What protection method is used in 4F MS-SPRing networks？（）
A. Each fiber has half of its capacity reserved for protection.
B. Two fibers carry their full capacities while the other two fibers 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.
微信支付 
支付宝支付