@drinkingbird Thanks again. Ideally, I would like to do minimal tweaking (I'm not too good at these things). I note two things in your response:
1. "It is fine to have two routers in a row." - I was doing all this as my ISP
modem+router combo box can't be set in bridge mode - it will remain as a router. And I read you can't have 2 routers in a LAN - and you should setup one as AP. If it is fine to have two routers, as you say then I'm sorted.
But just to be sure I understand clearly, below (which is a default setup for XT8 I guess) will work then as per you?
ISP modem+router (
this will remain a router due to ISP restriction) <---- <wired> ---->
1st XT8 (as MESH router) <-- <wired> ---->
2nd XT8 (as MESH node/AP)
Have I understood correctly?
2. "If all you need is an AP, that box may be overkill/expensive though." - So I do not know. My limitation/requirement is (A) ISP modem+combo can't be setup in bridge - and (B) I need to provide seamless wifi (without changing SSID) across the whole house. For (B) I went for mesh and for (A) I thought of putting them in AP mode. Happy to go with another more practical suggestion.
Yes you've understood perfectly. The only time having two routers in a row like that can really be a problem is if you have game consoles that require UPNP (automatic port forwarding) to work. However in cases like that, most ISP routers let you put your own router into "DMZ mode" which solves that problem. There are other workarounds too if they don't support DMZ mode. Less and less these days relies on UPNP anyway. If you have nothing that requires inbound port forwarding (whether static or automatic) then just ignore that whole part, not a concern for you.
If you want easy mesh setup and management, then the two XT8s as you've outlined above will do just that. You can also use a less expensive Asus router as part of your aimesh system (as long as it is a model that supports Aimesh), but the XT8 actually doesn't look that expensive for what it is, and will give you a single model/firmware/GUI and keep things simple. Since you won't be using wireless backhaul, you'll have two separate 5ghz bands at your disposal on each node which you can set up with two different SSIDs to balance your traffic out and get more wireless bandwidth. Or just don't use the second one if that isn't something you need.
In reality, having the two routers lets you have better security, not knowing how good the firewall in your ISP router is (plus they have control over the firmware and can remotely access their router), having two layers of firewall, NAT, etc is a good thing. If there is a vulnerability in their router, likely it won't be in your router, and vice-versa.
So if you want the convenience of Aimesh, go for the dual XT8s running AiMesh. If you are ok with setting up and tweaking two individual APs, you can use whatever brands/models you want and set them up to be the same as a "mesh" it just requires more involvement and configuration on your part. For some, not using AIMesh gives them more flexibility, for others, the convenience is worth it. In your case it sounds like leaning toward convenience since you are new to this and probably don't want to get into tweaking everything separately on the two devices.
To put it simply - Aimesh = auto mesh. Two independent routers/aps = manual mesh. Either way, the wiring you have above works.
Obviously the "left" side of each XT8 in your flow above is the WAN port, and the right side is the LAN port. You can even hang a wired device off the 2nd XT8 LAN port if needed (a PC or whatever).
The statement "can't have two routers in a LAN" is too broad. There are certain ways you could wire them that it might cause problems, but what you have above is perfectly fine and done by probably tens or hundreds of thousands of people all the time due to having the same ISP limitations as you.
It would be nice if Asus or someone else would come out with a mesh mode that lets you run them all in AP mode rather than requiring one to be a router, but it really isn't a big deal, in fact may even be better like I said to have that second router.