Media Convergence Servers provide highly available server platforms to host IP Communications applications. These platforms address enterprise customer requirements for Cisco CallManager installations from 2 to 30,000 IP phones within a single Cisco CallManager cluster as well as providing platforms for Cisco Conference Connection, Cisco Emergency Responder, Cisco IPCC Express (ICD), IP Interactive Voice Response (IP IVR), IP Phone Messenger, Cisco Personal Assistant, Cisco Queue Manager and Cisco Unity.