mod_cc (4)

Leading comments

Copyright (c) 2010-2011 The FreeBSD Foundation
All rights reserved.

This documentation was written at the Centre for Advanced Internet
Architectures, Swinburne University of Technology, Melbourne, Australia by
David Hayes and Lawrence Stewart under sponsorship from the FreeBSD
Foundation.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:
1. Redistributions of source code must retain the above copyri...

(The comments found at the beginning of the groff file "man4/mod_cc.4freebsd".)

NAME

mod_cc - Modular congestion control

DESCRIPTION

The modular congestion control framework allows the TCP implementation to dynamically change the congestion control algorithm used by new and existing connections. Algorithms are identified by a unique ascii(7) name. Algorithm modules can be compiled into the kernel or loaded as kernel modules using the kld(4) facility.

The default algorithm is NewReno, and all connections use the default unless explicitly overridden using the TCP_CONGESTION socket option (see tcp(4) for details). The default can be changed using a sysctl(3) MIB variable detailed in the Sx MIB Variables section below.

MIB Variables

The framework exposes the following variables in the net.inet.tcp.cc branch of the sysctl(3) MIB:

available

Read-only list of currently available congestion control algorithms by name.

algorithm

Returns the current default congestion control algorithm when read, and changes the default when set. When attempting to change the default algorithm, this variable should be set to one of the names listed by the net.inet.tcp.cc.available MIB variable.

SEE ALSO

cc_chd4, cc_cubic4, cc_hd4, cc_htcp4, cc_newreno4, cc_vegas4, tcp(4), mod_cc9

ACKNOWLEDGEMENTS

Development and testing of this software were made possible in part by grants from the FreeBSD Foundation and Cisco University Research Program Fund at Community Foundation Silicon Valley.

HISTORY

The ifconfig modular congestion control framework first appeared in Fx 9.0 .

The framework was first released in 2007 by James Healy and Lawrence Stewart whilst working on the NewTCP research project at Swinburne University of Technology's Centre for Advanced Internet Architectures, Melbourne, Australia, which was made possible in part by a grant from the Cisco University Research Program Fund at Community Foundation Silicon Valley. More details are available at:

caia.swin.edu.au/urp/newtcp

AUTHORS

An -nosplit The ifconfig facility was written by An Lawrence Stewart Aq lstewart@FreeBSD.org , An James Healy Aq jimmy@deefa.com and An David Hayes Aq david.hayes@ieee.org .

This manual page was written by An David Hayes Aq david.hayes@ieee.org and An Lawrence Stewart Aq lstewart@FreeBSD.org .