How to buy Wi-Fi 6 access points

With more unlicensed wireless spectrum and specifications for MU-MIMO and OFDMA, the Wi-Fi 6 standard promises faster, more reliable networks, but not all vendors meet all the specs.

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Wi-Fi 6 has some impressive improvements over its predecessor Wi-Fi 5 including lower latency, faster speeds, higher throughput, and increased range that can make it a better fit to serve both dense clusters of clients and clients running high-bandwidth applications.

As Wi-Fi in general replaces wired networks in some enterprises and with the increased use of tablets, laptops, and mobile phones within enterprises, wireless-network responsiveness and versatility are becoming more desirable. Wi-Fi 6 (802.11 ax) can help. It can also improve the efficiency of IoT Wi-Fi networks by letting sensors lie idle more of the time so their batteries last longer.

It does this access-point (AP) capabilities that Wi-Fi 5 (802.11ac) lacked, including the ability to provide channels for up to eight clients at once rather than four, and to break those channels down into smaller segments to support even more clients simultaneously.

Beyond these improvements, regulators worldwide are designating more public radio-frequency bands for unlicensed Wi-Fi use, creating a new variant—Wi-Fi 6E—that provides more bandwidth to each AP that supports the 6E standard.

So it’s no wonder that sales of Wi-Fi 6 wireless-LAN gear are booming. The shipment of Wi-Fi 6 units grew from 26.7% of total Wi-Fi shipments in Q3 2020 to 32.2% in Q4, then to 37.1% in Q1 2021, according to IDC, and it projects that for the calendar year 2021, Wi-Fi 6 will account for more than 50% of all Wi-Fi shipments.

According to IDC the top five vendors by market share in 2020 were Cisco, (42.%), HPE-Aruba (13.5%), Ubiquiti (8.4%), Huawei (6.2%), and CommScope (4.8%). Gartner evaluations in its wireless LAN magic quadrant report for 2020 named four vendors as leaders: Juniper Networks, HPE-Aruba, Cisco, and Extreme Networks. Two, Huawei and Fortinet, were named visionaries.

With the upgrades within the Wi-Fi 6 and standards, it might seem that picking a vendor would be straightforward, but it’s more complicated. As vendors adopt the standards, they are shipping APs that, over time, will support more fully the specifications in the standards. So it’s important to ask vendors whether they have the features you need and which ones are on their product roadmaps. 

This guide will help steer you through the process.

New features

OFDMA

Orthogonal Frequency-Division Multiple Access (OFDMA) within Wi-Fi 6 divides channels into smaller segments and allows multiple devices to connect simultaneously, each in its own bandwidth segment known as a resource unit (RU). This is especially beneficial in high-density environments, improving AP-to-user capacity. The more RUs supported, the more flexibility the network has to allow more simultaneously talk between Wi-Fi devices within a given channel. The number of Rus depends on their size, which is technically known as a tone. A tone could be as big as the whole channel, and that channel could be 20MHz, 40MHz, 80MHz, or 160 MHz wide. But the real benefit comes when tones are smaller, allowing more RUs in the channel space.

The more densely your Wi-Fi clients are placed, the more simultaneous communication will be required, so you’ll want more RUs available. The supported sizes and number of RUs an AP supports varies, so that’s something to ask about when looking at APs.

MU-MIMO

Multi-user Multiple-Input, Multiple-Output (MU-MIMO) is similar to OFDMA in that they both support simultaneous two-way communications between clients and APs, but they do it in different ways. MU-MIMO enables communication between APs and multiple clients using radio-frequency multi-path technology. A version of it was supported in Wi-Fi 5, but with fewer capabilities. In Wi-Fi 6, MU-MIMO supports up to eight clients at once, while with Wi-Fi 5 the number was four. With Wi-Fi 6, MU-MIMO is bidirectional, whereas before it was only supported on the downlink from AP to client. Moreover, MU-MIMO is now also supported in the 2.4GHz band with W-Fi 6 not just the 5GHz band as before. The number of streams an access point supports and the number it supports in each band varies brand to brand, so be sure to consider this during your product comparisons.

You’ll see the number of streams supported listed as transmit/receive numbers such as 4x4 for four streams for both transmit and receive or 8x8 for eight streams. It’s unusual for an AP to support a different number of transmit and receive streams like 4x2. Determine what number of streams you are likely to need, ask what the vendors support, then buy accordingly.

