BroadWorks does not detect call desynchronization and does not distribute an unsolicited CallSubscriptionEvent event, if the call originates from an agent or the new call signal alerts the agent. CSTA Connector can force BroadWorks to distribute a CallSubscriptionEvent event at any time by sending an UpdateSubscriptionRequest request to BroadWorks.
The main purpose of the UpdateSubscriptionRequest request is to renew the call event subscription for agents. CSTA Connector issues this request before the subscription expiration to receive further call state updates for agents. CSTA Connector renews the event subscription only once every 30 (+10/-0) minutes. This time is counted starting from the last UpdateSubscriptionRequest for a specific agent.
CSTA Connector handles CallSubscriptionEvent events associated with the UpdateSubscriptionRequest request in the same way as an unsolicited CallSubscriptionEvent event. CSTA Connector clients (T-Servers) are informed by using CSTA Event Connection Cleared message, if necessary.
A CSTA Connector client may request call synchronization by issuing a CSTA Snapshot Device request. CSTA Connector processes it as an UpdateSubscriptionRequest request. The call information received in the associated CallSubscriptionEvent event is reported back to the client-requestor in the CSTA Snapshot Device response. If any unsynchronized calls are discovered then the other CSTA Connector clients are informed using a CSTA Event Connection Cleared message.
This functionality is implemented in T-Server for CSTA Connector. T-Server for CSTA Connector uses the CSTA Snapshot Device request to validate calls on the agent where the call party remains in the Alerted or Originated state for longer than average. T-Server for CSTA Connector calculates the average time between the Dialing (or Ringing) and the Established event for specific agent and requests call synchronization, if this time is exceeded.
Note: Call information in CallSubscriptionEvent events reflect the current call configuration in the BroadWorks system. For AS Failover scenarios, BroadWorks does not guarantee the full synchronization with an agent end-point. There is a possibility that the BroadWorks and CSTA Connector are synchronized and report that the agent is free, but actually, the agent is still in the same conversation that was established before the AS Failover.