The AirPort Extreme BaseStation includes some advanced functions but they're harder to find than on most routers. This is likely due to Apple's emphasis on ease of use. If you dig around in the utility, though, you can find some useful features (unfortunately, the included setup guide is of little help). For example, you can use the AirPort Extreme Base Station as a point in a wireless distribution system (WDS), where each point increases the spread of the wireless network. WDS requires using products from the same vendor (though not all products from a single vendor will necessarily interoperate), as there is no universal standard for implementing WDS.
Another feature is the ability to assign specific IP addresses to specific devices on your network. That way, if your router resets, you can still easily locate your devices. Apple also has future-proofed the AirPort Extreme by offering support for IPv6 addressing.
The AirPort Extreme also offers dual-band capability; that is, it can operate in the 2.4GHz band or the 5GHz band. The benefit of that option is that many common household devices--including cordless phones, microwave ovens, and baby monitors--operate in the 2.4GHz band, which can cause interference on your network. Also, the 5GHz band makes the Base Station 802.11a-compatible, though it's not compatible with 802.11b/g products. Keep in mind, though, that Mac PCs using older PowerPC processors operate only in the 2.4GHz band; Intel-based Macs can operate in either band.
Using IXIA's IxChariot console and Performance Endpoints for Macs, we recently retested the AirPort Extreme Base Station. Because the Extreme Base Station offers both 2.4GHz and 5GHz operation, we tested both bands. In the 2.4GHz band and in N-only mode, the Extreme Base Station scored 58.84Mbps at 10 feet (maximum throughput) and 37.48Mbps at 200 feet (long-range throughput). In mixed mode at 10 feet (with 11g and 11b clients on the network), it scored 13.72Mbps. In the 5GHz band in N-only mode, the Extreme Base Station scored 77.17Mbps at 10 feet and 58.47Mbps at 200 feet.
In the course of our normal testing, we test routers in their default mode, that is, we don't switch channels. However, we noticed that the scores we obtained using IxChariot were still lower than the scores other publications got for the AirPort Extreme Base Station. Curious, we did try switching channels and found that in our case, using channel 6 showed improved throughput--between 10Mbps to 15Mpbs faster than in default mode. For example, in 2.4GHz at 10 feet, testing in channel 6 gave us a throughput of 71.01Mbps and at 200 feet, channel 6 scored 45.50Mbps.
The Apple AirPort Extreme Base Station is within the range of performance we've seen from other draft 11n-based wireless routers. Unfortunately, all of the draft 11n routers we've tested fall well short of the promised speed improvements of 802.11n, widely advertised to be about 200Mbps. We're curious to see whether products based on the finalized spec will improve upon these speeds. Your mileage will vary, possibly depending on the "noisiness" of your environment, that is, how many wireless networks are active in your area.Service and support
Apple backs the AirPort Extreme Base Station with a standard one-year support, though you can purchase an extended coverage plan. You get 90 days of complimentary, toll-free phone support. Apple's site offers FAQs, troubleshooting articles, user forums, and manual and software downloads.