Takeover Capability - Nortel DMS-100 Series Maintenance Manual

Functional overview 2-43
reduces memory blocks with a change of system parameters of memory block
overload. This procedure reduces the amount of memory blocks available for
new work. This design aspect makes the new overload system dynamic. The
system adjusts to allow very high processor occupancy under any traffic
configuration.

Takeover capability

Power connections are present between the two shelves of the LCM. The
LCM can operate in a load-sharing mode. When one power converter loses
service, the mate converter supplies power to both shelves. This condition is
a takeover state. In the takeover state, the in-service unit assumes control of
the lines associated with the OOS mate unit. In addition, the in-service unit
controls the InSv mate unit lines. The InSv unit has access to the DS30A
C-side ports used by the OOS mate. The DCC of the InSv unit accesses all 20
line subgroups.
The mate converter distributes ringing, ANI and coin control voltages to all 20
LSGs of the two LCAs. One of the two ringing generators in the HIE supplies
the ringing and ANI and coin control voltages.
Takeover occurs when one LCA control complex, like the LCM processor and
digroup card fails. When this condition occurs, the control complex that
remains can support all DS-1 links and the LSGs of both LCAs.
Calls in process at the time of takeover terminate and require redial. Calls
already connected and in progress are maintained.
LCC takeover
The LCC provides an interface between the LCA and the DS-1 interface cards
in the HIE shelf. Each LCA associates with an LCC in the HIE shelf. When
an LCA shelf fails, the LCA shelf is considered inactive and takes down the
associated LCC.
When an LCC fails, an LCC takes down the associated LCA shelf. When an
LCC or an LCA shelf fails, the active LCC and LCA perform a takeover. The
LCC and LCA support the DS-1 links of the inactive LCC and LCA. Takeover
is possible because duplicated paths are present between the LCA shelves. A
takeback occurs when the inactive LCC and LCA become active again.
Takeback
When the failed unit is RTS, the subscriber lines in takeover state are
distributed back to the normal processor. A loss of calls in the talking or
ringing state does not occur during the RTS.
DMS-100 Family OPM Maintenance Manual ISN07 (TDM)/SN07 (DMS) and up