OK, this may seem nuts, but I have my reasons. On my C9300, Gig0/0 is the mgmt-vrf interface; it has an IP address on a management network and can't be part of any other VLAN (if I understand it correctly). It acts almost as a separate host; if I patch it into a port on another switch that is configured as "switchport access vlan [mgmt-vlan for entire LAN]" it comes alive.
Now - that C9300 already has some interfaces that are in fact configured for that management VLAN, for devices like SAN management interface, or management of some other switches, or OOB interfaces on some servers. That VLAN is then on a trunk into core so I can get to any of those devices from other routed LANs. So - can I patch the C9300's OOB interface into one of those ports as well? Intuitively, it seems wrong to patch a switch into itself, but if it's just the management for that switch, it doesn't seem any different, logically, from patching some other switch into the C9300 and carrying the IP traffic over that trunk. If the OOB is segregated properly, wouldn't this work?
