问题：
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.
● 参考解析
本题暂无解析
