High-speed Wi-Fi on test

Pro

1 April 2005

While some people are still moseying along with poky old 11Mbit/sec 802.11b Wi-Fi network cards and routers, the second generation of 802.11g is already here, promising rip-roaring speeds of 108Mbit/sec to 125Mbit/sec.

Our informal testing shows that the real-world throughput of these souped-up devices is actually more like 22 to 24Mbit/sec, still significantly faster than the real-world speed of 18Mbit/sec you get with basic 54Mbit/sec 802.11g cards.

The catch with all of this is that the ‘high-speed’ wireless mode is non-standard: To get the promised speed increases, you have to use both cards and routers that have the same type of speed-boosting technology, currently selling in two competing flavours —
108Mbit/sec and 125Mbit/sec. The 108Mbit/sec Super G technology, which came out last autumn, is based on Atheros chipsets and is used by D-Link and NetGear, among others.

The 125Mbit/sec Afterburner technology, which shipped this spring, is based on Broadcom chipsets and is found in products from Belkin, Buffalo, Linksys, and US Robotics, among others.
We tried three of these new high-speed routers (and their companion adapters) to see how they stacked up: Buffalo Technology’s AirStation 125 High-Speed Mode Wireless Cable/DSL Router with AOSS (WHR3-G54); Linksys’ Wireless-G Router with
SpeedBooster; and D-Link’s AirPlus XtremeG DI-624.

Though all these devices are certified Wi-Fi G-compatible — that simply means they will perform in the standard 54Mbit/sec 802.11g mode with G cards and routers from other manufacturers. So if you have a network with a 108Mbit/sec card and a 125Mbit/sec router, the whole thing will run at a maximum of 54Mbit/sec, negating the advantages of the speed-boosting technologies. Similarly, if you have a mixed network of high-speed and regular 802.11g devices, performance will drop when the regular devices are connected.
However, if you are just setting up a wireless home network and can buy matching equipment, either of these technologies will do the job about 33 per cent faster than basic 802.11g equipment — but you will be paying about 30 per cent more money.

Just how do the Super G and Afterburner modes work? Super G gets part of its speed increase from ‘bonding’ data from two non-overlapping wireless channels together (normal Wi-Fi uses only one out of the 11 channels in the 2.4GHz range). This channel bonding, though, increases the potential for troublesome interference with microwave ovens, with mobile phones and with other Wi-Fi networks. In particular, Super G has been criticised in the past for using so much of the Wi-Fi band that other networks in the vicinity, which normally would automatically seek out and use non-overlapping channels to avoid interference problems, could be severely impacted. During our week of tests, we experienced no noticeable drop in performance in either network when we used the D-Link 108Mbit/sec router in the same house with the Linksys 125Mbit/sec router. In contrast, the 125Mbit/sec Afterburner technology uses just one channel. Instead of bonding two channels of data together, it squeezes more data through a single channel by reducing overhead, and also by aggregating smaller packets
of data into larger ones. Some of this technology will be used in the upcoming 802.11e wireless multimedia enhancements standard, which is designed to improve delivery of streaming audio and video.

The 125Mbit/sec Afterburner companies claim that their products are all interoperable in high-speed mode, while Super G products may not be. In a separate test, we found that D-Link and NetGear Super G products were in fact compatible in the 108Mbit/sec mode; however, such compatibility may not be true of products from all Super G companies. In our informal tests of file transfers from a local server to a wireless client — performed with encryption off, 1.2 metres from the router, and in 802.11g-only mode — the two
technologies provided similar real-world performance, ranging from 22 to 24Mbit/sec in wireless throughput. That’s still significantly slower than their 108Mbit/sec and 125Mbit/sec monikers would lead you to believe. Nevertheless, both models boost speeds well above the 802.11g rate of 18Mbit/sec and the 802.11b rate of about 4.5Mbit/sec we achieved with the same test procedure, and they can be a boon to users who need to transfer large files from one computer to another wirelessly or to stream high-quality multimedia files. Just surfing the Internet? Most broadband services connect at well under 1Mbit/sec, so even using enhanced wireless equipment, you won’t experience faster performance.

All three shipping routers were easy to connect to the Internet, and all of them have very good router and firewall features, such as MAC address filtering and WPA (Wi-Fi Protected Access) encryption. The D-Link and Buffalo routers also include WDS (wireless distribution system), a convenient way to link multiple routers wirelessly to
cover a larger area; for households with children, the Linksys router offers a fee-based parental control system.

The Linksys also had the best set-up utility and documentation. However, all three routers and adapters were difficult to get working together in high-speed mode — we fiddled for hours with advanced router settings and card drivers before we got them humming at their top speeds. The job would have taken only a few minutes had better set-up utilities been provided. We suspect that many users, after paying the considerable price premium, will simply get the routers working and will never know that the products are not performing in high-speed mode. Such users should probably not be buying these routers in the first place, though. If all you need is a reliable and compatible Wi-Fi service for typical broadband connections, an inexpensive 802.11g router will provide all the speed you require. But if you really need the performance boost that these new routers provide, then by all means step up.

PC Live! Verdict

Dlink AirPlus XtremeG DI-624
4 stars
Excellent performance, stout firewall features, and wireless distribution system support.