单项选择题
What protection method is used in 4F BLSR networks?（）
A. Each fiber has half of its SONET capacity reserved for protection.
B. Two fibers in the span carry working traffic, while the other two fibers in the span are reserved for protection.
C. The signal is sent simultaneously in both directions around the ring. The receiver determines which fiber to listen to based on signal quality.
D. The signal is sent simultaneously in both directions around the ring. The transmitter determines which fiber has the working bit set for the receiver to acknowledge.
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相关考题
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单项选择题
Which is a legitimate bandwidth matched pair?（）
A. DS-1; E1
B. DS-1; STM-1
C. OC-3; STM-1
D. STS-1; STM-1
E. OC-192; STM-192 -
多项选择题
SONET Path Terminating Equipment (PTE) requires which three line codes to be supported for DS1 and DS3 circuits?（） (Choose three.)
A.AMI
B.ESF
C.DUS
D.SSM
E.B3ZS
F.B8ZS -
单项选择题
Which timing mode is appropriate for a SONET NE that is adjacent to a SONET NE using BITS-1 timing source?（）
A.DUS
B.line timing
C.loop timing
D.internal timing
E.through timing
