Clarification : Implicit server authentication

[Dan Davidson <dan.davidson%commatch.com@localhost>]

Hi,

	Apologies for the following, maybe trivial, question, however I
would appreciate
some help in understanding the following point in the SSH Transport
Protocol.

The draft mentions:
	"Server authentication in the key exchange MAY be implicit"

What is do the authors mean by "implicit server authentication" ?
How does this reflect on the behavior of the server and the client ?

Thanks for the help and best regards,
Dan