LEDBAT++: Congestion Control for Background Traffic

Document Type Expired Internet-Draft (iccrg RG)
Authors Praveen Balasubramanian  , Osman Ertugay  , Daniel Havey 
Last updated 2021-03-08 (latest revision 2020-08-25)
Replaces draft-balasubramanian-iccrg-ledbatplusplus
Stream Internet Research Task Force (IRTF)
Intended RFC status (None)
Expired & archived
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This Internet-Draft is no longer active. A copy of the expired Internet-Draft can be found at


This informational memo describes LEDBAT++, a set of enhancements to the LEDBAT (Low Extra Delay Background Transport) congestion control algorithm for background traffic. The LEDBAT congestion control algorithm has several shortcomings that prevent it from working effectively in practice. LEDBAT++ extends LEDBAT by adding a set of improvements, including reduced congestion window gain, modified slow-start, multiplicative decrease and periodic slowdowns. This set of improvement mitigates the known issues with the LEDBAT algorithm, such as latency drift, latecomer advantage and inter-LEDBAT fairness. LEDBAT++ has been implemented as a TCP congestion control algorithm in the Windows operating system. LEDBAT++ has been deployed in production at scale on a variety of networks and been experimentally verified to achieve the original stated goals of LEDBAT.


Praveen Balasubramanian (pravb@microsoft.com)
Osman Ertugay (osmaner@microsoft.com)
Daniel Havey (dahavey@microsoft.com)

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