3Com 3CRWEASY96A - 11 Mbps Wireless LAN Outdoor Bridge... User manual

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User Guide
Wireless LAN Outdoor Bridge Solution
3CRWEASY96A
Complete Building-to-Building Outdoor Wireless LAN Kit
Published February, 2003
Document Version 1.2.0

3Com Corporation
5500 Great America
Parkway
Santa Clara, California
95052-8145
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If you are a United States government agency, then this documentation and the software
described herein are provided to you subject to the following:
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Contents
1
Introduction
Basic Network Topologies 7
Point-to-Point 7
Point-to-Multipoint 8
Basic Operating Modes 9
2
Installing the Outdoor Bridge
Installation Requirements 10
Power Requirements 10
Administration Requirements 11
Installation Guidelines 11
Proper Grounding 11
Alignment 12
Polarization 12
Restrictions on Antenna Use 12
Safety Information 13
Mounting the Bridge to a Mast 14
Connecting the Bridge to the LAN 15
Using the Power Supply 15
Using a Power-Over-Ethernet LAN Port 15
Installing Software Utilities 16
Establishing Wireless Association 17
3
Configuring the Building-to-Building Bridge
Using the 3Com Wireless Device Manager 18
Launching a Wireless Device Configuration 18
Using the Pre-IP Configuration Wizard 20
Using the RSSI Monitor 20
Saving Configuration Changes 21
Changing System Properties 21
Setting IP Network Properties 22

Setting up Protocol and Port Filtering 23
Setting Wireless Network Properties 24
Setting Advanced Performance Properties 26
Setting up an Ad Hoc Network 28
Optimizing an Ad Hoc Installation 29
Setting up an Access Point Infrastructure Network 30
Changing Security Settings 31
No Security (Open System) 32
40-bit Shared Key (Wi-Fi) 32
128-bit Shared Key 33
128-bit Dynamic Security Link 33
Setting up the Wireless Network Login 33
Resetting the Bridge 33
Restoring a Bridge to Factory Defaults 34
Upgrading the System 34
Changing the Administration Password 35
Backing up a Configuration 35
Restoring a Configuration 36
Viewing the Client List 36
Resetting Statistics Listings 37
Clearing the Client List 37
Viewing Connection Status 37
Viewing the System Summary 37
Interoperating with Third-Party Equipment 37
4
Troubleshooting
Diagnosing Problems 38
Disconnecting the Bridge 40
Uninstalling Software and Documentation 40
Upgrading Bridge Firmware 40
A
Technical Support
Online Technical Services 41
Support from Your Network Supplier 42
Support from 3Com 42
Returning Products for Repair 43

Regulatory Compliance Information
Index

7
1
I
NTRODUCTION
The 3Com® Wireless LAN Outdoor Bridge Solution is a comprehensive
building-to-building outdoor wireless LAN kit that reduces the need to evaluate,
purchase and assemble separate components. One convenient package includes
everything you need to offer an easy-to-manage building-to-building wireless
LAN. The package features a 3Com Wireless LAN Building-to-Building Bridge with
integrated antenna and power-over-Ethernet cable in a durable,
weatherproof enclosure.
This all-in-one wireless LAN solution delivers three to four times the bandwidth of
T1 links, with significantly lower operational costs. The wireless bridge lets you
connect cross-campus buildings, or portable or temporary classrooms, at
distances up to 16 kilometers (10 miles), where local regulations allow. The
building-to-building bridge interoperates seamlessly with other Wi-Fi certified
access points in large multi-vendor environments.
B
ASIC
N
ETWORK
T
OPOLOGIES
The 3Com bridge can be used in two types of wireless network topologies:
■
Point-to-point
■
Point-to-multipoint
P
OINT
-
TO
-P
OINT
Point-to-point topology is the simplest way to use the 3Com bridge, and it offers
the highest performance level. Two 3Com outdoor bridges form a direct wireless

