Below from my notes :
Both dot1x and MAB are methods of authentication for a port, whereas authentication open provides no authentication for a port, it allows all traffic through if a host is authenticated successfully or not.
It is used when setting up dot1x configurations in monitor mode. You could have both dot1x/MAB authentication and authentication open to log authentication details but allow a user access even if they fail authentication.
The authentication order commands only specify which method of authentication to try first between mab, dot1x and webauth. If you are looking at a dot1x setup the authentication order commands don't provide authentication, it would be the mab and dot1x pae authenticator interface commands.
