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Cisco ONS 15600 SDH Reference Manual, Release 9.0
78-18400-01
Chapter 8 SDH Topologies and Upgrades
8.3.2 MS-SPRing Bandwidth
Figure 8-4
Four-Node, Two-Fiber MS-SPRing Traffic Pattern Following Line Break
8.3.2 MS-SPRing Bandwidth
MS-SPRing nodes can terminate traffic coming from either side of the ring. Therefore, MS-SPRings are
suited for distributed node-to-node traffic applications such as interoffice networks and access networks.
MS-SPRings allow bandwidth to be reused around the ring and can carry more traffic than a network
with traffic flowing through one central hub. MS-SPRings can also carry more traffic than a subnetwork
connection protection (SNCP) ring operating at the same STM-N rate.
shows the bidirectional
bandwidth capacities of two-fiber MS-SPRings. The capacity is the STM-N rate divided by two,
multiplied by the number of nodes in the ring minus the number of pass-through VC circuits.
shows an example of MS-SPRing bandwidth reuse. The same VC4 carries three different
traffic sets simultaneously on different spans around the ring: one set from Node 3 to Node 1, another
set from Node 1 to Node 2, and another set from Node 2 to Node 3.
Node 0
Node 1
Node 2
Node 3
STM-16 Ring
159598
Traffic flow
Fiber 1
Fiber 2
Table 8-1
Two-Fiber MS-SPRing Capacity
OC Rate
Working Bandwidth
Protection Bandwidth
Ring Capacity
STM-16
VC4 1-8
VC4 9-16
8 x N
1
– PT
2
1.
N equals the number of ONS 15xxx SDH nodes in the ring. Nodes can be configured as MS-SPRing nodes
but be in another MS-SPRing.
2.
PT equals the number of VC-4 circuits passed through ONS 15xxx SDH nodes in the ring (capacity varies
depending on the traffic pattern).
STM-64
VC4 1-32
VC4 33-64
32 x N – PT