Cisco ONS 15454 - Four-Fiber Blsrs

12-6
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 12-3 Four-Node, Two-Fiber BLSR Traffic Pattern Following Line Break
12.2.2 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 Figure 12-4. To
implement a four-fiber BLSR, you must install four OC-48, OC-48 AS, or OC-192 cards at each BLSR
node.
Node 0
Node 1
Node 2
Node 3 OC-48 Ring
61957
Traffic flow
Fiber 1
Fiber 2