Nortel DMS 100 Series Maintenance Manual page 61

Maintenance overview 2-45
SWACT-back to the originally active unit. The software that drives this feature
is the SWACT controller in the CC. An autonomous capability added to the
RSC-M software also drives this feature
SWACT controller
All manual requests and selected system requests for warm SWACTs are
routed to the SWACT controller in the CC. The SWACT controller polls PM
diagnostic history data. This data is in the CC and RSC-M state data.
Diagnostic history data is not static data. The SWACT controller denies the
request for a warm SWACT or allows a warm SWACT to proceed. This
condition is based on the data polled. During the SWACT, the newly inactive
unit remains in service. This unit initiates a process to clean data structures
left in states that are not normal.
Pre-SWACT audit
Before a SWACT occurs, the active RSC-M unit queries the mate RSC-M unit
over the intermodule communication (IMC) links. The RSC-M unit messages
the SWACT controller in the CC. Feature AN0538 improves the pre-SWACT
audit of the inactive unit to include the state of the unit during diagnostics. The
RSC-M unit assigns a weighted value to the results of the diagnostics. The
result of the pre-SWACT audit query is a boolean pass or fail.
The SWACT controller can deny a manual request for a warm SWACT. If the
controller denies the request, the system informs the user on the MAP terminal
that the SWACT denied the request. The system provides a detailed reason for
the denial. The system informs the user that the user can supersede the
SWACT controller. To supersede the SWACT controller, enter the SWACT
FORCE command. If the user overrides the SWACT controller, the system
attempts a warm SWACT without consulting diagnostic history or state.
Post-SWACT audit
After a SWACT occurs, two-way communication can be available with the CC
and the newly active unit can maintain activity. If these conditions occur, the
inactive unit is system-busied and returned to service. The unit that was active
earlier remains in service. This unit remains in service until the newly active
unit can verify two-way communication with the CC. This unit also remains
in service until the unit can maintain activity. The RSC-M can execute a
SWACT-back to the originally active unit. The SWACT-back occurs if
communication fails, or the newly active unit cannot maintain activity.
SWACT-back
If an RSC-M does not receive a gain-acknowledged message from the CC, the
originally active RSC-M unit initiates a SWACT-back. During a
SWACT-back, the originally active RSC-M unit attempts to regain activity. If
successful, the inactive unit is set SysB and returned to service. The active unit
remains in service. Normal calls from the originally active unit are preserved
on the SWACT-back. The system drops all new calls made before and after
DMS-100 Family Remote Switching Center Multi-Access Maintenance Manual XPM11 and up