Cisco Systems 15454M6DC 3.6.1 Network Timing Example

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Cisco ONS 15454 Installation and Operations Guide
November 2001
Chapter3 Node Setup
Setting Up ONS 15454 Timing
3.6.1 Network Timing Example
Figure 3-8 shows an ONS 15454 network timing setup example. Node 1 is set to external timing. Two
timing references are set to BITS. These are Stratum 1 timing sources wired to the BITS input pins on
the Node 1 backplane. The third reference is set to internal clock. T he BITS outp ut pins on the backpl ane
of Node 3 are used to provide timing to outside equipment, such as a Digital Access Line Access
Multiplexer.
In the example, Slots 5 and 6 contain the trunk cards. Timing at Nodes 2 , 3, and 4 is set to line, and the
timing references are set to the trunk cards based on distance from the BITS source. Reference 1 is set
to the trunk card closest to the BITS source. At Node 2, Reference 1is Slot 5 because it is conne cte d to
Node 1. At Node 4, Reference 1 is set to Slot 6 because it is connected to Node 1. At Node 3, Reference
1 could be either trunk card because they are equal distance from Node 1.
Figure3-8 An ONS 15454 timing example
Node 4
Timing Line
Ref 1: Slot 6
Ref 2: Slot 5
Ref 3: Internal (ST3)
Node 2
Timing Line
Ref 1: Slot 5
Ref 2: Slot 6
Ref 3: Internal (ST3)
Node 1
Timing External
Ref 1: BITS1
Ref 2: BITS2
Ref 3: Internal (ST3)
Node 3
Timing Line
Ref 1: Slot 5
Ref 2: Slot 6
Ref 3: Internal (ST3)
BITS1
out BITS2 out
BITS1
source BITS2 source
Third party
equipment
34726
Slot 5
Slot 5
Slot 5
Slot 5
Slot 6
Slot 6
Slot 6
Slot 6