Clarification of "authentication"

["Jim Sermersheim" <jimse@novell.com>]

I'm not sure why the word "authentication" is in the following sentence from section 4.2.2 of RFC 2251. Does it mean that you could supply a simple password, but it's somehow associated with authentication secrets that have been negotiated securely at a lower layer, thus rendering the transmission of the cleartext password useless to others?

"Note that the use of cleartext passwords is not recommended over open networks when there is no authentication or encryption being performed by a lower layer; see the "Security Considerations" section."