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

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363-206-285
Applications
Issue 3 June 2001 2-59
Gateway Between SONET and Asynchronous
Interfaces
2
Figure 2-41 shows an OC-12 STS-1 drop and continue to DS3 interface
application for DDM-2000 OC-12 ring releases. The application is a DRI network
with the following components and releases:
■
DDM-2000 OC-3 Multiplexers with Release 7.1 or later software/ SLC -2000
with Release 3.1 or later software path switched ring with VT1.5 drop and
continue to EC-1 interfaces.
■
DACS IV-2000 Release 3.0 or later to provide EC-1/DS3 (M13)
conversions and cross-connections
■
DDM-2000 OC-12 Multiplexers with Release 3.1 or later software.
This configuration is a specific application for interfacing DS1 signals at one end
of a SONET system and DS3 interfaces at the other end.
NOTE:
A complete loss of CO 1 or CO 2 would protect the end-to-end path.
However, unless there is a specific application requiring this gateway
functionality, it is recommended that DRI be done with standard SONET
EC-1 interfaces. This is because incoming asynchronous DS3 failures,
such as AIS at drop and continue nodes, will not generate SONET STS AIS
if drop and continue cross-connections are made on a 3DS3 circuit pack.
As a result, path protection switching will not occur on the OC-12 ring
resulting in unusable signals at the terminating end. (R5.1 OC-12.) DS3
LOS, however, will generate AIS.