Broadband industry research body CableLabs is warning that attempts to make Wi-Fi 7 access points accommodate older devices can create compatibility problems of their own, and wants hardware makers to prioritize support for the industry's workaround.

Wi-Fi 7 products have been finding their way into buyers' hands for a couple of years now, with the Wi-Fi Alliance kicking off its certification program for the latest iteration of the wireless network tech at the start of 2024.

CableLabs is concerned about how Wi-Fi 7 hardware implements WPA3, the latest version of the Wi-Fi Protected Access security standard.

The Wi-Fi Alliance made WPA3 mandatory on the 6 GHz band used by Wi-Fi 6E and Wi-Fi 7. WPA3 itself is not new, having been supported by Wi-Fi 6, while access points operating on the older frequency bands could use a transition mode to accommodate WPA2 devices.

According to CableLabs, more than 23 billion Wi-Fi devices are in use worldwide, many of them based on Wi-Fi 5 or even Wi-Fi 4 hardware. This is especially true in domestic environments, where networks often comprise an eclectic mix of client devices, meaning that compatibility issues can arise despite industry efforts to maintain seamless interoperability.

WPA3-Personal Transition Mode allows an access point to offer WPA2 and WPA3 authentication on the same network, supporting both legacy and newer clients.

Alas, some legacy clients are not as forward-compatible as intended. They are supposed to ignore any security options they don't recognize when setting up a connection, but some may misinterpret this information, leading them to fail to connect to the access point.

A consumer may therefore upgrade to a Wi-Fi 7 router or access point only to find that some older devices can no longer connect, "causing confusion and increased customer service calls for operators," CableLabs notes.

There is a technical answer, and CableLabs wants chipset vendors and makers of Wi-Fi 7 access points and clients to prioritize support for it.

The Wi-Fi Alliance devised WPA3-Personal Compatibility Mode (PCM), which moves the WPA3 and Wi-Fi 7-specific security information into Robust Security Network Override (RSNO) elements.

The access point can then advertise WPA2-Personal through the legacy RSN element, while clients that understand the new RSNO element can negotiate the stronger security required for Wi-Fi 7.

But nothing is ever that simple. Doing this introduces a new requirement that client devices must support the RSNO elements mechanism in order to operate in Wi-Fi 7 mode with a Wi-Fi 7 access point.

With WPA3-PCM enabled, clients that do not support RSNO will be limited to Wi-Fi 6 operation using WPA2-Personal, even if their hardware might otherwise support Wi-Fi 7.

Because RSNO support is still relatively new, many devices lack it. CableLabs therefore wants hardware makers to treat the capability as a priority.

CableLabs also wants makers of low-cost and smart home devices, many of which rely on older chipsets, to test their products against the latest Wi-Fi access points. Good luck with that.

The Register asked CableLabs why the WPA3 problem hadn't been encountered before, when WiFi 6 and 6E supported it.

It responded: "WPA3 itself is not new - it has been part of the Wi-Fi ecosystem for several years. Prior to Wi-Fi 7, whenever some legacy devices had problems connecting to a network with WPA3 enabled, the alternate configuration was to use WPA2 only and that allowed all devices across the different Wi-Fi generations to connect.

"Today, Wi-Fi 7 requires WPA3 and its deployment in residential networks continues to grow. The alternate configuration that was used is no longer feasible so another solution has been developed. This new solution is the WPA3 Personal Compatibility Mode that uses the RSN Override mechanism mentioned in the blog."

CableLabs works with cable operators and the industry ecosystem to test interoperability across the diverse mix of devices deployed in real home networks, which gives us early visibility into compatibility issues like this one before they reach consumers at scale.

All this fuss concerns Wi-Fi 7, which now accounts for about 7.2 percent of the US market, according to some estimates. But hold onto your hats, as Wi-Fi 8 is just around the corner as well, with vendors such as Broadcom setting out their silicon stall already. ®