Datasheet

Table Of Contents
12-7
Cisco ONS 15454 SDH Reference Manual, R7.0
October 2008
Chapter 12 SDH Topologies and Upgrades
12.2.2 Four-Fiber MS-SPRings
Figure 12-5 Four-Fiber MS-SPRing Span Switch
Ring switching occurs when a span switch cannot recover traffic (Figure 12-6), such as when both the
working and protect fibers fail on the same span. In a ring switch, traffic is routed to the protect fibers
throughout the full ring.
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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