize button to hide the dialog box and reduced progress
information is then displayed on the status bar.

You can perform other operations on you map while discovery is running,
although certain tasks are restricted.

Network Discovery Summary dialog box

The Network Discovery Summary dialog box is automatically displayed
when the discovery process completes:

Components 77

Figure 28 Network Discovery Summary Dialog Box

The summary dialog box provides you with the following information:

Discovery problems: This shows the number of problem conditions,
such as timeouts, that 3Com Network Supervisor encountered during the
discovery process. It allows you to view the Discovery report, using the
View Report button, to find out what the problems were. Note that this
button will be disabled if no problems were encountered.

Network Misconfigurations: When the discovery process is complete
3Com Network Supervisor analyses the results in an attempt to establish
if any part of your network has been misconfigured. This could be due to
the way a device is set up or the way it is connected to another device.
The number of misconfigurations detected is shown here. You can view
the Misconfigurations and Optimizations report, using the View Report
button, to find out what the problems are. Note that this button will be
disabled if no misconfigurations were detected. Also note that this
analysis is performed against the whole, updated map, not just the parts
that were discovered in the recently completed discovery.

78 CHAPTER 4: DISCOVERING THE NETWORK

Network Optimizations: As part of the post-discovery analysis, 3Com
Network Supervisor looks for any areas of your network that could be
improved. The number of potential optimizations is shown here. You can
view the Misconfigurations and Optimizations report, using the View
Report button, to find out what the suggestions are. Note that this
button will be disabled if there are no suggested optimizations. Also note
that this analysis is performed against the whole, updated map, not just
the parts that were discovered in the recently completed discovery.

Network Changes: This entry will only be displayed on the dialog box
for a rediscovery of a non-empty map. It indicates the number of changes
detected, such as new devices, compared to the contents of your existing
map. You can view the Changes report, using the associated View Report
button, to find out what the changes are. Note that this button will be
disabled if no changes were detected.

If you choose not to view any of these reports at this point in time, you
can view them later from the history tab of the Tools > Reports dialog
box. The reports are saved with your current map. See “

Reports” on page 275 for further information.

Creating

When you close this dialog box, using the OK button, your map will be
updated to reflect the changes detected by the discovery process.

The Discovery Report The Discovery report is produced at the end of a successful discovery, that

is, a discovery that was not cancelled. It lists any problems that the
discovery process encountered while performing the discovery. Typically
these relate to 3Com Network Supervisor not being able to retrieve all the
information it requires to accurately depict your network. For example it
may have lost communication with some of the devices during the
discovery process.

The report is divided into two main sections:

Discovery

This section lists any problems encountered in the detecting devices part
of the discovery process. There is a separate sub-section for each subnet
that was discovered. Within each subnet section the report lists the
problems encountered and the devices to which the problems apply. For
instance, it may have failed to determine the write community string for a
device.

Components 79

Topology

This section lists any problems encountered in the discovering links part
of the discovery process. There is a separate sub-section for each multinet
that it attempted to determine the topology of. Within each multinet
section the report lists the problems encountered and the devices to
which the problems apply. For instance, it may have lost communication
with a device when reading the bridge FDB tables.

Each of the problems listed within the report has a severity level
associated with it, either Warning or Error. For instance, failing to
determine the write community string is considered a warning, since,
although it is required for other areas of 3Com Network Supervisor it is
not essential for discovery. However, a loss of communication is
considered an error since it is likely to adversely affect how 3Com
Network Supervisor depicts your network.

Discovery Report Errors and Warnings” on page 86 for a full list of

See “
the possible errors and warnings

The

Misconfigurations

and Optimizations

Report

When a discovery operation is complete, 3Com Network Supervisor
analyses the results in order to establish if any devices have been
misconfigured, or if any improvements could be made to the
configuration of your network in order to improve its efficiency. Both the
misconfigurations and improvements (optimizations) are included in the
same report, but in separate sections. If there are no misconfigurations or
if there are no optimizations then the entire corresponding section will be
omitted from the report.

Note that the analysis is always performed on the whole of your map, not
just the recent additions. You can force a new version of the report to be
generated from the Tools > Reports dialog box, although generally there
should be little need to do this since it should be the same as the one
from the most recent discovery, unless you have manually changed the
map.

Report Examples” on page 401 for a full list of the

See “
misconfigurations that may be detected, and possible suggested
optimizations.

