Maintenance signals
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Overview
Metropolis
®
DMXplore provides maintenance signaling compliant
with the SONET standard (ANSI T1.105) and GR-253-CORE. When
Metropolis
®
DMXplore detects failure conditions on transmission
signals, maintenance signals are inserted into the transmission signals
in the upstream or downstream direction to notify other network
elements.
Metropolis
®
DMXplore supports the following maintenance signals:
•
Alarm indication signals (AIS)
•
Remote failure indicator (RFI)
•
Path unequipped signals
Alarm indication signals
(AIS)
Alarm indication signals (AIS) notify downstream equipment that a
failure has been detected and alarmed by some upstream equipment.
Metropolis
®
DMXplore generates the following alarm indication
signals:
•
Line AIS (AIS-L): Line AIS is generated when an incoming loss
of signal (LOS) or loss of frame (LOF) is detected on the
incoming signal.
•
STS Path AIS (AIS-P): STS path AIS is generated when an
incoming loss of signal (LOS), loss of frame (LOF), line AIS
(AIS-L), or path loss of pointer (LOP-P) is detected.
•
VT Path AIS (AIS-V): VT path AIS is generated when an
incoming loss of signal (LOS), loss of frame (LOF), line AIS
(AIS-L), path loss of pointer (LOP-P), STS path AIS (AIS-P),
STS path unequipped (UNEQ-P), or VT loss of pointer (LOP-V)
is detected.
Remote failure indicator
(RFI)
When downstream terminating equipment detects a defect (see below
for explanation of the defects), the terminating equipment sends a
remote defect indication (RDI) upstream to the node that originated
the signal. After receiving an RDI that persists for two seconds (±0.5),
the originating node (upstream node), generates a remote failure
Maintenance overview
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365-372-333 R2.1
Issue 4, June 2005
Lucent Technologies
4 - 5
