eWEEK Labs: 802.11n Is a Gamble

Tech Analysis: The newest wireless LAN specification—802.11n—isn't ratified yet, but that's not stopping vendors from releasing products based on a draft version of it. Is this gear worth the gamble? Not if you expect your wireless expe

The newest wireless LAN specification—802.11n—isnt ratified yet, but thats not stopping vendors from releasing products based on a draft version of it. Is this gear worth the gamble? Not if you expect your wireless experience to be easy, reliable or consistent, eWEEK Labs tests reveal.

The 802.11n spec promises throughput well north of 100M bps—a tempting proposition for users whose performance thirst cannot be slaked. But products based on the draft version of the spec may not be compatible with the shipping spec, which means that users could be looking at significant upgrades or even total overhauls of the draft-based gear once "real" 802.11n products are released (sometime next year).

After last months joint announcement by Atheros and Broadcom, trumpeting the interoperability of products using their respective wireless chip sets based on Draft 1.0 of the 802.11n standard, eWeek Labs decided it was time for a reality check.

Click here to check these products for Draft 2.0 802.11n WiFi Certification. We found that interoperability among products based on different manufacturers chip sets is possible out of the box, but it wont come easy or reliably. For corporations and consumers alike, our purchase recommendation for these products remains the same—dont—but we do recognize the quick maturation of these wares in the brief time since they were introduced this spring.

We brought in four sets of products representing the three chip-set makers that are currently delivering gear based on the draft 802.11n standard. Netgears RangeMax Next Wireless Router—Gigabit Edition (WNR854T) and RangeMax Next Wireless Notebook Adapter—Gigabit Edition (WN511T) are both based on Marvells TopDog technology, while Belkins N1 Wireless Router (F5D8231-4) and N1 Notebook Card (F5D8011) represent Atheros Communications XSpan chip set. Representing Broadcoms Intensi-fi chip set are Buffalo Technologys Nfiniti Wireless-N Router and Access Point (WZR-G300N) and Notebook Adapter (WLI-CB-G300N).

We also brought back for another look the Linksys Wireless-N Broadband Router (WRT300N) and Notebook Adapter (WPC300N), both of which are based on the Broadcom chip set. (See "First 802.11n Products Show Standards Promise" at eweek.com.) Since we last tested these products, Linksys updated the router firmware to Version 93.3, which improved performance slightly at longer distances in our tests.

Netgears products proved to be the unrivaled speed champs at close distances—topping 130M bps of real throughput—but performance started to lag considerably as the client moved away from the router. (See "Unencrypted throughput" chart, Page 33.) The Belkin pairing also fared poorly at longer distances, and we could not crack the 100M-bps barrier at close range.

All the Linksys and Buffalo gear based on the Broadcom chip set worked together easily at high speeds. Power users looking to mix and match draft 802.11n products at this time are advised to stick with Broadcom-based products. But users also should take care to ensure that driver and firmware revisions are of similar generation on the client and router. Click here to read a review of Buffalo Technologys draft 802.11n products. This can be a herculean task because Linksys and Buffalo use different versioning schemes for their respective routers firmware. Of the products we tested here, we determined that Buffalo is using a newer client driver than Linksys is, while the Linksys router firmware is more up-to-date than that of the Buffalo Nfiniti Router.

As noted in a joint release, Broadcoms and Atheros products worked together at high speeds out of the box. (See "Interoperability matrix" chart, above.) However, we saw this compatibility only in certain pairings. Connecting the Atheros-based Belkin adapter to either of the Broadcom-based routers we tested produced solid results—in the 70M- to 90M-bps range. While this performance is less than Broadcom and Atheros have claimed in their joint testing, we found it acceptable at this time.

Using the Broadcom-based client adapters with the Belkin router was another story, unfortunately. We saw poor perform-ance—less than 20M bps at short distances—despite the fact that the connections link rate hovered at about 300M bps.

The Marvell-based products did not interoperate at high speeds with any other products in our tests. The link rate topped out at the 802.11g-maximum 54M bps, which produced the expected 802.11g performance (in the neighborhood of 20M to 22M bps).

This leaves Netgear in the unenviable position of having two draft 802.11n product lines in its stable—from Marvell and Broadcom—that will not yet work together at high speeds. Click here to read a review of Netgears WNR854T RangeMax Next Wireless Router—Gigabit Edition. Customers taking the plunge with Netgears draft 802.11n gear need to ensure they purchase an adapter and router that will work well together at high speeds. Netgear draft 802.11n products with a model name ending in "T" are Marvell-based products, while a "B" in the model name stands for Broadcom.

According to David Henry, Netgears marketing director for consumer products, Netgear engineers have Marvells interoperable code in their labs and are fine-tuning it to improve throughput performance. While we could not get our hands on the beta interoperability code for these tests, we expect to see a software upgrade available on Netgears Web site within the next month.

Next Page: Testing out backward compatibility, security.