In Huawei CloudCampus wireless solutions for small- and medium-sized campus networks,refined traffic controlmeans the ability to precisely limit and manage bandwidth consumption at theindividual user level. Among the available rate limiting modes,user-based rate limitingis specifically designed to meet this requirement.

User-based rate limiting applies bandwidth control policiesper authenticated user, regardless of which SSID, AP, or radio the user is connected to. This allows administrators to ensure fair bandwidth allocation, prevent a single user from monopolizing wireless resources, and provide differentiated service levels for different user roles, such as employees, guests, or VIP users. This fine-grained control aligns with identity-based access and policy management promoted in HCIP Datacom Campus Network design.

In contrast,SSID-based rate limitingcontrols bandwidth at the service level. It limits total traffic for an entire SSID, which affects all users connected to that SSID collectively, rather than individually.Radio-based rate limitingcontrols bandwidth per radio interface, focusing on wireless resource optimization instead of user-level fairness.ACL-based rate limitingis mainly used for traffic classification and control in wired or advanced scenarios and is not suitable for per-user refined wireless traffic control in CloudCampus WLAN deployments.

Therefore, when the requirement is refined traffic control foreach individual wireless user,user-based rate limitingis the most appropriate and effective option. Hence, the correct answer isA.