Esa Operation - Nortel DMS-100 Series Maintenance Manual

Figure 2 ESA hardware representation in ESA mode
0
0
0
RMM

ESA operation

The OPM enters ESA mode when the OPM determines that the OPM cannot
communicate with the host site. The two conditions that cause entry into ESA
mode at the OPM are as follows:
•
•
When the OPM enters ESA mode a cold enter occurs. The system takes all
active calls down.
The line concentrating module (LCM) detects the loss of communication with
the host. The LCM determines when to use the ESA mode. To use the ESA
mode the LCM switches the C-side link from the host to the ESA processor.
The ESA processor detects the switching of links through the clock and tone
card.
When the ESA processor detects the switch of links, the system initiates
ESA-enter. The time span between loss of communication and the ESA mode,
depends on the type of failure.
The ESA processor has a nailed-up (direct) communication link with the DMS
CC at all times. The ESA processor is the only processor at the OPM that can
1 2
Unit 0
2 1
Unit 0
2 1
unusable communication links
looparound message audit failure
DMS-100 Family OPM Maintenance Manual ISN07 (TDM)/SN07 (DMS) and up
3
(up to 32 DS30 links)
LTC
Unit 1
(Links between the
3 OPM and the LTC
are inoperable.)
OPM
Unit 1
3
ESA processor acts as the
host PM. Links 2 and 3
act as P-side single
channel message links to
the OPM.
ESA
ESA maintenance overview 4-3