Fault Conditions; Unusable Communication Links; Looparound Message Audit Failure - Nortel DMS-100 Series Maintenance Manual

Fault conditions

The fault condition of unusable communication links triggers the ESA mode
of operation. The possible reasons for this fault condition appear in the
following paragraph.

Unusable communication links

Communication links from the RLCM to the DMS CC become unusable
because of the following conditions:
The RLCM_ESAENTRY_BADLINK office parameter determines the
desired delay time between failure of the C-side message link and the entry
of ESA mode.

Looparound message audit failure

The RLCM enters ESA mode when the looparound message audit detects
the failure of messaging between the RLCM and the DMS CC. The failure
occurs because of the following conditions:
The RLCM_ESAENTRY_BADCSIDE office parameter determines the
desired delay time between the failure of RLCM communication with the
C-side peripheral and entry of ESA mode. The delay time does not allow
the RLCM to enter the ESA mode while the system performs a restart. A
restart causes the looparound message to fail. The RLCM enters ESA mode
if the looparound messages in the time-out period fail.
Fault conditions that can occur during ESA operation are as follows:
The system does not support automatic number identification (ANI).
The links are severed between the RLCM and the host.
The peripheral side (P-side) message link (DS-1 cards) of the LTC are
pulled out.
The C-side message link (DS-1 cards) of the RLCM are pulled out.
An extended loss of communication occurs with the DMS CC for longer
than the time-out period specified in the
RLCM_ESAENTRY_BADCSIDE office parameter.
The two LTC units (C-side peripherals) are ManB.
Network planes of the LTC or LGC are ManB.
line errors
— too many originations
— confusion message received
— line translation error
DMS-100 Family RLCM Maintenance Manual XPM12 and up
ESA maintenance overview 3-27