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Cisco ONS 15454 Installation and Operations Guide
November 2001
Chapter5 SONET Topologies
Subtending Rings
c. Click Apply.
d. Repeat steps a – c for the second BLSR trunk card.
Step 9 Use the “Provision the BLSR” procedure on page 5-14 to configure the BLSR.
Step 10 Follow Steps 1– 8 for the other nodes that will be in the BLSR.
Step 11 Go to the network view to see the subtending ring.
The ONS 15454 can support two BLSRs on the same node. This capability allows you to deplo y an ONS
15454 in applications requiring SONET DCSs (digital cross connect systems) or multiple SONET
ADMs (add/drop multiplexers).
Figure 5-30 shows two BLSRs shared by one ONS 15454. Ring 1 runs on No des 1, 2 , 3, and 4. Ring 2
runs on Nodes 4, 5, 6, and 7. Two BLSR rings, Ring 1 and Ring 2, are provision ed on Nod e 4. Ri ng 1
uses cards in Slots 5 and 12, and Ring 2 uses cards in Slots 6 and 13.
Note Although different node IDs are used for the two BLSRs shown in Figure 5-30, nodes in different
BLSRs can use the same node ID.
Figure5-30 A BLSR subtending from a BLSR
After subtending two BLSRs, you can route circuits from nodes in one ring to nodes in the second ring.
For example in Figure 5-30, you can route a circuit from Node 1 to Node 7. The circuit would normally
travel from Node 1 to Node 4 to Node 7. If fiber breaks occur, for example between Nodes 1 and 4 and
Nodes 4 and 7, traffic is rerouted around each ring: in this example, Nodes 2 and 3 in Ring 1 and Nodes
5 and 6 in Ring 2.
55298
Node 5
Slot 6
West East
Slot 13
Node 7
Slot 13
East Slot 6
West
Slot 6
West
Slot 13
East
Node 6
Node 1
Slot 5
West
Slot 5
West
Slot 12
East
Slot 12
East
Node 3
Slot 12
East Slot 5
West
Node 2
Slot 5
West
Slot 12
East
Slot 13
East
Slot 6
West
Node 4
BLSR
Ring 1 BLSR
Ring 2