December 12, 2000, 3:00 PM — If you're a novice, you'll probably run into a few problems when installing wireless
access points (APs) for the first time. To ensure a successful installation, follow the
instructions the wireless LAN vendor provides in the box with the AP. Also, don't be
reluctant to call on the vendor's technical support people if problems arise.
- Run the initial AP configuration: Generally, you must
initially configure the AP via a PC or laptop connected through an RS-232 cable to the
AP's console port. Do this before mounting the APs out of easy reach. Most console
ports are ANSI-compatible, but you'll probably need your own nine-pin RS-232 cable;
vendors normally don't include one.
- Set the Service Set Identifier: The SSID is a 32-character unique
identifier that all packets traversing the wireless LAN need in their headers. The SSID
acts as a password when radio cards in mobile nodes attempt to join the network. All
access points and radio cards in the network must be set to the same SSID. You can
choose any combination of characters, but it's a good idea to use meaningful names.
- Set the IP address: The IP address differentiates APs. You need it
to gain remote access over the wired network to the AP's configuration screens via
Telnet, Web browser, or SNMP. Be sure to record each AP's IP address.
- Perform preliminary tests: Before mounting the AP in its
operational location, configure one or more radio cards in mobile nodes and make sure
they're able to associate with the AP. Don't forget -- be sure all SSIDs are set the
- Mount the AP as high as possible: For example, in warehouses,
install the APs on the highest beams.
Orient the antennas correctly: With most antenna propagation
patterns, setting the antennas parallel to the ground concentrates the signal power
right at the floor. A vertical antenna spreads the signal to a wider area.
When installing APs, especially when you're high above the ground, it's easy to get
confused as to which way to orientate the antennas. I remember fixing wireless LAN
connectivity problems that had plagued one company for weeks. The AP installation
company mounted the APs in the correct location, but the wireless LAN didn't support
roaming in areas where coverage was expected. The site survey looked OK; the problem
was that some of the AP antennas were orientated parallel to the ground, sending power
directly below, but not to other areas. After reorienting the antennas vertically,
roaming was restored to the uncovered areas.