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Cisco ONS 15454 SDH Reference Manual, R5.0
April 2008
Chapter11 SDH Topologies and Upgrades
11.7 Extended SNCP Mesh Networks
Figure11-29 Extended SNCP Mesh Network
Extended SNCP rings also allow spans with different SDH speeds to be mixed together in “virtual rings.” Figure 11-30 shows Nodes 1, 2, 3, and 4 in a standard STM-16 ring. N odes 5, 6, 7, and 8 link to the backbone ring through STM-4 fiber. The “virtual ring” formed by Nodes 5, 6, 7, and 8 uses both STM-1 6 and STM-4 cards.
Figure11-30 Extended SNCP Virtual Ring
= Primary path
= Secondary path
Working traffic
Protect traffic
Source
Node
Destination
Node
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Node 1
Node 11
Node 2
Node 4
Node 5
Node 6
Node 7
Node 8Node 10
Node 9
Node 3
STM-16 SNCP STM-4STM-4
ONS 15454 SDH
Node 5
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Node 1
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Node 6
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Node 2
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Node 4
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Node 8
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Node 3
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Node 7
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