mutually stacked trunk(4)s

[Vladimir Kirillov]

Hello t...@!

I was playing with trunk(4) and discovered that trunks can be mutually
stacked, i.e.
# ifconfig trunk0 trunkport trunk1
# ifconfig trunk1 trunkport turnk0

trunk0: flags=8943<UP,BROADCAST,RUNNING,PROMISC,SIMPLEX,MULTICAST> mtu 1500
        lladdr 00:bd:ab:43:15:02
        priority: 0
        trunk: trunkproto roundrobin trunkdev trunk1
                trunkport trunk1 stack,active
                trunkport em0 master
        groups: trunk
        media: Ethernet autoselect
        status: active
        inet 192.168.111.1 netmask 0xffffff00 broadcast 192.168.111.255
trunk1: flags=8943<UP,BROADCAST,RUNNING,PROMISC,SIMPLEX,MULTICAST> mtu 1500
        lladdr 00:0d:60:cb:54:f7
        priority: 0
        trunk: trunkproto roundrobin trunkdev trunk0
                trunkport trunk0 master,stack,active
        groups: trunk
        media: Ethernet autoselect



Does it really have any practical use? Or is it just a nop feature, or
what?..