Suitability of Ubiquiti Amplifi HD Mesh WiFi

I'm considering buying the Ubiquiti Amplifi HD mesh kit (router plus 2 mesh units) to improve WiFi coverage of my home and would appreciate any comments on whether this is likely to be a good solution for my particular use case.

I live in a bungalow with a VDSL connection, a pfSense router/firewall and most of the computing and network gear in a study at one end of the house. A WiFi AP located here doesn't provide a useable signal at the far end of the house and I don't really want to use an Ethernet cable to connect to the far end. Over the years, I've used a WiFi extender at the mid-point but this had poor reliability and performance. I've also tried using a separate AP at the far end, linked to the LAN in the study via powerline adaptors. I've experimented with the secondary AP having the same SSID as the main WiFi AP and with it having a different SSID. None of these configurations have been entirely satisfactory: when there are two APs with the same SSID, portable devices tend not to switch to the stronger signal; when there are two APs with different SSIDs, it's a nuisance having to reconfigure devices when they move around.

So (sorry that description is rather long), I'm considering a mesh system and quite like Ubiquiti gear. The Amplifi HD user guide illustrates a multi-hop configuration with the main AP at one end, a mesh unit at the midpoint and another mesh unit at the far end. This seems like a good match for my needs but the documentation doesn't explain how it works. My concern is that so-called mesh systems that rely on the central unit communicating directly with each outlying unit in a star configuration is unlikely to work in my particular case.

Can anyone confirm that with the Amplifi system, the middle mesh unit acts as a relay between the two ends? If so, and providing that performance is adequate and that mobile devices switch automatically to the nearest unit, this seems like it could be the solution that I need. Any comments are most welcome.

Use the same SSID throughout where devices are attaching to the same underlying network (the intended purpose of having the same SSID and what this means to the client).

But turn down the 2.4GHz radios by some amount relative to the 5GHz
- initially by 6dBm but can be experiment to taste (at most 10dBm).

If you use different SSIDs you will end up stuck on a weaker signal if that SSID is higher in your preferred networks list, or the one most recently connected to (as you have experienced).

If your 2.4GHz signal is on full power after something joins that band it may just stay there.
You want the client to switch to 5GHz when closer to an AP by virtue of the difference in received signal and back to 2.4GHz when further away, as well as a more decisive offset between signals from neighbouring APs.

The roaming decision between APs is ultimately made by algorithms on the client, though the AP can assist in terms of handover if both AP and client support it e.g. 802.11r.

How long is the bungalow on the longest axis and how many dividing walls between study and the far end where connectivity becomes poor? And are all your devices capable of 5GHz operation?

A wired LAN connection to the primary AP in the middle point would probably work better technically but you have already said that doesn't suit your case. Have you considered running a cable externally if an internal cable route is not practical?

You could use either the Amplifi or the Unifi models.
Does the bungalow have loft space such that APs could be ceiling mounted (suiting the UniFi models)?

The UniFi APs are best managed by a software controller running on a server or virtual machine, which can be on-site or on an external VPS, and can manage single or multiple sites, but for small deployments an app can be used, or the controller run on a temporary basis during setup and changes.

Channel planning can wait until you have kit in hand, but for 2 or 3 APs you will be able to have non-overlapping channels unless your neighbours are nearby (current trend has vendors pre-configure stupid-wide 80MHz and 160Mhz channels to justify numberwang marketing).

Edited by prlzx (Sat 20-Jun-20 01:55:15)

If you decide to go along the Ubiquiti Amplifi route, which I have, I suggest you do not buy the HD mesh kit (router plus 2 mesh units). The components are "tied" to each other & can't be reconfigured.

I would suggest that you buy a couple of routers, and see how you get on, you can add a third router if necessary.

You should also consider linking the routers with CAT6E cable, if possible.

I suggest you should read the Amplifi forums & reviews which will assist you.

Good luck

NJSS

Post deleted by ashdown

Thanks for the pointer to the Amplifi forum. There's a lot of useful information there.

Edited by ashdown (Sat 20-Jun-20 13:17:22)

Thanks for the advice.

To answer some of the questions: the long axis of the bungalow is about 25 metres with 5 walls between the main AP in the study and the bedrooms at the far end, where the main AP is detectable but provides intermittent and very slow connectivity. All my devices are 5 GHz-capable. When I had two APs with the same SSID, I did experiment with reducing the output power of the bedroom AP but to little effect - this may be worth trying again. The problem with 2 APs using the same SSID on the same underlying network is that most devices seem very reluctant to switch APs, even when connected to one that's very weak.

I'm hoping that a mesh system will somehow force devices to roam on to the strongest signal but I'm very vague about the technical detail of how this works. I'm fairly capable about networking generally, just not with WiFi. Perhaps I neeed to read some of the formal standards.

I'm well aware that wired APs would be best and that a single AP at the midpoint may well suffice but I'm trying to avoid drilling holes in walls. Similar concerns apply to ceiling-mounting.

