Architecture, Clock operation, Tracking mode – Nortel Networks 1000 User Manual
Page 345
Architecture
345
Use
Table 146 "Switch setting for MSDL external card" (page 345)
to set
the card address.
Table 146
Switch setting for MSDL external card
Switch Setting
DNUM (LD 17)
1
2
3
4
0
OFF
OFF
OFF
OFF
1
ON
OFF
OFF
OFF
2
OFF
ON
OFF
OFF
3
ON
ON
OFF
OFF
4
OFF
OFF
ON
OFF
5
ON
OFF
ON
OFF
6
OFF
ON
ON
OFF
7
ON
ON
ON
OFF
8
OFF
OFF
OFF
ON
9
ON
OFF
OFF
ON
10
OFF
ON
OFF
ON
11
ON
ON
OFF
ON
12
OFF
OFF
ON
ON
13
ON
OFF
ON
ON
14
OFF
ON
ON
ON
15
ON
ON
ON
ON
Architecture
Clock operation
There are two types of clock operation - tracking mode and free-run mode.
Tracking mode
In tracking mode, the DDP2 loop supplies an external clock reference to
a clock controller. Two DDP2 loops can operate in tracking mode, with
one defined as the primary reference source for clock synchronization,
the other defined as the secondary reference source. The secondary
reference acts as a back-up to the primary reference.
As shown in
Figure 95 "Clock Controller primary and secondary tracking"
, a system with dual CPUs can use two clock controllers (CC-0
and CC-1). One clock controller acts as a back-up to the other. The clock
controllers should be completely locked to the reference clock.
Nortel Communication Server 1000
Circuit Card Reference
NN43001-311
02.06
Standard
27 August 2008
Copyright © 2003-2008 Nortel Networks
.