D-Link AirPlus Enhanced 2.4GHz Wireless Range Extender

Model:
DWL-800AP+
Price: $99
Rating:
4 out of 5
Features
Performance

One of the frequent challenges encountered when setting up a WLAN is limited
range and the resultant dead spots where the wireless signal can’t reach. You
needn’t live in a mansion to have this problem — depending on the configuration
of and materials used in your abode you may suffer signal propagation problems
even in a relatively small space. This is also likely if you’re trying to extend
your home wireless network outside the confines of your home (like to your backyard).

D-Link offers a way to ameliorate this problem in its AirPlus Enhanced 2.4
GHz Wireless Range Extender
(DWL-800AP+). Although the device can function
as an ordinary access point, its real value is in the device’s repeater mode,
which promises to considerably extend the range of your wireless network.

In case you’re wondering the difference between the DWL-800AP+ range extender
and the DWL-900AP+ repeating access point (I did), the DWL-900AP+ does everything
the 800AP+ does but it also adds two bridging modes and can be used as a client
adapter. The 800AP+ can be used as an access point in a pinch, but it has only
basic features. The only slightly more expensive ($99) and slightly larger 900AP+
is a better choice as a dedicated access point.

The good news is that the DWL-800AP+ is based on the TI enhanced 802.11b chipset,
so it’s capable of handling bandwidth of 22 Mbps (and 256-bit WEP encryption).
The bad news is that the device is currently only compatible with certain
D-Link products
. D-Link says that third-party products will eventually be
supported via firmware updates, but so far, the few I had on hand didn’t work
with the DWL-800AP+. The chances are probably better with another TI chipset-based
device.

Given the unambiguous function of the DWL-800AP+, I expected that the setup
and configuration of the unit would be relatively straightforward. It wasn’t.

Like many products nowadays, the DWL-800AP+ employs a Wizard for the initial
configuration. To configure it as a repeater, you specify the MAC address of
the remote router. If you’re like me, you might retrieve the MAC address of
your router from the underside of the unit. That would be a mistake, because
that is probably not the right one. An access point has two interfaces (LAN
and WLAN), so it will in turn have two MAC addresses. Moreover, a broadband
router will have a third MAC address for the WAN interface, as was the case
with my D-Link DI-614+ router.

The DWL-800AP+ requires the MAC address from the remote device’s LAN interface
to repeat its signal, though it does not specify this anywhere it its documentation.
Having hastily used the MAC address printed on the router, (it was the WAN interface
address and thus the wrong one) I wasn’t initially able to connect to the repeater
with my wireless client.

After a bit of head scratching and trial and error, I realized the error of
my ways and finally entered the correct MAC value. This did cause the DWL-800AP+
to show its face during a site scan. However, although I was then able to successfully
connect to the repeater, I had no IP connectivity to my LAN or the Internet
beyond it.

More head-scratching ensued, but to make a long story short, the culprit turned
out to be a bug in the firmware version of the DI-614+ router I had–specifically,
version 2.18. The kicker is that there are actually TWO versions of this firmware.
One is dated 2/28/03 and is the one with the problem. The other is dated 3/14/03
and works fine. To make sure you get the good one, go to D-Link
Support’s product page
directly and drill down to the DI-614+,
under "Gateways." As of the time of this writing, if you go to the
support page and then look up DI-614+, you are only offered the older, malfunctioning
version.

Aside from the setup hassles I experienced, there is one other potential downside
of the DWL-800AP+. Once configured as a repeater, it becomes transparent to
the network; you can’t ping it, and you can’t access the browser configuration.
As a result, you’ll have to directly connect to the LAN port to change configurations
— something to remember if you mount the device in an inaccessible location.

Once I had all of the configuration issues behind me, I got down to the business
of determining whether the DWL-800AP+ did in fact extend the range of my wireless
network. I began by testing performance of the unassisted DI-614+ router (using
NetIQ’s Chariot). The throughput was solidly in the 6-7Mbps range from 10 feet
until about 125 feet, the point when virtually every wireless signal substantially
wanes in my office environment. Based on the D-Link client utility, at 125 feet
the wireless signal strength was mired in the poor range– around 40%, which
cut throughput to a little more than 4 Mbps. Just beyond this distance, the
signal vanished entirely.

Introducing the DWL-800AP+ at a point approximately 100 feet from the router
indeed improved signal strength considerably. The signal strength at the 125
foot point (25 feet from the repeater) jumped up to a few points below full
strength and yielded throughput of about 3 Mbps. A strong signal was also obtained
at the 150 foot point–good for a throughput of 2.52 Mbps.

In fact, though 50 feet was as far away as I could get from the DWL-800AP+
within the confines of my building, I was able to continue to get a strong signal
(greater than 50%) outside the building and 100 feet down the street (and through
a stone and masonry wall), though at this point the throughput had admittedly
dwindled down to the sub-1 Mbps level. This made for a combined total of over
250 feet from the original router.

Incidentally, the D-Link client software automatically switched its association
from the router over to the repeater within a few seconds after contact with
the former was lost.

While DWL-800AP+ does greatly extend range, it doesn’t necessarily do much
to improve throughput. This is not unexpected, since DWL-800AP+ must use its
22 Mbps of bandwidth to simultaneously communicate with a client and a router.
Because of this you’re not going to enjoy the throughput you would if you were
associated directly with the router. Of course, using the device in straight-802.11b
mode or with multiple clients will further impact throughput.

No matter, since the DWL-800AP+ does what it advertises; it gives you stronger
wireless signals and significantly extended network range. Because of its vague
documentation and the perplexing firmware issue I encountered, the DWL-800AP+
was more of a hassle to set up than it needed to be. On the other hand, depending
on what product you use in conjunction with it and what firmware version it
has, you may not have the same trouble. If you have compatible D-Link hardware
and want to extend the reach of your network, I recommend it.

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