HighSpeed TCP (HSTCP)
RFC 3649: HighSpeed TCP for Large Congestion Windows
RFC 3649, Experimental, December 2003.
RFC 3742: Limited Slow-Start for TCP with Large Congestion Windows
RFC 3742, Experimental, March 2004.
S. Ratnasamy, and
Modifying TCP's Congestion Control for High Speeds
Rough draft, May 2002.
November 2001 version.
HighSpeed TCP and Quick-Start for Fast Long-Distance Networks
tsvwg, IETF, March 2003.
Congestion Control for High-Bandwidth-Delay-Product Networks:
XCP vs. HighSpeed TCP and QuickStart,
ICIR Wednesday Lunch, September 11, 2002
HighSpeed TCP for Large Congestion Windows
Quick-Start for TCP and IP,
tsvwg, July 18, 2002
TCP for Large Congestion Windows
End-to-End Research Group,
May 13, 2002.
A Comprehensive TCP Fairness Analysis
in High Speed Networks,
S. Molnár, B. Sonkoly, T. A. Trinh,
to appear in Computer Communications Journal, 2009.
"We present our comprehensive performance evaluation results of both inter-
and intra-protocol fairness behavior of different TCP versions."
A Simulation Based Comparison Between XCP and HighSpeed TCP.
Gleb A. Chuvpilo and Jae Wook Lee,
6.829 Computer Networks Final Project. Massachusetts Institute of
Technology, Cambridge, Massachusetts, December, 2002.
Implementations and Experimental Reports:
Riverbed uses High-Speed TCP.
from SLAC, comparing HS TCP, FAST TCP, Scalable TCP, and stock TCP.
TCP Stacks comparison with a single stream,
with multiple streams,
A. Antony, J. Blom, C. de Laat, J. Lee, and W. Sjouw,
Macroscopic Examination of TCP Flows over Transatlantic Links,
"We have shown that tuning the host parameters and
HSTCP are very important when trying to make best use
of avaliable bandwidth over high-bandwidth long-delay
networks. The maximum throughtput obtained over the
Trans-Atlantic link (96 msec RTT) was 730 Mbps using
a single TCP stream."
Hadrien Bullot, R. Les Cottrell, and Richard Hughes-Jones,
Evaluation of Advanced TCP Stacks on Fast Long-Distance Production
Networks (with slides),
Yee-Ting Li, Stephen Dallison, Richard Hughes-Jones, Peter Clarke,
A Systematic Analysis of High
Throughput TCP in Real Network Environments (with slides),
"Preliminary studies show that HighSpeed TCP is safely deployable."
Notes on the HighSpeedTCP code in NS.
Souza, E., and Agarwal, D.A.,
A HighSpeed TCP Study: Characteristics and
Deployment Issues. LBNL Technical Report LBNL-53215.
"In this paper, simulation results showing the performance of HighSpeed
TCP and the impact of its use on the present implementation of TCP are
Evandro's web site.
Sally's very simple
simulations of Slow-start.
Note on the HighSpeed TCP code in NS:
The code in NS,
in case 8 of procedure opencwnd()
and in procedure slowdown()
in the file tcp/tcp.cc,
includes the following comment:
"For an efficient implementation, this would just be looked up
in a table, with the increase and decrease being a function of the
The current code is rather inefficient, and calculates the increase and
decrease parameters separately each time. If anyone ever
wanted to improve the code to use a more efficient lookup approach,
I would be happy to add it to the NS distribution. - Sally
I would also recommend the following:
Agent/TCP set numdupacksFrac_ 10
This was just added to NS in October, 2002.
With the new option, numdupacks() is set to the
maximum of numdupacks_ (with a default of 3 packets) and
cwnd/numdupacksFrac_. Thus, when the congestion window is large,
the numdupacks threshold is increased, to allow a larger wait before
retransmitting the lost or delayed packet. The purpose of this is
to reduce the chances that the retransmitted packet is itself dropped,
without appreciably increasing the delay for a retransmitted packet.
One of the issues with HighSpeed TCP is that of long convergence
times between new and old HighSpeed TCP flows. This can be a
particularly severe problem in simplier scenarios (e.g.,
no web traffic, no reverse-path traffic, no range of round-trip
times) with Drop-Tail queues.
R.N. Shorten, D.J. Leith, J. Foy, and R. Kilduff,
Analysis and Design of
Congestion Control in Synchronised Communication Networks. Proc. 12th
Yale Workshop on Adaptive & Learning Systems, May 2003.
"We show that networks of communicating devices operating
additive-increase multiplicative-decrease (AIMD) congestion control
algorithms may be modelled as a positive linear system."
Section 5 of the paper considers convergence times for TCP,
High-Speed TCP, and H-TCP in environments with global synchronization.
M. Nabeshima, K. Yata,
Improving the Convergence Time of HighSpeed TCP,
IEEE International Conference on Networks (ICON2004), pp. 19-23, Nov. 2004.
"This paper proposes a new mechanism to improve the convergence time
of HS-TCP." The simulations in the paper also examine the effect of
background traffic, bandwidth, and the number
of competing flows on convergence times.
S. Hassayoun and David Ros,
Loss Synchronization and Router Buffer
Sizing with High-Speed Versions of TCP, 2008.
"Our preliminary ﬁndings suggest that high-speed versions of TCP do
levels of synchronization. However, in spite of a strong drop synchronization,
versions can achieve both high goodput and link utilization, as long as
This material is based in part upon work supported by the National
Science Foundation under Grant Nos. 0205519.
Any opinions, findings and conclusions or recomendations expressed in
this material are those of the author(s) and do not necessarily reflect
the views of the National Science Foundation (NSF).
Last modified: June 2009. Links checked October 2008.