@R1D2
Cheers and thank you for the reply, R1D2. I'm glad to be educated about the BSSID and ESSID difference. Because of that, I realized thread title is incorrect; it should be reworded "band steering based on RSSI / signal quality, instead of band steering based on load balancing number of clients per-band".
Some terminology overlap is perhaps expected between "band steering" and "Smart Connect" as each vendor plays up their marketing. To be more precise, I'm looking for signal-quality-based band steering versus load-balancing-based band steering (what Omada has today, according to the documentation). Smart Connect is technically the former.
Band steering as defined by the Omada documentation decides purely on "how many connected clients", which is not quite Smart Connect. Omada choose 2.4 GHz vs 5 GHz purely by the number of clients. "How many on 2.4 GHz? That's too many. Switch to 5 GHz if capable."
Smart Connect is a somewhat more complex system, i.e., noted by the "algorithm" term used by TP-Link, that also includes connection quality. The word "algorithm" is pure marketing. Broadcom goes into much more detail of how they implemented 2.4 GHz vs 5 GHz steering for their XStream architecture [link 1]:
The last element is software to assign 5 GHz clients to a radio based on the client's speed. The assignment algorithm takes not only client class into account, but actual link rate, which depends on signal strength and other factors. So XStream is smart enough, for example, to take a 2x2 AC867 class client with a low signal level and move it to the same radio as a 1x1 N150 device sitting close to the router. The Broadcom graphic below is goofy but illustrates the point simply.
Clients can be moved from radio to radio dynamically as link rates change. But router manufacturers will be able tune this feature as needed since changing radios requires devices to reassociate, i.e. break connection, which tends to make users unhappy.
The upshot of all this is that bandwidth use will be increased because fast clients won't have to wait for slow clients. And since MU-MIMO (or even 802.11ac) support isn't required, XStream can help improve Wi-Fi performance of any mix of 5 GHz clients.
2.4 / 5 GHz band steering is also part of XStream. But since its benefits are not as straightforward to calculate and require radios to drop and re-establish connection, implementation will be up to the end-product manufacturer. Finally, if you think you can do a better job of client assignment, product vendors may also elect to provide separate SSIDs for each 5 GHz radio and let you have at it.
You may see some of the implementations used by Ubiquiti, ASUS, and Synology below. Note difference between balancing the number of clients versus the quality of the client connection, as Synology shows. ASUS is simply too much user control, for what it's worth, but this article gives a brief overview of how to manage steering beyond simply totaling the number of clients [link 2]. Aruba also offers this type of band steering [link 3].
As an example: if my dual-band laptop is far away with more obstructions, it'll be steered towards 2.4 GHz. If I close my laptop, move to the same room as the router, and re-open my laptop (triggering another association), Smart Connect will automatically nudge my device towards the 5 GHz radio because the connection quality is sufficiently high enough (or so the wireless AP guesses).
This article explains more about the feature I meant to describe [link 4]
Some AP vendors offer multiple modes of band steering when it's explicitly enabled. While different vendors use different terminology, these modes generally can be categorized as follows:
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Force 5 GHz connections: With force 5 GHz, a dual-band client device will only be allowed to connect to the network on the 5 GHz band, and any requests to connect on the 2.4 GHz band will be ignored. This mode works quite well when the signal strength is good on the 5 GHz band, but will prove problematic if there are weak coverage areas on 5 GHz because the network will not allow the client device to “fall back” to the 2.4 GHz network.
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Prefer 5 GHz connections: This mode involves specifying a threshold received signal strength indicator (RSSI) such that so long as the client device has an RSSI value above the threshold, the access point will preferentially encourage the client device to connect on the 5 GHz band. When the 5 GHz RSSI dips below the threshold, the client device will be allowed on the 2.4 GHz band. The challenge here is selecting an appropriate RSSI threshold. Set the threshold too high, and devices that really should be connecting on the 5 GHz band are actually connecting at 2.4 GHz. Set the threshold too low, and devices may be getting relatively poor performance on the 5 GHz band when they would get better performance on the 2.4 GHz band.
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Load-balance connections: In environments with a high density of client devices, it may be advantageous to balance connections between the 2.4 GHz and 5 GHz bands. As an example, take a classroom with 30 student iPads. In a normal load-balancing scenario, all 30 devices would be connected on the 5 GHz radio, leaving the 2.4 GHz radio (and the band) idle. One would get better airtime utilization from the AP by purposely shifting some proportion of the clients to the 2.4 GHz band. Such a mode usually allows the specification of a load-balancing threshold and/or percentage of clients to allow on the 5 GHz band vs. the 2.4 GHz band.
Best practice: If there are tunable options for band steering available, then the safest option is to select prefer 5 GHz with a relatively low threshold, such as -80 dBm. This will make client devices connect normally on the 5 GHz band, but will allow them to connect on 2.4 GHz in areas where 5 GHz coverage is weak but 2.4 GHz coverage is still available.
Omada seems to only offer load-balanced band steering (the 3rd bullet). I'm curious about the client-signal-quality bandsteering (the 2nd bullet).
EDIT: unfortunately, I cannot post links externally.
Link 1
Search, with quotes "The last element is software to assign 5 GHz clients to a radio based on the client's speed."
Link 2
Search, with quotes "ASUS RT-AC3200 Smart Connect: The Missing Manual"
Link 3
Search, with quotes "In this band steering mode, the AP uses client load and RSSI information balance the clients across" Aruba
Link 4
Search, with quotes "4 WiFi Band Steering Myths"