Specifications

37
Cisco ONS 15327 Product Overview, R3.3
June 2002
Cisco ONS 15327 Product Overview
Network Configurations
traffic flows in one direction on the ring and the second fiber provides a protection
path flowing in the opposite direction. If a problem occurs in the working traffic
path, the receiving node switches to the path coming from the opposite direction.
Services can originate and terminate on the same UPSR or can be passed to an
adjacent access or interoffice ring for transport to the service-terminating
location. Because each traffic path is transported around the entire ring, UPSRs
are best suited for networks where traffic concentrates in one or two locations and
is not widely distributed.
Figure 28 shows a basic UPSR configuration. If Node ID 0 sends a signal to Node
ID 2, the working signal travels on the working traffic path through Node ID 1.
The same signal is also sent on the protect traffic path through Node ID 3. If a
fiber break occurs, Node ID 2 switches its active receiver to the protect signal
coming through Node ID 3.
Figure 28 Unidirectional path-switched ring example
ONS 15327
Node ID 0
ONS 15327
Node ID 1
ONS 15327
Node ID 2
ONS 15327
Node ID 3
48398
= Fiber 1
= Fiber 2