Hello
Is there a guide for hardware requirements for decent Mesh support in terms of the bandwidth as well as to explain how it actually works? ( I suppose I can Google the latter part)
I own a Linksys MR8300 and while my router supports Mesh (802.11s), I would like to understand how it would practically work if I were to buy an OpenWrt-with-Mesh supporting AP and whether it would be worth it.
For example, would the same radio be used for mesh and SSID on 5GHz or 2.4GHz? does that mean that if the router supports 800Mb throughput that that would be halved since the bandwidth would be used to serve the wifi connected devices as well as the connection between the two APs?
I would like to learn about the practicalities of this and what one would need to take into account so that I can decide whether to replace all the hardware or buy a dumb AP.
Ideally my preferred design would be for 2-3 dumb APs that don't necessarily have to support OpenWrt as long as they can be used just as APs to connect to OpenWrt. I was thinking of something from Mercusys or any Wifi 6 supporting system with one of them physically connected to my Openwrt router. They manage the Wifi side of things and OpenWrt does the FW, DHCP, DNS and all the goodies that OpenWrt supports. I could even replace my MR8300 with RPi 4 if that ends up being better.
For proper Mesh support you need a triple band device with two 5Ghz radios + one 2.4GHz radio. In this case one 5Ghz radio is dedicated for wireless backhaul traffic, while the other 5Ghz radio provides the connection to your devices (together with the 2.4GHz radio)
See this post for an overview of triple band devices.
Regarding other questions like practicalities or what has to be taken into account, I don't have the answer (I don't own such devices myself)
Your setup isn't "improper" per se, but mesh is meant to be used with a secondary radio as a back-haul is because it can leave the primary radio solely to deal with client devices. Letting a single radio do both of those tasks means you'll have suboptimal performance as the radio switches between not only handling client traffic, but also the traffic to the upstream device. Additionally, a secondary radio can operate on a different channel with your client devices, so it can multitask and simultaneously handle both upstream and downstream connection without interference.
It's not that you can't do mesh with a single radio, but simply that there's hardware designed to do it more effectively.
Mesh is not "meant" to be used with a secondary radio at all.
Mesh requires a virtual interface specifically configured in mesh mode and this is used as an 802.11s multipoint to multipoint link.
This can be a virtual interface sharing a physical radio with other virtual interfaces or it can be the only virtual interface on a physical radio.
It all depends on what level of performance is required in a particular case.
A shared 2.4GHz radio can be perfectly adequate.
At the other extreme, there are (expensive) multi-radio outdoor routers designed specifically for building mesh infrastructure with the very best performance.
There are also many variations for everything in between.
It is better not to make sweeping statements on a topic, about which you admit to having no knowledge.
With regards to the wifi channels and frequencies, how do the routers deal with the secondary SSID with the same name? i.e "My-WifiNetwork" on the main router and "My-WifiNetwork" on the Mesh AP?
I guess I'm trying to understand how the Mesh AP is different from a Wifi Extender if the Wifi Extender were given the same name as the main SSID?
There is also the channels, is the point to use the same 2.4GHz channel 4, for example? Even if using a different channel, doesn't that cause "interference"?
You can use different channels only on different radios that is if only 1 radio is available it will use the same channel to receive and to "repeat" and yes it definetely affect performance ( and could call this interfernce)
Thanks for that.
I'm struggling to understand the benefits of Mesh technology in that case?!
How is it different from a fancy extender?
I am not being sarcastic intentionally, I am really struggling to understand the difference especially since there is an actual standard for this (802.11s).
I once connected two wifi APs via OpenWrt by simply "Joining" the other one from the remote AP and it worked.
I thought Mesh would overcome issues such as interference etc.
To my mind, unless the remote AP is connected via an ethernet cable and is out of the range of the main AP then you will potentially end up with a worse experience and throughput because they could interfere with each other especially if you're meshing via wifi because the remote AP would need to be within the range of the main AP for the backhaul link!
Is the above correct or am I getting something wrong? Is it all a hype and marketing by companies wanting to sell more hardware!?
If you are connecting just two APs then this, in terms of traffic, is pretty much the same as an 802.11s mesh.
A mesh though, uses a virtual interface on the wireless radio (mesh mode) and can autonomously build a multi-point to multi-point network of MANY mesh nodes using the mesh 802.11s built in mac-routing protocols.
Simply speaking, to add another mesh node you just give it the same mesh id and mesh key and it will search for others in its "mesh" family and join in completely transparently.
Beware though, some manufacturers market "Mesh" as a proprietary range extender technology with "roaming" of user devices from one to another. Usually these are incompatible with other manufacturer's similarly marketed products.
These products have nothing to do with 802.11s mesh and cause great confusion to those who are not aware of the bad marketing being used.
If I'm not utterly mistaken then all "extender" solutions need to hear the "main AP". So your possible range is limited.
A mesh can be build with nearly every physical topology you can think of if at least 2 neighbor mesh nodes see each other. Like you have 2 buildings: each building has 2 mesh nodes on the roof and within the build like 12 mesh nodes each. Or what ever you like. Or take a huge warehouse as an other example.
This is the power of a mesh network. A mesh can have multiple possible paths between nodes and the underlying protocol works out the best path to use and self heals if a node in a path fails.
This is a good way to think of it, but it is not strictly true, a downstream extender only needs to see an upstream AP (or a previously connected extender).
So it is possible to manually construct a "daisy chain" of extenders, but obviously this is not particularly scaleable.
Good to know. My mentors just told me to avoid it and don't touch it and just use adhoc networks and later 802.11s and it did not failed me yet. It also feels somehow more sane to divide these functions. Having a backbone network and having an access network "on top"...
