@MedMez 

Hey

Honestly, 100 is a LOT of devices to run over a M5 deco.  You could start to upgrade to the X range as these support a lot more devices (150 on the x68 for example) and that might help

However if you have that many devices you really should be considering either cabling between the Deco nodes to reduce the air traffic and using "Access Point Mode"      or   upgrading to the X range for more capacity

The X range is likely the best option, start to upgrade the most busy nodes to WiFi 6.   Usually these are the closest to the router  (Main and first Hop)

Personally, if I was in your scenario and the budget was possible...  I would be looking for an Omada network installed with wired APs around the house.  It would handle the client volume you have much better.   

You really are at the limits of "home grade" use with that many devices.  Deco X range is likely the cheapest option for you to start

  @Philbert 

Thank you for your feedback. Here is attached the exact setup I have. The dash links are actually wired links.

If I follow you right, cheapest option would be to change main deco to X range ? And any other busy deco node? But what do you mean by busy as the other nodes handle max 15 devices per unit... I believe most traffic goes through the main deco?

  @MedMez 

If you don't mind me interjecting in your conversation.

It might be possible that your Main Deco runs out of IP addresses. This could happen if you have large number of moblie devices with MAC address randomization enabled, coming to your premises and leaving them, or moving inside your house and jumping between Deco nodes. I don't think Deco would allow to reduce DHCP Lease time, to release idle IP addresses faster, so instead I would suggest to expand IP range to see if that helps.

See How to change LAN IP address of Deco. In Step 3 don't change IP address, but choose the following subnet mask: 255.255.0.0

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Another recommendation you've already got is to replace Main Deco by more powerful Deco model. Before doing that, I would suggest checking if your Main Deco is running hot, because if it is not - the problem might be somewhere else. 

Login to Main Deco web interface using its IP address, should be http://192.168.68.1 in your case. Scroll down to the bottom of the web page and you should see it reporting CPU Load and Memory Usage, in real time. Example:

Wait few moments till it settles down, because usually right after login these numbers spike high. After some time, when numbers (hopefully) got down and are steady, does CPU run hot? What does Memory Usage show?

  @Alexandre. 

Dear Alexandre, 

Thank you for your feedback.... I don't have many clients entering/leaving the house, just occupants that change from node to node when rooming through the house (max 5persons).

Most devices are Shelly devices which are at fixed places...

I checked the main deco and yes it is really hot (please check attachments)....

In my config do you think that changing the main deco might dolce the problem?

I didn't try yet changing the subnet to 255.255.0.0

Thanks !

  @MedMez 

Hey

Something jumps at me about this picture that, you mentiond that the dotted lines are cable connections.   Are you running the Deco in Access Point Mode?     The fact you have a Main Deco makes me think you are not.

If not then its likely those cables are not being used, instead the deco is defaulting to a wifi backhaul.   Deco will only use the LAN to connect the nodes when in Access Point mode

Also in your last post you listed all the deco nodes, some of your hops are 4 deep, really hops should be kept a small as possible as each time you hop it adds overhead to the upstream deco.  

  @Philbert 

Hi

I am running the decos in router mode and they are all connected to main deco via Ethernet. App confirms it too apparently.

The deco are too distant from each other, if Ethernet wasn't the used link, signal would be poor I believe...

  @Alexandre. 

Not sure how that helps but there seem to be congestion on channel 6... Could that be the problem ?

I apparently can't change channel allocation on M5s

  @MedMez 

I don't think you should be worrying about this. You have WiFi mesh, overlapping signal from Deco nodes is expected. Without it, mobile device can't seamlessly roam between nodes. 

You can force Deco mesh to rescan enviroment and look for better WiFi channel by forcing "Reboot All" in Deco app. Touch Internet globe on main screen of Deco app, then three dots in right upper corner and menu will appear with Reboot All in it. 

There is no guarantee reboot will force Deco mesh to choose the different channel, but you can try.

Back to your original issue. I do support what @Philbert suggested, let me put it for you in more itemized way. You have three options, exactly as he said, here they are from easiest to hardest:

1. Replace Main Deco with more powerful Deco node.

Challenge: that might still not be enough to handle all your devices.

2. Get (almost) enterprise grade wired router which will handle networking heavy lifting, switch Deco mesh to Access Point mode and it'll only provide WiFi coverage.

With proper router this should work, but challenge is to figure what is the proper router and for you to configure it and manage it. Heavy duty routers are Network Admin heaven, but for a regular user managing them might be overwhelming.

3. Replace Deco mesh by different WiFi mesh brand (one that @Philbert suggested).

I am not an expert in that brand, but I know it means redoing your wireless network and throwing away large number of Deco nodes. Better keep it as a last resort.

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So, try first option and if it does not work, come back and we will discuss next. 

Because first option may or may not work, I would recommend buying Deco unit from place with return policy. If new Deco unit performance is still not enough, you'll just return it.

I would suggest Deco X90, if you can find retailer selling single unit. X90 is top of the line Deco, and TP-Link used to sell them as single units, but for some reason I could only find nearby a 2-unit set. You don't need 2-unit X90 set. https://www.tp-link.com/us/deco-mesh-wifi/product-family/deco-x90/

If you can't get single Deco X90, buy Deco X60: https://www.tp-link.com/us/deco-mesh-wifi/product-family/deco-x60/

Add that Deco unit to your Deco mesh as regular Satellite Deco, then promote it to Main Network. See Changing the Main Unit for your Mesh Network

You can check CPU load and Memory utilization on your new Main Deco using same steps as you did for M5. That'll tell you if your new Main Deco handles load well.

  @Alexandre. 

Ok thank you very much for all your help all.

1/ I will try that this week.

2/ I can't change the provider router... He doesn't allow that.

3/ yes Philbert suggested to go for Unify but this brand is not sold where I live. The only option I have is go for Omada system with wifi controller. 

Apparently it can handle more clients .... But then the constraint will always be the provider router...

  @MedMez 

I thought you have provider Modem and forced to use Main Deco as a router. 

If you have provider router, there is another option you can try, before buying Deco node. Just in case that provider router is more capable than Deco M5 in handling network traffic. Also, provider router may be able to give you more info on your home network and you could even get Tech Support from your provider to tune your router to support 100 wired clients (they are wired as far as router concerned).

The option: change Deco mesh to run in Access Point mode, and make sure network traffic does not pass through Main Deco, goes to router directly. 

First step will be to change Deco mesh to run in Access Point mode: How to set up Deco to work in Access Point mode

After successful change, next step would be to eliminate Main Deco from the switch to router link, making your network layout into the following:

You can connect your Main Deco to either switch Ethernet port if Main Deco is closer to the switch, or to provider router Ethernet port if Main Deco is closer to the router. The point here is second Ethernet port of Main Deco stays not connected to anything.

This will tunnel all Internet traffic to your provider router through the switch, and not through single Deco M5.