On our most recent IoT Podcast, John called in with a Wi-Fi upgrade question. He currently has four wireless networks (regular and guests) on both 2.4 GHzand 5 GHz frequencies using a single router. He’s thinking about upgrading to a Wi-Fi mesh network. John wants to know if he’ll have to reconfigure his IoT devices if he goes with a mesh system.
Unfortunately, he may, at least on some of his connected devices. With multiple SSIDs, or network names, in his current setup, he can only reuse one of those with a Wi-Fi mesh network. And although he currently likes to keep some devices on separate 2.4 GHz and 5 GHz networks, he won’t be able to do that either.

This is because Wi-Fi mesh networks are designed for simplification. They combine the two WiFi frequencies into one contiguous network with a single name. So instead of having a separate 2.4 GHz and a separate 5 GHz network run from a single router, for example, mesh networks aggregate them.
For most people, this simplicity is a benefit, even though it can cause challenges when adding smart devices that only have a 2.4 GHz radio. The issue here is that John wants a little more customization, along with an easy transition for the devices he has.
Our recommendation is to find the current network that has the most IoT devices connected to it. Then, use its SSID and password when setting up the new mesh Wi-Fi. This way, those IoT devices will connect to the new network without any configuration changes required.

John can also set up a guest network on the mesh router using the same SSID and password as one of his current guest networks. Devices on that existing network will also connect without intervention.
The rest of them though? Typically, they’ll need to be manually updated with the SSID and password for the mesh network.
Another option that may help is finding a mesh Wi-Fi router that supports multiple networks, like John currently has, and follow a similar approach. Not every mesh router offers this option though. Google Nest WiFi doesn’t for example, nor do TP-Link routers.
Based on our research, it appears the latest Asus, Eero and Netgear Orbi routers support multiple networks, so we’d recommend looking at those for a situation like John’s.
If the mesh router does allow for multiple networks, the approach outlined above will help: Just set up the second network with the SSID and passwords of the old router for the remaining IoT devices.
To hear John’s question in full, as well as our discussion on the topic, tune in to the IoT Podcast below:
Some TP Link models do allow for adding a guest network, and some even allow for adding one 5.0 GHz guest network and one 2.4 GHz guest network, which gives you a total of three Different SSIDs. For example, the deco X20, a TPLink Wi-Fi 6 mesh router, allows this setup.
For many people, the 2.4 GHz network would be a good choice for IOT devices, allowing the 5.0 GHz network to be used as a guest network and the dual band regular network used for regular use cases like video streaming, gaming, and non IOT cloud services.
These days, quite a few residential mesh routers will offer a single guest network option even if they don’t have any other way of setting up VLANs.
If you need more than three networks total, obviously that doesn’t help, but if you’re just looking to isolate your 2.4 GHz IOT devices, it’s worth considering if you like the router’s other features.
Is L2 the right place to be sorting out IP connected devices? If you’ve got any battery powered devices, they’ll be on a different physical connection. For large scale IoT systems, I’ve tended to go with the the relevant IETF standards (Homenet), rather than technology focused approaches, but I can see that not many router manufacturers (or ISPs) are being very helpful, and consumers don’t really want to have to understand how to put LEDE on all of their routers even if it does mean continuous re-configuration of devices.
Of course, you’re only going to want to use IPv6 for this, or you’ll get into a real security mess.