Although UniFi has not yet publicly released its first Wi-Fi 6 compatible access point, the production is ramping up. This is the forth Wi-Fi 6 model showing up in FCC in the last couple months. Two are already purchasable through early access store, and the third has recently been on the early access store (by accident) with coming soon tag. This time the AP is successor of Flex HD, named U6-Mesh.
UniFi 6 MeshThe U6-Mesh is a four-stream Wi-Fi 6 access point that deliversup to 2.7 Gbps aggregate radio rate with 5 GHz (MU-MIMO andOFDMA) and 2.4 GHz (MIMO) radios. It can be placed on adesktop or mounted on a pole, wall, or ceiling*. The modern yetdiscreet design allows placement near users for optimalperformance. The U6-Mesh shares its form factor with the UAP-FlexHD, so U6-Mesh can use FlexHD mounting accessories.* Ceiling mount sold separately.
https://fccid.io/SWX-U6MESH/Users-Manual/Product-Information-4776397
Its spec is no surprise. This is essentially what we expect from Wi-Fi 6 dual band access point. In fact, this is just different form factor from the already revealed U6-LR or U6-IW.
What is interesting; however, is how Ubiquiti advertising this product. They are calling this AP, U6-Mesh rather than U6-Flex. So their intent is such that people will use this as a mesh node.
Let’s compare it to the both Flex HD and UniFi Mesh Access Point.
As with other models, it looks like U6-Mesh is still staying with Wi-Fi 5 standard for its 2.4 GHz band. UBNT is proposing this to be used as Mesh, so how does it compare to existing mesh? Well, WiFi-6’s true performance gain, especially immediately noticeable one, is indeed relates to wireless backhaul link. This has been proven by other consumer mesh system.
Wi-Fi 6 as Mesh link
Good example is Asus Ax-92U pair. It has two 5GHz band with one being WiFi 6 capable but other is Wave 2 Wi-Fi 5. When used in wireless mesh mode, the link between mesh nodes use Wi-Fi 6 5 GHz band as a dedicated link. This is so that mesh link won’t be a bottleneck.
No more gigabit ethernet?
With 2402 Mbps throughput, can U6-Mesh replace full gigabit ethernet cable? The answer is absolutely “No”. The most Wi-Fi 6 client to AP connection uses 2×2 MIMO, which has peak PHY link speed of 1201 Mbps. Due to 50% Wi-Fi inefficiency, the practical throughput peaks around 600 Mbps (practical test). For more detail of this concept, you can refer to Wi-Fi College article series here.
However, you may ask with mesh link it is now 4×4 MIMO so that’s twice the 2×2. With 2400 Mbps PHY even with 50% inefficiency, the connection should still be over 1 Gbps, right?
The issue with this assumption is that you need dedicated backhaul/wireless uplink. Since UniFi does not use dedicated backhaul for mesh link, when clients will share the 5 GHz band with mesh link. For instance, when 2×2 client connects to mesh node, the backhaul link is left with 2×2 for mesh link rather than 4×4.
So I expect the peak, practical link speed is around 600 Mbps. If UBNT can pull off more efficient system, it may go up to 700-800 Mbps range, but definitely it won’t reach 1 Gbps i.e. ethernet link speed. This has not even counted the fact Wi-Fi connection is half duplex i.e. transmission and receive must take a turn, so actual time it takes to transfer whole data may be twice that of full duplex ethernet link.
Having said this, don’t be disappointed. This is still far better than current UniFi Mesh AP. The real challenge ethernet cable will face is when Wi-Fi 6E comes out. With 6 GHz band opening up for Wi-Fi, it is expected that those Wi-Fi 6E compatible units will be tri-band (2.4 GHz, 5 GHz, and 6 GHz). So it is highly likely either 6G or 5G will be used as a dedicated wireless backhaul. At which time, we will see over 1 Gbps.