Nortel DMS-100 Series Maintenance Manual page 115

Figure 13 Processor occupancy—memory block reduction after real-time
overload detection
Processor occupancy
100%
0%
The XLCM is memory block limited. The XLCM cannot handle real-time
overload. This condition can result in outages because of the following
reasons:
• An overload report was not sent. The XLCMs cannot detect real-time
overload. As a result, the CM does not suspend functions that require a
response from the XLCM. The CM suspends functions when overload is
reported. When the XLCM does not respond in time, the CM system
busies the XLCM.
• The XLCM cannot handle lack of memory when lower priority tasks do
not run. This condition can lead to traps or severe software errors that
cause the CM to SysB the XLCM.
Improvements to the overload protection system
The improved XLCM overload protection system performs the following:
• detects when the XLCM is in real-time overload
• reports overload to the CM
• takes protective measures to assure XLCM sanity
The XLCM overload protection system performs the above functions in
addition to current functions. These protective measures are active for the
smallest amount of time to retain the XLCM call processing capacity.
This improvement adds three new components to the Overload Protection
System. The three improvements follow.
• The processor occupancy data collection component. This component is
distributed over key areas of the XLCM code. This component collects
DMS-100 Family OPM Maintenance Manual ISN07 (TDM)/SN07 (DMS) and up
P-phone MADN traffic
0 Adjusted
max
Functional overview 2-39
POTS traffic
Memory blocks
Normal
max