Cisco Systems 15454M6DC Manual Do Utilizador

3-13

Cisco ONS 15454 Installation and Operations Guide

November 2001

Chapter 3 Node Setup

Setting Up ONS 15454 Timing

3.6.1 Network Timing Example

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. The BITS output pins on the backplane
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 connected 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.

Figure 3-8

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 6