Is a LAN to LAN with different subnet configuration secure?

I plan to implement the following network configuration :

Internet [(cable A)]

Router A (192.168.0.x)[(WAN:cable A)(LAN1:cable B)(LAN2:)(LAN3:)(LAN4:)]

Router B (192.168.1.x)[(WAN:)(LAN1:cable B)(LAN2:)(LAN3:)(LAN4:)]

The first LAN port of router A is connected into the first LAN port of router B, but both routers are in a different subnet.

Usually, when I setup two routers together, I do a double NAT configuraton (LAN to WAN) or a LAN to LAN in the same subnet.

I know the following facts: In a double NAT configuration such as this one,

Internet [(cable A)]

Router A (192.168.0.x)[(WAN:cable A)(LAN1:cable B)(LAN2:)(LAN3:)(LAN4:)]

Router B (192.168.1.x)[(WAN:cable B)(LAN1:)(LAN2:)(LAN3:)(LAN4:)]

Hosts from router B can communicate with hosts from router A. Hosts from router A can’t communicate with hosts from router B.

In a LAN to LAN in the same subnet configuration, any hosts can communicate to any. It’s the same subnet.


In the network configuration I plan to implement, LAN to LAN but in a different subnet, I noticed that hosts from both network can’t be reached. Is this a secure way to isolate networks, at least better than double NAT ?

The connected router B gets an IP address in the router A subnet (192.168.0.x).

Also, I did not have to define any static routes to get internet access, I have difficulties to understand how this is possible since router A gateway does not ping.