This amendment specifies procedures, managed objects, and protocol extensions that: - Define a class of service for time-critical frames that requests the transmitter in a bridged Local Area Network to suspend the transmission of a non-time-critical frame, and allow for one or more time-critical frames to be transmitted. When the time-critical frames have been transmitted, the transmission of the preempted frame is resumed. A non-time-critical frame could be preempted multiple times. - Provide for discovery, configuration, and control of preemption service for a bridge port and end station. - Ensure that preemption is only enabled on a given link if both link partners have that capability.