Datasheet

12-15
Cisco ONS 15454 SDH Reference Manual, R7.0
October 2008
Chapter 12 SDH Topologies and Upgrades
12.3 Subnetwork Connection Protection
Figure 12-14 SNCP Ring with a Fiber Break
Because each traffic path is transported around the entire ring, SNCP rings are best suited for networks
where traffic concentrates at one or two locations and is not widely distributed. SNCP ring capacity is
equal to its bit rate. Services can originate and terminate on the same SNCP ring, or they can be passed
to an adjacent access or interoffice ring for transport to the service-terminating node.
Figure 12-15 shows a common SNCP ring application. STM-1 path circuits provide remote switch
connectivity to a host V5.x switch. In the example, each remote switch requires eight E-1s to return to
the host switch. Figure 12-16 on page 12-17 and Figure 12-17 on page 12-17 show the shelf layout for
each node in the example.
Span 1
Span 2
Span 3
Span 4
Span 8
Span 7Span 6
Span 5
Fiber
break
Source
Destination
ONS 15454 SDH
Node A
ONS 15454 SDH
Node B
ONS 15454 SDH
Node C
ONS 15454 SDH
Node D
= Fiber 1
= Fiber 2
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