For the MCS 7845 server, the maximum values for "Silent Monitoring" and "Recording and Playback" sessions are dependent upon whether the deployed environment is making use of SPAN or Desktop-based monitoring.
SPAN-based monitoring is performed by the VoIP Monitoring Service that resides on the Unified CCX server. The VoIP Monitor Service enables the silent monitoring and recording features across the configured domain of agent phones (devices). This VoIP Monitoring Service has a hard-coded maximum of 58 concurrent sessions. An agent that is recorded, or monitored, or recorded and monitored at the same time will consume one session. Since both the Silent Monitoring and Recording features receive packets from a common VoIP Monitoring Service, concurrent use of one feature can impact the number of sessions available for use by the other. As a result, in a Unified CCX environment configured for SPAN-based monitoring, no more than 58 agent devices can be monitored and recorded simultaneously.
For deployments utilizing non-7845 MCS servers, this limitation does not impact the listed maximums, since the combined values listed for maximum concurrent "Silent Monitoring" and "Recording and Playback" are fewer than 58. However, in a 7845 Premium deployment, the stated maximums are 32 monitoring and 64 recording and playback. It would only be possible for the system to operate at both maximums if the combined monitoring sessions and recording sessions are fewer than or equal to 58 and the remainder are playback sessions. For more information on the maximum number of supported "Silent monitoring" and "Recording and Playback" sessions for each server platform, refer to the Cisco Unified CCX Data Sheet available here:
Desktop-based monitoring is performed by the VoIP Monitoring Service that resides on the Agent Desktop. It also enables silent monitoring and recording, but its domain is the single device to which the agent station is physically attached. Because the VoIP Monitoring Service runs on the agent PC, and not the Unified CCX server, it does not contribute any CPU load to the Unified CCX server. And, unlike the SPAN-based environment, the concurrent monitoring sessions have no impact on concurrent recording and playback sessions. As a result, in a Unified CCX environment configured for Endpoint-based monitoring, the maximum number of concurrent silent monitoring sessions is limited by the number of concurrent supervisor sessions supported for the MCS server. Similarly, in this environment, the maximum number of concurrent recording and play back sessions is also limited by the MCS server size.