80 CHAPTER 4: DISCOVERING THE NETWORK

The Changes Report When a rediscovery is performed on a map that already contains some

devices, 3Com Network Supervisor compares the contents of the current
map with the newly acquired information. Any differences it finds are
used to populate the Changes report. Typical changes are, a device has
changed configuration (e.g. a new unit has been added), or a device has
been moved and as a result its link properties have changed.

The Changes report will not produce information on IP address changes
to avoid large reports being generated on networks using DHCP. For a
similar reason, the Changes report will not produce information on
devices that appear between network discoveries as users log in and log
out due to the Network Login support.

Also see “

Report Examples” on page 401 for a full list of the changes

that may be detected.

The Displayed Map After a discovery operation has completed and you have dismissed the

Network Discovery Summary dialog box, the map and tree views will be
updated to reflect the new information.

Initial Map Creation

After the first discovery on a new map, 3Com Network Supervisor simply
adds all the new devices to the map as it feels appropriate. The map is
initially shown at the top-level map of the Grouped Network View. This
map shows all the subnets it has detected and any routers it discovered
on those subnets. It also includes the additional subnets that were
detected, when communicating with the routers, that weren’t part of the
list of subnets to discover. These are shown as undiscovered subnets.
3Com Network Supervisor attempts to arrange (layout) the devices and
subnets so that they do not overlap. For information on using the map,
and navigating between the subnets, see “

page 93

.

Working with the Map” on

Examples 81

Subsequent Map Updates

Whenever you perform a discovery on a map that already contains
subnets and devices, 3Com Network Supervisor intelligently attempts to
update the existing map. Any newly discovered devices and subnets will
be added to the map, while any existing devices and links will be
updated. See “

The Discovery Process – Rediscovery” on page 58 for the

rules on how device and link properties are updated. If you have modified
the position of devices on the current map 3Com Network Supervisor
preserves the layout of the changes you have made and attempts to
position the new nodes relative to your changes. If you are not happy
with the results you can manually move the nodes yourself or you can
force 3Com Network Supervisor to perform a clean layout of the view by
selecting View > Relayout Map.

Examples This section provides examples of how you may use the Network

Discovery features of 3Com Network Supervisor to accurately discover
the areas of your network you are interested in.

I have four separate

subnets - how do I

specify them?

While 3Com Network Supervisor is capable of automatically discovering
your local subnet and its immediate neighbors, you may only want to
discover selected subnets. In the following example, you want to specify
four subnets. To do this:

1 Launch the Network Discovery wizard (e.g. by selecting Tools > Network

Discovery).

2 On the first pane of the wizard, select the Specify Subnets radio button

and click Next

3 On the Specify Subnets pane of the wizard, add the subnets you wish to

discover

■ If the subnets are all within one router hop of your work station you

can use the Find Subnets button to save having to enter all the
information, go to step 8, below.

■ If the subnets are not all within one router hop, you should continue

from 4, below.

4 Click the Add button to launch the Add Subnets dialog box

5 Enter the information for your first subnet (you must enter at least the

network address and subnet mask of the subnet).

82 CHAPTER 4: DISCOVERING THE NETWORK

6 Click OK on the Add Subnets pane to return to the wizard. Your subnet

should now appear in the list on the wizard.

7 Repeat 4 to 6 above for your remaining three subnets

8 You can now click Finish on the wizard if you do not wish to change any

of the remaining defaults. Alternatively, continue through the wizard
using the Next button.

Once you click Finish on the wizard, 3Com Network Supervisor will start
discovering your subnets.

I am using different

SNMP community

strings for different

devices on my

network - how do I

specify this?

3Com recommends that you change the community strings on your
network devices from the factory defaults. You may want to leave the
read community strings as public for your switches but may wish to
change them to something more secure for your routers.

To specify a community string for a network device for use during
discovery, do the following:

1 Launch the Network Discovery wizard (e.g. by selecting Tools > Network

Discovery).

2 Navigate through the wizard until you reach the Community Strings pane

Figure 29 Community Strings Pane

3 Select the Yes option. The Add… buttons will now be enabled.

Useful Information and References

Useful Information and References 83

4 Use the Add button below the Read list box to enter the read community

string of your routers.

5 Use the Add button below the Write list box to enter the write

community string of your routers, and additionally the write community
string of your switches.

6 Click Finish if you do not wish to change any of the remaining defaults.

Alternatively, continue through the wizard using the Next button.

Once you click Finish, 3Com Network Supervisor will discover the devices
on your network, using any default community strings, and also
attempting to use the ones you specified in the wizard.

