363-206-295
Transmission and Synchronization Interfaces
5-18
Issue 1
December 1997
As shown in Figure 5-7a (Figure 5-7 is an OC-3 linear application used to explain
the concepts of synchronization messaging.), SONET synchronization messaging
notifies the DDM-2000 Multiplexer at the slave site to place alarm indication signal
(AIS) on the DS1 timing output. This BITS can then enter holdover or switch to an
alternate reference.
Figure 5-7.
DS1 Timing Output — Dual Homing Linear
BITS
DDM-2000
DS1
CO
PRS
Traceable
DDM-2000
loop-timed
RT
DDM-2000
loop-timed
DDM-2000
OC-N
OC-N
OC-N
Normal
BITS
CO
DS1
Failure/Recovery
RT
BITS
DDM-2000
DS1
CO
PRS
Traceable
DDM-2000
RT
DDM-2000
loop-timed
DDM-2000
OC-N
OC-N
OC-N
BITS
CO
DS1
RT
holdover
AIS
PRS
Traceable
PRS
Traceable
BITS
DDM-2000
DS1
CO
PRS
Traceable
DDM-2000
RT
DDM-2000
loop-timed
DDM-2000
OC-N
OC-N
OC-N
BITS
CO
DS1
RT
AIS
PRS
Traceable
Reconfigured
loop-timed
a.)
b.)
c.)
Sync Flow
Ext
Timed
Ext
Timed
Ext
Timed
Ext
Timed
Ext
Timed
Ext
Timed