The latest standard in Wi-Fi denoted as 802.11ax and branded as Wi-Fi 6 has been big news lately. Wi-Fi 6 promises a multitude of exciting new features that are set to be the most radical changes to the 802.11 spec that we know and love. The name of the game here is efficiency — the more efficient the radios are getting on and off the air, the more data can be moved, resulting in a better performing network.
New Eye-Opening Wi-Fi 6 Features
There are tons of very detailed technical documents on what Wi-Fi 6 brings, but I want to briefly highlight what I find most exciting:
Target Wait Time: TWT gives clients the ability to deterministically go to sleep for long periods of time, reducing power consumption and, in many devices, likely saving battery life. The other added benefit of an access point (AP) being able to schedule TWT is that it can try to orchestrate times that do not overlap for clients on the same cell, reducing contention and freeing up the medium that much faster.
Orthogonal Frequency-Division Multiplexing Access: OFMDA is probably the most critical new feature we’re getting in Wi-Fi 6. OFDMA works by slicing up the existing channel into smaller resource units (RUs), allowing multiple clients to be able to communicate with the AP simultaneously.
Previously, only one transmission could happen at a time (client or AP) and typically it did not fully pack each frame with the maximum amount of data possible for the transmission. OFDMA, via multiple RUs, allows organizations to fully utilize the airtime by packing much more data into each transmission, which yields more efficiency on the air.
Basic Service Set Coloring: BSS coloring lets you “cheat” the traditional 802.11 requirement of backing off when other stations are heard on the same channel, known as clear channel assessment (CCA). By setting each BSS with a “color” (some bits in the physical layer, or PHY, header), the client and AP can be more deterministic about using the medium to talk to each other. Now ignoring overlapping BSS transmissions, devices do not have to back off because they no longer consider the medium busy unless indicated in their own BSS color. This provides less wait time, which aids in maintaining average throughput.
It would be remiss of me not to mention that yes, Wi-Fi 6 does, in fact, provide higher modulation rates all the way up to 1024 Quadrature Amplitude Modulation (QAM). As with previous standards, increasing the bits per symbol will give higher data rate and hypothetical speed. What hasn’t changed is that Wi-Fi is still a half-duplex, shared medium that requires all these frames to be properly decoded.
What we saw with 802.11ac was that many times it was very difficult, especially as you moved away from the AP, to achieve the highest rates because of the noise and interference. While higher modulations will help, these same limitations will exist with Wi-Fi 6, and won’t outshine the previously mentioned features. Don’t believe the hype, efficiency is where it counts, not raw data rates.
Navigating the Early Adoption Market for Wi-Fi 6 APs
As we’ve seen before with 802.11ac and 802.11n, manufacturers release “pre-standard” APs to provide a platform for both early adopters and customers looking to maximize longevity with a near term purchase. Wi-Fi 6 is no different in this case, and even at the time of writing this blog the IEEE has not yet fully approved the 802.11ax standard.
Cisco and other manufacturers work closely with chip vendors during the early draft stages of the standard to understand the technology and start work on what typically becomes a late-version draft compatible AP for first entry into the new technology. Often, after the standard has been completely ratified, these APs are able to be certified with little to no changes required by the manufacturer.
Some APs, as is the case with the Cisco 9117, are considered compatible but not likely to be fully certified after ratification. This may seem like strange tactic, but dropping a feature that is listed as required by the standard that the manufacturer doesn’t feel will be widely implemented to start with or isn’t available in chipsets can provide more flexibility into lower-cost model APs.
Wi-Fi 6 Backwards Compatibility
As always, choosing the appropriate model of AP for the environment is deeply tied into the relationship with the end user client capabilities. This means that customers shouldn’t be scared off by compatible AP models if the features provided align with their environment and client-side requirements. Often, this is a great way to stay on the leading edge of technology for organizations that might not be interested in the more feature-packed (and typically more expensive) models like the 9120, which are fully Wi-Fi 6 certifiable.
Another benefit Wi-Fi 6 brings that organizations also previously enjoyed is backwards compatibility with the previous 802.11 standards. In the early days of adoption, this is probably one of the most crucial benefits as client adoption will be slower than updated AP availability. In a mixed client environment of 802.11a/b/n/ac, everything that worked yesterday must continue to work from day 1 with the new Wi-Fi 6 AP and it must do so in a stable state.
I was fortunate enough over the last few months to participate in early field trails for both Cisco’s and Meraki’s entries in to the Wi-Fi 6 market. Among many other features we tested, stability and backwards compatibility are the ones we gave the highest scrutiny. All the bells and whistles don’t mean a thing if the AP itself (and the code it’s running on) isn’t rock solid. I’m pleased to say that by the end of the trials for both Cisco and Meraki I was confident that both product lines would be released on stable code capable of delivering the expected performance.
Wi-Fi 6 Is Ready for Prime Time
Wi-Fi 6 adoption is gaining momentum, and it’s only a matter of time until mobile device manufacturers put new 802.11ax chipsets in everything, causing a huge proliferation of clients in the real world. If you’re still thinking about the three factors to consider that I blogged about previously, now is the time to make those changes. If you’ve already considered the three factors, reviewed your requirements and found Wi-Fi 6 to be a fit, there’s no reason to delay any longer. Wi-Fi 6 is ready for prime time and both Cisco and Meraki’s AP options can give you a stable and backwards compatible network that’s ready for a more efficient Wi-Fi future.