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

Page: 2140 / 2536

DLP-513
: Detailed Level Procedure 363-206-285
Page 8 of 20 Issue 2, February 2000
DDM-2000 OC-3 M
ULTIPLEXER
External - Mult Line Timing - Sync Out This topology is used when one of the NE’s does
not have access to an external synchronous
reference, needs to be synchronized to an NE
whose timing is traceable to a PRS, and timing is
needed to be distributed where NE 2 is located.
The NE provisioned for Line Timing - Sync Out will
derive its timing from the NE provisioned for
External - Mult timing thus operating synchronously
with that respective NE. Its DS1 output could serve
as a reference to distribute timing to a BITS in that
CO. The NE provisioned for External - Mult timing
could use its DS1 output to distribute its incoming
DS1 timing reference to other shelves in the bay to
conserve ports on the BITS.
External - Sync Out Line Timing Caution! This topology might create a timing loop.
In this topology the NE provisioned for Line Timing
will derive its timing from the NE provisioned for
External - Sync Out timing thus operating
synchronously with that respective NE. The NE
provisioned for External - Sync Out should be
reprovisioned for External - Mult to prevent the
potential timing loop existing in the actual
provisioning. If Synchronization Messaging is
enabled on both NE’s, the DS1 output reference of
the NE provisioned for External - Sync out will carry
an unframed all ones DS1 signal (DS1 AIS) in the
present topology. If automatic synchronization
reconfiguration is supported and enabled in a
system, both NEs will attempt to break the potential
timing loop. NE 1 will attempt to break the loop by
inserting DS1 AIS on its DS1 output port. NE 2 will
attempt to switch to another line timing source, if
available, to prevent the timing loop.
External - Sync Out Line Timing - Sync Out Caution! This topology might create a timing loop.
In this topology the NE provisioned for Line Timing
will derive its timing and that of the DS1 output
reference from the NE provisioned for External -
Sync Out timing thus operating synchronously with
that respective NE. The NE provisioned for External
- Sync Out should be reprovisioned for External -
Mult to prevent the timing loop existing in the actual
provisioning. If Synchronization Messaging is
enabled on both NE’s, the DS1 output reference on
NE 1 will carry DS1 AIS and NE 2 will derive its
timing and that of the DS1 output port from NE 1. If
automatic synchronization reconfiguration is
supported and enabled in a system, both NEs will
attempt to break the potential timing loop. NE 1 will
attempt to break the loop by inserting DS1 AIS on
its DS1 output port. NE 2 will attempt to switch to
another line timing source, if available, to prevent
the timing loop.
Table E – BBF2B/BBF2C TGS/BBF4 TG3 Synchronization Provisioning
Topologies (Contd)
NE 1 NE 2 Application Comments