What type of traffic is described as requiring latency to be no more than 400 milliseconds (ms)?

The type of traffic that requires latency to be no more than 400 milliseconds is indeed associated with real-time communications and applications that are sensitive to delays. Specifically, voice traffic typically requires a lower latency threshold, often recommended to be under 150 milliseconds to ensure clear and undistorted conversation flow. Video traffic, while it can tolerate some latency, generally prefers it under 200 milliseconds for optimal user experience, particularly for interactive video calls.

Streaming audio can accommodate slightly higher latency, but for a truly seamless experience, it is still advisable to keep it below 400 milliseconds. File transfers do not have stringent latency requirements as they can tolerate higher latency levels without affecting the integrity or quality of the data being transmitted.

Given these considerations, voice traffic is the correct type of communication that necessitates maintaining a latency of no more than 400 milliseconds to ensure effective and reliable communication, making it vital for maintaining clear audio without interruptions.