T1600 Sonet Clock Generators (Scgs) Description - Juniper T1600 Hardware Manual

T1600 Core Router Hardware Guide
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T1600 SONET Clock Generators (SCGs) Description

50
Table 13: LCC-CB LEDs (continued)
Label Color
–
JCSLINK
T1600 Host Subsystem Description on page 36
T1600 Control Boards Description on page 45
T1600 Line-Card Chassis Control Board (LCC-CB) Description on page 48
The SONET Clock Generators (SCGs) provide 19.44-MHz Stratum 3 clock signal for the
SONET/SDH interfaces on the router (see Figure 31 on page 50).
One SCG is shipped as part of the standard router configuration, but up to two SCGs can
be installed to provide redundancy. SCGs are installed into the upper rear of the chassis
in the slots labeled and
SCG0
A nonredundant SCG is hot-pluggable. For redundant SCGs, the master SCG is
hot-pluggable. The backup SCG is hot-removable and hot-insertable if the master SCG
is functioning. Removing the backup SCG does not affect the functioning of the router.
Taking the master SCG offline might result in a brief loss of SONET clock lock while the
backup SCG becomes the master.
Figure 31: SCG
Each SCG consists of the following components:
19.44-MHz Stratum 3 clock.
Field-programmable gate array (FPGA) that performs multiplexing of clock sources.
SCG online/offline button, located on the SCG faceplate.
Two external clock inputs.
State Description
– This port is not used.
.
SCG1
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