First draft-N routers don't impress

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The next step in Wi-Fi standards, 802.11n, which promises unprecedented and spectacularly fast networking, won't be out for months -- but products based on the first draft of the standard are appearing now. Our testing, unfortunately, shows that these new products are generally somewhat slower than equipment already on the market.

And despite the fact that all of the new products are based on the same draft standard, our testing found that some won't work together without dropping to much slower speeds.

Numbers games

Our tests of draft-N-compliant routers and notebook cards from Buffalo Technology (USA) Inc.'s Nfiniti, Cisco Systems Inc.'s Linksys Wireless-N and Netgear Inc.'s RangeMax Next lines suggest that you might want to wait if you're not desperate to buy new networking gear.

At midrange distances (about 25 feet and through a couple of walls), speeds for networks based on these products averaged about 24M bit/sec. While more than double the 11M bit/sec. speeds we saw for a standard 802.11g network on the same test, the result is still far short of 10/100 Ethernet's 80M bit/sec. real-world speed in the same test.

More notably, the draft-N networks were also significantly slower than those based on slightly older, nonstandard Linksys SRX400 products (which use Airgo Networks Inc.'s Gen3 MIMO

chips): In our tests, midrange throughput on an SRX400 network averaged about 30M bit/sec. Note that this speed is slower than what we reported in our initial tests of an Airgo Gen3-based router and PC Card a few months ago. Those tests were performed with a network test utility, which typically makes networks look faster because it eliminates the software overhead of real-world network use. Our speed calculations for this story are based on the time necessary to transfer a large (87MB) file with WPA2 encryption turned on.

One draft-N product line -- the Netgear RangeMax Next router with 10/100 Ethernet (not to be confused with Netgear's RangeMax Next Gigabit Edition router, the only draft-N router we received with Gigabit Ethernet) and corresponding PC Card -- did beat the SRX400 network, and all others in our test group, at long range (50 feet, through several walls). At that range the Buffalo and Linksys draft-N products couldn't maintain a connection long enough to complete the file transfer.

Draft-N products based on the same underlying chips from Broadcom Corp. (the Buffalo, Linksys and Netgear RangeMax Next 10/100 lines) worked together fine. But Netgear's RangeMax Next Gigabit Edition router, which is based on chips from Marvell International Ltd., was able to connect to the other products only at 802.11g speeds; Netgear says it hopes to address the interoperability problem in firmware upgrades. We ultimately decided against including the test results for Netgear's Gigabit line, as it performed extremely poorly and we did not have time to determine whether our shipping unit was defective.

The final 802.11n standard promises theoretical throughput of 300 to 600M bit/sec. (up to 12 times as fast as 802.11g). Once certified products conforming to the standard appear, probably in a year or so, they'll be guaranteed to interoperate. But it's not certain whether you'll be able to upgrade any draft-N products to the final standard.

'Bad neighbor' confusion

Another issue with draft-N products relates to 802.11n's default use of two 20-MHz channels of Wi-Fi spectrum bandwidth (a throughput-enhancing practice known as channel bonding). Previous standards use only one channel, and since the 2.4-GHz band used by 802.11b, g, and n has only three nonoverlapping channels, channel bonding leaves little space for neighboring networks, which can experience dropped connections as a result. In fact, the Wi-Fi Alliance will not certify 802.11g products that use channel bonding unless they by default revert to a single channel when other Wi-Fi networks are in range.

While the 802.11n standard does specify that routers should not overly interfere with other networks in the area (the industry refers to this as "good-neighbor" policy), it does not specify exactly how to address the issue, and each chip maker handles the problem in its own way.

Broadcom says routers based on its draft-N chips will continuously scan for other networks and choose the best bandwidth and channel, dropping down to 20 MHz if necessary (with a consequent reduction in speed). However, the routers won't change bandwidth or channels while a client is associated, so if your network is based on Broadcom's draft-N chips and it detects a potentially interfering network while you're online, you'll be a bad neighbor until you disconnect and reconnect.

Netgear says its Marvell-based router "will also ramp down to 20 MHz, but only after it has attempted to slow transmission in 40 MHz so as not to collide." In our tests a plain 802.11g router kept working in the same house as each of the draft-N routers, although we had to be sure to set both routers to automatic channel-selection mode so that they could avoid each other, a feature that is not available in all routers.

The Airgo-based SRX400 also uses channel bonding to achieve top speeds and has technology that steps down to a single channel, if need be, to avoid interfering with neighboring networks. But like the chips themselves, the technology is proprietary.

Wait if you can

Given the underwhelming performance and range from the draft-N products in our preliminary tests, as well as their interoperability and interference issues, we'd recommend waiting for a more mature standard, if at all possible.

If you must buy now, though, you have a couple of ways to go. Products based on Airgo's Gen3 chips deliver top performance, and are generally more stable since they've been out longer, but you'll never be able to upgrade them to the eventual 802.11n standard.

Draft-N products might not be the speediest available, and as with most new Wi-Fi products we ran into occasional problems with installation and/or performance. Ultimately, however, all of them work, all of them are reasonably fast, and each piece is priced about the same as Airgo-based competitors (routers range from $150 to $180 for those models with 10/100 Ethernet, Netgear's Gigabit-equipped router goes for $250, and PC Cards run about $120 to $130). Also, while no vendor is making promises, there's at least a chance that you will be able to upgrade to the final standard, which would make these products a better investment in the long run.

If you do buy draft-N products, we strongly recommend that you check periodically for firmware upgrades. Most of the vendors indicate they'll be offering such updates to improve performance and interoperability.

Tested draft-N products

  • Buffalo AirStation Nfiniti Wireless Router & Access Point (WZR-G300N), $180

  • Buffalo AirStation Nfiniti Wireless Notebook Adapter (WLI-CB-G300N), $130

  • Linksys Wireless-N Broadband Router (WRT300N), $150

  • Linksys Wireless-N Notebook Adapter (WPC300N), $120

  • Netgear RangeMax Next Wireless Router (WNR834B), $180

  • Netgear RangeMax Next Wireless Adapter (WN511B), $130

  • Netgear RangeMax Next Wireless Router Gigabit Edition (WNR854T), $250

  • Netgear RangeMax Next Wireless Notebook Adapter Gigabit Edition (WN511T), $130

This story, "First draft-N routers don't impress" was originally published by PCWorld.

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