OpenWrt with Ethernet Backhaul

Installing and Using OpenWrt Network and Wireless Configuration
1

Hello all!

I'm VERY new to this, so go easy on me. I know i'm beating a dead horse with this: is there a way to get openwrt to be a controller for several AP's interconnected via ethernet (backhaul) around a home or building with roaming? it seems as though users 'get by' with having different channels or other various work-arounds to get a similar result.

My family's home has ethernet to every room and i have all the equipment in the basement. I want to have true roaming with ethernet 'backhaul' (as i guess it's called), I don't want to have multiple AP's spread around that are wirelessly linked to one-another..

Thanks!

2

There are a few different concepts that are coupled into this question, so I'll try to unpack them.

  • Ethernet/wired backhaul: this is actually the preferred physical topology, whenever possible, for working with multiple APs. OpenWrt can handle this easily, as can generally any standards based devices on the market, even many standard wireless routers (you just configure them as a dumb AP and connect LAN - LAN). The one exception is for some products that are sold as mesh devices -- some of those don't like be wired together or don't allow you to run in a true dumb AP mode (this happens when the product is designed for a really simple user experience with a mesh setup).

  • Mesh or wireless backhaul: Mesh uses a wireless backhaul, but often adds some additional smarts to optimize the experience. Wireless backhaul, in general, means that you are using a device effectively as a repeater and it requires no wiring (other than power). This is good when wires are not an option, but there can be performance penalties and it is never as good an experience as a wired backhaul. OpenWrt supports these technologies, too, but there are some nuances for setup.

  • Roaming: Client devices will roam from one AP to another based on wireless signal. This is actually a client side process. In general, the APs do not have direct control over the roaming decisions, although there are things that can be done such as force-disconnecting a client when the signal strength or signal to noise ratio hits some threshold. This is not the recommended approach, though -- the better approach is to select channels so there is no overlap (to the greatest extent possible) and reduce power levels such that there is minimal overlap in the physical coverage areas -- this encourages the client devices to roam to a closer AP.

  • Management: in general, you don't need a unified management interface to get multiple APs to work together in a network, especially when they are using a wired backhaul. The advantage of a management system is really for a "single-pane-of-glass' environment to configure and monitor the devices, but this is not necessary for a system to function seamlessly with client roaming and high performance. I personally use Ubiquiti Unifi for my network which is a fully managed environment (I'm using the stock firmware from UI). I haven't tried any similar packages on OpenWrt, but I did see something called DAWN that may fit the bill (never tried it, can't vouch for it at all) if you're looking for similar fleet management capabilities.To be clear, though, this is not strictly necessary, but it can be a nice thing to have to simplify the management of multiple devices.

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3

Well, thank you very much for such an explanation!

Currently, my home is set up as having two AP's, both with the same SSID/PW etc.. and whenever someone crosses on their phone from one area to the next, there's a hesitancy. I've heard people on important calls all of a sudden "hello?.. hello?... oh, ok.." and i'm looking to prevent that from happening.. where it all just seemlessly transfers from one AP to the other, like when we're using our phones outside.

i think a lotta people are trying for that, but not sure how to make it happen. I was considering using a raspberry pi with openWRT and trying to set that up as a controller, and then having 2-3 AP's with OpenWRT on them as well.
I thought OLSR was the way to go, but the more i dive into this, the more confusing it becomes.

Again, thank you for your time!

4

There is 802.11r (aka fast roaming) as an option to help improve the transitions, but not all devices support the protocol.

It is not uncommon for there to be a very brief interruption in things like video chats or phone calls when roaming between APs, but it should ideally be barely noticeable (not a multi second "hello? hello?" type situation). And for this to be the case, there is no need for a centralized controller -- just well tuned radio settings is all that is necessary (and a client that handles this smoothly -- a function of the radio hardware and the OS on those devices). For example, at my dad's house, I have setup 5 APs -- as he roams from one to the next during a FaceTime call, I might see a cutout for around a quarter of a second or so (maybe as much as a half second), but it is not disruptive.

Regarding wifi tuning, here is a video that is worth watching -- it is centered around Unifi, but the concepts apply equally across any wifi AP setup (provided you can control the channels and power levels).

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5

I've been reading through this conversation almost 2 years later.

There is one simple problem here apart from roaming: automatic rearrangement based on load balancing.

I have 4 Asus ZW XT8 on a wired backhaul. At first one could think that this is like having 4 random AP on WAP mode. But apart from seamless roaming, which more or less is the same as described in this post I find that the nodes automatically arrange the nodes not only based on the signal strenght but on the saturation of the node, like load balancers, probably because they support all 802.11 standards and some algorithms going inside these machines.

I've been digging more on this topic and there seem some centralized managers like the one provide by Ubiquiti with Unify also mentioned in the last post of @psherman and also from TP-Link something similar called Omada.

I don't think that OpenWRT or any WRT-like system can accomplish this because there is no Unified controller for devices, unless the routers are pretty well packed and use something like DAWN as suggested. Problem with DAWN is that this requires a ton of router capabilities (802.11 k, r and v) to be somewhat equivalent to a centralized controller like Unify or Omada.

I was thinking on building a very cheapo wired backhaul for a ton of devices connected all around the place without having to assigned each single device manually with a couple of budget routers (like those $20 on average, like TP-Link WR841N, but after some research, this is not going to be possible given that they lack of capabilities). So if one would have to aim for a bigger budget, and looking for this specific scenario, then Omada or Unify are the way to go (with an Unifiy controller or a Omada OC200 or something of the liking)

PS: I've watched the video from the Toast, and basically what he does is disabling all the options that make Unify great for for increasing a WAP compatibility. Basically the same as configuring each single node without Unify, manually, straight from CLI. No point on using Unify except for the comfort of being able to configure all nodes from a single interface. In the video, he removes Advanced options which are all those load balancing options that make Unify great to some extent.

Personally I see this from a home automated house, that may have like 100 devices with ease (for example I have just in light relay switches more than 50 units). This devices are constantly pinging the network, which saturate a lot of the nodes they sit in and I have to keep them on a individual WLAN (not only VLAN) because the nodes generally suffer a ton from them (this is why many people consider instead of moving through Wifi, going to other protocols like Zigbee to keep things away from users Wireless devices). So having some sort of load balancer here is pretty useful. Roaming and that is also useful if you are talking through Whatsapp or Telegram wifi connected but I find that load balancing is more clutch for wired backhaul mesh, something that WAP cannot handle by default.

6

The TL-WR841N only falls flat on its face because it's not meeting minimum system requirements for OpenWrt (4/32), the wireless hardware supports 802.11k/v/r and even 802.11w and WPA3 just fine (since h/w rev v1).

7

There is a revision, v13 that has 8/64 and it's currently supported on 22.03.3
Where have you found it supports 802.11w?