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.

A. the DCC-E
B. the DCC-M
C. the DCC-R
D. the Line DCC
E. the Section DCC

A. J0 errors detected in a in a specified interval
B. errors detected in a given Errored Seconds （ES）
C. errors detected in a given Severely Errored Seconds （SES）
D. errors the encryption algorithm detects in a specified interval
E. Bit Interleaved Parity （BIP） errors detected in a specified interval

A. fiber failure between Sites A and D
B. EDFA failure at Site A （clockwise direction）
C. EDFA failure at Site C （clockwise direction）
D. 15216 multiplexer at Site A （counter-clockwise direction）
E. OADM pass-through （West "OUT"） failure at site D （clockwise）
F. wavelengths 1 and 3 transmitter failures at Site A （clockwise direction）

A. All "Add" channels require uniform power levels.
B. The flexibility of wavelengths per OADM is limited.
C. It is easier to balance "Pass-Through" and "Add" channels.
D. There is lower pass-through loss using multi-channel OADMs.
E. You can extract a single channel without dropping other channels.