Cisco Cisco ONS 15454 SONET Multiservice Provisioning Platform (MSPP) Guide De Dépannage
Slip *
1
1 x 10
−11
N/A
N/A
72 Days
2
1.6 x 10
−8
Must be able to
synchronize to
the clock with an
accuracy of
+/−1.6 x 10
synchronize to
the clock with an
accuracy of
+/−1.6 x 10
−8
1 x
10
10
−10
/day
7 Days
3E
4.6 x 10
−6
Must be able to
synchronize to
the clock with an
accuracy of
+/−4.6 x 10
synchronize to
the clock with an
accuracy of
+/−4.6 x 10
−6
1 x
10
10
−8
/day
17 Hours
3
4.6 x 10
−6
Must be able to
synchronize to
the clock with an
accuracy of
+/−4.6 x 10
synchronize to
the clock with an
accuracy of
+/−4.6 x 10
−6
3.7 x
10
10
−7
/day
23
Minutes
Minutes
SONET
Minimum
Clock
Minimum
Clock
20 x 10
−6
Must be able to
synchronize to
the clock with an
accuracy of
+/−20 x 10
synchronize to
the clock with an
accuracy of
+/−20 x 10
−6
Not yet
specified
specified
Not Yet
Specified
Specified
4E
32 x 10
−6
Must be able to
synchronize to
the clock with an
accuracy of
+/−32 x 10
synchronize to
the clock with an
accuracy of
+/−32 x 10
−6
Same as
Accuracy
Accuracy
Not Yet
Specified
Specified
4
32 x 10
−6
Must be able to
synchronize to
the clock with an
accuracy of
+/−32 x 10
synchronize to
the clock with an
accuracy of
+/−32 x 10
−6
Same as
Accuracy
Accuracy
N/A
* In order to calculate the slip rate from drift, assume a frequency offset equal to the drift in 24 hours, which
accumulates bit slips until 193 bits (frame) accumulate. Drift rates for various atomic and crystal oscillators
are well known. However, drift rates are usually neither linear nor continually on an increase.
accumulates bit slips until 193 bits (frame) accumulate. Drift rates for various atomic and crystal oscillators
are well known. However, drift rates are usually neither linear nor continually on an increase.
Jitter, Wander and Slips
Jitter and Wander
Jitter is the instantaneous deviation of a digital signal (frequency) from the nominal value (that is, the
reference clock). Jitter commonly occurs when digital signals pass through network elements that use stuffing
bits in the transmission protocol. The removal of these stuffing bits can cause jitter. You can express jitter in
terms of Unit Interval (UI). UI is the nominal period of one bit. Express jitter as a fraction of one UI. For
example, at a data rate of 155.52 Mbits/s, one UI is equivalent to 6.4 ns.
reference clock). Jitter commonly occurs when digital signals pass through network elements that use stuffing
bits in the transmission protocol. The removal of these stuffing bits can cause jitter. You can express jitter in
terms of Unit Interval (UI). UI is the nominal period of one bit. Express jitter as a fraction of one UI. For
example, at a data rate of 155.52 Mbits/s, one UI is equivalent to 6.4 ns.
Wander is very slow jitter (frequency less than 10 Hz). When you design the synchronization distribution
sub−system for a network, your targets for sync performance must be zero slips and zero pointer adjustments
during normal conditions. You can express wander in terms of TIE (Time Interval Error). TIE represents the
sub−system for a network, your targets for sync performance must be zero slips and zero pointer adjustments
during normal conditions. You can express wander in terms of TIE (Time Interval Error). TIE represents the