8
association between the wired LANs in two remote buildings. See the following
diagram of the point-to-point topology.
P
OINT
-
TO
-M
ULTIPOINT
Point-to-multipoint topology allows communication among three or more
buildings. In the central building, an access point equipped with an
omnidirectional antenna provides wireless association among the wired LANs in
the other buildings where 3Com outdoor bridges are installed.
If a 3Com 11 Mbps Wireless LAN Access Point 8000 is used (with an 8dBi
omnidirectional antenna) this topology can connect wired LANs over distances up
to 10 kilometers (6 miles). If an access point from another Wi-Fi compliant
manufacturer is used, the range depends on that manufacturer’s device
limitations.

9
B
ASIC
O
PERATING
M
ODES
Two operating modes relate to the basic WLAN topologies:
■
Ad hoc mode is the basis for point-to-point topology. Operating in ad hoc
mode, two outdoor bridges can associate without an access point, allowing
the LANs to which they are connected to communicate.
■
Access Point (Infrastructure) mode is the basis for point-to-multipoint
topology. Operating in access point mode, multiple 3Com outdoor bridges act
as clients to an Access Point 8000 or a Wi-Fi compliant access point from
another manufacturer.

10
2
I
NSTALLING THE
O
UTDOOR
B
RIDGE
This equipment must be installed in compliance with local and national building
codes, regulatory restrictions, and FCC rules. For the safety of people and
equipment, only professional network personnel should install the bridge, cables,
and antennas.
I
NSTALLATION
R
EQUIREMENTS
The following items are required for installation:
■
For a point-to point configuration, two 3Com outdoor bridges.
■ For a point-to-multipoint configuration, one 3Com 11Mbps Wireless LAN
Access Point 8000 (or other Wi-Fi compliant access point) with an
omnidirectional antenna for one building, and one 3Com outdoor bridge for
each other building.
■
Mounting hardware (supplied with each bridge).
■
Properly grounded outdoor mast or wall mount.
■ Lightning arrestor properly grounded at each building in the topology.
■
Outdoor rated category 5 Ethernet cable (3Com part number
3CWE487 recommended).
P
OWER
R
EQUIREMENTS
The bridge complies with the IEEE 802.3af power-over-Ethernet standard. It
receives power over outdoor rated Ethernet cable (3Com part number 3CWE487
recommended). Installation requires the use of either the 3Com power supply
provided or IEEE 802.3af compliant power supply equipment (output power rated
48 V dc @ 200 mA minimum). Such equipment must b
e safety certified according
to UL, CSA, IEC or other applicable national or international safety requirements
CAUTION : Before installing, see the important warnings and cautions in “Safety
Information” on page 13.

11
for the country of use. All references to the power supply in this document refer
to equipment that meets these requirements.
Because the power supply plug is the only means of disconnecting the bridge
from power, make sure the power outlet is accessible.
See “Using the Power Supply” on page 15 and “Using a Power-Over-Ethernet
LAN Port” on page 15.
A
DMINISTRATION
R
EQUIREMENTS
To use the administration tool, which helps you select 3Com wireless LAN devices
and launch their configuration management systems, you need a computer
running one of the following operating systems and one of the
following browsers:
I
NSTALLATION
G
UIDELINES
The 3Com outdoor bridge is housed in a durable, waterproof enclosure and is
specifically designed for outdoor use in most climates. Optimal performance can
be maintained at outdoor temperature ranges from -20˚ C to 50˚C (-4˚F to 122˚F).
It is extremely important to avoid mounting the bridge in any area where it could
be vulnerable to extreme or hazardous conditions of any kind. Nor should the unit
be mounted flush with the roof of a building.
P ROPER G ROUNDING
To ensure the physical safety of anyone near the bridge and to prevent damage to
the unit, follow the building codes for antenna installations in your area. Make
certain that bridges and masts are appropriately grounded to prevent injury and
Note for use of the 3Com power supply (part number 61-0107-000) in Norway:
This product is also designed for use on an IT power system with phase-to-phase
voltage of 230 V.
Operating Systems Windows XP
Windows 2000
Windows NT 4.0
Windows Me
Windows 98
Browsers Netscape 6.0 or later
Internet Explorer 5.0 or later

