Cisco Systems 15454M6DC Manuel D’Utilisation
5-4
Cisco ONS 15454 Installation and Operations Guide
78-13453-01
Chapter 5 SONET Topologies
Bidirectional Line Switched Rings
Figure 5-3
Four-node, two-fiber BLSR traffic pattern following line break
5.2.2 Four-Fiber BLSRs
Four-fiber BLSRs double the bandwidth of two-fiber BLSRs. Because they allow span switching as well
as ring switching, four-fiber BLSRs increase the reliability and flexibility of traffic protection. Two
fibers are allocated for working traffic and two fibers for protection, as shown in
as ring switching, four-fiber BLSRs increase the reliability and flexibility of traffic protection. Two
fibers are allocated for working traffic and two fibers for protection, as shown in
. To
implement a four-fiber BLSR, you must install four OC-48 or OC-48AS cards, or four OC-192 cards at
each BLSR node.
each BLSR node.
Node 0
Node 1
Node 2
Node 3
OC-48 Ring
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Traffic flow
Fiber 1
Fiber 2