A device using which protocol would typically function at 100Mbps?

The choice of protocol that typically functions at 100Mbps is Ultimo. This protocol is specifically designed for low-cost audio and enables efficient transmission of audio data over Ethernet networks while supporting a data rate of 100Mbps. This capacity is essential for maintaining adequate audio quality and system reliability in various environments, particularly in installations focused on professional audio networking.

Other protocols like Brooklyn II, AVB (Audio Video Bridging), and EtherSound may operate at different speeds, with AVB, for instance, is built to support higher bandwidth applications with more sophisticated networking needs, including quality of service features at speeds often higher than 100Mbps. Therefore, understanding the characteristics and intended use cases of each protocol helps clarify why Ultimo is the correct answer as it is specifically tailored for 100Mbps functionality.