12
minimize damage from lightning strikes. A lightning arrestor, properly grounded
and installed at each building in the topology, will protect networking equipment
in the building, as well as the people working there, from lightning-induced
surges that travel on Ethernet cables.
A LIGNMENT
Position bridges so that they are aimed at each other wherever possible. While
maintaining a direct line of sight between antennas helps to ensure a strong
signal, it is not strictly necessary, nor is it always possible. Conditions such as long
distances, mountainous regions, and architectural barriers could make a direct
line of sight nearly impossible to achieve.
In a campus setting, where buildings are short distances apart, and especially in a
point-to-point configuration, align each unit to point at the antenna with which it
will communicate. If you place two units at different heights, tilt them up or
down toward each other for optimal signal strength.
P
OLARIZATION
Polarization is a physical phenomenon of radio signal propagation. In general, any
two antennas that are to communicate with each other must be set for the same
horizontal or vertical polarization. If polarization on both antennas does not
match—a situation called
cross-polarization —the link will either work poorly or
not at all. Follow these polarization guidelines:
■
Vertical polarization is preferred for point-to-multipoint configuration.
■ For point-to-multipoint configurations, the omnidirectional antenna
connected to the access point should be vertically aligned in relation to
the ground.
■ Unidirectional antennas that link with omnidirectional antennas should always
be oriented for vertical polarization.
R
ESTRICTIONS ON
A
NTENNA
U
SE
The following restrictions apply to the use of the bridge’s 18 dBi antenna:
■FCC regulations require that in the United States, use of channels 12 and 13 in
conjunction with an 18 dBi antenna is allowed only at very reduced power,
which the 3Com unit sets automatically.
■The highest allowable power level is set automatically when the country
selection is made from the pulldown menu in the configuration tool.
■To work properly with 18 dBi antennas, bridges must be separated by at least
61 Meters (200 Feet).

13
SAFETY INFORMATION
WARNING: Do not install the bridge near overhead power lines, electric light or
power circuits, or where it can come into contact with such circuits. Provide ten
feet or more clearance between the bridge and such power lines or circuits. Do
not install the bridge flush with the rooftop or wall. When installing the bridge, do
not come into contact with such circuits, which can cause serious injury or death.
Follow local and national codes for proper installation and grounding of antennas.
WARNING: To comply with FCC radio frequency (RF) exposure limits, antennas
should be located at least two meters (six feet) or more from the bodies of
all persons.
WARNING: Do not install the bridge or connect and disconnect cables during
periods of lightning activity.
WARNING: To avoid possible injury or damage to equipment, you must use either
the provided power supply or IEEE 802.3af compliant power supply equipment
that is safety certified according to UL, CSA, IEC, or other applicable national or
international safety requirements for the country of use. All references to power
supply in this document refer to equipment meeting these requirements.
WARNING: It is the responsibility of the installer to ensure that the
Power-over-Ethernet (POE) power supply is properly connected. Connection to any
other device, such as a standard Ethernet card or another POE supply, may result
in permanent damage to equipment, electric shock, or fire. Refer to the
installation instructions for proper installation.
WARNING: The 3Com power supply (part number 61-0107-000) input relies on a
16A rated building fuse or circuit protector for short circuit protection of the line
to neutral conductors.
CAUTION: A lightning arrestor will not prevent damage from direct lightning
strikes. It is extremely important to ensure that the bridge is installed at least 1
meter (3 feet) below the top of the grounded pole or mast.
CAUTION: If you supply your own Ethernet cable for connecting power, be sure
that it is outdoor rated category 5 straight-through (8-wire) cable that has not
been altered in any way (3Com part number 3CWE487 recommended). Use of
nonstandard cable could damage the bridge.
CAUTION: Minimize damage from direct lightning strikes by mounting the bridge
at least 1 Meter (3 feet) below the top of the mast.

