Mesh setup - subnet issue?

[#1]

Hi. I have recently invested in a mesh setup to improve the Wifi coverage around my home - happens to be a set of Tp-Link Deco S4s, but I suspect that won't matter.

Initial setup was simple enough (I have disabled the DHCP server on the Plusnet router, so the mesh is running in 'Router' mode), and I now have (almost) everything working through the mesh.  I have a couple of devices which need ethernet connection rather than WiFi, which are physically close to the Plusnet router (my main Deco unit is remote and connected via a long ethernet cable).  However if I simply plug these devices in to the spare sockets on the Plusnet unit, they are not picked up by the Deco network and so are not assigned IP addresses - despite the cabling apparently joining them.

With my (very!) limited knowledge, I suspect this is a subnet issue.  My Plusnet router has IP address 192.168.1.254 and subnet mask of 255.255.255.0, while the main Deco unit has LAN IP of 162.168.68.1 and subnet mask of 255.255.255.0.  

What do I need to tweak to allow these devices access to my Deco-controlled network?

[#2 · Accepted solution]

@GarethTH 

What do I need to tweak to allow these devices access to my Deco-controlled network?

I'm not sure you can in your current configuration. I'm assuming that the WAN configuration on the DECO is set to static IP and is in the 192.168.1.x subnet with a gateway of 192.168.1.254 ( the PN router ). There's no way that anything plugged in to the PN router will be able to get to the DEc subnet (192.168.68.x ). 

In order for anything plugged in to the PN hub directly to access the internet , it will either need a static IP in the 192.168.1.x subnet and gateway of 192.168.1.254 or DHCP will need to be enabled on the PN hub.

Is there a good reason why you aren't operating the DECo in AP mode with the DHCP server enabled on the PN Hub, its much simpler ?

[#3]

Thanks for your answer, @MisterW .

The Deco defaulted to 'Router' mode rather than Access Point, and seemed to indicate (to a novice like me) that there were disadvantages to switching.

It sounds like I need to swap the Deco over to Access Point mode; presumably I'll need to switch to using the PlusNet router as DHCP server rather than Deco.  Is this right?

I was previously using old routers from other ISPs for this task, but found that the coverage around the house was disappointing, which is why I invested in the mesh system.

[#4]

presumably I'll need to switch to using the PlusNet router as DHCP server rather than Deco.  Is this right?

@GarethTH that's correct.

[#5]

Thanks for your swift help @MisterW .  I'll wait for my wife to take a break from work (can't imagine it would be a seamless swap over!) and give it a go.

[#6]

All up and running now, with the Deco mesh system acting as simple Access Points, and control of the network returned to the Plusnet router.  Thanks for your help, @MisterW !

[#7]

No problem, thanks for the update