Dual-band SSID with optional client load balancing

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In this recipe, you will configure your FortiAP to broadcast the same SSID on both WiFi bands: 2.4GHz and 5GHz. This recipe also contains information about using client load balancing, if required.

This recipe requires using a FortiAP model with two radios. It also assumes that you have already configured a FortiAP in your network. For more information, see Setting up WiFi with a FortiAP (tunnel mode) or Setting up a WiFi bridge with a FortiAP (bridge mode).

1. Configuring the dual-band SSID

In this example, a FortiAP 221C is used to broadcast the dual-band SSID. For this model, Radio 1 broadcasts using the 2.4GHz band while Radio 2 uses the 5GHz band.

Go to WiFi & Switch Controller > FortiAP Profiles and create a FortiAP profile. Set Platform to the model of your FortiAP and set your Country/Region.

Under Radio 1, set SSIDs to Manual and select your SSID.

 
Under Radio 2, set SSIDs to Manual and select your SSID.
Go to WiFi & Switch Controller > Managed FortiAPs and right-click on the FortiAP. Select Assign Profile and set the FortiAP to use your new profile.
The FortiAP is now listed with both Radio 1 and Radio 2 broadcasting the same SSID.

2. Results

Connect to the SSID from various devices.

Go to WiFi & Switch Controller > Managed FortiAPs. Clients are shown connecting to the same SSID on both WiFi bands.

 
On the devices, you can also see that the same SSID is used on both bands (in this example, an Android device and Mac OS X computer are used).

 

 

3. (Optional) Adding client load balancing

In a dual-band SSID configuration, it is best to have as many clients as possible using the 5GHz band, leaving the 2.4GHz band for clients that do not support 5GHz. Because modern WiFi clients automatically choose the 5GHz band, client load balancing may not be necessary.

However, if you notice that most clients are using the 2.4GHz band, you can use the frequency hand-off method of client load balancing (also known as band-steering), which encourages clients to use the 5GHz band if possible.

It is also recommended to use FortiOS 5.6.2, which supports use of 802.11 k/v/r, which is also used by modern clients to select the appropriate AP and band.

Go to WiFi & Switch Controller > FortiAP Profiles and edit the FortiAP profile. Set Client Load Balancing to Frequency Handoff for both Radio 1 and Radio 2.

For further reading, check out Access point deployment in the FortiOS 5.6 Handbook.

Victoria Martin

Victoria Martin

Technical Writer & Head Cookbook Chef at Fortinet
Victoria Martin works in Ottawa as part of the FortiOS technical documentation team. She graduated with a Bachelor's degree from Mount Allison University, after which she attended Humber College's book publishing program, followed by the more practical technical writing program at Algonquin College. She does need glasses but also likes wearing them, since glasses make you look smarter.
Victoria Martin
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When client load balancing is used, a message to the client from the AP, which can cause the client to search mode find other SSIDs. Because of this, it may take longer for clients to connect to the WiFi network.