PageRenderTime 23ms CodeModel.GetById 15ms app.highlight 3ms RepoModel.GetById 2ms app.codeStats 0ms

/share/man/man4/cc_cubic.4

https://bitbucket.org/freebsd/freebsd-head/
Forth | 114 lines | 114 code | 0 blank | 0 comment | 3 complexity | 353f4abb7d11673df61e850de96f1da8 MD5 | raw file
  1.\"
  2.\" Copyright (c) 2009 Lawrence Stewart <lstewart@FreeBSD.org>
  3.\" Copyright (c) 2010-2011 The FreeBSD Foundation
  4.\" All rights reserved.
  5.\"
  6.\" Portions of this documentation were written at the Centre for Advanced
  7.\" Internet Architectures, Swinburne University of Technology, Melbourne,
  8.\" Australia by David Hayes under sponsorship from the FreeBSD Foundation.
  9.\"
 10.\" Redistribution and use in source and binary forms, with or without
 11.\" modification, are permitted provided that the following conditions
 12.\" are met:
 13.\" 1. Redistributions of source code must retain the above copyright
 14.\"    notice, this list of conditions and the following disclaimer.
 15.\" 2. Redistributions in binary form must reproduce the above copyright
 16.\"    notice, this list of conditions and the following disclaimer in the
 17.\"    documentation and/or other materials provided with the distribution.
 18.\"
 19.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 20.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 21.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 22.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
 23.\" ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 24.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 25.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 26.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 27.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 28.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 29.\" SUCH DAMAGE.
 30.\"
 31.\" $FreeBSD$
 32.\"
 33.Dd September 15, 2011
 34.Dt CC_CUBIC 4
 35.Os
 36.Sh NAME
 37.Nm cc_cubic
 38.Nd CUBIC Congestion Control Algorithm
 39.Sh DESCRIPTION
 40The CUBIC congestion control algorithm was designed to provide increased
 41throughput in fast and long-distance networks.
 42It attempts to maintain fairness when competing with legacy NewReno TCP in lower
 43speed scenarios where NewReno is able to operate adequately.
 44.Pp
 45The congestion window is increased as a function of the time elapsed since the
 46last congestion event.
 47During regular operation, the window increase function follows a cubic function,
 48with the inflection point set to be the congestion window value reached at the
 49last congestion event.
 50CUBIC also calculates an estimate of the congestion window that NewReno would
 51have achieved at a given time after a congestion event.
 52When updating the congestion window, the algorithm will choose the larger of the
 53calculated CUBIC and estimated NewReno windows.
 54.Pp
 55CUBIC also backs off less on congestion by changing the multiplicative decrease
 56factor from 1/2 (used by standard NewReno TCP) to 4/5.
 57.Pp
 58The implementation was done in a clean-room fashion, and is based on the
 59Internet Draft and paper referenced in the
 60.Sx SEE ALSO
 61section below.
 62.Sh MIB Variables
 63There are currently no tunable MIB variables.
 64.Sh SEE ALSO
 65.Xr cc_chd 4 ,
 66.Xr cc_hd 4 ,
 67.Xr cc_htcp 4 ,
 68.Xr cc_newreno 4 ,
 69.Xr cc_vegas 4 ,
 70.Xr mod_cc 4 ,
 71.Xr tcp 4 ,
 72.Xr mod_cc 9
 73.Rs
 74.%A "Sangtae Ha"
 75.%A "Injong Rhee"
 76.%A "Lisong Xu"
 77.%T "CUBIC for Fast Long-Distance Networks"
 78.%U "http://tools.ietf.org/id/draft-rhee-tcpm-cubic-02.txt"
 79.Re
 80.Rs
 81.%A "Sangtae Ha"
 82.%A "Injong Rhee"
 83.%A "Lisong Xu"
 84.%T "CUBIC: a new TCP-friendly high-speed TCP variant"
 85.%J "SIGOPS Oper. Syst. Rev."
 86.%V "42"
 87.%N "5"
 88.%D "July 2008"
 89.%P "64-74"
 90.Re
 91.Sh ACKNOWLEDGEMENTS
 92Development and testing of this software were made possible in part by grants
 93from the FreeBSD Foundation and Cisco University Research Program Fund at
 94Community Foundation Silicon Valley.
 95.Sh HISTORY
 96The
 97.Nm
 98congestion control module first appeared in
 99.Fx 9.0 .
100.Pp
101The module was first released in 2009 by Lawrence Stewart whilst studying at
102Swinburne University of Technology's Centre for Advanced Internet Architectures,
103Melbourne, Australia.
104More details are available at:
105.Pp
106http://caia.swin.edu.au/urp/newtcp/
107.Sh AUTHORS
108.An -nosplit
109The
110.Nm
111congestion control module and this manual page were written by
112.An Lawrence Stewart Aq lstewart@FreeBSD.org
113and
114.An David Hayes Aq david.hayes@ieee.org .