Atheros and Broadcom demo 802.11n interoperability

Stuart Corner
Thursday, 01 June 2006 18:01

Business IT - Technology

See also:
US Robotics warns on pre 802.11n' products
802.11n hits a roadblock

Two of the leading WiFi chipset makers, Atheros Communications and Broadcom Corporation have demonstrated interoperability between devices using the draft 802.11n versions of their chipsets. In a joint statement they said: "During the last month, the companies have jointly conducted interoperability testing between Atheros' XSPAN and Broadcom Intensi-fi chipsets. Tests have verified that the wireless LAN solutions work together at throughput speeds greater than 100 Mbps, using mandatory modes of the IEEE 802.11n specification (draft 1.0)."

There has been much controversy surrounding 802.11n since a draft standard was agreed on in January. Several vendors have already brought out products conforming to the draft spec, but critics, notably US Robotics and Airgo, say there are major problems with the spec.

And while Atheros and Broadcom may have demonstrated interoperability, there is yet to formal process for certifying this. They said that "This is the first in what is expected to be a series of interoperability tests conducted with leading wireless companies to broaden the scope of interoperable systems. Over the coming months, the testing will lay the groundwork for successful Wi-Fi Alliance testing when the organization's certification process is finalized."

Also the testing to date has been limited. In a summary of the results the two companies noted that: The 802.11n specification (currently at Draft 1.0 status) contains a large number of mandatory and optional features. Interoperability is not trivial due to the complexity of the standard as well as the number of mandatory elements. It is particularly important that devices support the mandatory elements as their presence is assumed by other vendors, and omitting them can prevent interoperability between vendors." They tested only six of the mandatory elements.

Nevertheless they claim that the tests demonstrate that the 802.11n draft is sound. Atheros CTO, Bill McFarland said: "The excellent performance demonstrated between Atheros and Broadcom devices shows that the 802.11n draft, when adhered to and properly implemented, supports multi-vendor interoperability...As the market moves toward these interoperable 802.11n draft chipsets, consumers will be able to purchase a wide range of networking gear from numerous vendors that interoperate at unprecedented speeds."

Bill Bunch, director of 802.11n product management for Broadcom's Home and Wireless Business Unit said: "The progress towards interoperability is a strong validation that the draft 802.11n specification will deliver the benefits of a high-performance wireless ecosystem built on industry standards."

However criticism of the draft has been directed less at interoperability between different implementations and more at an alleged lack of backward compatibility with the established slower speed 802.11a/b/g standards.

Early in May Airgo issued a statement saying that the 802.11n draft had failed to get sufficient votes to move forward. "The rejection of Draft 1.0 by the working group highlights the clear desire for significant changes to the draft. The most significant changes required are changes to improve interoperability with legacy devices; Draft 1.0 is clearly deficient in protecting the operation of installed networks...By the end of 2006 there will be around 80 million installed .11b/g networks and these need better protection than Draft 1.0 can offer."

On 31 May US Robotics announced that it was holding off on 802.11n products for the same reasons. " Initial testing of those 'Pre-N,' 'MIMO,' and '802.11n-compatible' products has shown increased speed and throughput, but problems remain with legacy and neighbour networks. Even early versions of 802.11n Draft 1.0 based products have shown issues with interoperability and legacy networks."