With the advent of wireless products with even bigger "numbers on the box", it’s time to update our classification system. But first, let’s recap what this whole "class" thing is about.
In a rare attempt to reduce consumer confusion, wireless networking product makers have adopted a relatively uniform method of naming products to reflect the technology inside. The industry generally uses NXXX and ACXXXX nomenclature, i.e. N300, N900, AC1750. This is not "official" nomenclature supported by either the IEEE or Wi-Fi Alliance. So, for lack of a better term, we call this wireless “class”.
Manufacturers don’t always use the same class numbers for 802.11ac (AC class) products, terms are generally uniformly applied for N products.
Table 1 shows the base numbers used to come up with the current "N" and "AC" class designations. The numbers shown are the maximum link (connection) rates each product type can support. Link rates are not the actual throughput your wireless connection will produce. They are more an indication of the technology used in the product and only good as a relative performance indicator. Think of the link rates like number of cylinders in a car and you’ll have the right idea.
|Number of Spatial Streams||802.11n/ac
20 MHz mode
40 MHz mode
80 MHz mode
Table 1: Stream / Channel width / Maximum Link Rate summary (Mbps)
- "Spatial streams" is a term that comes from the MIMO (Multiple Input Multiple Output) technology at the heart of 802.11n and 802.11ac products. It refers to the number of data channels (streams) that can be simultaneously sent or received. The number of streams generally correlates to the number of transmitters / receivers used in the product.
We often describe products with number pairs, i.e. "3×3", "2×2", etc. The first number refers to the number of transmitters; the second, receivers. Most designs use the same number of transmitters and receivers
- The channel number under the mode listing in each column refers to the number of 20 MHz wide Wi-Fi channels used in the mode. 802.11ac uses 80 MHz wide channels to achieve its significantly higher throughput. This means that the eight commonly available 5 GHz band channels available in the U.S. (36, 40, 44, 48, 149, 153, 157, 161) are reduced to two in 802.11ac.
- The numbers in Table 1 have been rounded in many cases from the numbers found in the MCS table found at the end of this article.
AC routers have both 2.4 and 5 GHz radios that support simultaneous operation in both bands. So AC class is simply the sum of the maximum link rates for each band’s radio, typically generously rounded up in some way to an even number for marketing purposes. N600 and N900 routers also support simultaneous dual-band operation and are similarly classed.
N750 routers support 450 Mbps on one band and 300 Mbps on the other. But there is no easy way of knowing from the "N750" number which band supports the higher link rate unless the manufacturer provides that information. (You can also try looking up the product on Wikidevi.)
Client / Bridge Class
Devices on the other end of a router’s wireless connection, i.e. wireless clients or bridges, usually have one radio. AC client radios are always dual-band. N devices might be dual-band, but that is not guaranteed. Nevertheless, manufacturers use the same class designations on wireless adapters and bridges as they do with routers. Note, however, that client devices operate in only one band at a time and the maximum link rate achieved will be that of the band the devices is connected on.
Table shows our Class system for all wireless device types.
|"Class" designation||2.4 GHz N Radio
Maximum Link Rate (Mbps)
|5 GHz AC Radio
Maximum Link Rate (Mbps)
Table 2: Wi-Fi Device classification table – routers / APs and clients
- For routers and access points, classes from N600 up indicate products capable of simultaneous dual-band operation.
- For routers and access points, classes from N450 down indicate products capable of single-band operation.
- Wireless clients are capable of single-band operation only. So, for example, an AC1200 client can connect at a maximum 300 Mbps link rate in 2.4 GHz or 867 Mbps in 5 GHz, but never both simultaneously
- Wireless bridges, repeaters and extenders follow Rule 3 unless they explicitly specify simultaneous dual-band operation
- AC3200 class routers have two 5 GHz radios, each supporting 1300 Mbps maximum link rate
- 600 Mbps and 800 Mbps link rates in 2.4 GHz require both router and client device to support 256-QAM modulation. Clients supporting 256-QAM are rare.
- 1000 Mbps link rates in 2.4 GHz and 2165 Mbps in 5 GHz require both router and client device to support 1024-QAM modulation. 1024-QAM is supported only on Broadcom’s new 4×4 chipset that is scheduled to start shipping in routers in mid-2015. No 1024-QAM clients have been announced. Only one manufacturer (D-Link) has announced 1024-QAM based products.
- Some manufacturers use AC2400 vs. AC2350.
- G54 (802.11g) has been added because we use it when referring to some "legacy" products.
Here’s the MCS table for your reference.