Filter
Top Products
11-5
Cisco ONS 15454 SDH Reference Manual, R5.0
April 2008
Chapter 11 SDH Topologies and Upgrades
11.2.1 Two-Fiber MS-SPRings
Figure 11-3 shows how traffic is rerouted after a line break between Node 0 and Node 3.
• All circuits originating on Node 0 and carried to Node 2 on Fiber 2 are switched to the protect
bandwidth of Fiber 1. For example, a circuit carried on VC4-1 on Fiber 2 is switched to VC4-9 on
Fiber 1. A circuit carried on VC4-2 on Fiber 2 is switched to VC4-10 on Fiber 1. Fiber 1 carries the
circuit to Node 3 (the original routing destination). Node 3 switches the circuit back to VC4-1 on
Fiber 2 where it is routed to Node 2 on VC4-1.
• Circuits originating on Node 2 that were normally carried to Node 0 on Fiber 1 are switched to the
protect bandwidth of Fiber 2 at Node 3. For example, a circuit carried on VC4-2 on Fiber 1 is
switched to VC4-10 on Fiber 2. Fiber 2 carries the circuit to Node 0 where the circuit is switched
back to VC4-2 on Fiber 1 and then dropped to its destination.
Figure 11-3 Four-Node, Two-Fiber MS-SPRing Traffic Pattern After Line Break
Node 0
Node 1
Node 2
Node 3
STM-16 Ring
Traffic flow
Fiber 1
Fiber 2
71277