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

4-26 ESA maintenance overview

Fault conditions

The fault condition of unusable communication links triggers the ESA mode
of operation. The possible reasons for this fault condition are described below.

Unusable communication links

Communication links from the OPM to the DMS CC cannot be used when the
following conditions exist:
•
•
•
The RLCM_ESAENTRY_BADLINK office parameter determines the desired
delay time between failure of the C-side message link and the entering of ESA
mode.

Looparound message audit failure

The OPM enters ESA mode when the looparound message audit detects the
failure of messaging between the OPM and the DMS CC. The looparound
message audit detects this failure because of the following conditions:
•
•
•
The RLCM_ESAENTRY_BADCSIDE office parameter determines the
desired delay time between the following two events:
•
•
The delay time prevents the OPM from entering the ESA mode during a
restart. A restart causes the looparound message to fail. The OPM enters ESA
mode if all looparound messages in the time-out period fail.
297-8361-550 Standard 04.02 December 2004
The links are severed between the OPM 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 OPM are pulled out.
A loss of communication with the DMS CC, longer than the time-out
period specified in the RLCM_ESAENTRY_BADCSIDE office
parameter.
Both LTC units (C-side peripherals) are ManB.
Network planes of the LTC or LGC are ManB.
the failure of OPM communication with the C-side peripheral
the entrance of the OPM into ESA mode