Nortel Meridian 1 Option 11C, Администрирование и обслуживание

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Page 146 of 492 Chapter 4 — Network clocking
553-3011-311 Standard 7.0 May 1999
In Example 4, a digital connection to the local exchange may exist (i.e. Loops
X and Y). When a second Digital loop from the local exchange or Master M-1
becomes available, it can be used as a Secondary Clock Source in case the
Primary Source fails.
To avoid timing loops, in Example 4 the most reliable slave system should not
have a Secondary Clock Source (SREF= <cr>). In this example, this is
illustrated by the node which supports loops X and Z.
Example 4
Alternate Clocking from the same local exchange
553-7564.EPS
LD 60
TRCK PCK
LD 73:
PREF loop X
SREF <cr>
LD 60
TRCK PCK
LD 73:
PREF loop Y
SREF loop Z
Option 11 Option 11
Slave Slave
loop Z
Clocking off Master:
Tracking on Primary
loop X and leave the
Secondary Reference
blank. Clocking off Master:
Tracking on Primary
loop Y and loop Z
used as a secondary
clock source.
Master Clock
Master clock source:
Non-tracking (Free-run)
LD 60
TRCK FRUN
LD 73:
PREF <cr>
SREF <cr>
loop Y loop X
Option 11 or
local exchange