I think I need to better understand how mesh systems work. Manufacturers' information seems heavy on marketing guff and light on technical detail.

In reply to a post by ashdown:

Can anyone confirm that with the Amplifi system, the middle mesh unit acts as a relay between the two ends? If so, and providing that performance is adequate and that mobile devices switch automatically to the nearest unit, this seems like it could be the solution that I need. Any comments are most welcome.

Yes, it does.

Also the mesh nodes can talk to each other so any unit can act as a relay for the other i.e

Node <> Master <> Node

or

Node <> Node <> Master

If you added another node, it would do the same too..

Node <> Node <> Master <> Node or Node <> Node <> Node <> Master

The main master unit also gives out wifi for clients.

I tried multiple mesh products but this one worked best for me. Until recently I had the kit but recently changed to the Unifi kit instead but still using this in a mesh setup and not technically different (re wifi) to how the Amplifi stuff works.

Matt

Edited by uno (Sat 20-Jun-20 14:06:21)

OK so without any obstructions, 25m is well within range of an access point, even more so for a centrally placed one if never more than 15m away.

Sounds more likely to do with materials in dividing walls, such as a thicker supporting wall and/or the properties of some insulation materials.
Kitchens and bathrooms may also have more metal in their construction (e.g. water tanks, boilers) or appliances.

Depending on layout 2 access points ought to be sufficient spaced 8-10m apart - if you can take advantage of a connecting hallway or other circulation space to reduce the number of walls between most devices and their nearest AP. Unfortunately the study isn't the best place for the first AP if it is at one end of the property.

In home setups aesthetics takes precedence over technology compared with office spaces, understandably so.

It's also why I mentioned loft spaces and ceiling mounting as that would enable you to have hidden cabling between study network and APs, and to use the disc APs with a flattened doughnut pattern which probably suits a bungalow layout not needing much vertical propagation.

If you have an Android smartphone or tablet you can install one of the many free Wi-Fi visual apps (UniFi has one) and walk from room to room to see where the biggest drops in signal occur. Similar programs also available for laptops - you don't need to pay for a commercial survey tool either.

(Even though devices can detect an AP and hold a connection at the bottom end of sensitivity say -90 to -96dBm)
If your received signal drops below -70dBm it's becoming marginal - things like email, social media and background apps will still update but streaming, TVs, audio/video chat and other real-time services are more likely to notice it.

For 802.11ac and faster, -60dBm or better throughout is preferred.

On a networking point as you already have a very capable pfSense router, you don't necessarily need more routers, only access points, which just take care of attaching Wi-Fi devices to the underlying wired network rather than other responsibilities such as DHCP, DNS, routing, firewalling, NAT and Internet, likely all handled on the pfSense box.

Edited by prlzx (Sat 20-Jun-20 16:18:24)

It's good to know that a linear arrangement of APs should work.

A couple of interesting points noted from reading the Amplifi forums:

As mentioned earlier, the kit of router and two mesh points are hardware-locked, which means that an out-of-warranty failure of the router means that the mesh points become useless. The kit has little price advantage over buying the unlocked components separarately, so it's probably worth avoiding the kit.

It seems that the router can be configured as a mesh point and costs only a little more while having a useful display and higher processing capacity. So an option is to use several routers instead of a router with mesh points.

I'm still a little unsure about handover. I understand from further reading that the client is always in charge of deciding which AP to use when several are available and can't be told by a mesh system which to use. All the mesh system can do is force a client to disconnect. Am I correct in thinking that the Amplifi system monitors the signal strength from each client to all the APs and forces a disconnection when it decides that a client would be better connecting to another of the APs and that, in the event of disconnection, the client then autmatically reconnects to the strongest mesh AP?

In reply to a post by ashdown:

I'm still a little unsure about handover. I understand from further reading that the client is always in charge of deciding which AP to use when several are available and can't be told by a mesh system which to use. All the mesh system can do is force a client to disconnect. Am I correct in thinking that the Amplifi system monitors the signal strength from each client to all the APs and forces a disconnection when it decides that a client would be better connecting to another of the APs and that, in the event of disconnection, the client then autmatically reconnects to the strongest mesh AP?

I don't believe so. It is down to the client but it does support fast migration between points.

On the more "enterprise" Unifi kit, you can specify a minimum acceptable signal level (https://ibb.co/vVh3kmm) that a client can have before being booted but this still causes a notable disconnect if the client does not reconnect quick enough.

I recently changed to the Unifi kit as I wanted to have something to integrate a VPN with that was native instead of needing connecting to each time. I went down the UDM Pro route with three FlexHD points in a mesh configuration. The UDM Pro may be extreme for your use but you could check out the UDM (Unifi Dream Machine) which unlike the Pro has wifi built in so you'd only need two FlexHDs to mimic the setup of the Amplifi.

Matt

Edited by uno (Sat 20-Jun-20 16:20:19)