Proper channel planning and assignment is one of the most crucial aspects of a functional wireless deployment. This encompasses planning configurations such as the channel width and available channels/channel selection within each band for devices to broadcast on for the 2.4-GHz, 5-GHz, and 6-GHz bands.

To try and mitigate as much wireless interference as possible, it’s necessary to ensure that each AP is broadcasting on a frequency and at a power that allows clients to communicate with the AP without producing interference for other nearby APs or clients. In many deployments, this is accomplished by manually configuring the TX power and 802.11 channels for each band on each AP to ensure that nearby APs are not using overlapping channels, or broadcasting at a power that will cause interference with other potentially nearby APs on the same channel if in a high-density deployment.

With the power of the Meraki Dashboard, you can simplify the planning and configuration even further by utilizing the Meraki Auto RF feature set. Before we explain that, however, we will briefly address some of the common configuration areas and provide a few general recommendations to follow when deploying a wireless network, as a refresher.

Frequency Bands

When you’re working with legacy clients that do not support newer 802.11 standards, we recommend to limit those clients to connecting to a dedicated legacy device’s SSID and the 2.4-GHz band, allowing newer and more capable devices to better utilize the 5-GHz band or even 6-GHz band.

When you’re working with SSIDs that are broadcasting across multiple frequency bands, such as both the 2.4- and 5-GHz bands, we recommend enabling band steering to try and steer clients toward connecting on the highest supported band when possible while still allowing devices to fall back to an alternate band if necessary.

If you’re configuring an SSID for the 6-GHz band, be aware that only clients that are capable of WPA3 and 6 GHz will be able to connect without also enabling the 5-GHz band.

Pro Tip

Enable the Capable Wi-Fi Standards column on the Network-wide > Clients page to check the wireless capability of previously connected clients.

Channel Width

The default value (and Meraki-recommended value) for channel width across spectrum bands is 20 MHz, which supports the largest selection of available channels to prevent channel overlap and provides the greatest flexibility for planning your deployment.

If your deployment is in a low-density environment, a wider channel width will allow for greater throughput for connected clients at the cost of fewer channels available per band to use for channel planning while preventing overlap, as well as potentially increased RF interference for each channel as a result of the wider channel width. For example, a channel width of 20 MHz allows for 28 non-overlapping 5 GHz channels, while a channel width of 80 MHz allows for only 7 non-overlapping channels and is more likely to see potential interference on any given channel due to the large frequency width of each channel.

Channel Selection: DFS Channels

In an effort to help provide additional airspace to prevent interference and channel overlap, the 5-GHz band includes several channels known as Dynamic Frequency Selection (DFS) channels. The specific frequencies used for these channels varies by country, but generally the frequencies are those reserved and prioritized for other use cases, such as military, weather, and aviation radar, as well as satellite communications.

Because these frequencies are generally reserved for non-802.11 use, there are several restrictions in place when being used for an 802.11 implementation. Primarily, these channels are available for use on the condition that the primary use of these frequencies (radar, etc.) is not impaired. As a result, when in use by an AP to broadcast an SSID, the AP must be constantly monitoring for non-802.11 use of that frequency and, if detected, must immediately stop broadcasting on that frequency and move to any other available frequency. As a result, any connected clients would be forced to roam immediately anytime a DFS event is detected, which can cause a noticeable interruption in client service.

Because of the nature of DFS channels, their feasibility for use is dependent on the specific deployment in question and the airspace surrounding that location. For example, a site in rural Kansas may be able to use multiple DFS channels without issue, but a site located next to a military base or airport would likely be unable to use DFS channels with any amount of consistency due to the likelihood of interfering transmissions taking priority in the surrounding airspace.

Fortunately, Meraki makes it easy to determine if DFS channels are feasible for each deployment by actively reporting in the Network-wide > Event Log whenever a DFS event is detected by an AP in the network, as shown in Figure 8-11. This, combined with properly configured network alerts, makes it easy to determine if the use of DFS channels is causing an impact on your deployment.

Figure 8-11 Network-wide > Event Log Filtered to Show Only Recent DFS Events

For deployments that should exclude the use of DFS channels, you can disable them by navigating to Wireless > Radio Settings > Edit Profile > Change Channels Used by AutoChannel > Deselect DFS Channels and deselecting the DFS channels in each RF profile. Figure 8-12 shows the 5-GHz channel selection list with several DFS channels enabled.

Figure 8-12 5-GHz Channel Availability Configuration with Non-Weather Radar DFS Channels Enabled