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Cisco ONS 15454 Reference Manual, R7.0
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Chapter 12 SONET Topologies and Upgrades
12.2 12.2.4 BLSR Application Example
Figure 12-7 shows an example of BLSR bandwidth reuse. The same STS carries three different traffic
sets simultaneously on different spans around the ring: one set from Node 3 to Node 1, another set from
Node 1 to Node 2, and another set from Node 2 to Node 3.
Figure 12-7 BLSR Bandwidth Reuse
12.2.4 BLSR Application Example
Figure 12-8 shows a two-fiber BLSR implementation example with five nodes. A regional long-distance
network connects to other carriers at Node 0. Traffic is delivered to the service provider’s major hubs.
Carrier 1 delivers six DS-3s over two OC-3 spans to Node 0. Carrier 2 provides twelve DS-3s
directly. Node 0 receives the signals and delivers them around the ring to the appropriate node.
The ring also brings 14 DS-1s back from each remote site to Node 0. Intermediate nodes serve these
shorter regional connections.
Table 12-3 Four-Fiber BLSR Capacity
OC Rate Working Bandwidth Protection Bandwidth Ring Capacity
OC-48 STS 1-48 (Fiber 1) STS 1-48 (Fiber 2) 48 x N1 – PT2
1. N equals the number of ONS 15454 nodes configured as BLSR nodes.
2. PT equals the number of STS-1 circuits passed through ONS 15454 nodes in the ring (capacity can vary
depending on the traffic pattern).
OC-192 STS 1-192 (Fiber 1) STS 1-192 (Fiber 2) 192 x N – PT
STS#1 STS#1
STS#1 STS#1
Node 0
Node 1
Node 2
Node 3
32131
= Node 3 – Node 1 traffic
= Node 1 – Node 2 traffic
= Node 2 – Node 3 traffic