OpenBSD: Configure Network Interface As A Bridge / Network Switch

How do I setup bridge0?

Create a file called /etc/hostname.bridge0, enter:
# vi /etc/hostname.bridge0
Append the following interface names:

add vr0
add vr1
add vr2
add vr3
add rl0
up

Save and close the file. This is saying set up a bridge consisting of the five NICs, vr0, vr1, vr2, vr3, and rl0 and activate it. The order the cards are listed does not matters. Make sure each NICs is configured as per your requirements:
# cat /etc/hostname.vr0
Sample outputs:
up media autoselect
The rest of the config:
# cat /etc/hostname.vr1
up media autoselect

# cat /etc/hostname.vr2
up media autoselect

# cat /etc/hostname.vr3
up media autoselect

However, NIC rl0 has static IP address configuration as follows:
# vi /etc/hostname.rl0
Sample outputs:

inet 192.168.1.254 255.255.255.0 192.168.1.255

Save and close the file. Reboot the server to test new settings:
# reboot
Verify new switch settings:
# ifconfig bridge0
Sample outputs:

bridge0: flags=41<UP,RUNNING>
        groups: bridge
        priority 32768 hellotime 2 fwddelay 15 maxage 20 holdcnt 6 proto rstp
        designated: id 00:00:00:00:00:00 priority 0
        run0 flags=3<LEARNING,DISCOVER>
                port 8 ifpriority 0 ifcost 0
        vr3 flags=3<LEARNING,DISCOVER>
                port 4 ifpriority 0 ifcost 0
        vr2 flags=3<LEARNING,DISCOVER>
                port 3 ifpriority 0 ifcost 0
        vr1 flags=3<LEARNING,DISCOVER>
                port 2 ifpriority 0 ifcost 0
        vr0 flags=3<LEARNING,DISCOVER>
                port 1 ifpriority 0 ifcost 0
        rl0 flags=3<LEARNING,DISCOVER>
                port 5 ifpriority 0 ifcost 0
        Addresses (max cache: 100, timeout: 240):
                74:44:01:40:57:fb vr0 0 flags=0

To see rl0 config:
# ifconfig rl0

References:

• OpenBSD bridge FAQ
• man 4 bridge
• Debian / Ubuntu Linux setup a network switch bridge