Cisco UC Operating System

CUCM Cluster

Clustering allows the network to scale to several thousands of endpoints, provides redundancy in case of network or server failure, and provides a central point of administration. Figure 1-5 displays a Publisher database synchronizing database components to all the other servers in the cluster. The servers running the CCM.exe process are performing call processing, and the other servers are taking on special roles described in later chapters of this book. CUCM clustering creates scalability by segregating processes to other machines, which increases performance.

CUCM Cluster

Device settings are stored in the IBM IDS database. The database is the repository for service parameters, features, device configurations, and dial plan configurations.

The database replicates nearly all configuration information in a hub-and-spoke topology (one publisher, many subscribers). CUCM nodes also use a second communication method to replicate runtime data using a mesh topology. (Every node updates every other node.) A mesh topology of information sharing provides dynamic registration and active call information that changes much more frequently than database changes. Real-time mesh replication is used to communicate newly registered phones, gateways, and digital signal processor (DSP) resources, guaranteeing optimum call routing.

Cisco 7800 Series Media Convergence Servers

Although it is possible for CUCM to run on most computers, Cisco supports CUCM running only on Cisco-approved hardware that they will support. The minimum hardware requirements for CUCM Release 6.0 are as follows:

2-GHz processor

2 GB RAM

72-GB hard disk

Minimum requirements for CUCM 6 are the same as for Cisco Unified CallManager Version 5, but only specific MCS models are approved.

The 7800 series servers are available in the –H or –I variants. –H stands for Hewlett-Packard, and –I stands for IBM server platforms. The 7825 server is a 19-inch or 23-inch rack-mountable server that provides a single SATA hard drive and one power supply. The 7835 server improves reliability and performance by including hot-swappable SCSI hard drives, hardware RAID 1 disc duplexing, and redundant power supplies. The 7845 improves reliability and performance by providing a second CPU and a backup fan assembly.

CUCM must be installed on a server that meets Cisco configuration standards. Cisco actively collaborates with two server hardware manufacturers to meet this requirement: Hewlett-Packard (HP) and IBM. You can find additional information at the following sites:

Cisco UC Operating System

The CUCM operating system is based on Red Hat Linux. Operating system and application updates are provided by Cisco through patches that are digitally signed by Cisco. Unsupported software and applications (not digitally signed by Cisco) cannot be uploaded or installed into the system.

Root access to the file system is not permitted. The operating system has been hardened by disabling all unnecessary accounts and services. There is also no access to native operating

system debug interfaces. Traces, alarms, and performance counters can be enabled and monitored through the CUCM GUI. Some files and directories are accessible through the Cisco CLI and GUI for maintenance purposes.

Remote-access support allows Cisco Technical Assistance Center (TAC) engineers to remotely access the CUCM server for a restricted time interval. Remote-access support can be enabled in CUCM serviceability tools.

The IBM IDS is the database for the Cisco UC applications. The IDS database installation and configuration is scripted into the CUCM installation DVDs. No UNIX or IBM IDS database knowledge is required to configure and operate CUCM.

Cisco Secure Agent is included with the appliance to provide protection against known and unknown attacks. Cisco Secure Agent is a host-based intrusion prevention system (HIPS).

A DHCP server is integrated into CUCM to provide IP telephony devices with their IP addressing requirements.

The Cisco UC operating system is also used for these Cisco UC applications:

Cisco Emergency Responder 2.0

Unity Connection 2.0

Cisco Unified Presence 6.0