Why the discovered

map may not exactly

reflect the network

This section covers the common problems encountered with Network
Discovery.

Some devices haven't appeared

3Com Network Supervisor attempts to detect which devices exist by
pinging them with an ICMP ping message. A device may not respond in
time if it or the network is very busy, or potentially may not receive, or be
able to respond to, the ICMP ping message if it is placed beyond a
firewall. If a device fails to respond to a ping then 3Com Network
Supervisor will not add it in to the map as an IP device (although it may
still be added as a MAC-only device).

If a device responds to a ping, 3Com Network Supervisor then attempts
to determine if it supports other protocols, in particular SNMP. See

Device Capability Detection ” on page 47. If the device supports SNMP,

“

it reads the IP address table to establish if the device has any additional IP
addresses. If any of those addresses conflict with the addresses of another
device then one of the two nodes may be discarded.

It is possible to inadvertently assign duplicate IP addresses to some
devices. Certain 3Com devices provide resilient management by allowing
you to assign an IP address to each of the units in a stack. If you
reconfigure your network and move a unit from one stack to another, if
the unit has been assigned an IP address, then that address will move
with it. If you do not want the address to move you should delete the IP
address from the unit when you transfer it.

84 CHAPTER 4: DISCOVERING THE NETWORK

Some devices are the wrong type

SNMP-capable devices can appear as generic IP icons on the map if the
wrong read community string was specified for the device or if SNMP
requests to the device timed-out.

If a device appears as a generic SNMP icon it usually means that 3Com
Network Supervisor does not recognize the sysObjectID returned by the
device. 3Com Network Supervisor only recognizes a limited number of
third party sysObjectIDs.

All 3Com devices should be recognized by 3Com Network Supervisor.
However, for new devices that have been released after the version of
3Com Network Supervisor you are using, the devices may be shown as
Generic SNMP or 3Com Device. In this case you should check the 3Com
web site for 3Com Network Supervisor service packs that support these
newer devices.

There are clouds in my map

If 3Com Network Supervisor cannot deduce exactly how devices are
connected together it sometimes creates clouds during topology process.
This is quite common with third party devices, particularly hubs. Wireless
links are also depicted using clouds. See “
further information.

Clouds” on page 108 for

Support for 3Com

devices

For a detailed list of FAQs about the discovery process refer to the
Advanced Help that is supplied with 3Com Network Supervisor. You can
view this by launching any previously generated Discovery report and
following the hyperlink Discovery and Topology Frequently Asked
Questions in the first line of the report. To view a previously generated
discovery report select Tools > Reports from the main menu, and click on
the History tab of the Reports dialog.

3Com Network Supervisor has support for all 3Com devices. The most
recent 3Com devices may not be fully recognized, but support should be
available in the latest 3Com Network Supervisor service pack, available
from the 3Com Web site. For many non-SNMP 3Com devices (i.e.
Web-managed), 3Com Network Supervisor will only retrieve a limited
amount of information from them, typically just their type. However,
most web-managed devices are not switches or routers, so this limited
recognition should not significantly affect 3Com Network Supervisor's
topology map of your network.

Useful Information and References 85

3Com Network Supervisor uses specific images and text for the different
families of 3Com devices that are displayed on the map, and also uses
different border types depending upon the device’s capabilities. See “

The

Map” on page 94

Support for third

party devices

For third party devices, 3Com Network Supervisor attempts to gather as
much information as it can, using standard protocols and, for SNMP
devices, using standard MIBs. The standard protocols are summarized
below:

■ HTTP - If the device supports the HTTP protocol (i.e. Web

management) 3Com Network Supervisor will detect this and enable
the Web management right-click menu option. See “

Device Capability

Detection ” on page 47 for more information)

■ Tel ne t – If the device supports the Telnet protocol 3Com Network

Supervisor will detect this and enable the Telnet management
right-click menu option. See “

page 47

■ SNMP – If the device supports SNMP 3Com Network Supervisor

for more information)

Device Capability Detection ” on

attempts to determine whether it is a router or switch

■ Routing: It uses MIB II tables to establish if the device has

IP-forwarding enabled and has interfaces on multiple subnets. If so
it is flagged as a router and will appear on the map at the top level
with a diamond border. See “

■ Switching: It attempts to read the dot1dBaseType from the bridge

Working with the Map” on page 93.

