SessionId the session identifier 

There are some reserved SessionId's that serve a special purpose. The following table lists the reserved SessionId's: 

Console Sessions The system console session is usually identified as session 0 in the Session list when you connect to a terminal server. A console session is defined as the session you connect to at the physical console of the remote computer, as though you were logging on locally instead of remotely. You can send a message to the console session, but you cannot perform any of the other administrative actions on it. In Windows XP, Microsoft Windows Server 2003, and earlier versions of the Windows operating system, all services run in the same session as the first user who logs on to the console. This session is called Session 0. Running services and user applications together in Session 0 poses a security risk because services run at elevated privilege and therefore are targets for malicious agents who are looking for a way to elevate their own privilege level. The Vista operating system mitigates this security risk by isolating services in Session 0 and making Session 0 noninteractive. In Windows Vista, only system processes and services run in Session 0. The first user logs on to Session 1, and subsequent users log on to subsequent sessions. This means that services never run in the same session as users’ applications and are therefore protected from attacks that originate in application code. 

Listener Sessions Listener sessions are different from regular sessions. These sessions listen for and accept new Remote Desktop Protocol (RDP) client connections, thereby creating new sessions for the client requests. If you have configured more than one connection in Terminal Services Configuration, several listener sessions are available. You have the option to reset a listener session. However, this is not recommended, because doing so resets all sessions that use the same Terminal Services connection. Resetting a user's session without warning can result in loss of data at the client. 

Idle sessions To optimize the performance of a terminal server, idle sessions are initialized by the server before client connections are made. These sessions are available to clients for connection. Two idle sessions are created by default. User sessions can also be in idle state. 

TJwWTSSession Properties