CTI Manager and Related Failures

CTI Manager (Cluster Support)

The CTI Manager, along with the Cisco Unified TSP, provide an abstraction of the Cisco Unified
Communications Manager cluster that allows TAPI applications to access Cisco Unified Communications Manager resources and functionality without being aware of any specific Cisco Unified Communications Manager. The Cisco Unified Communications Manager cluster abstraction also enhance the failover capability of CTI Manager resources. A failover condition occurs when a node fails, a CTI Manager fails, or a TAPI application fails.

N.B: Cisco does not support CTI device monitoring or call control with 3rd-party devices.

Cisco Unified Communications Manager Failure

When a Cisco Unified Communications Manager node in a cluster fails, the CTI Manager recovers the affected CTI ports and route points by reopening these devices on another Cisco Unified Communications Manager node. When the failure is first detected, Cisco Unified TSP sends a PHONE_STATE (PHONESTATE_SUSPEND) message to the TAPI application. When the CTI port/route point is successfully reopened on another Cisco Unified Communications Manager, Cisco Unified TSP sends a phone PHONE_STATE (PHONESTATE_RESUME) message to the TAPI application. If no Cisco Unified Communications Manager is available, the CTI Manager waits until an appropriate Cisco Unified Communications Manager comes back in service and tries to open the device again. The lines on the affected device also go out of service and in service with the corresponding LINE_LINEDEVSTATE (LINEDEVSTATE_OUTOFSERVICE) and LINE_LINEDEVSTATE
(LINEDEVSTATE_INSERVICE) events Cisco Unified TSP sends to the TAPI application. If for some reason the device or lines cannot be opened, even when all Cisco Unified Communications Managers come back in service, the system closes the devices or lines, and Cisco Unified TSP will send PHONE_CLOSE or LINE_CLOSE messages to the TAPI application.

When a failed Cisco Unified Communications Manager node comes back in service, CTI Manager “re-homes” the affected CTI ports or route points to their original Cisco Unified Communications Manager. The graceful re-homing process ensures that the re-homing only starts when calls are no longer being processed or are active on the affected device. For this reason, the re-homing process may not finish for a long time, especially for route points, which can handle many simultaneous calls. When a Cisco Unified Communications Manager node fails, phones currently re-home to another node in the same cluster. If a TAPI application has a phone device opened and the phone goes through the re-homing process, CTI Manager automatically recovers that device, and Cisco Unified TSP sends a PHONE_STATE (PHONESTATE_SUSPEND) message to the TAPI application. When the phone successfully re-homes to another Cisco Unified Communications Manager node, Cisco Unified TSP sends a PHONE_STATE (PHONESTATE_RESUME) message to the TAPI application. The lines on the affected device also go out of service and in service, and Cisco Unified TSP sends LINE_LINEDEVSTATE (LINEDEVSTATE_OUTOFSERVICE) and LINE_LINEDEVSTATE (LINEDEVSTATE_INSERVICE) messages to the TAPI application.

Call Survivability
When a device or Cisco Unified Communications Manager failure occurs, no call survivability exists; however, media streams that are already connected between devices will survive. Calls in the process of being set up or modified (transfer, conference, redirect) simply get dropped.

CTI Manager Failure

When a primary CTI Manager fails, Cisco Unified TSP sends a PHONE_STATE (PHONESTATE_SUSPEND) message and a LINE_LINEDEVSTATE (LINEDEVSTATE_OUTOFSERVICE) message for every phone and line device that the application opened. Cisco Unified TSP then connects to a backup CTI Manager. When a connection to a backup CTI Manager is established and the device or line successfully reopens, the Cisco Unified TSP sends a PHONE_STATE (PHONESTATE_RESUME) or LINE_LINEDEVSTATE (LINEDEVSTATE_INSERVICE) message to the TAPI application. If the Cisco Unified TSP is unsuccessful in opening the device or line for a CTI port or route point, the Cisco Unified TSP closes the device or line by sending the appropriate PHONE_CLOSE or LINE_CLOSE message to the TAPI application. After Cisco Unified TSP is connected to the backup CTI Manager, Cisco Unified TSP will not reconnect to the primary CTI Manager until the connection is lost between Cisco Unified TSP and the backup CTI Manager.
If devices are added to or removed from the user while the CTI Manager is down, Cisco Unified TSP generates PHONE_CREATE/LINE_CREATE or PHONE_REMOVE/LINE_REMOVE events, respectively, when connection to a backup CTI Manager is established.

Cisco Unified TAPI Application Failure

When a Cisco TAPI application fails(the CTI Manager closes the provider), calls at CTI ports and route points that have not yet been terminated get redirected to the Call Forward On Failure (CFF) number that has been configured for them. The system routes new calls into CTI Ports and Route Points that are not opened by an application to their CFNA number.