The term processor occupancy (or simply, occupancy) is defined as the percentage of time the configuration’s processor is busy performing call processing tasks, maintenance tasks, administration tasks, and operating system tasks. As a contrast, the percentage of time the processor is not used is referred to as idle occupancy.

In Communication Manager, processor occupancy, also known as server occupancy, consists of three main categories: static occupancy (ST), call processing occupancy (CP), and system management occupancy (SM).

Static occupancy: The processing required for keep-alive operations. Despite the nomenclature, the value of static occupancy in a List Measurements report can slightly vary.

Call processing occupancy: The processing required for setting up, maintaining, and tearing down calls, and for executing vectoring operations in call centers. The processor occupancy limit of Communication Manager Release 6.3.6 and later for H.323 registrations (RAS) is 65%.

System management occupancy: The processing required for maintaining the sanity of the system, including periodic maintenance and audits. Due to the bursty nature of system management functions, a fixed portion of the overall processing capacity is allocated to system management for design purposes. For all Communication Manager servers, 27% of the total system processing capacity is assigned for system management. The 27% occupancy is not dedicated to system management but only used for traffic configuration calculations.

The primary objectives of the processor occupancy reports are:

You can use four different processor occupancy commands:

The first three commands provide processor occupancy data and associated call traffic for different measurement intervals. The last command provides a picture of the traffic data generated on each processor interface link.

You can execute the processor occupancy commands from all valid user logins. However, for most systems, the two primary users are the telecommunications manager of the customers and the service technician.

The type of application can significantly affect processor occupancy. For the purpose of determining processor occupancy, your calling traffic is defined as one of the following applications:

Depending on your specific application, the calling traffic can be simple or complex. A simple calling traffic includes a single switch with only CO trunks and analog sets. A complex calling traffic includes a switch in a multinode private network that uses both DCS and ISDN features and is configured with digital sets. You can define the traffic range in the following four call categories:

Your usage profile is defined as the percent mix of traffic from each of the four call categories.

Once the traffic application, usage profile, and certain feature use loading factors are determined you can then calculate the Busy Hour Call Capacity (BHCC). The BHCC is a measure of the configuration’s capacity and is defined as the maximum number of completed calls the configuration can support in an hour without degradation of service.

As a part of the RFP process, Avaya marketing can calculate the theoretical maximum BHCC for the specified application when provided with the following information:

Avaya marketing can now determine whether the proposed configuration can accommodate the traffic load. This number, the theoretical maximum BHCC, is an estimate and is referred to as the predicted maximum BHCC.