How do i stop a device in networkmanager on redhat?

[amurleopard]

Show the status of devices.

$ nmcli device status
DEVICE      TYPE      STATE      CONNECTION 
virbr0      bridge    connected  virbr0     
eth0        ethernet  connected  eth0       
vnet0       tun       connected  vnet0      
lo          loopback  unmanaged  --         
virbr0-nic  tun       unmanaged  --         

I want to disconnect device vnet0, and ensure it does not get started in anyway. See quote from redhat documentation below.

It is recommended to use nmcli dev disconnect iface-name rather than nmcli con down id id-string because disconnection places the interface into a “manual” mode, in which no automatic connection will be started until the user tells NetworkManager to start a connection or until an external event like a carrier change, hibernate, or sleep, occurs.

$ sudo nmcli dev disconnect vnet0
Device 'vnet0' successfully disconnected.

Check the device status again. It has changed to unmanaged.

$ nmcli device status
DEVICE      TYPE      STATE      CONNECTION 
virbr0      bridge    connected  virbr0     
eth0        ethernet  connected  eth0       
lo          loopback  unmanaged  --         
virbr0-nic  tun       unmanaged  --         
vnet0       tun       unmanaged  --