DualQ Coupled AQM for Low Latency, Low Loss and Scalable Throughput

Document Type Replaced Internet-Draft (tsvwg WG)
Last updated 2017-05-04 (latest revision 2016-10-31)
Replaces draft-briscoe-aqm-dualq-coupled
Replaced by draft-ietf-tsvwg-aqm-dualq-coupled
Stream IETF
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Expired & archived
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Stream WG state Adopted by a WG
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IESG IESG state Replaced by draft-ietf-tsvwg-aqm-dualq-coupled
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This Internet-Draft is no longer active. A copy of the expired Internet-Draft can be found at


Data Centre TCP (DCTCP) was designed to provide predictably low queuing latency, near-zero loss, and throughput scalability using explicit congestion notification (ECN) and an extremely simple marking behaviour on switches. However, DCTCP does not co-exist with existing TCP traffic---throughput starves. So, until now, DCTCP could only be deployed where a clean-slate environment could be arranged, such as in private data centres. This specification defines `DualQ Coupled Active Queue Management (AQM)' to allow scalable congestion controls like DCTCP to safely co-exist with classic Internet traffic. The Coupled AQM ensures that a flow runs at about the same rate whether it uses DCTCP or TCP Reno/Cubic, but without inspecting transport layer flow identifiers. When tested in a residential broadband setting, DCTCP achieved sub-millisecond average queuing delay and zero congestion loss under a wide range of mixes of DCTCP and `Classic' broadband Internet traffic, without compromising the performance of the Classic traffic. The solution also reduces network complexity and eliminates network configuration.


Koen De Schepper (koen.de_schepper@nokia.com)
Bob Briscoe (ietf@bobbriscoe.net)
Olga Bondarenko (olgabnd@gmail.com)
Ing Tsang (ing-jyh.tsang@nokia.com)

(Note: The e-mail addresses provided for the authors of this Internet-Draft may no longer be valid.)