Nortel DMS 100 Series Maintenance Manual page 306

8-18 RSC-M trouble isolation and correction
reports the fault. The state of the unit can be active or inactive. The same CM
handles all three types of faults.
When the CM detects a parity fault in the active unit of the XPM, the CM sets
the unit ISTb with a reason of parity. The CM recovers the unit during a
maintenance window. The maintenance window to recover a parity fault on
the active unit is the XPM REX test window. The time for the XPM REX test
window can match the current time of the switch. If this event occurs, an audit
checks if the active unit of the RSC-M has an ISTb of parity. If an ISTb occurs,
the CM SWACTs and reload the XPM. The CM performs these tasks if
requirements are not present. This action clears the ISTb parity fault and the
short term failure (STF) parity fault peg. This action resolves the parity fault
in the XPM.
When the active unit reports a parity fault, the system generates a PM181 log.
This action notifies operating company personnel of the problem. The CM
performs recovery actions. The CM performs a SWACT of the RSC-M and
loads the newly inactive unit with the XPM software load. The associated
inventory table defines this software load. The CM considers this loading
action an autoload. A manual CM or mate reload of the XPM software clears
the ISTb to the affected unit.
The CM does not permit a REX test to occur
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The CM does not allow two XPMs to perform a parity reload when the XPMs
are in the same configuration. This restriction means a P-side node cannot
perform a parity reload at the same time as the associated C-side node. A
C-side parity reload cannot occur at the same time as its P-side node. This
restriction makes sure that only one XPM in a configuration is in simplex at a
time.
The CM generates PM logs to inform operating company personnel of a parity
fault. This log is the primary trouble indicator. Operating company personnel
can check for associated logs to understand the actions the CM takes. An
example of an associated log is the PM128. This section provides examples of
the messages associated with the PM181 and PM128 logs.
The RSC-M unit can be set ISTB with multiple reasons at the same time.
When you perform a QUERYPM FLT at the MAP level, all ISTb reasons that
occurred on the unit appear. These reasons are not cleared.
297-8223-550 Standard 04.02 November 2000
on a P-side or C-side node of the XPM that is recovered from a parity fault
on the XPM if a P-side or C-side node is recovered from a parity fault