Cisco 15454-DS1-14= - 1.544Mbps Expansion Module Reference Manual page 429

Chapter 12 SONET Topologies and Upgrades
Figure 12-19
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).
Figure 12-19
Node 5
Node 10
Figure 12-20
traffic routing occurs at two nodes, rather than four. This is achieved by installing an additional OC-N
trunk at the two interconnect nodes. Nodes 3 and 8 are the interconnect nodes.
78-18106-01
shows ONS 15454 nodes in a traditional BLSR-DRI topology with opposite-side routing.
ONS 15454 Traditional BLSR Dual-Ring Interconnect (Opposite-Side Routing)
Node 1
Ring 1
Primary
Node
Node 4
Node 9
Secondary
Node
Ring 2
Node 6
Drop and Continue
Service Selector
Primary Path, Drop and Continue to Bridge
Secondary Path
shows ONS 15454s in an integrated BLSR-DRI topology. The same drop-and-continue
BLSR
Secondary
Node
Node 3
Node 8
Primary
Node
BLSR
Cisco ONS 15454 Reference Manual, R8.5
12.4.1 BLSR DRI
Node 2
Node 7
12-21