The Apple AirPort Extreme Base Station
Modem+Broadband edition sports a WAN port, a LAN port, a USB port for the
built-print server, a connector for an external antenna, and an integrated V.90
modem (as opposed to just a serial port to connect your own). That’s quite a
lot for the Airport Extreme’s $249 list price. Get the version that omits the
modem and the antenna connector, and you can pick up the unit for $199.
I probably don’t need to tell anyone this, but I will just in case: Although
you can get wireless access from the AirPort Extreme with a Windows PC as well
as a Mac, the product is most definitely not for a PC-centric household. For
example, there is no Web browser-based utility by which to perform either initial
or ongoing configuration. You need a Mac-based application using Apple’s Rendezvous
technology — in fact you need to be running MacOS X in order to take advantage
of many of the features of the unit and to get it working.
Another limitation: although the AirPort Extreme has the built-in print server
(and remember, it’s USB, not a parallel port–other vendors, please take note)
only Mac clients are supported. Apple tells me you can get it to work with the PC inelegantly (and sans tech support) by using GIMP (GNU Image Manipulation Program) printer drivers.
Perhaps the biggest limitation of the unit affects Macs and PCs equally–it
relates to how you can configure IP addresses. In this regard, the AirPort Extreme
is about as flexible as dry pasta.
For example, the AirPort can function as a DHCP server, but you must use the
pre-defined private subnet (10.0.1.x) or else supply a handful your own global
IP addresses (the "real" ones you get from your ISP). Moreover, if
you turn off DHCP, then you can’t use NAT. In effect this means that you can’t
use a private LAN subnet range of your own choosing under any circumstances.
The ability to define your own LAN subnet range is a feature I’ve seen in every
other product I’ve ever looked at and as a result take for granted at this point.
The AirPort’s inability to do so might make adding an it to an existing network
in particular much more trouble than it needs to be.
Security features are fairly limited. The AirPort Extreme does of course feature
NAT protection, which is de rigueur for any self-respecting router. On
the other hand, it lacks a configurable firewall, or any intrusion detection
or notification features. In fact, the AirPort Extreme lacks any kind of security
logging or alerting capabilities at all.
On the other hand, if you’re worried more about what the inside users are accessing,
you’re looking for some kind of content control. The AirPort Extreme gives it
to you–sort of. The unit doesn’t have any inherent content control capabilities,
but it is compatible with AOL content controls, which essentially means that
it will only allow the AOL client software to get out through the WAN port.
The Airport Extreme supports RADIUS, which provides the centralized authentication
that will come in handy in say, an academic or commercial environment. That’s
not surprising, since this is doubtless where a great many of these units will
find a home.
The AirPort Extreme does have a couple of neat
features that are worth mentioning. One is the fact that you can adjust the
transmitter power via a slider bar (ranging from 10%-100%). Few WLAN devices
in this class and price have and that and, frankly, every single one should.
Throttling the radio power is not only a useful (though rudimentary) security
feature; it comes in handy when you’re trying to place multiple access points
without much overlap.
The unit can perform point-to-multipoint bridging with up to four
other AirPort units, allowing you to extend the range of your network. This is another feature that relatively few competitors have, but more should. When
operating in this mode, it can still accommodate clients while it bridges from
other access points.
In any event, getting the AirPort Extreme functional via the included Setup
Assistant application, and then configuring it via the separate administration
utility was very easy.
The unit operates in three wireless modes; 802.11b only, 802.11g only, and
802.11b/g. I did most of my evaluation (and performance testing) using the G
only mode. I did notice that the AirPort had an annoying tendency to become
unresponsive after a period of time (usually several hours, but no obvious pattern
was apparent), requiring the unit to be power-cycled to get back online again.
An update to the newest version of the firmware seemed to ameliorate the problem.
At a 10 foot distance, the AirPort Extreme Base Station yielded a throughput of 14.38 Mbps, a figure consistent with comparable 11g-based products. On the other hand, as distance increased, the performance dropped markedly, and the clients had difficulty communicating with the unit at longer ranges.
For example, at 50 feet, the throughput was 5.34 Mbps, and at 100 feet it had dropped to a paltry 1.25 Mbps (compared to 11.86 and 9.66 Mbps, respectively, for the D-Link DI-624). Also, I was unable to obtain a signal from the AirPort beyond 100 feet whereas the DI-624 still managed 2.33 Mbps at 125 feet.
I also tested the AirPort against a PowerBook G4 using IPerf, an open-source network performance utility. Doing so yielded a similar (though not identical) performance curve — throughput at 10 feet was quite good at over 13 Mbps, but it dropped off to less than 1 Mbps at 100 feet.
How to explain this disparity? The most obvious difference between the Apple and D-Link units (aside from the different silicon they use) is the D-Links external antennae, as opposed to the internal antenna of the AirPort Extreme. This is the most likely cause of the range issues, so I would recommend getting the version of the AirPort Extreme with the external connector and opting for one of the optional antennas that are available.
The Apple AirPort Extreme, is a competent product that boasts
some interesting features, It deserves kudos for being the only router available with a built-in modem and USB print server.
However, unless you have fairly rudimentary requirements and are just looking “to set it and forget it,” the AirPort imposes many configuration limitations that can cause consternation, especially if you have a PC-centric environment.