Mitel SX-200 Practices page 625

2
' TRAFFIC MEASUREMENT
METHODS
2.1 Traffic measurement data is accumulated in periods of from I to 60 mjnutes in length.
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The start time, which is specified to the nearest minute, and the duration (required
number of periods) identify the daily time when measurements are collected. These
three parameters are entered from the console or maintenance terminal. Once set,
traffic measurement will begin at the same time each day and continue for the same
duration, until changed or stopped. The system clock times the length of each period;
however, a guard timer also monitors each period and can terminate the period if it
times out before the system clock does. This would occur only if the system clock has
been changed during a measurement period. The period length is not guaranteed if
the clock is changed or the system is reset during a measurement period.
Data is accumulated into active registers during each measurement period. At the end
of each period, data is transferred to storage registers and the active registers are set
to zero in preparation for receiving data from the next period. The data is held in these
storage registers from which it may be printed or written to magnetic tape or a similar
storage device. At the end of each period, the data in the storage registers is replaced
by the data accumulated in the active registers during the period. If the data was not
retrieved from the storage registers during a period, new data received at the end of
that period overwrites the data, and it is lost. This sequence then repeats for the
specified duration.
Types of Traffk Counts Accumulated
2.2 Two basic types of data are accumulated in the registers: peg counts and usage
counts. Usage counts may be further divided into normal usage and maximum value
counts.
Peg Count. Each time a facility (device, service, or feature) is used, the call processing
software increments its register by one count. A peg count is not concerned with the
length of time of usage.
Usage Count. The amount of time for which a facility is used may be calculated from
the usage count. At IO-second intervals, the call processing software scans each
facility and increments the register if it is in use. The usage count is directly proportional
to the time that a circuit is in use. Each accumulated usage count is converted into CCS
or Erlangs for the traffic measurement report. The maximum usage is 6554 CCS or 182
Erlangs which will occur if 182 devices in a facility are all busy for I hour. The consoles
are scanned every second to increase accuracy in the average waiting time for an
answered call.
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