What's Ahead for 802.11n
Given the relatively mediocre performance and the interoperability problems we found with draft-n products, it's worth asking why vendors have rushed them to market. Two wireless companies that have chosen to stay out of the draft-n fray (at least for now)--Wi-Fi chip maker Airgo Networks and network equipment vendor USRobotics--say they don't want to ship products that may not be upgradable to the final standard, a guarantee none of the current crop can make. Instead, Airgo says it will have chips ready for 802.11n compliance testing as soon as the specification is ratified.
The rest of the wireless universe, however, doesn't seem to be waiting--and customers aren't either. "Our Wireless-N family offers customers technology they can immediately take advantage of to get the most out of their networks," Linksys said in a statement, noting that in June its Wireless-N router came in third on the best-seller list for all home networking products.
Draft-N Timetable: Products in 2007?
Meanwhile, the standards process is moving, albeit slowly. Voting is set for January on Draft 2.0 of 802.11n, which could possibly be ratified as final--but most observers expect a third draft to appear later in 2007, followed by ratification and certified products by the end of the year or early 2008.
While 802.11n will include a host of enhancements to the current 802.11g standard, the most notable are theoretical data speeds that will range from 270 to 600 mbps, depending on the device (PDAs, for example, are likely to stick to lower rates to conserve power consumption). The zippy data rates, like those of the non-draft-n routers in our review, are made possible by MIMO (multiple-input, multiple-output) antenna technology that Airgo Networks pioneered a couple of years ago. That's why you typically see three antennas poking up from these routers.
High speed Wi-Fi also uses channel bonding, which combines two side-by-side 20-MHz Wi-Fi channels into one wide 40-MHz pipe. Channel bonding, however, can blast out neighboring 802.11b or g networks since it takes over virtually the entire 2.4-GHz spectrum that these products use. Clear Channel Assessment (CCA) technology to protect nearby networks is included in the first 802.11n draft, but it's not clear whether CCA will be mandatory.
A fix for spectrum overcrowding is available, thanks to 802.11n's support for both the 2.4-GHz and 5-GHz frequencies. Most experts expect the broader 5-GHz band (currently used by 802.11a) to emerge as the unimpeded fast lane for high-bandwidth applications. And by next year most vendors will likely introduce dual-band routers, although some of them may not simultaneously support 5-GHz and 2.4-GHz devices.
Networks based on 802.11n will also slow down if one or more clients use older WEP or WPA security. Only WPA2 encryption (which began appearing in the last year or so) supports certain performance-enhancing techniques specified in the standard. Netgear says to expect about a 5 percent performance drop with WPA and an even bigger hit with WEP--issues that will persist until you retire all legacy devices lacking WPA2 support.
Expect to see several draft-n gigabit ethernet routers for customers who also want faster wired networks. Netgear already sells the RangeMax Next Gigabit Edition, and Linksys should ship a gigabit draft-n router by the time you read this.