CXR Larus 80-100-400 2-2
Issue
1,
July
2006
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lly recommended but
has been found to work well and solve many problems.
2.19
ded that all networks be timed to minimize phase noise (jitter and
wander).
2.191
sen is
the same as the SONET/SDH reference, problems can be minimized.
.2 Timing Distribution and Central Clock Considerations
.21 Synchronization
Networks
2.211
cted by
phase wander and jitter accumulated along the transmission paths.
the case with many modern fiber and radio networks, using the traffic-carrying
DS1 or E1 signal to drive the timing systems is not genera
SONET and SDH networks are designed to operate in a maintenance mode
when not timed. In this mode, the jitter may be larger than that of a properly
timed network. It has been noted that for voice traffic, and even for digital traffic
between switches and digital crossconnects, no impairments are observed
even when the SONET or SDH system is untimed. However, it is
recommen
With either SONET or SDH, the multiplex equipment must be timed. If the
timing of the dropped DS1s or E1s is different from the multiplex timing, there
will be unsatisfactory jitter and wander performance which may or may not
affect the connected equipment. By timing all network sources of DS1/E1
signals from the same reference, and making sure that the reference cho
2
2
Synchronization networks provide timing signals to all synchronizable network
elements (NEs) at each node in a digital network. These timing signals are
traceable to a highly accurate Primary Reference Source (PRS) clock. The aim
is to ensure that all outgoing transmissions from a digital network node have
the same average frequency. Buffer elements at important transmission
interfaces absorb differences between the average local frequency and the
actual short-term frequency of incoming signals which may be affe