14
MOUNTING THE BRIDGE TO AMAST
The bridge can be placed in any suitable outdoor location (see “Installation
Guidelines” on page 11). Refer to the adjustable mount instruction sheet that
comes with the bridge mounting hardware, and the illustrations below:
Make sure that all bridges
are properly oriented for
polarization as described
in “Polarization” on
page 12. Use the
polarization indicators on
the antenna panel to
guide orientation. VERT
POL indicates vertical
polarization and HORIZ
POL indicates horizontal
polarization.

15
CONNECTING THE BRIDGE TO THE LAN
You can connect to the LAN either through the 3Com power supply or through
IEEE 802.3af power-over-Ethernet compliant equipment.
USING THE POWER SUPPLY
The power supply can be located indoors at any point between the bridge and
the LAN access port where an accessible power outlet exists.
Connect the cable coming from the bridge to the port labeled To Access Point on
the power supply.
Connect another Ethernet cable from the port labeled To Hub/Switch on the
power supply to an Ethernet LAN port, as shown.
USING APOWER-OVER-ETHERNET LAN PORT
If your LAN equipment complies with the IEEE 802.3af power-over-Ethernet
standard, you can connect the bridge directly to a LAN port. For example, the
CAUTION: To avoid damaging network equipment, make sure that the cables
are connected from bridge to power supply to LAN as shown and
described above.

16
illustration shows the connection through a 3Com Ethernet Power Supply to a
3Com SuperStack®Switch.
INSTALLING SOFTWARE UTILITIES
The 3Com installation CD includes the Wireless Infrastructure Device Manager
tool, which helps you set up and administer the wireless components of your
network. It also contains documentation, including the help files for device
configuration screens.
To install the tool and documentation from the CD:
1Power up the computer and insert the 3Com CD in the CD-ROM drive.
2The setup menu should appear when the CD autostarts. If no menu appears,
you can run the startup program from the Windows Start menu:
Start/Run/d:setup.exe (where d: is the CD-ROM drive)
3From the menu, select Install the Tools and Documentation. This option
installls the 3Com Wireless Infrastructure Device Manager (WIDMAN) Tool,
which you can use to monitor bridges and select devices for administrative
changes. It also installs the User Guide in HTML and PDF formats.
4Follow the instructions on the screen.

17
ESTABLISHING WIRELESS ASSOCIATION
After the bridge and software utilities are installed, you can configure the bridge
as follows:
■Launch the bridge configuration. (See “Configuring the Building-to-Building
Bridge” on page 18 for details on how to launch the configuration and
make changes.)
■For a point-to-point association between two bridges, see “Setting up an Ad
Hoc Network” on page 28 and “Optimizing an Ad Hoc Installation” on
page 29.
■For a point-to-multipoint association between an access point and one or
more bridges, see “Setting up an Access Point Infrastructure Network” on
page 30.

18
3CONFIGURING THE
BUILDING-TO-BUILDING BRIDGE
If the configuration that was set at the factory does not meet your network
requirements, or if you want to customize the settings, you can configure the
bridge through your Web browser.
The 3Com Wireless Infrastructure Device Manager helps you locate 3Com
wireless LAN devices on the network, select a device and view its properties, and
launch the device’s configuration in your Web browser. To configure a bridge, the
device manager must be installed on a computer that has an Ethernet adapter
and is running a supported Windows operating system and Web browser.
USING THE 3COM WIRELESS DEVICE MANAGER
After the 3Com Wireless Device Manager is installed, ensure that the device to be
configured is either wired to the network, associating with the wireless network,
or connected directly to the computer, and connected to power. If more than one
device using the factory default name is connected, make a note of the MAC
address of the device you want to select so that you can identify it in the
device manager.
LAUNCHING AWIRELESS DEVICE CONFIGURATION
If you do not have a DHCP server on your network, it can take up to one minute
for a device to become discoverable after it has been powered up.
1To launch the 3Com Device Manager, select Start /Programs /3Com
Wireless/Wireless Infrastructure Device Manager.
If you have more than one network adapter installed on your computer, you
may be prompted to choose a network adapter. Choose the appropriate
adapter and click OK.
The Wireless Network Tree appears in the 3Com Wireless Infrastructure
Device Manager window. The tree lists all WLAN service areas on the network
and expands to show the 3Com wireless LAN devices that are associated to
each service area. Devices in a different subnet than your computer are

