Specifications

Cisco ONS 15327 Product Overview, R3.3

June 2002

Cisco ONS 15327 Product Overview

Timing

Figure 22 ONS 15327 timing example

Synchronization Status Messaging

Synchronization status messaging (SSM) is a mechanism for managing

synchronization (or network timing) in SONET networks. It allows BITS timing

sources, nodes, and combinations of the two to exchange information about the

Node 4

Timing Line

Ref 1: Slot 4

Ref 2: Slot 3

Ref 3: Internal (ST3)

Node 2

Timing Line

Ref 1: Slot 3

Ref 2: Slot 4

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 3

Ref 2: Slot 4

Ref 3: Internal (ST3)

BITS1

out

BITS2

out

BITS1

source

BITS2

source

Third party

equipment

Slot 3

Slot 4

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