Linking up two networks on two physicallly neighbour routers

• Subnet on router A: 192.168.50.0/24
• Subnet on router B: 192.168.55.0/24
• On both routers, eth0 (WAN port) are connected to modem (ISP). eth1 (LAN 1) are connecting to each another.
• Clients on each router are accessing to their own WAN (ISP).
• Router A clients can access router B clients and vice versa.

On router A

• Go to "Network" > "Interfaces". Select "Devices" tab.

• Click "Configure" on br-lan.

• On bridge ports, uncheck the port you are going to use to connect to router B. "Save" > "Save & Apply".
• Go to "Interfaces" tab. Click "Add new interface". Give a name. Choose "Static address", and select the device you have just unchecked on the previous step. Click "Create interface".

• Specify a IP address. Make sure the IP address is not on the DHCP pool of router B. Leave all other field untouched.

• Select "Firewall Settings" tab. Choose "lan".

• Click "Save" > "Save & Apply".
• Go to "Network" > "Routing". On the "Static IPv4 Router" page, click "Add".

• Follow the configuration above. Click "Save" > "Save & Apply".

On router B

• Go to "Network" > "Routing". On the "Static IPv4 Router" page, click "Add".

• Follow the configuration above. Click "Save" > "Save & Apply".