| technology | networking - David Zomaya
When to Use 802.11 a, b, g, b, nc: WiFi Standards
When the Wi-Fi Alliance came up with Wi-Fi Generations labels, they made sorting through the different 802.11x standards a little easier. Intuitively, you can infer that Wi-Fi 5 (802.11ac) is faster and newer than Wi-Fi 4 (802.11n). Similarly, Wi-Fi 6 (802.11ax) is an improvement over Wi-Fi 5. However, while those labels help, they don't tell you everything you need to know about when to use the different 802.11x standards.
CBT Nuggets trainer Jeff Kish has a primer on Wi-Fi 6 in this Trainer Talk:
Here, we'll go a step further and look at when you would use the various standards 802.11x that the Institute of Electrical and Electronics Engineers (IEEE) has published over the years.
802.11x Wi-Fi Standards: From 1997 to Today
There have been plenty of 802.11x standards since the original 802.11-1997. Before we explore which Wi-Fi standards you should use, let's take a look at what those standards are. Because they are/were/will be common on home/business networks, we'll focus on the original standard and the "Wi-Fi 1"** through "Wi-Fi 7" generations of Wi-Fi in this table.
|Standard||Year Published||Theoretical Maximum Speed in Mbps (Megabits per second)*||GHz (gigahertz) Band||Notes|
|802.11-1997||1997||2 Mbps||2.4 GHz||802.11-1997 quickly became obsolete and was replaced by 802.11b|
|802.11a / "Wi-Fi 2"||1999||54 Mbps||5 GHz|
|802.11b / "Wi-Fi 1"||1999||11 Mbps||2.4 GHz|
|802.11g / "Wi-Fi 3"||2003||54 Mbps||2.4 GHz|
|802.11n / Wi-Fi 4||2009||600 Mbps||2.4/5 GHz|
|802.11ac / Wi-Fi 5||2013||1,300 Mbps||5 GHz|
|802.11ax / Wi-Fi 6 & Wi-Fi 6E||2019||9,600 Mbps||2.4/5/6 GHz|
|802.11be / Wi-Fi 7||Not yet finalized, projected draft in 2021 and a final version in 2024||40,000 Mbps***||2.4/5/6 GHz|
*Keep in mind that max speeds for Wi-Fi ranges are NOT the same as what you'll get in practice. In practice, your numbers will almost always be significantly slower. Additionally, with newer Wi-Fi technologies, there are different max speed numbers available. For example, 802.11ac Wave 2 has a theoretical maximum over 3 Gbps. The takeaway: always take maximum speed numbers with a grain of salt. Use them to generally compare standards, but not as an indicator of achievable real-world speeds for most practical applications.
**The "Wi-Fi 1", "Wi-Fi 2", and "Wi-Fi 3" labels are unofficial. The Wi-Fi Alliance did NOT give generations of Wi-Fi before Wi-Fi 4 an official name. However, many refer to 802.11b as "Wi-Fi 1", 802.11a, as "Wi-Fi 2", and 802.11g as "Wi-Fi 3".
***The 802.11be Project Authorization Request calls out a max throughput of at least 30 Gbps, but this IEEE document indicates the new PHY will have over 40 Gbps. As we get closer to a final draft of the standard, we should learn more.
When to Use 802.11x Standards: A Cheat Sheet
Before we go into the details, here's a quick breakdown of the general takeaways. For a deeper dive on the 802.11x standards and some insight on how we got to these conclusions, keep reading.
|802.11x Wi-Fi Standard||When to use|
|802.11a/"Wi-Fi 2"||Only for legacy support|
|802.11b/"Wi-Fi 1"||Only for legacy support|
|802.11g/ "Wi-Fi 3"||Only for legacy support|
|802.11n/Wi-Fi 4||Almost legacy in 2020. Some 802.11n use cases on existing 802.11n networks/with 802.11n devices (e.g. older phones, IoT devices, etc) where optimizing performance isn't a must.|
While technically 802.11ac does NOT support 2.4 GHz bands, in practice most 802.11ac routers are dual-band and can fallback to 802.11n if needed.
Decent speeds and many modern devices have 802.11ac compatible Wi-Fi radios.
802.11ax is backward compatible with older 802.11x standards. However, because most devices aren't Wi-Fi 6 compatible yet, there are many cases where upgrading to 802.11ax will have limited performance impact.
Because 802.11ac is backward compatible with 802.11n and most 802.11ac routers are dual-band (2.4 & 5 GHz) in practice, for most of us this all boils down to: 802.11ac vs 802.11ax. When you consider cost and how common support for the two standards is, 802.11ac is often the right answer today. However, if you only rarely update your Wi-Fi hardware, future-proofing with 802.11ax may be the better option.
Of course, if you're walking into an existing network and need to get things to work, that's when things get tricky. Backward compatibility can bail you out in most cases, but there are some exceptions:
- 802.11a and 802.11b cannot communicate with one another
- 802.11g and 802.11g cannot communicate with one another
Common 802.11x Wi-Fi Standards: A Closer Look
To get an idea of how we got to the conclusions in our cheat sheet, let's take a closer look at each of the protocols.
802.11a: Legacy 5 GHz Wi-Fi
802.11a supported the 5 GHz band and a theoretical maximum speed of 54 Mbps. In the early 2000s, many business/enterprise wireless devices used 802.11a Wi-Fi radios. The 5GHz bandwidths allowed for higher speeds than 802.11b and 2.4 GHz. However, the higher GHz frequency also meant the signal did not transmit as far and was harder to transmit through physical obstructions. Today, 802.11a is considered a legacy protocol.
It may seem odd that 802.11b is "Wi-Fi 1" instead of 802.11a. The reason for this is that 802.11b radios were cheaper and grew in adoption quicker, even though the standards were released in the same year. 802.11a mostly saw adoption with businesses, while 802.11b saw more widespread general use.
