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5-5
Cisco ONS 15454 Installation and Operations Guide
November 2001
Chapter 5 SONET Topologies
Bidirectional Line Switched Rings
Figure 5-4
A four-node, four-fiber BLSR
Four-fiber BLSRs provide span and ring switching:
•
Span switching (
Figure 5-5
) occurs when a working span fails. Traffic switches to the protect fibers
between the nodes (Node 0 and Node 1 in the
Figure 5-5
example) and then returns to the working
fibers. Multiple span switches can occur at the same time.
•
Ring switching (
Figure 5-6
) 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 2
Span 3
Span 4
Span 8
Span 7
Span 6
Span 5
OC-48 Ring
= Working fibers
= Protect fibers
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Содержание 15454-TCC - Network Processor Card
Страница 22: ...Figures xxii Cisco ONS 15454 Installation and Operations Guide November 2001 ...
Страница 32: ...Procedures xxxii Cisco ONS 15454 Installation and Operations Guide November 2001 ...
Страница 158: ...3 20 Cisco ONS 15454 Installation and Operations Guide November 2001 Chapter 3 Node Setup Viewing CTC Software Versions ...
Страница 388: ...11 10 Cisco ONS 15454 Installation and Operations Guide November 2001 Chapter 11 SNMP SNMP Remote Network Monitoring ...