Cluster:LowLatency

Low Latency TCP/IP for Linux notes

• Comparisons & Instrumentation

• • Web100
    • http://www.psc.edu/~mathis/papers/mathis03web100.ps
    • http://www.web100.org/

• • Comparison of time between layers in network stack. Patch only for 2.6.9.
    • http://user.informatik.uni-goettingen.de/~kperf/
    • http://user.informatik.uni-goettingen.de/~kperf/gaug-ifi-tb-2005-03.pdf

• • Comparing while varying link delay times
    • http://developer.osdl.org/shemminger/LK2004_TCP.pdf
    • http://developer.osdl.org/shemminger/LWE2005_TCP.pdf
    • Reno - Linux 2.4
    • Westwood - Wireless
    • Vegas
    • Binary Increase Congestion Control (BIC) - Default for Linux 2.6

• • Lots of discussion
    • http://www.ggf.org/Public_Comment_Docs/Documents/May-2005/draft-ggf-dtrg-survey-1.pdf
    • HS-TCP
    • Scalable TCP
    • FAST TCP
    • BIC & CUBIC
    • Westwood
    • .....

• Misc
  • Dynamic Right Sizing (DRS)
  • Window Scaling RFC
    • http://www.faqs.org/rfcs/rfc1323.html
  • Modifying buffer sizes manually
    • http://proj.sunet.se/E2E/tcptune.html
  • Kernel options
    • http://www.lam-mpi.org/MailArchives/lam/2005/01/9529.php
  • Default Linux TCP/IP options field contains:
    • Maximum Segment Size(MSS) http://rfc.activedomain.org/0500-0999/rfc0879.html
    • Selective Acknowledgement(Sack) ftp://ftp.isi.edu/in-notes/rfc2018.txt

• Low Latency Kernel Option
  • net.ipv4.tcp_low_latency sysctl
    • /proc/sys/net/ipv4/tcp_low_latency