Cisco Unified Communications Manager Architecture

CUCM signals the calling party to initiate ringback, so the user at phone A will hear the ringback tone. CUCM also signals the call to the destination phone, which plays the ringdown tone. Additional information is provided to the phones to indicate the calling and called party name and number. (Phone A will show the destination device name and number, and phone B will show the calling party name and number.)

When the user at phone B accepts the call, CUCM sends a message to the devices letting them know the IPv4 socket (IPv4 address and port number) information in which they should communicate for the duration of the call. The RTP media path opens directly between the two phones.

The Cisco IP Phones require no further communication with CUCM until either phone invokes a feature, such as call transfer, call conferencing, or call termination.

CUCM Hardware, Software, and Clustering

CUCM Release 6.0 is a complete hardware and software solution that works as a network appliance. A network appliance is a closed system that supports only Cisco-authorized applications and utilities. Goals of the appliance model are to simplify the installation and upgrade of the system and to hide the underlying operating system. An appliance-based model makes it possible for an administrator to install, implement, and manage a CUCM server without requiring knowledge of or having access to the underlying operating system.

The CUCM appliance has these features: Cisco call manager

Complete hardware and software solution.

CUCM servers are preinstalled with all software that is required to operate, maintain, secure, and manage a server or cluster of servers (including Cisco Security Agent).

CUCM is also provided as a software-only product, which may be installed on supported Cisco Media Convergence Servers (MCS) or Cisco-approved third-party server platforms.

Appliance operating system provides ease of installation and upgrade, while also providing security and reliability.

You can upgrade CUCM servers while they continue to process calls.

System administration is performed via graphical user interface (GUI), command-line interface (CLI), and through documented APIs for third-party access.

Outputs a variety of management parameters via a published interface to provide information to approved management applications, such as NetIQ Vivinet Manager, HP OpenView, and Integrated Research PROGNOSIS.

Appliance operates with or without keyboard, mouse, and monitor (also known as headed or headless). Third-party access is allowed via documented APIs only.

CUCM supports clustering of servers for the purpose of redundancy and load sharing. Database redundancy is provided by sharing a common database across multiple servers. Call-processing redundancy is achieved through the Call Manager Group setting, in which multiple servers are assigned to a device for the purposes of providing fault tolerance.