In order to connect and battle, the host will need to open the necessary ports.
It is possible to play on the same network with FBS.
A single network with two routers can cause network connectivity issues.
"If there are two or more IP addresses starting with 192.168 you have two routers.
If this is the case, set the second router to bridge mode."
Search keyword ： Double router forwarding
Check the model of router, and search how to open it's ports.
Search keyword: Router + Model + Open Port
"While hosting a room in this way, check your current port status.
Using a port check tool, input the desired port and make sure the port is properly opened.
That done, tell your opponent your IP address and opened port number to play.
Search keyword : Port Check Online