DEFICIT ROUND ROBIN

'Deficit round robin' ('DRR')^[1], also 'deficit weighted round robin' ('DWRR'), is a modified weighted round robin scheduling discipline. DRR was proposed by M. Shreedhar and G. Varghese in 1995. It can handle packets of variable size without knowing their mean size. A maximum packet size number is subtracted from the packet length, and packets that exceed that number are held back until the next visit of the scheduler.
WRR serves every nonempty queue whereas DRR serves packets at the head of every nonempty queue which ''deficit counter'' is greater than the packet's size. If it is lower then ''deficit counter'' is increased by some given value called ''quantum''. ''Deficit counter'' is decreased by the size of packets being served.
Compared with Fair queueing (FQ) scheduler that has complexity of ''O''(log(''n'')) (''n'' is the number of active flows), the complexity of DRR is ''O''(1).

Contents

See also

References

External links

See also

★ scheduling disciplines

References

1. Efficient fair queueing using deficit round robin, , M., Shreedhar, ACM SIGCOMM Computer Communication Review, 1995

External links

Efficient fair queueing using deficit round robin
Source Applications, Technologies, Architectures, and Protocols for Computer Communication archive
Proceedings of the conference on Applications, technologies, architectures, and protocols for computer communication table of contents
Cambridge, Massachusetts, United States
Year of Publication: 1995
ISSN:0146-4833
Authors
M. Shreedhar Microsoft Corporation
George Varghese Washington University in St. Louis.
Sponsor
SIGCOMM: ACM Special Interest Group on Data Communication
Publisher
ACM Press New York, NY, USA