Hi,

you can't close a Lightstreamer session at the moment a client disconnects.
A Lightstreamer session expires after a timeout after the client disconnection.
This is done so that sessions does not expire because of a delay on the network during polls or bind requests.
After such timeout the notifySessionClose method is called on your MetadataProvider

Note that you can edit the timeout after which a session is considered closed editing the <session_timeout_millis> element in the Lightstreamer configuration file (LS_HOME/conf/lightstreamer_conf.xml)

Btw I don't understand what do you mean with "I am not able to go further", Lightstreamer itself does not pose any limit on the number of sessions opened by a user, so if your user logs out and then logs in again you can open a new session on Lightstreamer without waiting for the previous session to expire.

HTH