MIB. If this is present it is flagged as a switch and will appear with
an octagonal border on the map. See “

page 93

.

Working with the Map” on

For third party switches 3Com Network Supervisor reads bridge FDB
tables during the topology process. However, it does not attempt to
retrieve spanning tree information for these devices.

No attempt is made to determine the topology of third party hubs. They
will simply be treated as end stations by the topology process.

3Com Network Supervisor attempts to determine the manufacturer of
third party devices, only if they support SNMP. However, it does attempt
to determine the type of certain end stations, such as Unix workstations.

86 CHAPTER 4: DISCOVERING THE NETWORK

Key Considerations

Discovery Report

Errors and Warnings

The Discovery report contains a list of problems that were encountered
during the discovery process. For the detecting devices part of discovery,
these are grouped by subnet. For the topology part of the discovery
process, the problems are grouped by multinet.

Discovery Section

The potential issues that may be detected and reported in the detecting
devices phase of discovery are listed below, along with their potential
causes:

This subnet can contain more devices than 3Com Network
Supervisor currently allows during discovery, and will therefore

not be discovered

Subnets that can contain more than 65535 devices can take an extremely
long time to discover. Therefore, 3Com Network Supervisor ignores these
subnets during all discovery operations. This message can only occur if
you chose the second option on the first pane of the Network Discovery
wizard, since this is where 3Com Network Supervisor interrogates any
routers it detects in order to determine the additional subnets to discover.
If you still wish to discover this subnet then you should use the Specify
Subnets option in the wizard and use restricted IP ranges.

3Com Network Supervisor failed to resolve the MAC addresses for
the following devices

3Com Network Supervisor needs to determine the MAC addresses of
devices for use in the topology process. For non-SNMP devices 3Com
Network Supervisor achieves this by reading the ARP cache of a router or,
if the devices are on the local subnet, it reads the ARP cache of the PC
running 3Com Network Supervisor. This message may be logged if 3Com
Network Supervisor failed to detect any routers whose ARP caches
contained entries for the MAC addresses, possibly because they are
outside the ranges of addresses you specified. Alternatively, the
appropriate router may have been discovered as an IP-only node if a valid
read community string was not provided for the router in the Network
Discovery wizard.

Key Considerations 87

The consequences of this failure are that any IP-only nodes will appear at
the top of their submap, not connected to anything. Another node may
also appear within the map that just has the correct MAC address of the
node and is connected to the correct switch port.

3Com Network Supervisor was unable to determine the write
community string for the following SNMP devices

As part of the Device Capability Stage, 3Com Network Supervisor
attempts to validate the write community strings for certain devices. See

Device Capability Detection ” on page 47 for further information. 3Com

“

Network Supervisor only attempts to do this for devices that it thinks it
will need write access to in the future (e.g. to set up the trap table for
monitoring for use by administrative tools such as Agent Update). If all
attempts to validate the write community strings fail then this message is
logged.

Multiple responses were detected during discovery from the IP
addresses listed below

During the IP Ping stage, 3Com Network Supervisor sends an ICMP ping
message to each device IP address in the ranges specified for the subnet it
is currently detecting. It does not send ICMP ping messages to the subnet
address or broadcast address. If 3Com Network Supervisor receives more
than one response from an ICMP ping message then it assumes that this
must be a broadcast address on the subnet and does not attempt to
discover or manage any devices using that IP address.

This may occur if one or more devices on the subnet have their subnet
mask configured incorrectly, or if the subnet address and mask were
entered incorrectly in the Specify Subnets pane of the Network Discovery
wizard.

3Com Network Supervisor was unable to obtain information from
the following NBX devices

This is likely to occur if incorrect usernames or passwords were provided
in the wizard. Note that even if you specified in the wizard that you do
not have an NBX voice system, if 3Com Network Supervisor detects an
NCP device during the discovery process it will attempt to retrieve phone
information from it.

88 CHAPTER 4: DISCOVERING THE NETWORK

3Com Network Supervisor was unable to read the information

from the following NBX devices

This is due to the fact that 3Com Network Supervisor does not support
the version of software running on the NBX unit. A service pack may be
available for 3Com Network Supervisor on the 3Com web site that
supports this version.

Topology Section

The potential issues that may be detected and reported in the discovering
links phase of discovery are listed below, along with their potential

causes.

