CSTA Connector responds to Keep-Alive requests from the XSP link. CSTA Connector may not always receive timely notification when the XSP link stops functioning. In order for CSTA Connector to detect link failure and initialize alarm and recovery procedures, CSTA Connector usually needs to actively check the link's integrity. This is referred to as Keep-Alive or KPL functionality.
CSTA Connector sends BroadWorks KPL request on an established XSP link when the interval from the last message that is received from the XSP link is greater than the value specified by the kpl-interval configuration option. Setting the value of this option to 0 (zero) switches off any active KPL functionality.
For each KPL request, CSTA Connector expects to receive a BroadWorks keepaliveResponse message from the XSP link. The XSP link is considered as unresponsive when a number of missing KPL responses become greater than the value specified by the kpl-tolerance configuration option. Setting the value of the kpl-tolerance option to a value of 0 (zero) marks the link as unresponsive after a single KPL response goes missing.
CSTA Connector then closes the unresponsive link and tries to re-establish it by using the timeout value specified by the link-recovery-tout configuration option.