802.1Qbu - Frame Preemption
The full title of this PAR is "Standard for Local and Metropolitan Area Networks-Media Access Control (MAC) Bridges and Virtual Bridged Local Area Networks - Amendment: Frame Preemption".
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.
The purpose of this amendment is to provide reduced latency transmission for scheduled, time-critical frames in a bridged LAN.
A large, non-time-critical frame may start ahead of time-critical frame transmission. This condition leads to excessive latency for the time-critical frame. The lack of transmission preemption severely inhibits the capabilities of an application that uses scheduled frame transmission to implement a real-time control network.
| Status | PAR approved 15th May 2012. |
| Date | Document |
|---|---|
| 18 Jul 2012 | Presentation bu-mjt-bu-goals-for-ethernet-0712.pdf |
| 20 Mar 2013 | Presentation bu-boiger-TAS-in-combination-with-Qbu-0313.pdf |
| 16 May 2013 | Presentation bu-boiger-IET-and-TAS-0513.pdf |
| 15 May 2014 | Presentation bu-nfinn-status-for-802-3-0514-v01.pdf |
| 10 Sep 2014 | Presentation bu-boiger-CBS-Preemption-Support-0914-v01.pdf |
| 11 Sep 2014 | Presentation bu-thaler-iet-management-model-alternatives-v01.pdf |
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