Traffic Measurement in the System

This section discusses the manner in which traffic data is measured and tabulated in the system. It shows that the system, though not a non-blocking switch, offers virtual non-blocking characteristics to users.

In a large switching system, featuring a distributed processing architecture and the coexistence of voice and data switching facilities, traffic analysis appears complex. However, the design of the system greatly simplifies traffic analysis requirements through a virtually non-blocking switching arrangement where only a minimum of components are traffic-dependent, and that the resulting analysis of traffic data is very simple. Two terms of importance in traffic measurement will be used in the following paragraphs and are defined as follows:

1. Period. This term refers to the duration of an individual traffic measurement period. This period is the amount of time over which traffic data will be accumulated and can be set by the user to be either 15, 30, or 60 minutes. At the end of each period, the system produces a traffic report.

2. Time Slot. This term refers to the span of time during which traffic data will be collected on a given day. The time slot of a traffic session is measured in periods. For example, if measurements are to take place from 8:00 A.M. to 5:00 P.M. and reports are produced every 30 minutes, then the traffic session is said to consist of periods 30 minutes in length and has a time slot of 18 periods (9 hours).

System Call Processing

Traffic Measurement in the system shows the hardware and software components that are relevant to traffic measurement. The software components are shown within the dashed box representing the system. External components involved in traffic measurement and monitoring include all peripheral devices (voice and data stations and trunks) as well as the maintenance devices (maintenance terminal and printers). In the course of call processing, traffic data is gathered as follows:

1. As service requests are generated from either telephones, data stations or trunks, the Call Processing module responds and establishes connections through the circuit switch matrix to other peripheral devices.

2. As each request is served by Call Processing, the Performance Monitor module records the event (peg count), the state of the connection (successful or busy), and the duration of the connection.

3. The Performance Monitor continually records data, storing it in internal buffers.

4. At the end of each traffic measurement period, the data is transferred to the Traffic Buffer where the information is processed by the Traffic Measurement module.

5. The Traffic Measurement module then generates a file in the system Mass Storage devices which represents a formatted and printable traffic report for a given period.

6. The traffic report file lists peg count, usage (Erlangs or CCS) and number of circuits used in comparison to the number of circuits available (for outgoing trunk groups). The traffic report file also records traffic on individual trunks, as well as call processing statistics for each Attendant Group.

Call Processing and Traffic Measurement

The various inter-connections allowed by the Call Processing module which are recorded by the Performance Monitor are listed in the following table. The data collected concerns trunks, DTMF receivers. The traffic reports provide a complete record of traffic on individual circuits and groups. The trunk-related information is relevant in streamlining the performance of Automatic Route Selection (ARS) by providing the traffic analyst with the ability to evaluate the effectiveness of trunk grouping by Route and the overflow capabilities of Route Lists.

Message Summary

The following table lists all status and error messages which may appear at the Maintenance Terminal during traffic measurement.