BBR Congestion Control

Document Type Expired Internet-Draft (individual)
Authors Neal Cardwell  , Yuchung Cheng  , Soheil Yeganeh  , Van Jacobson 
Last updated 2018-01-04 (latest revision 2017-07-03)
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This Internet-Draft is no longer active. A copy of the expired Internet-Draft can be found at


This document specifies the BBR congestion control algorithm. BBR uses recent measurements of a transport connection's delivery rate and round-trip time to build an explicit model that includes both the maximum recent bandwidth available to that connection, and its minimum recent round-trip delay. BBR then uses this model to control both how fast it sends data and the maximum amount of data it allows in flight in the network at any time. Relative to loss-based congestion control algorithms such as Reno [RFC5681] or CUBIC [draft-ietf-tcpm-cubic], BBR offers substantially higher throughput for bottlenecks with shallow buffers or random losses, and substantially lower queueing delays for bottlenecks with deep buffers (avoiding "bufferbloat"). This algorithm can be implemented in any transport protocol that supports packet-delivery acknowledgment (thus far, open source implementations are available for TCP [RFC793] and QUIC [draft-ietf-quic-transport-00]).


Neal Cardwell (
Yuchung Cheng (
Soheil Yeganeh (
Van Jacobson (

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