Huawei's iMaster NCE-Fabric is an SDN controller for the CloudFabric data center network solution, providing network management and automation. The rollback feature allows administrators to revert configuration changes to previous states in case of errors. According to Huawei's documentation, iMaster NCE-Fabric supports four rollback levels, enabling the system to store and restore up to four previous configuration versions. This ensures flexibility in undoing changes during network management tasks like upgrades or policy adjustments.
Options Analysis:
A . 3: Incorrect, as it underestimates the supported levels.
B . 4: Correct, aligning with Huawei's specified rollback capability.
C . 2: Incorrect, as it is fewer than the supported levels.
D . 1: Incorrect, as it limits rollback to a single state, which is insufficient for complex management.
Thus, the answer is B (4).