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Group II errors
Group II alarms occur when an alarm persists for a predefined period. The alarm is considered
cleared when it does not occurred for a predefined period.
See
Table 11
for incoming-signal Group II errors listed from highest to lowest priority. Group II
errors are ordered by priority; when a high priority error exists, any errors of lower priority are
irrelevant.
Table 11 Incoming signal errors
Alarm
Loss of Signal (LOS)
Alarm Indication Signal (AIS)
Out-of-Frame (OOF)
Out Of Multiframe TS16 -
(OOM
)
TS16
Alarm Indication Signal in TS16
(AIS
)
TS16
Loss of CRC-4 Multiframe
Alignment (OOM)
Remote Alarm Indication (RAI)
Remote Alarm Indication TS16
(RAI
)
TS16
Alarms propagation
This section describes the actions taken when alarms occur or stop. When alarms occur, the
far-end is alerted by a remote alarm indication, and an alarm is transmitted on the opposite link.
Table 12
table shows the reactions for Group I alarms when they enter the Out-Of-Service (OOS)
state.
Table 12 Group I Alarms propagation (Sheet 1 of 2)
Error Condition
BPV
FBER
Slips
Chapter 6 R2MFC MBM maintenance
Cause
No reception of incoming electrical signal on the line (cable cut or
removed).
Reception of incoming signal is all ones. Usually indicates that the
far-end is out-of-service
No detection of Frame Alignment Signal. The incoming signal is
corrupted. This alarm is also known as Loss of Frame (LFA).
No detection of Multiframe Alignment Signal. When this alarm is active,
Channel Associated Signaling (R2) is impossible. This alarm is not
applicable to the PRI (internal link). This alarm is also known as Loss of
Multiframe Alignment - (LMA).
Reception of AIS is all ones in TS16. This is an optional alarm. It can be
enabled or disabled in configuration. By default, this option is off. When
this alarm is active, any signaling on TS16 is impossible.
CRC-4 multiframe cannot be recognized. When this alarm is active,
CRC-4 errors (of group I) cannot be measured. This alarm is relevant
only when CRC-4 multiframe mode is used.
Indication that the far-end has trouble with its incoming signal. This
alarm is also known as yellow alarm.
Indication that the far-nd has lost TS16 multiframe alignment on its
incoming signal.
This alarm is not applicable to PRI (internal link).
Alarm Transmitted to far end
RAI
RAI
RAI
R2MFC Media Bay Module Installation and Configuration Guide
Alarm sent on opposite link
AIS
AIS
AIS
65
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