Extending your Small Business Wireless Network
A wireless network can be more than just one access point or gateway. A
number of wireless access points can be used to create one large wireless
network or a number of smaller individual networks. Expanding your wireless
network need not be a complex procedure.
This document will detail what is needed to expand your wireless network
from one wireless access point or gateway to incorporate multiple access
points. And steps on how to expand your wireless network from an
OfficeConnect Wireless Cable/DSL Gateway to include a 3Com Access Point
For general information on wireless networking for the small business please
refer to Wireless Networking for Small and Home Offices. For information on
wireless security please refer to Improving Your Wireless Security. Both white
papers are available from www.3com.com.
Components Needed To Expand A Wireless Network
Once the basis of a wireless network has been installed it is easy to expand
the network to cover a wider range or to implement a separate wireless
network alongside the existing one. All that is required is another Wi-Fi
certified wireless access point (such as the 3Com Access Point 2000), and
Ethernet access to the wired network. If the network is being expanded from a
wireless gateway then this can be achieved by connecting the new access
point into the built-in switch incorporated into the gateway. If the network is
being expanded from an access point then this can be achieved by
connecting the new access point into the existing network, or by purchasing a
switch or hub to connect the access points.
This is all the networking equipment that is required. Wireless NICs will be
needed if there are new clients that are being added to the wireless network.
Expanding Your Wireless Network
Figure 1: Extended Wireless Network using 3Com OfficeConnect Wireless Cable/DSL
Gateway and 3Com Access Point 2000
A wireless network can be extended simply by adding another access point to
your LAN and by configuring the new access point with the same ESSID or
Service Area Name, and WEP security settings as the first access point or
gateway. The access points should be placed so that the wireless ranges are
just overlapping – allowing roaming between the two This will enable wireless
users to roam between the two access points with no break in connection.
To calculate where to position the new access point it is necessary to know
the range of the both access points and therefore where the overlap occurs.
This is not as complicated as it sounds and it accomplished by performing a
wireless site survey, which is covered in detail later in this document.
In a multiple access point wireless network, to maximise the bandwidth of the
wireless network, each access point should have a different channel to
access points next to it. This will maximise the speed of the connection to
each access point. For example, if the original access point was on channel 1,
by selecting channel 6 for the second access point the communications are
easily kept separate by the two access points.
Roaming on a wireless LAN can be seen as analogous to roaming between
cells with a mobile or cell phone. The phone will associate itself with a cell,
and once the signal from that cell becomes weak, the phone will search for a
new cell and associate itself with that cell instead. Therefore roaming between
the two cells with no break in connection. This is demonstrated in the wireless
network diagram below.
Channels on access points differ by at least 5
Figure 2: Multiple access points in extended wireless network showing different channels
needed for maximum bandwidth on each access point
This is a method of carrying out a simple, rudimentary Site Survey using the
3Com WLAN Utility software that is shipped with 3Com Wireless NICs.
Look at your site floor plan and make a list of work areas where clients are
likely to be positioned. For example, list the office cubicles and conference
rooms where users will be logging on to the 3Com Wireless LAN. Then select
several trial locations for the access point and make a list of these locations.
For example, you may wish to test the access point mounted on the ceiling,
on a desk, and on a wall. Look for locations in the center of the room and
away from potential transmission barriers.
Ensure that only one access point is operational and using a laptop PC
connect to that access point. Launch the utility software that will monitor the
strength and speed of the wireless signal.
Move away from the access point until the signal is weak but the connection is
still present. This connection might be 2Mbps or 1Mbps, depending on the
number of wireless clients attaching to the access point and the bandwidth
needed on the network. Make a note of where this point is and continue to
move around the access point, in effect, marking the edge of the range of the
Power down that wireless access point and power up the new wireless access
point. Position the new access point so that there is a signal present in the
same positions as tested before. This will ensure that one of the access points
is reachable from all points between the two.
This should be enough to get your expanded wireless network up and
Steps to expand an OfficeConnect Wireless Cable/DSL Gateway wireless
network with a 3Com Access Point 2000
Assuming you have an OfficeConnect Wireless Cable/DSL Gateway installed
1. Purchase a 3Com Access Point 2000 wireless access point
2. Connect the Access Point 2000 to the OfficeConnect Wireless
Cable/DSL Gateway with an RJ-45 Ethernet cable
3. Position it so that the wireless ranges of the multiple access points
slightly overlap. This can be done by following the Site Survey
4. Configure the new access point with the same ESSID and WEP
security configuration as the Gateway
5. Configure the new access point with a different wireless channel to
surrounding access points to maximise the available bandwidth.