/mcpCTI Manager (Cluster Support) The CTI Manager, along with the Cisco Unified TSP, provide an abstraction of the Unified Communications Manager cluster that allows TAPI applications to access Unified Communications Manager resources and functionality without being aware of any specific Unified Communications Manager. The Unified Communications Manager cluster abstraction also enhances the failover capability of CTI Manager resources. A failover condition occurs when a node fails, a CTI Manager fails, or a TAPI application fails, as illustrated in the following figure. Cisco does not support CTI device monitoring or call control with 3rd-party devices. Note Figure 2: Cluster Support Architecture Cisco Unified Communications Manager Failure When a 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 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 Unified Communications Manager, Cisco Unified TSP sends a phone PHONE_STATE (PHONESTATE_RESUME) message to the TAPI application. If no Unified Communications Manager is available, the CTI Manager waits until an appropriate 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 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 Unified Communications Manager node comes back in service, CTI Manager “re-homes” the affected CTI ports or route points to their original 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 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 Cisco Unified TAPI Developers Guide for Cisco Unified Communications Manager, Release 15 and SUs 15 Overview CTI Manager (Cluster Support)