19
identified with exclamation points (!). You can refresh this display by clicking
Refresh. You should refresh the display, for example, after you change a
device IP address.
2In the Wireless Network Tree, select the device you want to configure.
If more than one wireless LAN device appears in the tree and you are not sure
that you have selected the right one, click Properties and check the MAC
address to verify that it is the one you want.
3Click Configure.
■If the selected device is on the same subnet as your computer, the
Configuration Management System main page appears in your Web
browser. (If a password is set on the device, enter it when prompted.)
■If the selected device is on a different subnet, the Pre-IP Configuration
Wizard is activated automatically. This wizard lets you configure the IP
settings for the selected wireless device. It proposes IP address and subnet
mask settings derived from your computer’s settings, so the selected device
will then reside on the same subnet as your computer. You can accept the
suggested settings or change them as required. For more information, see
“Using the Pre-IP Configuration Wizard” on page 20.
The next window prompts for an administrative password to allow the new IP
address to be set. When the units are shipped from the factory, there is no
administration password and you should leave the password field blank. If an
administration password has been set for the device, enter the password and
click Next. The 3Com Web Configuration Management System main screen
appears in your Web browser.
The following table describes the functions of the buttons in the 3Com Wireless
Infrastructure Device Manager window.
Button Description
Properties Displays the following properties of the selected device: Device Name,
Device Type, Wireless LAN Service Area (ESSID), IP Address, Subnet Mask,
and MAC Address.
Configure Launches the Configuration Management System for the selected device. If
the selected device is on a different subnet, you are prompted to assign an
address on the same subnet as your computer.
Refresh Scans the network and displays the connected 3Com 11 Mbps Wireless
LAN devices.
Choose NIC If your computer has more than one network interface card installed,
allows you to choose which card you want to use.
Close Closes the device manager window and ends the session.
Help Launches the device manager help page in your browser.

20
USING THE PRE-IP CONFIGURATION WIZARD
You can only configure devices that are on the same subnet as your computer. To
configure a device on a different subnet, you must first assign it an IP address on
the same subnet as your computer. After you launch the configuration, you can
change settings as usual. Just before you finish, you must change the device IP
address back to its original setting.
Follow this procedure:
1In the Wireless Infrastructure Device Pre-IP Configuration window, accept the
suggested settings or change them as required. You can assign a static IP
address or specify that the device obtain its IP address from a DHCP server.
2The next window prompts for an administrative password. When the units
are shipped from the factory, there is no administration password and you
should leave the password field blank. If an administration password has
been set for the device, enter the password and click Next.
The Configuration Management System main page appears in your
Web browser.
USING THE RSSI MONITOR
The device manager can display a dynamic graphical representation of a device’s
received signal strength indication (RSSI). By monitoring the RSSI while making
antenna adjustments, you can ensure optimal device placement and orientation.
To monitor signal strength, the devices must be set to the same BSSID and RSSI
broadcasting must be enabled.
The following procedure uses the device manager RSSI Monitor to monitor the
signal strength of two 3Com bridges:
1In the device manager window, launch the first bridge configuration and
configure for ad hoc mode.
Enable RSSI broadcasting as follows:
aIn the main menu under System Configuration, click Wireless Network.
bIn the Wireless Network page, click the link to go to advanced wireless
network configuration.
cIn the Advanced Wireless Network page, click the Broadcast RSSI On radio
button, and click Save.
dNote the device BSSID.
In the main configuration menu under System Status, click
Connection Status. The status window shows the BSSID.