en>Addbot: Bot: Migrating 1 interwiki links, now provided by Wikidata on d:q5367164

2013-03-16T12:49:59Z

Bot: Migrating 1 interwiki links, now provided by Wikidata on d:q5367164

← Older revision		Revision as of 14:49, 16 March 2013
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	~~The name~~ of the ~~writer~~ is ~~Jayson~~. I'~~ve usually loved residing in Alaska. Since I was eighteen I~~'~~ve been operating~~ as ~~a bookkeeper but soon my wife~~ and ~~I will start our own business~~. ~~To play lacross~~ is ~~some thing he would by no means give up~~.<br><br>~~my web site; best psychic readings~~ ([http://www.~~familysurvivalgroup~~.~~com~~/~~easy~~-~~methods-planting-looking-backyard~~/ ~~my website~~])		'''TCP-Illinois''' is a variant of [[Transmission Control Protocol\|TCP]] [[congestion control]] protocol, developed at the [[University of Illinois at Urbana-Champaign]]. It is especially targeted at high-speed, long-distance networks. A sender side modification to the standard TCP congestion control algorithm, it achieves a higher average throughput than the standard TCP, allocates the network resource fairly as the standard TCP, is compatible with the standard TCP, and provides incentives for TCP users to switch.


			== Principles of operation ==

			TCP-Illinois is a loss-delay based algorithm, which uses packet loss as the ''primary'' congestion signal to determine the ''direction'' of window size change, and uses queuing delay as the ''secondary'' congestion signal to adjust the ''pace'' of window size change. Similarly to the standard TCP, TCP-Illinois increases the window size W by <math>\alpha/W</math> for each acknowledgment, and decreases <math>W</math> by <math>\beta W</math> for each loss event. Unlike the standard TCP, <math>\alpha</math> and <math>\beta</math> are not constants. Instead, they are functions of average queuing delay <math>d_a</math>: <math>\alpha=f_1(d_a), \beta=f_2(d_a)</math>, where <math>f_1(\cdot)</math> is decreasing and <math>f_2(\cdot)</math> is increasing.

			There are numerous choices of <math>f_1(\cdot)</math> and <math>f_2(\cdot)</math>. One such class is:

			<math>
			\alpha=f_1(d_a)= \left\{ \begin{array}{ll}
			\alpha_{max} & \mbox{if } d_a \leq d_1 \\
			\frac{\kappa_1}{\kappa_2+d_a} & \mbox{otherwise.}
			\end{array} \right.
			</math>

			<math>
			\beta=f_2(d_a)= \left\{ \begin{array}{ll}
			\beta_{min} & \mbox{if } d_a \leq d_2 \\
			\kappa_3+\kappa_4 d_a & \mbox{if } d_2 < d_a < d_3 \\
			\beta_{max} & \mbox{otherwise.}
			\end{array}\right.
			</math>

			We let <math>f_1(\cdot)</math> and <math>f_2(\cdot)</math> be continuous functions and thus <math>\frac{\kappa_1}{\kappa_2+d_1} = \alpha_{max}</math>, <math>\beta_{min}=\kappa_3+\kappa_4 d_2</math> and <math>\beta_{max}=\kappa_3+\kappa_4 d_3</math>. Suppose <math>d_m</math> is the maximum average queuing delay and we denote <math>\alpha_{min}=f_1(d_m)</math>, then we also have <math>\frac{\kappa_1}{\kappa_2+d_m} = \alpha_{min}</math>. From these conditions, we have

			<math>
			\begin{array}{lcl}
			\kappa_1 = \frac{ (d_m-d_1) \alpha_{min} \alpha_{max} }{\alpha_{max}-\alpha_{min}} & \mbox{and} &
			\kappa_2 = \frac{(d_m-d_1) \alpha_{min} }{\alpha_{max}-\alpha_{min}} - d_1 \,, \\
			\kappa_3 = \frac{ \beta_{min} d_3- \beta_{max} d_2}{d_3-d_2} & \mbox{and} & \kappa_4 = \frac{\beta_{max}-\beta_{min}}{d_3-d_2} \,. \end{array}
			</math>
			This specific choice is demonstrated in Figure 1.

			[[Image:Tcpillinois1.jpg]]

			== Properties and Performance ==
			TCP-Illinois increases the throughput much more quickly than TCP when congestion is far and increases the throughput very slowly when congestion is imminent. As a result, the window curve is concave and the average throughput achieved is much larger than the standard TCP, see Figure 2.

			[[Image:tcpillinois2.jpg]]

			It also has many other desirable features, like fairness, compatibility with the standard TCP, providing incentive for TCP users to switch, robust against inaccurate delay measurement.


			== References ==
			* {{Cite doi\|10.1145/1190095.1190166}}

			==See also==
			* [[H-TCP]]
			* [[BIC TCP]]
			* [[HSTCP]]
			* [[Transmission Control Protocol\|TCP]]
			* [[FAST TCP]]

			==External links==
			*[http://www.princeton.edu/~shaoliu/tcpillinois/index.html TCP-Illinois Homepage]

			* [http://www.hamilton.ie/net/delay_tests_final.pdf Paper on experimental evaluation of TCP Illinois] [http://www.hamilton.ie Hamilton Institute] and [http://netlab.caltech.edu Caltech], March 2008.

			[[Category:TCP congestion control\|Illinois]]
			[[Category:Internet Standards]]

en>TisovcikRasto: Fixed the elongatedness equation - added 2d into the brackets

2011-12-22T12:14:37Z

Fixed the elongatedness equation - added 2d into the brackets

New page

The name of the writer is Jayson. I've usually loved residing in Alaska. Since I was eighteen I've been operating as a bookkeeper but soon my wife and I will start our own business. To play lacross is some thing he would by no means give up.<br><br>my web site; best psychic readings ([http://www.familysurvivalgroup.com/easy-methods-planting-looking-backyard/ my website])

Elongatedness - Revision history

en>Addbot: Bot: Migrating 1 interwiki links, now provided by Wikidata on d:q5367164

en>TisovcikRasto: Fixed the elongatedness equation - added 2d into the brackets