Datasheet

12-20
Cisco ONS 15454 SDH Reference Manual, R7.0
October 2008
Chapter 12 SDH Topologies and Upgrades
12.4.1 MS-SPRing DRI
Figure 12-19 shows ONS 15454 SDH nodes in a traditional MS-SPRing 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 8). Similarly, at Node 8, traffic is dropped (to Node 3) and continued (to Node 4).
Figure 12-19 ONS 15454 SDH Traditional MS-SPRing Dual Ring Interconnect (Opposite-Side
Routing)
Figure 12-20 shows ONS 15454 SDH nodes in an integrated MS-SPRing DRI topology. The same
drop-and-continue traffic routing occurs at two nodes, rather than four. This is achieved by installing an
additional STM-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
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MS-SPRing
Ring 1
Primary
Node
Secondary
Node
Node 5
Node 4 Node 3
Node 9 Node 8
Node 1
Node 2
MS-SPRing
Ring 2
Secondary
Node
Primary
Node
Node 10
Node 6
Node 7