Cisco Cisco Computer Telephony Integration Option 9.0 Developer's Guide

The CTI Server may respond to a HEARTBEAT_REQ message with a FAILURE_CONF. This indicates 
to the CTI client that the CTI Server is off-line, and the CTI client should reset the TCP connection.

The CTI client may initiate the graceful termination of a communication session by sending a 
CLOSE_REQ message. The CTI Server responds with a CLOSE_CONF message. Upon receipt of the 
CLOSE_CONF message, the CTI client can reset the TCP connection. The CTI client should wait up to 
5 seconds for the CLOSE_CONF message before resetting the connection.

The CTI Server may indicate to the CTI client that it no longer wishes to communicate by sending an 
unsolicited FAILURE_EVENT message with the Status field set to E_CTI_CTI_SERVER_OFFLINE. 
Upon receipt of this message, the CTI client should close the session.

For information on the FAILURE_EVENT message, see 

The CLOSE_REQ message includes a status code that indicates the reason for closing the session. You 
can set the status code to one of the following: 

E_CTI_NO_ERROR if the CTI client initiated the request that the session be terminated 

E_CTI_CTI_SERVER_OFFLINE if the CTI Server is no longer online

E_CTI_TIMEOUT if the CTI Server does not respond to a request message within the time-out 
period.

 depicts the session termination message flow. The CLOSE_REQ and CLOSE_CONF 

messages are defined in 

 and 

CTI Client

CTI Server  

CLOSE_REQ

CLOSE_CONF