CHAPT ER
12-1
Cisco ONS 15454 Reference Manual, R7.0
78-17191-01
12
SONET Topologies and Upgrades
Note The terms "Unidirectional Path Switched Ring" and "UPSR" may appear in Cisco literature. These terms
do not refer to using Cisco ONS 15xxx products in a unidirectional path switched ring configuration.
Rather, these terms, as well as "Path Protected Mesh Network" and "PPMN," refer generally to Cisco's
path protection feature, which may be used in any topological network configuration. Cisco does not
recommend using its path protection feature in any particular topological network configuration.
This chapter explains Cisco ONS 15454 SONET topologies and upgrades. To provision topologies, refer
to the Cisco ONS 15454 Procedure Guide.
Chapter topics include:
• 12.1 SONET Rings and TCC2/TCC2P Cards, page 12-1
• 12.2 Bidirectional Line Switched Rings, page 12-2
• 12.3 Dual-Ring Interconnect, page 12-13
• 12.4 Comparison of the Protection Schemes, page 12-18
• 12.5 Linear ADM Configurations, page 12-19
• 12.6 Path-Protected Mesh Networks, page 12-19
• 12.7 Four-Shelf Node Configurations, page 12-21
• 12.8 OC-N Speed Upgrades, page 12-22
• 12.9 In-Service Topology Upgrades, page 12-25

12.1 SONET Rings and TCC2/TCC2P Cards

Table 12-1 shows the SONET rings that can be created on each ONS 15454 node using redundant
TCC2/TCC2P cards.
Table 12-1 ONS 15454 Rings with Redundant TCC2/TCC2P Cards
Ring Type Maximum Rings per Node
BLSRs 5
2-Fiber BLSR 5
4-Fiber BLSR 1