Specifications

5-9
Cisco ONS 15454 Installation and Operations Guide, R3.2
March 2002
Chapter 5 SONET Topologies
Bidirectional Line Switched Rings
5.2.5 Sample BLSR Application
Figure 5-9 shows a sample two-fiber BLSR implementation. A regional long-distance network connects
to other carriers at Node 0. Traffic is delivered to the service provider’s major hubs.
• Carrier 1 delivers six DS-3s over two OC-3 spans to Node 0. Carrier 2 provides twelve DS-3s
directly. Node 0 receives the signals and delivers them around the ring to the appropriate node.
• The ring also brings 14 DS-1s back from each remote site to Node 0. Intermediate nodes serve these
shorter regional connections.
• The ONS 15454 OC-3 card supports a total of four OC-3 ports so that two additional OC-3 spans
can be added at little cost.
Figure 5-9 A five-node BLSR
Figure 5-10 shows the shelf assembly layout for Node 0, which has one free slot. Figure 5-11 shows the
shelf assembly layout for the remaining sites in the ring. In this BLSR configuration, an additional eight
DS-3s at Node IDs 1 and 3 can be activated. An additional four DS-3s can be added at Node ID 4, and
ten DS-3s can be added at Node ID 2. Each site has free slots for future traffic needs.
Node 0
56 local
DS-1s 4 DS-1s 14 DS-1s
14 DS-1s
14 DS-1s
14 DS-1s
8 DS-3s
4 DS-1s
2 DS-1s
Carrier 1
2 OC-3s
Node 1
Node 2
Node 3
Node 4
= Fiber 1
= Fiber 2
32138
Carrier 2
12 DS-3s