Specifications
2-2
Cisco ONS 15530 Planning Guide
OL-7708-01
Chapter 2 Protection Schemes and Network Topologies
Splitter Based Facility Protection
Splitter Based Facility Protection
To survive a fiber failure, fiber optic networks are designed with both working and protection fibers. In
the event of a fiber cut or other facility failure, working traffic is switched to the protection fiber. The
Cisco ONS 15530 supports such facility protection using a splitter scheme (see Figure 2-1) to send the
output of the DWDM transmitter on two trunk side interfaces.
Transponder line cards, 8-port multi-service muxponders, 2.5-Gbps ITU trunk cards, 10-Gbps ITU
tunable and non tunable trunk cards, and 10-Gbps ITU trunk cards support splitter protection.
Transponder Line Cards
With splitter protection, a passive optical splitter module on the transponder line card duplicates the ITU
signal. The front panel of each splitter transponder line card has connectors for two fiber pairs for cabling
to the two OADM modules. One fiber pair serves as the active connection, while the other pair serves as
the standby. The signal is transmitted on both connections, but in the receive direction, an optical switch
selects one signal to be the active one. If a failure is detected on the active receive signal, a switchover
to the standby receiver signal occurs under control of the LRC (line card redundancy controller).
Assume, for example, that if the active signal in Figure 2-1 is on the east interface, a failure of the signal
on that fiber would result in a switchover, and the signal on the west interface would be selected for the
receive signal. You can configure preferred working and protection interfaces in the software for the
system to use for the active and standby signals, as the signal quality allows.
Figure 2-1 Splitter Protection with Transponder Line Cards
Transponder
line cards
OADM
modules
West
East
SRC
LRC
Client optics
ITU optics
Performance
monitor
CPU
LRC
LRC
LRCLRC
OSC
OSC
Redundant
CPU switch
modules
Optical
fiber
connection
Electrical
backplane
connection
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