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Go To Sleep, Go To Sleep, Go To Sleep Little iPhone

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In some circles, Apple Wi-Fi devices are knows to have problems with lost connections.  iPhones and iPads will unexpectedly miss incoming calls, have delays in receiving push notifications and even be forced to reauthenticate.

There is a solution to Apple devices' connection problems, and as with most "device problems", the fix resides on the infrastructure.  The DTIM setting needs to be increased.  (Apple recommends a setting of 3 or higher.)  Here's why:

Some Apple Wi-Fi connection problems stem from Apple iOS devices' use of 802.11 power management.  To understand what Apple devices are doing with power management, one must first understand how 802.11 power management works.

Let's start with unicast data.  The 802.11 standard allows devices' Wi-Fi radios to enter the Doze state in order to conserve battery life.  Wi-Fi radios in the Doze state are unable to receive data from the AP, so APs buffer all unicast data that has a destination MAC address of a…
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Roam, If You Want to (As Long as Your Channels Are 20 Mhz Wide)

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Editor's note: In the original publication of this article, the relationship between Wi-Fi channel width and SNR was described imprecisely.  While the point of the article was correct -- that wider channel widths increase the likelihood of Wi-Fi frame failures for mobile client devices -- the mistakes have been corrected.  Thank you to Adrian Granados.

Ahh, roaming. Few things capture the spirit of freedom like the ability to Roam wherever you want to go.



 Wi-Fi has its own brand of roaming, and there is one aspect of Wi-Fi roaming that often gets overlooked: 40 MHz and 80 MHz wide channels can make Wi-Fi users feel like they've been bounced from the Love Shack.
Much has been written and spoken about the pros and cons of the three Wi-Fi channel widths: 20 MHz, 40 MHz, and 80 MHz.

20 MHz wide channels allow for the highest number of APs to be deployed -- nice for ultra high-density Wi-Fi -- because each AP takes up less of Wi-Fi's scarce frequency space.  In North America, up…
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WPA3 Adds Four Security Enhancements, One of Which Matters

The Wi-Fi Alliance announced its next security enhancement today, called WPA3.  The press release touts "four new capabilities", but only one of the four affects practical Wi-Fi security.

 As they are occasionally wont to do, the Wi-Fi Alliance announced a new certification today via a press release featuring an artisnal blend of normal words and corporate gobbledygook.  For those who speak fluent corporate gobbledygook, here are the four enhancements of WPA3:
Robust protections even when users choose passwords that fall short of typical complexity recommendations.Simplify the process of configuring security for devices that have limited or no display interface.Strengthen user privacy in open networks through individualized data encryption.A 192-bit security suite, aligned with the Commercial National Security Algorithm (CNSA) Suite from the Committee on National Security Systems to forther protect Wi-Fi networks with higher security requirements such as government, defense, a…
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