The following devices returned invalid port information

As part of sizing, 3Com Network Supervisor attempts to determine which
ports are enabled and have a link present since it is only those that can
take an active role in the topology. For third party devices it attempts to
do this using standard MIBs. However, not all devices implement these
MIBs and some implement slight variations of them. This can result in
3Com Network Supervisor not being able to establish the ports that are
used in topology. Consequently such devices are treated as end stations
by the topology process. Older agent versions of certain 3Com devices
may also exhibit this problem, in which case there may be additional
messages in this report indicating that the agent version is not supported.

The following devices are running with an unsupported version of
the management agent software

For 3Com devices, 3Com Network Supervisor has a minimum supported
agent version. If 3Com Network Supervisor detects a device running an
agent below this minimum it will log this message, since the details it
obtains from the device may not be complete, and the deduced topology
may not be accurate. You should endeavor to update such devices to at
least the minimum version.

Key Considerations 89

The following devices are running with an unknown version of
the management agent software

3Com Network Supervisor logs this message if it cannot determine the
agent software version of a device. It is most likely that the version is
below the minimum supported and the consequence will be that same as
that in the above message. It is also possible that the format used to
report the version to 3Com Network Supervisor has changed in the most
recent versions. In this case you should check the 3Com web site for
3Com Network Supervisor service packs which will support the latest
version.

The following devices have been configured into multiple
segments

This is a feature of the Port Switch Hub families of the devices which
allow the separation of groups of ports into segments. 3Com Network
Supervisor does not fully support these configurations and cannot
guarantee that will the deduced topology will be accurate. It will,
however, still attempt to determine the topology as best it can.

The segment configuration of the following devices could not be
determined

As with the previous message this only applies to the Port Switch Hub
family of devices. This message should only occur if the agent version is
below the minimum supported by 3Com Network Supervisor.

The exact position of the following devices could not be
determined

This message generally applies to end stations. It results in the devices
being arranged at the top of their submap, unconnected to other devices.
It is possible to disable address learning on certain families of switches,
which can result in 3Com Network Supervisor being unable to determine
the devices they are connected to. The most likely cause of this message,
however is the hubs/switches being configured in a way that is not
supported by 3Com Network Supervisor or if 3Com Network Supervisor
lost communication with any of the switches when attempting to read
topology information from them. In the latter case additional errors
appear in this report to indicate the loss of communication.

90 CHAPTER 4: DISCOVERING THE NETWORK

The following devices have one or more ports that have failed
self-test

During the power cycle (reboot), certain 3Com devices run diagnostic
tests against each port and disable any ports that fail these tests. 3Com
Network Supervisor is able to detect this condition and will report it here.
It will also add an event to the event log for this condition. Because the
port has been disabled by the device the topology that 3Com Network
Supervisor deduces may be inaccurate.

3Com Network Supervisor was unable to write to the following
devices, in order to get them to perform operations that could
lead to a more accurate topology detection

At a certain point in the topology process 3Com Network Supervisor may
decide to instruct one device to remote ping another. See“

Stage (broadcast ARP)” on page 52 and “Remote Poll Stage (directed
pings)” on page 53. It cannot do this if it was previously unable to

determine the write community string for this device – consequently you
should also see a warning relating the write community string for this
device. By not being able to perform the remote poll, the topology that
3Com Network Supervisor depicts may not be accurate.

Remote Poll

The following devices have one or more ports that could not be
included in the network topology. These ports are blocked by the
Spanning Tree Protocol. 3Com Network Supervisor was unable to
determine what these ports are connected to.

In order for 3Com Network Supervisor to correctly determine spanning
tree topologies it must correctly discover the devices at both ends of each
blocked spanning tree link. If the IP address ranges discovered prevents
3Com Network Supervisor from determining both devices at the end of a
blocked spanning tree link then 3Com Network Supervisor will be unable
to show the link in the map.

Key Considerations 91

The following devices have support for the Spanning Tree Protocol
enabled. Links connected to these devices may in the future be
blocked by the Spanning Tree Protocol. 3Com Network Supervisor
may not be able to detect this occurring.

Some third party devices do not provide suitable MIB support to allow
3Com Network Supervisor to initially determine and subsequently track
changes in spanning tree topology, or provide a non-standard
implementation. As a result, the topology that 3Com Network
Supervisor depicts may not be accurate.

A device has been seen (or "learned") on multiple ports of another
device. This implies there is a loop in the network. 3Com Network
Supervisor may not represent the topology of the network
accurately.

Changes in network topology, such as a wireless device moving from one
wireless access point to another, or changes in spanning tree topology,
may result in a device being seen to move ports on another device. If this
occurs during Network Discovery then 3Com Network Supervisor may
not be able to depict the topology of the network accurately.

