Lucent Technologies DDM-2000 OC-3, User & Service Manual

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363-206-285
Maintenance Description
9-12 Issue 3 June 2001
Maintenance Signaling 9
The DDM-2000 OC-3 Multiplexer provides maintenance signaling compliant with
the SONET standard (
ANSI
*
T1.105).The DDM-2000 OC-3 Multiplexer generates
and detects the following alarm indication signals (AISs), which notify downstream
equipment that a failure has been detected and alarmed by some upstream
equipment:
■
SONET line AIS
■
STS-1 path AIS
■
Virtual tributary (VT) path AIS
■
DS3 AIS
■
DS1 AIS (generated, not reported).
The DDM-2000 OC-3 Multiplexer also generates and detects the following
signals, which notify upstream equipment of a failure detected downstream:
■
Line far-end-receive failure (FERF)
■
STS-1 path yellow and VT path yellow
■
An STS-1/VT AIS signal is inserted on paths that are not cross-connected;
however, the user can provision a shelf to insert STS-1/VT unequipped
instead of AIS on paths that are not cross-connected.
For ring interfaces, the DDM-2000 OC-3 Multiplexer detects STS-1 and VT
unequipped signals. Figure 9-3 is an example of the AIS, yellow, and FERF
signals generated in response to an unprotected incoming OC-3 line failure.
* Registered trademark of American National Standards Institute.