Note	Required only in ICM Gateway SQL configurations.

As a general rule for all Unified ICM nodes, keep processor utilization below 60 percent of the maximum expected call load on the system. This is needed to smooth out call request "spikes" as well as to allow enough reserve capacity to perform activities such as re-synchronization and background cleanup. Non-ICM software can make up a part of the 60 percent maximum load. The processor utilization figure (60 percent) covers all software running on the platform.

In addition to the utilization requirement, no software on the system can run at a priority equal to or higher than the Unified ICM software for more than 100 milliseconds in uninterrupted bursts. In other words, the Unified ICM software needs to run on the system at least as frequently as once every 100 milliseconds. This is usually not a problem unless device drivers or other kernel-level software is installed, or process/thread priorities have changed incorrectly.

The most time-critical component of the Unified ICM system, the CallRouter node, must not be delayed due to disk I/O (that is, paging). The only disk I/O that should be occurring on Unified ICM machines is for log file writes and database I/O. The database I/Os occur on Logger and Administration & Data Server machines. The simple rule is to provide enough main memory so that the entire working sets of critical processes remain in memory.

For complete and current information about RAM and other platform requirements, see the Virtualization information https://www.cisco.com/c/dam/en/us/td/docs/voice_ip_comm/uc_system/virtualization/virtualization-unified-contact-center-enterprise.html .

Make sure the database platforms (Loggers, Administration & Data Servers, and Unified ICM Gateway SQL machines) have enough main memory so that all first level index pages are kept in main memory cache.

The Logger platform you order can include a combination of internal and external SCSI hard drives. As your call center enterprise grows, your database requirements typically grow as well. You may have more services, skill groups, and routes in your configuration, and you may route more calls each day. This database growth means more historical data stored in the central database.

When your database requirements change, contact your Unified ICM software support provider to have the storage capacity of the central database increased.

Note	For information about data storage in virtualized deployments, see Virtualization for Unified Contact Center Enterprise at http://www.cisco.com/c/dam/en/us/td/docs/voice_ip_comm/uc_system/virtualization/virtualization-unified-contact-center-enterprise.html.

You can allocate more database space after you install your system by:

• Remotely adding database space (if current disk space allows).

• Installing "hot-plugable" disk drives and configuring the disks while the system is running.

Note	After you install the Unified ICM system, see Administration Guide for Cisco Unified ICM Enterprise for information on how to manage database space.

To allow users to monitor current call center activity, the Unified ICM system forwards real-time data to Administration & Data Servers at selected sites throughout the call center enterprise. The following figure illustrates the real-time architecture of the Unified ICM system.

Real-time call and agent group status data arrives at the central controller from the Peripheral Gateways, which are constantly monitoring activity at each call center. The CallRouter acts as the real-time server. The CallRouter for the other side of the central controller acts as a back-up real-time server.

The CallRouter is responsible for providing real-time data to one or more Administration & Data Servers at each administrator site. Administration Clients at the site receive their real-time data through a connection to a Administration & Data Server. Administration Clients do not have the local database and Administration & Data Server processes are required to receive real-time data directly from the CallRouter.

Administration & Data Servers can be located with one or both sides of the central controller, at a call center, or at another site. An administrator site is any site that contains Administration & Data Servers. Each administrator site requires at least one Administration & Data Server. You should use two Administration & Data Servers (as shown in Administration and Data Server Planning) to provide fault tolerance in the real-time data distribution architecture.

The primary Administration & Data Server maintains an active connection to the real-time server through which it receives real-time data. The secondary Administration & Data Server also maintains connections to the real-time server; however, these connections remain idle until needed (for example, in cases where the primary Administration & Data Server is unavailable for some reason). In sites that have two Administration & Data Servers, the Administration Clients are configured to automatically switch to a secondary Administration & Data Server if the first distributor becomes non-functional for any reason.

An Administration & Data Server can serve many Administration Clients. See the Unified CCE Solution Compatibility MatrixContact Center Enterprise Compatibility Matrix at https://www.cisco.com/c/en/us/support/customer-collaboration/unified-contact-center-enterprise/products-device-support-tables-list.html for information about requirements.