12-16
Cisco ONS 15454 Reference Manual, R7.0
78-17191-01
Chapter 12 SONET Topologies and Upgrades
12.3 12.3.1 BLSR DRI
Figure 12-14 ONS 15454 Traditional BLSR Dual-Ring Interconnect (Opposite-Side Routing)
Figure 12-15 shows ONS 15454s in an integrated BLSR-DRI topology. The same drop-and-continue 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.
Service Selector
Secondary Path
Primary Path, Drop and Continue to Bridge
Drop and Continue
115234
BLSR
Ring 1
Primary
Node
Secondary
Node
Node 5
Node 4 Node 3
Node 9 Node 8
Node 1
Node 2
BLSR
Ring 2
Secondary
Node
Primary
Node
Node 10
Node 6
Node 7