The single-sign-on (SSO) feature allows end users to supply login credentials only once.
If you do not use the single-sign-on feature, end users must log in twice. They are first prompted to log in to View Connection Server and then are prompted log in to their remote desktop. If smart cards are also used, end users must sign in three times because users must also log in when the smart card reader prompts them for a PIN.
For remote desktops, this feature includes the Graphical Identification and Authentication (GINA) dynamic-link library for Windows XP and a credential provider dynamic-link library for Windows Vista, Windows 7, and Windows 8.