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Linux gains enhanced WiFi stack

May 1, 2006 — by LinuxDevices Staff — from the LinuxDevices Archive — 8 views

The day when WiFi cards “just work” under Linux may be fast approaching. WiFi software stack specialist Devicescape has released its “Advanced Datapath” 802.11 driver stack to the open source community under the GPL, and the Linux kernel developer community appears to be working to adapt it for mainline inclusion.

The Devicescape WiFi stack was previously only available to device vendors, under license.

WiFi card support is currently spotty in Linux, at best. Bright spots include Intel's Pro/Wireless or “Centrino” radios, and lots of essentially obsolete, difficult-to-find cards such as those based on Prism chipsets. Meanwhile, cards widely available at major retail outlets typically do not work at all, or do not work fully under Linux.

Devicescape specializes in selling WiFi stacks to device vendors, and it says that Linux's poor WiFi card support is limiting Linux uptake in wireless multimedia devices. It hopes its contribution will help developers quickly adopt the latest WiFi silicon technology into their wireless product designs, without having to wait for silicon vendors to release Linux drivers.

Additionally, Devicescape says its WiFi stack enables the Linux kernel to distinguish and properly handle different media streams, such as voice and video. It hopes these new capabilities will encourage open source developers to create new multimedia devices, such as voice-over-WiFi phones, streaming video clients, and devices that interact with Web-based services.

If merged into the mainline Linux tree, Devicescape's driver could provide native kernel implementations of a variety of things that currently make it challenging for companies and community developers to write WiFi device drivers. The driver includes an 802.11 stack with software MAC (media access controller), hostapd, wep, wpa, wme, a “link-layer bridging module,” and a QoS (quality of service) implementation. Marketing VP Glenn Flinchbaugh comments, “[Our driver] makes it easier for someone to add a WiFi driver, because they only have to write a thin, low-level driver that maps to the API, in order to enable the latest and greatest WiFi chipsets.”

Flinchbaugh says the Datapath driver stack was written largely by Simon Barber, chief scientist at Devicescape, along with Jouni Malinen, a Devicescape engineer well known for maintaining the open source HostAP/hostapd/wpa_supplicant code.

Will the driver be accepted? Flinchbaugh says the driver has been well-received in the kernel community, and acceptance appears likely.

Jonathan Corbett, of LinuxWeeklyNews, appears to concur; he attended the 2006 Wireless Networking Summit earlier this month, and wrote, “[The Devicescape driver] is regarded by many as being the best of the available free stacks,” adding, “Nobody at the summit was heard to argue against merging Devicescape.”

Currently, a version of the Devicescape stack “fixed up for the kernel” by Jiri Benc has been merged into an experimental tree maintained by John Linville, who was recently appointed maintainer of Linux's wireless networking stack, Corbett reports. Several WiFi chipset drivers, including those for Broadcom chipsets requiring a software MAC, have been backported to this experimental stack, and Linville “seems poised to merge this stack for a future kernel release,” Corbett writes.

According to Flinchbaugh, a merged Devicescape driver would also immediately offer full support for Atheros chipsets, something long hoped-for by many in the Linux community.

Still, the merger would cause some redundancy with other parts of the kernel, Corbett notes, and additional work needs to be done to bring the driver into compliance with current kernel coding standards. At the same time, the driver's clever handling of QoS could be generalized for use with other types of networking, Corbett reports.

Flinchbaugh comments, “Devicescape is committed to unlocking the full potential of Wi-Fi. We view Devicescape as a quintessential open source company: our company and product heritage are based on open source; we leverage code from the community to develop product; and we regularly donate code back. We have dedicated resources that support open source projects, and we look forward to additional contributions that will drive service-enabled devices.”

VDC Analyst Chris Lanfear stated, “This contribution provides the open source community with tested and proven Wi-Fi technology that can be leveraged in the development of Linux-based converged smartphones, wireless personal media players, and digital media adapters, among other multimedia devices. With this contribution, Devicescape aims to expand Linux as a core technology foundation for next generation devices.”

Additional details about the 2006 Linux Wireless Summit can be found in Corbett's report at LinuxWeeklyNews.

In other news, Devicescape on May 1 added standards-based self-configuration capabilities to its commercial WiFi stacks for consumer electronic devices and wireless infrastructure products, including those based on Linux. The “Easy Access” capabilities are based on Wi-Fi Alliance standards, and make setting up secure, WPA2-encrypted wireless networking trivial, the company claims.

Devicescape, formerly Instant802.11, sells WiFi client and access point stacks for a variety of platforms, including Linux, Windows CE, and Windows Mobile embedded operating systems.


 
This article was originally published on LinuxDevices.com and has been donated to the open source community by QuinStreet Inc. Please visit LinuxToday.com for up-to-date news and articles about Linux and open source.



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