Cisco Cisco Computer Telephony Integration Option 8.5 Technical References

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CTI Server Message Reference Guide (Protocol Version 17) for Cisco Unified Contact Center Enterprise
Release 10.0(1)
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CTI Client Application Guidelines
This chapter discusses some considerations to keep in mind when you are writing CTI client applications 
that will make use of CTI Server data. Topics discussed in this chapter include:
Invoke IDs
Heartbeat messages
ACD-specific considerations
Message masks
Message order
Symbolic constants definition file
TCP/IP connections
Data element alignment
InvokeIDs
The CTI protocol provides an integer InvokeID field in each request message. This field is always 
returned in the corresponding response message. You can set the Invoke ID to a unique value for each 
request you sent to the server. This allows you to have multiple requests outstanding and to correctly 
determine which request’s response has been received. For example, you can implement a simple counter 
that is incremented with each request.
Heartbeat Messages
The Heartbeat Interval designates the time in seconds between sending heartbeat messages to the CTI 
Server. A Heartbeat Interval of -1 disables heartbeats. The default setting for application developers is 
-1. You must determine the appropriate heartbeat interval for a production environment -- it depends on 
the application and the environment. It should represent a reasonable balance between the speed of 
failure detection and the network bandwidth consumed by heartbeat messages and their corresponding 
confirmations. In cases where there are very few CTI clients, such as a CTI Bridge, the minimum 
heartbeat interval of 5 seconds should suffice. Workstation (desktop) clients should use a much larger 
heartbeat interval (at least 90 seconds), since these clients typically number into the hundreds and