This counter tracks the number of Secure Sockets Layer (SSL) entries that are currently stored in the secure channel (Schannel) ...

This counter tracks the number of Secure Sockets Layer (SSL) entries that are currently stored in the secure channel (Schannel) session cache and that are currently in use.  The Schannel session cache stores information about successfully established sessions, such as SSL session IDs.  Clients can use this information to reconnect to a server without performaing a full SSL handshake.