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Cisco ONS 15600 SDH Reference Manual, Release 9.0
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Chapter 8 SDH Topologies and Upgrades
8.3 Multiplex-Section Shared Protection Rings
shows two ONS 15600 SDH nodes in a point-to-point ADM configuration. Working traffic
flows from Slot 1/Port 1 at Node 1 to Slot 1/Port 1 at Node 2. You create the protect path by creating a
1+1 configuration with Slot 2/Port 1 and Slot 2/Port 1 at Nodes 1 and 2.
Figure 8-1
Point-to-Point ADM Configuration
8.3 Multiplex-Section Shared Protection Rings
The ONS 15600 SDH can support up to 32 multiplex section-shared protection rings (MS-SPRings).
Because the working and protect bandwidths must be equal, you can create only STM-16 or STM-64
MS-SPRings (that is, you cannot create an MS-SPRing with a mixture of STM-16 and STM-64 line
rates). For information about MS-SPRing protection channels, see the
“7.7 Protection Channel Access
Circuits” section on page 7-14
.
Note
For best performance, MS-SPRings should have one LAN connection for every ten nodes in the
MS-SPRing.
8.3.1 Two-Fiber MS-SPRings
In two-fiber MS-SPRings, each fiber is divided into working and protect bandwidths. For example, in an
STM-16 MS-SPRing, VC4s 1 to 8 carry the working traffic, and VC4s 9 to 16 are reserved for protection
(
). Working traffic (VC4s 1 to 8) travels in one direction on one fiber and in the opposite
direction on the second fiber. Cisco Transport Controller (CTC) circuit routing routines calculate the
shortest path for circuits based on many factors, including user requirements, traffic patterns, and
distance. For example, in
, circuits going from Node 0 to Node 1 will typically travel on Fiber
1, unless that fiber is full, in which case circuits will be routed to Fiber 2 through Node 3 and Node 2.
Traffic from Node 0 to Node 2 (or Node 1 to Node 3) can be routed on either fiber, depending on circuit
provisioning requirements and traffic loads.
Node 1
Node 2
Slot 1/Port 1 to Slot 1/Port 1
Slot 2/Port 1 to Slot 2/Port 1
Working Path
Protect Path
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