Nortel DMS-100 Series Application Manual page 22

1-2 What is the switch performance monitoring system?
SPMS provides a medium-term review comprising detailed as well as
summary level index values. This makes deviations from desired results
easy to trace back to their origin.
SPMS produces performance indices covering all areas of switch operation.
Each index is standardized so that
The indices are calculated from OMs, normalized to compensate for
differences in office size and traffic volume. The formula for calculating
indices uses constants derived from data obtained from the large sample of
switches already in operation.
SPMS results can be used in switch performance index plans for
administrative purposes. An operating company has the choice of using
either the overall office performance index (OFCPERF), a selection of
lower-level indices, or both.
Another feature of SPMS is its ability to isolate problem areas. On a daily
basis, index results are used to detect and correct maintenance and
provisioning problems that are not detected from hour to hour. Severe
trouble spots are identified with two asterisks (**), and less serious problems
are marked with one asterisk (*).
Basic indices provide the most detailed information about problem areas.
They may be picked up directly from a complete SPMS report, or can be
found by working downward from unfavorable aggregate indices that appear
in summary reports.
Chapters 5, 6, and 7 provide a definition of each index, its mathematical
derivation, and the diagnostic information needed to isolate and correct
trouble spots.
To backtrack from an index to the cause of a problem, an operating company
must maintain necessary historical information. This data can be stored on
the switch or in a downstream database. Certain OM groups and logs (listed
in Chapter 6) should be retained for at least 24 hours, and possibly for
several days, to provide enough information to locate the source of a
problem.
297-1001-330 Standard 11.04 June 1998
an index result of 100 indicates perfect performance
an index result of 95 indicates average performance as observed over a
large sample of switches of various types and various performance
levels. A well-run switch generally exceeds a 95 index
an index result of 90 or below indicates a clearly abnormal situation
requiring immediate attention