D-Link AirPlus XtremeG High Speed 2.4GHz 108Mbps Router

Price: $109



: Fast performance, wide compatibility with 802.11g and 802.11

Cons: None

I know what you’re thinking–you’ve read a review of D-Link’s router model
DI-624 here before.
And it’s true, products with this model number have been out for quite some
time. So why are we looking at it again?

It’s very simple. D-Link is providing a free firmware upgrade for the device
that supports the new Super G capabilities of its Atheros chipset, effectively
making the DI-624 a whole new product. (Note: Rev A of the DI-624
was based on an Intersil chipset, and thus is not compatible with the upgrade.
D-Link says that only about 2% of the DI-624s sold fall into this category).

In addition to its new software, the DI-624 (which is also now $109, about
$40 cheaper than when we last looked at it) has received an external freshening
as well. The chassis has the same basic low-profile rectangular layout, but
has been put on a diet and is considerably smaller than the previous version.
Also, the latest DI-624 for sale
(known as "Rev C")
sports only a single dipole antenna, not duals
like its predecessor (the antenna is still movable and re-movable).

Like the Netgear WGT-624
router it competes with, the D-Link DI-624 carries over a considerable breadth
and depth of LAN/WAN-related features from previous products. The D-Link matches
the Netgear in providing capabilities like firewall and content filtering, remote
management, logging, and e-mail alerts.

On the WLAN side of the equation, the DI-624 has the full compliment of Super
G performance enhancing features, which include fast frames, dynamic packet
bursting, and hardware compression in addition to channel-bonding. The DI-624
also provides a dynamic performance setting, which allows the access point to
offer a compatible client these Super G features (except for channel bonding)
while still being able to communicate with regular 802.11g or even lowly 802.11b

Configuring the wireless side of the DI-624 takes a bit more forethought than
usual, owing to the high number of different Super G performance modes available.
There are no fewer than four, in fact, plus separate settings for 802.11g only
mode and CTS protection, which means you have to configure these options carefully
if you want to maximize performance and compatibility.

The four Super G modes are "static turbo", which enables all the
Super G features and locks out incompatible clients, "dynamic turbo"
which adds accommodation for regular g or b clients, "no turbo" which
disables the channel-bonding feature only, and "disabled" which turns
off all Super G features, effectively rendering the DI-624 a conventional 802.11g

In each of the numerous performance modes, the DI-624 yielded throughput performance
in excess of what is customary from a typical 802.11g device. All the performance
testing was conducted with a DWL-G650 CardBus client card, similarly updated
with new compatible drivers and firmware.

For distance testing, I configured the DI-624 for static mode. At a 10 foot
distance the throughput was over twice the 802.11g performance at 47.03 Mbps.
This figure was also in excess of the 40.49 Mbps posted by the Netgear WGT-624,
owing to the D-Link’s implementation of the full Super G feature list. As distance
increased, throughput stayed relatively high, starting with 38.84 at 25 feet
and 29.83 at 50 feet.

At 75 feet, I saw a strange anomaly, with throughput jumping sharply to 39.75.
I saw the same phenomenon with Netgear’s WGT-624, though it was significantly
less pronounced. I have not encountered anomalously high throughput at this
distance point before, but it was repeatable with these products. I can only
surmise that it’s a peculiar result of some combination of Super G channel-bonding
with the environmental characteristics of that particular spot. Throughput remained
strong through 100 and 125 feet, at 29.63 and 25.8 Mbps, respectively.

Overall, with the exception of 10 feet and 75 feet, where the D-Link was superior,
the throughput performance of the DI-624 and the Netgear WGT-624 were within
a stone’s throw of each other.

To determine the effectiveness of the compression feature, I configured the
Chariot test software to use a text file
as the source of the data, as opposed to randomly generated data which is the
default. Presumably given the fact that text is compressible to some degree
it should have improved performance, and indeed it did, boosting throughput
from 47.03 to 51.12 Mbps. While the number is somewhat shy of the 60+ Mbps D-Link
is quoting in its own tests, it clearly demonstrates that compression is working.

The idea behind dynamic mode is that Super G clients can utilize most of the
performance enhancing features while still allowing g and b clients to connect
to the network–albeit with a resultant decrease in performance for said Super
G clients. This turned out to be the case with the DI-624. At 10 feet and in
dynamic mode, the unit pushed through 36.33 Mbps to the DWL-G650. In this mode,
I was able to successfully associate an 802.11b client to the DI-624, which
dropped the throughput to the DWL-G650 to 17.19 Mbps– still well above the
10-14 Mbps an 802.11g device can provide in this scenario.

Adding the aforementioned 11b client to the test resulted in further throughput
degradation. Aggregate throughput for the two clients was 11.01 Mbps, with 8.23
for the g device and 2.83 for the b. These figures too, are somewhat better
than what can be had in a conventional 802.11g/b mixed scenario.

Rounding out the performance numbers, in "no turbo" mode, which disables
channel bonding but leaves the other Super G features intact, the throughput
was 23.11 Mbps. Disabling all Super G features resulted in slightly less throughput
of 21.93 Mbps. Two Super G clients simultaneously communicating with the DI-624
resulted in 46.20 Mbps of total throughput, almost exactly divided between the
two clients (23.38 for one, 23.56 for the other). One of the clients was the
Netgear WG511T, indicating that compatibility with non D-Link hardware is possible.
Finally, the DI-624’s throughput suffered only minimally with WPA (both 802.1x
and PSK are supported) turned on, managing 41.83 Mbps.

It’s also worth noting that D-Link is the first vendor I’ve seen to integrate
WPA support directly into their client utility, precluding the need for an external
supplicant or the Windows XP WPA supplement from Microsoft. However, due to
a bug in the utility, I couldn’t use WPA through the utility and had to fall
back to XP after all. D-Link says a fix is under development.

With a few exceptions, (like SNMP and syslog support) the D-Link DI-624 provides
almost any wired or wireless feature you might want in a broadband router in
this class. It also offers excellent performance for and compatibility the Netgear
can’t provide right now (though a forthcoming firmware upgrade should change
that.) When you consider that a DI-624 can be had for less than $100 street
price, or if you’re fortunate enough to already own a DI-624 that’s compatible
with the upgrade, then getting the speed is pretty much a no-brainer.

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