Enhanced Transmission Selection
Enhanced Transmission Selection (ETS) is a network scheduler scheduling algorithm that has been defined by the Data Center Bridging Task Group of the IEEE 802.1 Working Group.[1] It is a hierarchical scheduler that combines static priority scheduling and a bandwidth sharing algorithms (such as Weighted round robin or Deficit round robin).
Description
[edit]The Enhanced Transmission Selection algorithm is one scheduling algorithm supported by IEEE 802.1Q. In Enhanced Transmission Selection, they are two types or queues: Strict priority or Credit-based queues, and bandwidth-assigned queues. Each bandwidth-assigned queue has a bandwidth parameter, and the total for all bandwidth-assigned queue must be 100%.[2] [3][4][5]
If there is no frame ready for transmission, in the Strict priority and Credit-based queues, a frame from the bandwidth-assigned queue can be transmitted. A bandwidth-sharing algorithm is in charge of selecting the queue such that the bandwidth consumed by each queue approaches its percentage of the bandwidth leftover by the Strict priority and Credit-based queues. If a queue uses less than its percentage, the remainder of its percentage used by other queues.
The standard does not specify which bandwidth-sharing algorithm must be used since there are a number of variants of bandwidth sharing algorithm, but gives some constraints and references Weighted round robin. The Linux implementation of ETS does not consider Credit-based queues and uses Deficit round robin as bandwidth-sharing algorithm. ETS is also implemented in Microsoft Network Drivers [6]
See also
[edit]- Deficit round robin
- Fairness measure
- Max-min fairness
- Scheduling algorithm
- Statistical time division multiplexing
- Weighted round robin
- Data center bridging
- 802.1Qaz working group home page
References
[edit]- ^ Scarfò, Antonio (21–24 June 2011). "The Evolution of Data Center Networking Technologies". Proceedings of the First International Conference on Data Compression, Communications and Processing. Palinuro, Italy: IEEE. doi:10.1109/CCP.2011.30.
- ^ Media Access Control (MAC) Bridges and Virtual Bridged Local Area Networks — Amendment 18: Enhanced Transmission Selection for Bandwidth Sharing Between Traffic Classes, IEEE, September 2011, doi:10.1109/IEEESTD.2011.6034507, ISBN 978-0-7381-6655-1
- ^ Lama, Victor (23 March 2011). Enhanced Transmission Selection - IEEE 802.1Qaz (PDF) (Technical report). CISCO.
{{cite tech report}}: CS1 maint: date and year (link) - ^ "Managing Network Datalinks in Oracle® Solaris 11.2". ORACLE. 2014. Retrieved 5 October 2020.
- ^ Matheus Guedes de Andrade (2014). "Enhancement Transmission Selection". Universidade Federal do Rio de Janeiro. Retrieved 5 October 2020.
- ^ "Enhanced Transmission Selection (ETS) Algorithm". Microsoft. 2017. Retrieved 5 October 2020.