Design And Implementation Of IPPBX CTI Middleware Based On SIP And CSTA Protocol

The programmable interface(CTI middleware)integrated in the programcontrolled switch enables developers to realize the enterprise customization requirements without having to implement the basic functions and interfaces of the underlying equipment,and can quickly and conveniently realize the enterprise’s customized communication business requirements.The CTI middleware of traditional program-controlled exchanges mainly communicates through circuit switching.In order to solve the need of IP network program-controlled exchanges(IPPBX)to communicate through IP network messages,it is necessary to implement a CTI middleware based on the IP network communication protocol.This thesis takes IPPBX as the specific research object,designs and implements a CTI middleware based on computer-supported telecommunications application(CSTA)protocol and session initiation protocol(SIP)to meet the requirements of SIP communication server and other SIP application servers in the IP network.CTI middleware communication.The main work of this paper is as follows:1)Detailed design of CTI middleware.In order to realize application program association and control IPPBX telephone,realize CSTA transmission in IP network,design CSTA message through SIP transmission mechanism and support CSTA XML protocol;In order to enhance the robustness and compatibility of CSTA conversation,design conversation refresh and response error category Description and reason;In order to realize the controllable content of the IPPBX by the application,design services and events.2)The realization of CTI middleware.On the CSTA server side,a message queue is implemented between the transport layer and the session layer,which can better transmit CSTA XML codec messages;realize session management and event distribution,and speed up the session layer’s processing of CSTA services and events requested by the client Response;realize CSTA services and events,so that the application(client)can control the call of the device or obtain related events;realize the CSTA interface,so that the application(client)can control and observe the IPPBX through the CSTA interface.3)Test of interface and CSTA docking application.Interface testing includes testing of CSTA service and event interfaces and testing of CSTA transport layer and session layer interfaces to verify the corresponding functions of the function interface;CSTA docking application testing to verify the functionality and performance of the CSTA server and client docking.The verification shows that the IPPBX CTI middleware based on SIP and CSTA protocol in this paper can meet the requirements of using CSTA protocol in IP network to realize the docking,control and management of applications and IPPBX phones.Related methods have been applied to IP network program-controlled switches,which basically meet the expectations of market applications,and have achieved better application effects.