Max channel-width

The larger a channel’s width, the more data can be transmitted on it  at once, thus increasing throughput and bandwidth, which is important to performance when using high-bandwidth applications like streaming video. For the relatively narroa spectrum in the 2.4GHz band, you most likely won’t want to use any larger than the legacy 20MHz channel-widths. But for 5GHz and 6GHz (Wi-Fi 6E), it’s feasible to utilize 40MHz or 80MHz channel widths, and maybe even 160MHz, especially with Wi-Fi 6E.

Most Wi-Fi 6 enterprise APs will support channel widths up to 80MHz, but if you want 160MHz, keep in mind not all of them support it, so ask.

5GHz channel widths

The more channels an AP supports, the better it is for avoiding co-channel interference and the ability to utilize larger channel-widths. The number of channels in the 2.4GHz band doesn’t vary, but it does for the 5GHz range. The amount of authorized 5GHz channels has varied in the past, and some manufacturers stay away from the tricky channels that are shared with radar systems, limiting the channels they support. (In order to support those channels, the AP must also support Dynamic Frequency Selection (DFS) that detects nearby radar and leaves channels where it is detected.)

Typically, the number of supported 5GHz channels using legacy 20MHz size varies between 19 and 26, so if that number is important to providing adequate coverage, be sure to ask about it.

Radios and antennas

Most Wi-Fi 6 APs have two radios, and some have three. Consider what each radio can do. Are they single-band (one for 2.4GHz only and one for 5GHz only), or are they dual-band? Dual band provides the option to turn off 2.4GHz, which is often desirable to avoid interference on the heavily trafficked 2.4GHz range. If you want flexibility, go for dual-band radios.

Many enterprise APs also come with Bluetooth and/or Zigbee on-board for connecting to IoT devices that communicate using those protocols. Look for that support if you plan to network this type of IoT devices through your APs.

Also consider whether the AP has internal or external antennas. If you need directional, high-gain (for longer ranges) or other special antennas, go with an AP that has external antennas so you can attach the types you need.

6GHz support

Keep an eye out for Wi-Fi 6E that makes use of the unlicensed 6GHz spectrum that regulators in the US and elsewhere have opened up. Wi-Fi 6E devices have 28 additional 40 MHz-wide channels or 14 additional 80 MHz-wide or seven additional 160 MHz-wide channels. They can use them in addition to the existing channels offered in the 2.4GHz and 5GHz bands. This can help to drastically reduce interference and improve performance of the Wi-Fi network especially in congested areas and in high-density environments. If you need that kind of bandwidth and face interference issue, ask for 6GHz support.

Wireless security and privacy

Although the improved encryption in wireless protected access 3 (WPA3) is separate from the Wi-Fi 6 standard, some vendors are rolling it out with their Wi-Fi 6 APs. In addition to making password cracking more difficult, WPA3 brings individualized encryption so users can’t decrypt each other’s traffic. It also adds optional 192-bit security for even better encryption, which is good for networks carrying highly sensitive data.

Some vendors also support the new Wi-Fi Enhanced Open functionality. Although not a full security feature, it is a great privacy feature if you offer public or hotspot Wi-Fi access. It allows Wi-Fi communications on open networks to be encrypted without users entering passwords. Like WPA3, the encryption is individualized so users can’t snoop other traffic or execute attacks like session hijacking. Ask about both this and WPA3 to ensure you get the level of safety you need.

Other features

There are many more features and functionality you may want to compare. Most enterprise APs will support the following ones, but you may want to double-check those you’re really interested in:

  • Wireless-mesh support that enables connecting APs to the network wirelessly rather than providing a wired LAN connection.
  • Rogue access-point detection so the APs can be on the lookout for new or non-compliant APs nearby.
  • Spectrum analysis so the APs can be more intelligent, analyzing the whole RF space instead of just detecting Wi-Fi signals.
  • Noise reduction to allow better performance by reducing the effects of noise and interference.
  • Channel management and the intelligence behind how the Wi-Fi controller or AP chooses channels.
  • Roaming functionality and the mechanisms the AP uses to help Wi-Fi clients better roam between the APs.
  • Captive portal so you can perform authentication of users in the web browser or for public access to display terms of use and disclaimer info.
  • RADIUS server that can perform user authentication, such as for 802.1X when utilizing the enterprise mode of WPA security.

Finally, when choosing a Wi-Fi vendor, consider your other network gear and what experience your staff has with each vendor you’re considering. There may be compatibility issues and existing vendor relationships may ease the transition to new gear. Also, some networking vendors offer tools that for managing both their APs their other networking components.

(Eric Geier is a freelance tech writer and founder of NoWiresSecurity providing a cloud-based Wi-Fi security service, Wi-Fi Surveyors providing RF site surveying, and On Spot Techs providing general IT services.)

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Copyright © 2021 IDG Communications, Inc.

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