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Cisco ONS 15454 Reference Manual, R7.0
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Chapter 12 SONET Topologies and Upgrades
12.3 12.3.1 BLSR DRI
Figure 12-13 ONS 15454 Traditional BLSR Dual-Ring Interconnect (Same-Side Routing)
Figure 12-14 shows ONS 15454 nodes in a traditional BLSR-DRI topology with opposite-side routing. In Ring 1, Nodes 3 and 4 are the interconnect nodes, and in Ring 2, Nodes 8 and 9 are the interconnect nodes. Duplicate signals are sent from Node 4 (Ring 1) to Node 8 (Ring 2), and between Node 3 (Ring 1) and Node 9 (Ring 2). In Ring 1, traffic at Node 4 is dropped (to Node 9) and continued (to Node 3). Similarly, at Node 8, traffic is dropped (to Node 3) and continued (to Node 8).
Service Selector
Secondary Path
Primary Path, Drop and Continue to Bridge
Drop and Continue
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BLSR
Ring 1
Primary
Node
Secondary
Node
Node 5
Node 4 Node 3
Node 9 Node 8
Node 1
Node 2
BLSR
Ring 2
Primary
Node
Secondary
Node
Node 10
Node 6
Node 7