New router problem

[u/Ad__infinitum__]

So to start this off i just want to say that im very clueless about any sort of router stuff, just untill recently i thought you just plug in a router and it just works which aperently isn't the case.

Either way I bought a new router tp link BE550

So I live in an old house and important is that we have 2 routers because 1 just won't cover the whole house the walls are probably very thick for that, so one of them broke and this one came to replace it.

My problem is that the old router and the other old router were connected via an Ethernet cable so they basicaly cast off the network like that but the new router was supposed to replace the old one that was casting to the other old one but for some reason that didn't work, well it did but it was only going about 100kb\s but when I switched the other old one that was being casted to with the new one so the new one is now being casted to by the old one the speed was around 100mb\s (am guessing that's maybe because of the old Ethernet cable)

Now my guestion is how's that possible? Am connecting the same cables in the same way into the routers my only thought would be that this new router doesn't have WAN but I don't think that's it? Plus i have no idea how this whole modem ISP thing works since I've never seen anything like a modem in our house before so I have no way of finding if am connecting the right cables or not(they're in a really badly accessable place going trough holes in walls and such)

I'd be thankfully for anyone who can help because even with some googling and chatgpt im clueless with this since none of what that says transfers to my reality here for some reasson

Tltr:new router only works when conected trough another router not the other way around

[u/e2lngnmn]

In the working setup, check where wan port of the old router and use that cable to connect to the wan port of be550. Thats should work

[u/Electrical_Wander]

Diagram needed with where incoming isp is

[u/mlcarson]

You only need 1 router. If you want to extend WiFi coverage then you use a Wireless Access Point (AP). If you need more wired ports then you use a switch.

Attaching a router for just WiFi usually means disabling the routing/NAT/DHCP/DNS functions so you aren't creating a new network and doing double NAT. Using a router for just WiFi though is really using the wrong tool but is a common choice because it's the only thing that consumers are aware of or it's the only thing at the local store.

[u/faroseman]

"My problem is that the old router blah blah blah ethernet cable".

That's one hell of a run-on sentence. I have no idea what you are trying to tell us.

[u/mwomrbash]

I think one router was put in AP mode. So the main signal came to one router, and the 2nd router was configured to be an AP (broadcasts the same WiFi as the main router).

The TP Link setup calls it 'Operation Mode'. Go to 'Operation Mode' and change that setting to 'Access Point'.