Which of the following is considered a real-time function in Split-MAC architecture?

In Split-MAC architecture, the MAC management function is indeed considered a real-time function. This approach segregates the control and management functions between a centralized controller and distributed access points. Specifically, MAC management encompasses tasks related to managing the MAC layer for wireless clients, such as handling data frame transmission and reception, contention management, and ensuring timely delivery of frames.

By performing these functions in real time at the access point, the architecture can effectively manage the network traffic and meet the demands of wireless clients without introducing significant latency. This is crucial for maintaining high quality and responsiveness in wireless communication, which is why MAC management is classified as real-time.

In contrast, functions like client authentication, Quality of Service (QoS), and security management, while vital to the operation of a wireless network, do not require the immediate responsiveness associated with real-time processing. These tasks can often tolerate some degree of delay, as they may involve complex verification or configuration processes that don't need to happen instantaneously. Therefore, those functions are managed differently and are not classified as real-time in the context of Split-MAC architecture.