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

5-18 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 in the
following paragraphs.

Unusable communication links

Communication links from the Star Hub to the DMS-100 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 Star Hub enters ESA mode when the looparound message audit detects the
failure of messaging between the Star Hub and the DMS-100 CC. The failure
occurs because of the following conditions:
•
•
•
The RLCM_ESAENTRY_BADCSIDE office parameter determines the
desired delay time between the failure of Star Hub communication with the
C-side peripheral and entry of ESA mode. The delay time does not allow the
Star Hub to enter the ESA mode while the system performs a restart. A restart
causes the looparound message to fail. The Star Hub enters ESA mode if the
looparound messages in the time-out period fail.
297-8353-550 Standard 05.01 March 2001
The links are cut between the Star Hub and the host.
The peripheral side (P-side) message links (DS-1 cards) of the LTC are
pulled out.
The C-side message link (DS-1 cards) of the Star Hub are pulled out.
An extended loss of communication occurs with the DMS-100 CC for
longer than the time-out period defined in the
RLCM_ESAENTRY_BADCSIDE office parameter.
The two LTC units (C-side peripherals) are ManB.
Network planes of the LTC+ are ManB.