40MHz and 80MHz Control Channels

[jx12345]

I'm confused by how Meraki specifies the control channel frequency for 40 and 80MHz channels. The web UI and the API only allow selection of 20MHz-width 5GHz channels, and then the wider channel that overlaps that 20MHz channel is used if the operating width is greater than 20MHz. However, it seems like this causes confusion for some clients.

Consider the band from 5650–5730MHz for example. My understanding is that the "channel" should be set to 138 for this 80MHz channel. But that's not possible with the Meraki settings. I instead have to set it to 132 or 136 or 140 or 144. When I do that, I have clients that are only connecting at 20 or 40MHz width, and not connecting at 80MHz (even with the Meraki channel width forced to 80MHz in the UI or via the API).

This page is a good reference: https://en.wikipedia.org/wiki/List_of_WLAN_channels#5_GHz_(802.11a/h/j/n/ac/ax)

Does meraki designate channels other than the center frequency as the control channels for each 40MHz/80MHz channel? If so, do you have those listed somewhere? Can you shed any light on why it is designed this way, and if there is some way to force using the center frequency as the broadcasted channel number (which is the "right" way to do it according to this: https://support.metageek.com/hc/en-us/articles/203532644-802-11ac-Channels).

[alemabrahao]

@jx12345  It's an IEEE Standard:

IEEE 802.11 is part of the IEEE 802 set of local area network (LAN) technical standards, and specifies the set of media access control (MAC) and physical layer (PHY) protocols for implementing wireless local area network (WLAN) computer communication. The standard and amendments provide the basis for wireless network products using the Wi-Fi brand and are the world's most widely used wireless computer networking standards. IEEE 802.11 is used in most home and office networks to allow laptops, printers, smartphones, and other devices to communicate with each other and access the Internet without connecting wires.

The standards are created and maintained by the Institute of Electrical and Electronics Engineers (IEEE) LAN/MAN Standards Committee (IEEE 802). The base version of the standard was released in 1997 and has had subsequent amendments. While each amendment is officially revoked when it is incorporated in the latest version of the standard, the corporate world tends to market to the revisions because they concisely denote the capabilities of their products. As a result, in the marketplace, each revision tends to become its own standard.

IEEE 802.11 uses various frequencies including, but not limited to, 2.4 GHz, 5 GHz, 6 GHz, and 60 GHz frequency bands. Although IEEE 802.11 specifications list channels that might be used, the radio frequency spectrum availability allowed varies significantly by regulatory domain.

The protocols are typically used in conjunction with IEEE 802.2, and are designed to interwork seamlessly with Ethernet, and are very often used to carry Internet Protocol traffic.

Check this article:

https://www.cbtnuggets.com/blog/certifications/cisco/when-to-use-20mhz-vs-40mhz-vs-80mhz

[Ryan_Miles]

Meraki shows wifi channels like any other vendor. A 40MHz, 80MHz, and 160MHz wide channel is still referenced by the a primary channel in the set. The "center" frequency isn't a channel you can specify in Meraki or any AP.

Using 40 and 80MHz width channels I've never seen less capable clients have an issue associating. Are your clients all 80Mhz capable? Many clients only support 20 or 40 still.

[GIdenJoe]

@Ryan_MilesI think he is referring to the auto channel selection in RF profiles.  There if you go to the row of 40 MHz and 80 MHz channels they number them differently.  Like this it is impossible to know which channel will be used as primary and which as secondary.

[Ryan_Miles]

Why would it matter though? If for example an AP is set to ch 36 width 80 clients capable of 20, 40, 0or 80 MHz will connect on whatever they support.

[jx12345]

Ok, I think I understand a bit better now. I pick the "primary" 20MHz channel, and then if I've selected to transmit at 40 or 80MHz channel widths, then the equivalent 40MHz or 80MHz band that contains that primary channel will be used if one exists for the given regulatory domain. The client still identifies the primary channel number as its 20MHz channel, but should report its center frequency based on the center frequency of the full width.

But here's a follow-up question. I'm looking at one of my APs that is in Germany, under a CE regulatory domain. On the RF profile configuration page for autoChannel, I see the following options:

But then on the Radio Settings page, if I want to manually choose a channel, it looks like this:

Why is 144 listed as an available channel in the first selection, but not the second? I'm guessing that the first screen is a superset, and the second screen is specific to this MR33, and it doesn't support this channel because it is older and because Channel 144 was only added somewhat more recently? Can you confirm if that is correct, and if newer APs can operate on channel 144, and if so, which APs have that capability?

My initial reason for this line of questioning was that I expected to able to set this AP to channel 132, and the Channel Width to 80MHz. Instead, it only establishes a 40MHz-wide connection when I configure that way. I assume this is happening because the Meraki access point is saying that Channel 144 is not permitted for use, and thus the 80MHz channel there is not available.

Also, why are channels 149-161 not being allowed in an EU deployment? My understanding (admittedly may be wrong) is that is for short Range devices and would be allowed as long as the transmit power is less than some limit. Even if this particular AP doesn't support that range, why would they not show as permitted options for this RF profile in the first screenshot? They do show up as available on my APs in an American deployment. If this is also a limitation of this particular AP, can you tell me what newer models may support this range in Germany?

Thanks!

[cmr]

@jx12345 in the UK we have been allowed to use UNI3 channels for years and when I asked why we cannot use them in Meraki I was told that they were waiting for the EU to approve them.  Now that has happened I believe the devices need to be recertified with the new channels which does take some time, hopefully not too long...

[jx12345]

Does Meraki have any sort of documentation that shows which APs currently have the hardware/certs to support which Wi-Fi channels (agnostic of region - I understand that will result in a subset of the hardware capabilities based on where I put the AP).