Third-party call control in VoIP networks for call center applications

We discuss the problem of building third-party call control in a VoIP network based on ITU-T Recommendation H.323. We consider a specific case that could be used in the call center environment. We suggest and advocate a solution with H.323 gatekeepers connected to the CTI server via a special protocol. The CTI server contains all the logic for service execution while a gatekeeper implements only elementary switching functions. Some features of the protocol are considered.