Datasheet

12-5
Cisco ONS 15454 SDH Reference Manual, R7.0
October 2008
Chapter 12 SDH Topologies and Upgrades
12.2.2 Four-Fiber MS-SPRings
Figure 12-3 Four-Node, Two-Fiber MS-SPRing Traffic Pattern After Line Break
12.2.2 Four-Fiber MS-SPRings
Four-fiber MS-SPRings double the bandwidth of two-fiber MS-SPRings. Because they allow span
switching as well as ring switching, four-fiber MS-SPRings increase the reliability and flexibility of
traffic protection. Two fibers are allocated for working traffic and two fibers for protection, as shown in
Figure 12-4. To implement a four-fiber MS-SPRing, you must install four STM-16 cards or four STM-64
cards at each MS-SPRing node.
Node 0
Node 1
Node 2
Node 3
STM-16 Ring
Traffic flow
Fiber 1
Fiber 2
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