Which of the following description of discrete services is correct? (Multiple Choice)

• A. Discrete service management requires the U2000 license to have path management functions.
• B. Perform path search on the U2000 network management. Cross-connections that do not form a path are called high-bandwidth services.
• C. For the cross-connections, after a path search, either a discrete service or forming a path with other cross-connections, which is impossible to be a discrete service, and forming a path with other cross-connections.
• D. A service is searched for a discrete service, indicating that the service is not working properly on the NE side.

Which of the following reasons may cause a business error? (Multiple choice)

• A. The tail wire connector is seriously polluted
• B. The optical power of the incoming fiber is too high or too low
• C. Transmitting laser performance degradation of the originating OTU board
• D. The temperature in the equipment room is too high
• E. Dispersion compensation is unreasonable, such as under- or over-compensation

For the whole network error test in the commissioning test, which of the following statement is correct? (Multiple choice)

• A. To ensure the smooth passage of all channel services across the entire network, a 10-minute error prediction is required for each single channel.
• B. The duration of the full channel error test is 20 hours. If the error occurs within 20 hours, it needs to be retested for 20 hours after troubleshooting.
• C. The number of OTU boards or tributary boards connected in series for the whole channel error test is recommended to be no more than 13
• D. When the single channel error test is performed, the remote end needs to perform hardware loopback on the tributary board client side.

The OSN 8800 device is protected by fan redundancy. When any fan in the fan box is broken, the system can still operate normally for a long time.

• A. TRUE
• B. FALSE