Cisco ONS 15454 - Page 388

12-8
Cisco ONS 15454 Reference Manual, R7.0.1
OL-9217-01
Chapter 12 SONET Topologies and Upgrades
12.2 12.2.2 Four-Fiber BLSRs
Figure 12-5 Four-Fiber BLSR Span Switch
•
Ring switching (Figure 12-6) occurs when a span switch cannot recover traffic, 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
OC-48 Ring
= Working fibers
= Protect fibers
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