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CUBIC for Fast Long-Distance Networks

Document Type Expired Internet-Draft (individual)
Expired & archived
Authors Injong Rhee , Lisong Xu , Sangtae Ha
Last updated 2008-08-26 (Latest revision 2008-08-08)
Replaces draft-rhee-tcp-cubic
RFC stream (None)
Stream Stream state (No stream defined)
Consensus boilerplate Unknown
RFC Editor Note (None)
IESG IESG state Expired
Telechat date (None)
Responsible AD (None)
Send notices to (None)

This Internet-Draft is no longer active. A copy of the expired Internet-Draft is available in these formats:


CUBIC is an extension to the current TCP standards. The protocol differs from the current TCP standards only in the congestion window adjustment function in the sender side. In particular, it uses a cubic function instead of a linear window increase of the current TCP standards to improve scalability and stability under fast and long distance networks. BIC-TCP, a predecessor of CUBIC, has been a default TCP adopted by Linux since year 2005 and has already been deployed globally and in use for several years by the Internet community at large. CUBIC is using a similar window growth function as BIC-TCP and is designed to be less aggressive and fairer to TCP in bandwidth usage than BIC-TCP while maintaining the strengths of BIC- TCP such as stability, window scalability and RTT fairness. Through extensive testing in various Internet scenarios, we believe that CUBIC is safe for deployment and testing in the global Internet. The intent of this document is to provide the protocol specification of CUBIC for a third party implementation and solicit the community feedback through experimentation on the performance of CUBIC. We expect this document to be eventually published as an experimental RFC.


Injong Rhee
Lisong Xu
Sangtae Ha

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