CC_CUBIC(4)

🦋 CC_CUBIC(4) — Kernel Interfaces Manual 🦋

okay so bestie, welcome to the cc_cubic manual page — yes, the CUBIC Congestion Control Algorithm one. this is the group-chat recap, but make it factual, okay? 💖

💖 NAME 💖

cc_cubic — CUBIC Congestion Control Algorithm

🦋 DESCRIPTION 🦋

so CUBIC was designed to give you increased throughput in fast and long-distance networks — yes, the far-away-and-fast vibes. 🌈 It’s literally the default for TCP, no cap.

It tries to keep things fair when it’s competing with legacy NewReno TCP in lower-speed scenarios where NewReno can operate adequately. 🤝

The congestion window is increased as a function of the time elapsed since the last congestion event. During regular operation, the window increase function follows a cubic function, and the inflection point is set to be the congestion window value reached at the last congestion event. 📈

CUBIC also calculates an estimate of the congestion window that NewReno would have achieved at a given time after a congestion event. When updating the congestion window, the algorithm will choose the larger of the calculated CUBIC and estimated NewReno windows. 👑

CUBIC also backs off less on congestion by changing the multiplicative decrease factor from 1/2 (used by standard NewReno TCP) to 4/5. less backing off = more staying power, periodt. 💅

The implementation was done in a clean-room fashion, and is based on the Internet Draft and paper referenced in the “SEE ALSO” section below. 🧚

🌸 MIB Variables 🌸

There are currently no tunable MIB variables. not a single one. zero. none. 💀

🌈 SEE ALSO 🌈

• cc_cdg(4)
• cc_chd(4)
• cc_dctcp(4)
• cc_hd(4)
• cc_htcp(4)
• cc_newreno(4)
• cc_vegas(4)
• mod_cc(4)
• tcp(4)
• mod_cc(9)
• Sangtae Ha, Injong Rhee, and Lisong Xu, CUBIC for Fast Long-Distance Networks, https://tools.ietf.org/id/draft-rhee-tcpm-cubic-02.txt.
• Sangtae Ha, Injong Rhee, and Lisong Xu, “CUBIC: a new TCP-friendly high-speed TCP variant”, SIGOPS Oper. Syst. Rev., 5, 42, 64-74, July 2008.

🎀 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. 🫶 iconic support, honestly.

👑 HISTORY 👑

The cc_cubic congestion control module first appeared in FreeBSD 9.0. ⭐

This became the default congestion algorithm for FreeBSD in version FreeBSD 14.0, replacing cc_newreno(4). main character promotion, for real. 🔥

The module was first released in 2009 by Lawrence Stewart whilst studying at Swinburne University of Technology's Centre for Advanced Internet Architectures, Melbourne, Australia. More details are available at:

http://caia.swin.edu.au/urp/newtcp/

💜 AUTHORS 💜

The cc_cubic congestion control module and this manual page were written by Lawrence Stewart <lstewart@FreeBSD.org> and David Hayes <david.hayes@ieee.org>. 🫡

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that’s the whole page, bestie — source/version Debian, dated February 4, 2023, for CC_CUBIC(4). bye, love you, read your man pages 💋✨