Alcatel-Lucent 1665 DMX provides maintenance signaling compliant with the SONET standard (ANSI T1.105) and GR-253-CORE. When Alcatel-Lucent 1665 DMX 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.
Alcatel-Lucent 1665 DMX supports the following SONET maintenance signals:
Alcatel-Lucent 1665 DMX also supports the following Optical Transport Network (OTN) layer maintenance signals:
Alarm indication signals (AIS) notify downstream equipment that a failure has been detected and alarmed by some upstream equipment. Alcatel-Lucent 1665 DMX generates the following alarm indication signals:
Line AIS (AIS-L): For SONET Lines, loss of signal (LOS) and loss of frame (LOF) are the defects that cause the line terminating equipment (LTE) to send a line alarm indication signal (AIS-L) downstream.
STS Path AIS (AIS-P): For SONET STS Paths, loss of pointer (LOP-P) and unequipped (UNEQ-P) are the defects that cause the path terminating equipment (PTE) to send an STS Path alarm indication signal (AIS-P) downstream.
VT Path AIS (AIS-V): For SONET VT Paths, loss of pointer (LOP-V) and unequipped path (UNEQ-V) are the defects that cause the path terminating equipment (PTE) to send an VT Path alarm indication signal (AIS-V) downstream.
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 indicator (RFI) alarm. Alcatel-Lucent 1665 DMX generates the following remote defect indication signals:
For SONET Lines, loss of signal (LOS), loss of frame (LOF), and alarm indication signal (AIS-L) are the defects that cause the line terminating equipment (LTE) to send an RDI-L back upstream to the originating LTE which then declares an inc. OCN RFI-L on the line.
For SONET STS Paths, loss of pointer (LOP-P), unequipped (UNEQ-P), and alarm indication signal (AIS-P) are the defects that cause the path terminating equipment (PTE) to send an RDI-P back upstream to the originating PTE which then declares an inc. STSN RFI-P on the STS path.
For SONET VT Paths, loss of pointer (LOP-V), unequipped path (UNEQ-V), and alarm indication signal (AIS-V) are the defects that cause the path terminating equipment (PTE) to send an RDI-V back upstream to the originating PTE which then declares an inc. VT RFI-V on the VT path.
Important!
RFI-P and RFI-V are not reported at non-path terminating points because they are not actionable and because the impacted service is not terminated at that node.
Alcatel-Lucent 1665 DMX supports STS-N and VT1.5 path unequipped signals. Path unequipped signals are transmitted to notify downstream equipment that the path is incomplete (for example, the absence of a valid cross-connection).
Alcatel-Lucent 1665 DMX supports DS3 (path) idle signals. DS3 idle signals are transmitted to notify downstream equipment that the path is not used or incomplete (for example, the absence of a valid cross-connection).
The server signal failure (SSF) signal alerts the downstream client sublayer that a defect or equipment failure has been detected by the upstream server layer. It is sent to the client sublayer and is considered a defect when received.
The backward defect indication (BDI) signal alerts upstream nodes that a defect or equipment failure has been detected downstream. It is sent within the same layer and is considered a defect when received.
The open connection indication (OCI) signal alerts downstream nodes that an upstream connection is not connected.
The locked (LCK) signal alerts downstream nodes that an upstream connection is administratively locked and no signal is passed through.
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