Figure 5-4 A Four-Node, Four-Fiber Blsr - Cisco 15454-TCC - Network Processor Card Operation Manual

Chapter 5 SONET Topologies
Figure 5-4
Node 3
Four-fiber BLSRs provide span and ring switching:
Span switching
•
between the nodes (Node 0 and Node 1 in the
fibers. Multiple span switches can occur at the same time.
Ring switching
•
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.
November 2001
A four-node, four-fiber BLSR
Node 0
Span 4
Span 5
OC-48 Ring
Span 6
Span 3
Node 2
(Figure 5-5) occurs when a working span fails. Traffic switches to the protect fibers
(Figure 5-6) occurs when a span switch cannot recover traffic, such as when both
Bidirectional Line Switched Rings
Span 1
Span 8
Node 1
Span 7
Span 2
= Working fibers
= Protect fibers
Figure 5-5 example) and then returns to the working
Cisco ONS 15454 Installation and Operations Guide
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