Overload Resources - Nortel DMS-100 Series Maintenance Manual

Full peripheral test
this test makes sure necessary hardware is present. The full peripheral test
checks one speech channel on each specified LTC P-side link to the OPM.
This test is run when the LTC is in active mode.
OPM facility maintenance
The OPM invokes the no-LTU diagnostic for the following reason. The line
diagnostics are invoked for OPM-supported lines and the OPM does not have
a serving LTU or MTU. This software establishes a connection to a
transmission test unit (TTU) in the host office. The TTU uses this circuit for
limited line testing in place of the LTU or MTU.

Overload resources

When the traffic load or the amount of call processing on the OPM is greater
than the LCM processor cards can handle, the following event occurs. The
OPM accepts calls at a slower rate until the overload clears. Normally, when
the OPM processes calls, the OPM queues the call requests and assigns the
calls priorities in the OPM data store. As the data store fills close to capacity,
the OPM overload controls slow the rate of load acceptance. The OPM
overload control also halts the call process until store is available.
Overload control in the OPM occurs for the following activities:
• C-side communication
• line scanning
When the LCM processor cards slow or stop the C-side communication, the
following event occurs. The LCM processor cards decrease the rate that the
LCM processor cards scan for messages on the C-side. The demand for data
store decreases when the LCM processor decreases the incoming workload.
The MAP display queries of the OPM status slow and C-side responses to
OPM-supported terminals become slow.
During overload, the LCM processor cards do not scan the BIC until a
specified amount of data store is available. When the LCM processor cards do
not scan the BIC, incoming work from the P-side is prevented. The queue of
the incoming work in the output buffers of the BIC prevents incoming work
from the P-side. When the buffers are full, the LCM processor card does not
accept work. The results are partial dials or ignored keys on business sets.
Display of overload state
When the OPM overloads, the LCM status display changes to ISTb while the
two units show InSv. When you enter the QUERYPM FLT command at the
LCM level, the phrase LCM Overloaded appears in the response.
DMS-100 Family OPM Maintenance Manual ISN07 (TDM)/SN07 (DMS) and up
After the first two tests in the P-side link diagnostic,
Functional overview 2-35