Nortel Networks NN43001-301 - Manual (Page 29)

NT8D72 PRI2 29
Figure 6
Clock controller primary and secondary tracking
Free run (non-tracking) mode
The clock synchronization of the system can operate in free-run mode if:
• no loop is defined as the primary or secondary clock reference,
• the primary and secondary references are disabled, or
• the primary and secondary references are in local alarm
Reference clock errors
The system software checks at intervals of 1 to 15 minutes to see if a clock
controller or reference-clock error has occurred. (The interval of this check
can be configured in LD 73.)
In tracking mode, at any one time, there is one active clock controller which
is tracking on one reference clock. If a clock-controller error is detected, the
system switches to the back-up clock controller, without affecting which
reference clock is being tracked.
Nortel Communication Server 1000
ISDN Primary Rate Interface Installation and Commissioning
NN43001-301 02.03 Standard
Release 5.5 7 December 2007
Copyright © 2003-2007, Nortel Networks
.