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

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363-206-285 Detailed Level Procedure:
DLP-523
Issue 2, February 2000 Page 12 of 30
DDM-2000 OC-3 M
ULTIPLEXER
External - Sync Out External - Sync Out 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.
Line Timing Line Timing 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.
Table E – BBF2B/BBF2C TGS/BBF4 TG3 Synchronization Provisioning
Topologies (Contd)
NE 1 NE 2 Application Comments