802.11b: Legacy 2.4 GHz Wi-Fi
802.11b was slower than 802.11a, but the low cost helped drive its popularity. It was very common for Wi-Fi devices in the early 2000s to use 802.11b radios. However, today 802.11b is very much considered a legacy protocol.
802.11g: An improvement on 802.11b
802.11g, the last protocol in this list we're going to call legacy, was released in 2003 and had a theoretical maximum speed of 54 Mbps to the 2.4 GHz bands. As you might guess based on 802.11g supporting only 2.4 GHz: it was backward compatible with 802.11b, but NOT 802.11a.
802.11n a.k.a. Wi-Fi 4: Support for both 2.4 & 5 GHz
By supporting 2.4 & 5 GHz, backwards compatibility with 802.11a/b/g, and theoretical maximum speeds up to 600 Mbps, 802.11n was a big leap forward for Wi-Fi.
802.11n is certainly "old" for a Wi-Fi standard in the 2020s, but there are still plenty of 802.11n radios out there. 802.11n devices were still some of the most common throughout the late 2010s so you can expect to continue to see them in the wild for a bit longer.
Long story short: you probably don't want to build a brand-new network using 802.11n components, but there are use cases where 802.11n is still "good enough".
802.11ac a.k.a. Wi-Fi 5: Common on Modern Devices
802.11ac, while only supporting 5 GHz, offered plenty of ways to boost speeds and performance. For example, while 802.11n could support 4 antennas, 802.11ac can support 8. With more antennas, you can get more throughput. 802.11ac also helped drive the standardization of beamforming — a technique that helps better focus a wireless signal, which helps with performance optimization.
Published in 2013, 802.11ac or Wi-Fi 5 is what we'd call the "today's" Wi-Fi standard. That is, when you consider cost, availability, performance, and market adoption today 802.11ac is probably the right answer for most standard use cases today. 802.11n is beginning to show it's age and 802.11ax isn't as widespread or affordable as 802.11ac in general.
You may notice that 802.11ac is 5 GHz only, which you'd think would hurt backwards compatibility. However, since vendors realize the importance of backwards compatibility most 802.11ac routers and wireless access points (WAPs) have 2.4 GHz radios to support 2.4 GHz devices.
802.11ax a.k.a. Wi-Fi 6 and 6E: Wi-Fi's next big thing
Wi-Fi 6 is WI-Fi's next big thing. There are already some 802.11ax devices out there, but adoption isn't widespread enough that it's become the norm. Some of the benefits of 802.11ax include: support for 2.4 GHz & 5 GHz, theoretical maximum speeds up to 9,600 Mbps, and increased power efficiency.
Additionally, Wi-Fi 6E will allow Wi-Fi devices to take advantage of the 6 GHz frequency range. The addition of the 6 GHz range will mean more bandwidth available to reduce congestion and increase performance.
You can expect Wi-Fi 6/802.11ax adoption to grow in the coming years, but for now 802.11ax is more horsepower than most use-cases call for.
802.11be a.k.a. Wi-Fi 7: A work in progress
It's a bit early to start deploying Wi-Fi 7, but there are some big upgrades in the works. Like 802.11ax, 802.11be will support 2.4/5/6 GHz, but it will boost theoretical maximum speeds upwards of 30 Gbps.
Lesser Known Wi-Fi Standards
Our table above outlines the 802.11x Wi-Fi standards that are common to home and business networks, but there are more. Here is a quick explanation of some of the lesser-known 802.11x standards and their use-cases
- 802.11ah. Published in 2017, 802.11ah is also known as Wi-Fi HaLow. It allows for use of bandwidth spectrum below 1 GHz. By using lower frequencies, it can travel farther. Use cases for Wi-Fi HaLow are those where low power and long-range are important. For example, IoT (Internet of Things) devices in industrial and smart city use-cases may benefit from 802.11ah
- 802.11ad. The first Wi-gig standard, 802.11ad was published in 2012 and allowed for use of 60 GHz bandwidths. By upping the frequency, 802.11ad can generate high-throughput but short-distance Wi-Fi signals. The theoretical maximum speed is around 7 Gbps, but only has about 30 feet of range. With 802.11ax ramping up in popularity, it's unlikely 802.11ad will become common. However, it's successor 802.11ay may find some viable use-cases in the years to come.
- 802.11ay. The next Wi-Gig 802.11ay also uses 60 GHz bandwidths but should deliver significantly higher speeds (at least 20 Gbps theoretical maximum) and longer maximum distances (around 300-500 meters). The final approvals for 802.11ay should come in early 2021.
- 802.11ba. Also known as WUR (Wake-Up Radio), 802.11ba was designed to improve battery life for IoT devices.
Remember: Check your Wi-Fi Routers, Access Points, and Clients!
Your Wi-Fi devices will only perform as well as the highest protocol, access point, and client support. For example, if you buy a new high-performance 802.11ax Wi-Fi 6 certified router but all your client devices are 802.11n compatible, you can only get 802.11n speeds. This is because Wi-Fi communication is two (or more) wireless radios communicating with one another. Upgrading the router's Wi-Fi radio does nothing for the clients.
Final Thoughts: It isn't Just About the Wi-Fi standard
Making sure you are using the right 802.11x standards is important when designing and troubleshooting Wi-Fi networks. What we've covered here should help you get the 802.11x side of things right, but there is still more to consider. For example, positioning your wireless access points and deciding when to use 20 MHz vs 40 MHz vs 80 MHz are important too.
Simply put: there's no single formula for the right Wi-Fi network design that will work for everyone. However, knowing your 802.11x standards can go a long way.