Setting the DLDP authentication-mode

The authentication mode determines the type of authentication that DLDP uses. By default, no authentication is used. Hewlett Packard Enterprise recommends keeping the authentication mode the same between link partners or it will fail and log errors.

To set the DLDP authentication mode, use the following command:
```
dldp authentication-mode none|md5|simple
```
To reset the DLDP authentication mode to the default value (no authentication), use the following command:
```
no dldp authentication-mode
```

This is equivalent to specifying none when setting the authentication mode.

Authentication modes:

none: Do not perform DLDP authentication (default).
md5: Authenticate using MD5.
simple: Authenticate using a plain text password.