Datasheet

Table Of Contents
12-6
Cisco ONS 15454 SDH Reference Manual, R7.0
October 2008
Chapter 12 SDH Topologies and Upgrades
12.2.2 Four-Fiber MS-SPRings
Figure 12-4 Four-Node, Four-Fiber MS-SPRing
Four-fiber MS-SPRings provide span and ring switching.
Span switching occurs when a working span fails (Figure 12-5). Traffic switches to the protect fibers
between the nodes (Node 0 and Node 1 in the Figure 12-5 example) and then returns to the working
fibers that did not fail. Multiple span switches can occur at the same time.
Node 0
Node 1
Node 2
Node 3
Span 1
Span 2Span 3
Span 4
Span 8
Span 7Span 6
Span 5
STM-16 Ring
= Working fibers
= Protect fibers
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