363-206-295
Transmission and Synchronization Interfaces
5-30 Issue 1 December 1997
Network Timing Distribution 5
DS1 signals have long been used to pass timing information through the network
synchronization hierarchy. These DS1 timing references should be transmitted
between master and slave clock sources over the most reliable facilities available.
In some cases, these DS1 signals also carry traffic. The facility of choice has
evolved from T-carrier through asynchronous lightwave systems to SONET
lightwave systems. As these systems are upgraded to SONET systems, timing
distribution plans should be revisited to ensure the quality of the timing signals are
not degraded. With proper planning, SONET can be used to improve the overall
quality of the network timing.
Interoffice Timing Distribution 5
One way SONET can be used to improve the quality of interoffice network timing
is through the use of OC-N timing distribution. DDM-2000 supports the evolution
to interoffice OC-N timing distribution by providing a DS1 timing output derived
from the incoming OC-N signal. The DS1 timing output is traceable to the clock
source that times the DDM-2000 subnetwork and has extremely low jitter and
wander. This is true regardless of the number of DDM-2000 systems connected in
the network. This DS1 can be fed to the local BITS clock which subsequently
times the local DDM-2000 and the other equipment in the office. If a BITS clock is
not available in the office, the DS1 timing output can be used to time other
equipment (including another DDM-2000) directly. DDM-2000 can provide DS1
timing outputs in all supported topologies (for example, point-to-point, add/drop,
and ring).
To Next Page
Loading...
Need help?
General
