Lucent DDM-2000 OC-3 User And Service Manual page 894

363-206-285
Issue 2, February 2000
Table E – BBF2B/BBF2C TGS/BBF4 TG3 Synchronization Provisioning
Topologies (Contd)
NE 1
External - Sync Out
Line Timing
NE 2
External - Sync Out
Line Timing
DDM-2000 OC-3 M
Detailed Level Procedure:
Application Comments
Caution! This topology can potentially create
a timing loop if synchronization messaging is
not enabled on both NE's. In this topology both
NE's will derive the DS1 output reference from
each other thus creating a timing loop. The NE
with access to a BITS, which has an input
reference traceable to a PRS, and is sourced
from an element other than this NE, should be
reprovisioned for External - Mult to prevent the
timing loop. If Synchronization Messaging is
enabled on both NE's, the DS1 output
reference in one of the NE's will carry DS1 AIS
and the other NE will generate a DS1 output
carrying a framed DS1 all ones signal.
Caution! This topology creates a timing loop
and it is not. supported. The NE with access to
an external timing reference traceable to a
PRS, if available, should be provisioned for
External - Mult. If the reference available is an
optical reference provision to Line Timing with
the proper source using the set-sync
command. If automatic synchronization
reconfiguration is supported and enabled in a
system, both NEs will attempt to switch to
another line timing source, if available, to
prevent a timing loop.
ULTIPLEXER
DLP-523
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