It is usually possible to address this issue by rediscovering the subnet or
subnets of the devices in question.

The following devices have a device performing ARP proxies for
them.

If you have a 3Com SuperStack 3 Firewall in your network that is
operating in transparent mode then any ARP requests sent to devices on
the other side of the firewall will be handled by the firewall itself and it
will respond with the MAC address of the firewall. In addition the
firewall will substitute its MAC address as the source address in any
packets it receives that are destined for an IP address on the other side of
the firewall. This technique is known as ARP proxy.

3Com Network Supervisor is unable to determine the MAC addresses of
devices on the other side of a 3Com SuperStack 3 Firewall, but is able to
identify the IP addresses of such devices. As a result, 3Com Network
Supervisor may not be able to depict the topology of the network
accurately.

92 CHAPTER 4: DISCOVERING THE NETWORK

3Com Network Supervisor could not determine a speed for at least
one interface on the following devices.

3Com Network Supervisor uses interface speeds when monitoring links in
order to calculate utilization. If 3Com Network Supervisor was unable to
determine a speed for a connected interface and you start monitoring the
link corresponding to that interface then 3Com Network Supervisor will
be unable to provide the utilization monitor for that item.

This situation can arise on some third party devices that do not provide a
suitable speed via their MIBs. It may also occur if 3Com Network
Supervisor lost communication with the device during Network Discovery,
in which case additional errors should appear in this report to indicate the
loss of communication.

WORKING WITH THE MAP

5

Overview This chapter describes how to work with the map and tree in 3Com

Network Supervisor.

The map and tree provide the main interface for viewing and managing
your network. They enable you to choose how you want to view your
network, show the current health of monitored devices and links within
your network and act as a launching point for many of the tools available
within 3Com Network Supervisor.

The following topics are covered in this chapter:

■ Key Concepts

■ Components

■ Examples

■ Useful Information and References

94 CHAPTER 5: WORKING WITH THE MAP

Key Concepts This section describes the key concepts of the map and the tree within

3Com Network Supervisor.

The Map The map is displayed on the right-hand side of the 3Com Network

Supervisor main window. It presents a graphical representation of your
network topology for the devices discovered on the network.

Figure 30 The Map

The graphical representation consists of icons that represent devices,
subnets and other network components. The lines drawn between those
icons represent connections between the components.

The following table describes each of the set of icons used in the map:

Table 11 Icons Used in the Map

Icon Description

A diamond icon represents a router or a layer-3 switch.
The image within the diamond will indicate the type of
the router or layer-3 switch. For more information see

“

Device Icons” on page 100.

An octagonal icon represents a network infrastructure
device, such as a switch, hub, wireless access point, or
NBX call processor. The image within the octagon
indicates the type of the network infrastructure device.
For more information see “

Devices that form the components of an XRN Switching
Fabric are grouped together into a single XRN Fabric
icon in the map.

Key Concepts 95

Device Icons” on page 100.

A square represents any other discovered device on the
network. This includes end stations, servers and NBX
phones. It also includes devices that could not be
discovered fully, for example when 3Com Network
Supervisor cannot determine an IP address for a device,
or when the appropriate SNMP community strings are
not supplied to 3Com Network Supervisor in the
Network Discovery wizard. The image within the square
indicates the type of the device. For more information
see “

Device Icons” on page 100.

A triangle represents the PC that 3Com Network
Supervisor is running on. The image within the triangle
indicates the type of PC. For more information see

“

Device Icons” on page 100.

96 CHAPTER 5: WORKING WITH THE MAP

Icon Description

Clouds appear automatically in the network topology for
three reasons.

■ They are used to represent sections of the network

where 3Com Network Supervisor was unable to
determine the topology.

■ They are used to show the number of clients

connected to each wireless access point.

A circle represents a subnet within your network. The
label in the center of the circle indicates the address of
the subnet being represented. If the subnet has not yet
been discovered then the label includes the text
“(Undiscovered)”.

3Com Network Supervisor allows you to group related
devices together into a device group. Each device group
is represented by a cloud contained within a rectangle.
For more information about creating device groups see

“

Device Groups” on page 111.

The Tree The tree is displayed on the left-hand side of the 3Com Network

Supervisor main window and lists all of the devices that have been
discovered in your network, grouped into subnets and device groups.
Clouds are not listed in the tree.