220,379 research outputs found
TCP Congestion Control Identification
Transmission Control Protocol (TCP) carries most of the traffic on the
Internet these days. There are several implementations of TCP, and the most
important difference among them is their mechanism for controlling congestion.
One of the methods for determining type of a TCP is active probing. Active
probing considers a TCP implementation as a black box, sends different streams
of data to the appropriate host. According to the response received from the
host, it figures out the type of TCP version implemented.
TCP Behavior Inference Tool (TBIT) is an implemented tool that uses active
probing to check the running TCP on web servers. It can check several aspects
of the running TCP including initial value of congestion window, congestion
control algorithm, conformant congestion control, response to selective
acknowledgment, response to Explicit Congestion Notification (ECN) and time
wait duration. In this paper we focus on congestion control algorithm aspect of
it, explain the mechanism used by TBIT and present the results
Analytical Model of TCP Relentless Congestion Control
We introduce a model of the Relentless Congestion Control proposed by Matt
Mathis. Relentless Congestion Control (RCC) is a modification of the AIMD
(Additive Increase Multiplicative Decrease) congestion control which consists
in decreasing the TCP congestion window by the number of lost segments instead
of halving it. Despite some on-going discussions at the ICCRG IRTF-group, this
congestion control has, to the best of our knowledge, never been modeled. In
this paper, we provide an analytical model of this novel congestion control and
propose an implementation of RCC for the commonly-used network simulator ns-2.
We also improve RCC with the addition of a loss retransmission detection scheme
(based on SACK+) to prevent RTO caused by a loss of a retransmission and called
this new version RCC+. The proposed models describe both the original RCC
algorithm and RCC+ improvement and would allow to better assess the impact of
this new congestion control scheme over the network traffic.Comment: Extended version of the one presented at 6th International Workshop
on Verification and Evaluation of Computer and Communication Systems (Vecos
2012
A Taxonomy for Congestion Control Algorithms in Vehicular Ad Hoc Networks
One of the main criteria in Vehicular Ad hoc Networks (VANETs) that has
attracted the researchers' consideration is congestion control. Accordingly,
many algorithms have been proposed to alleviate the congestion problem,
although it is hard to find an appropriate algorithm for applications and
safety messages among them. Safety messages encompass beacons and event-driven
messages. Delay and reliability are essential requirements for event-driven
messages. In crowded networks where beacon messages are broadcasted at a high
number of frequencies by many vehicles, the Control Channel (CCH), which used
for beacons sending, will be easily congested. On the other hand, to guarantee
the reliability and timely delivery of event-driven messages, having a
congestion free control channel is a necessity. Thus, consideration of this
study is given to find a solution for the congestion problem in VANETs by
taking a comprehensive look at the existent congestion control algorithms. In
addition, the taxonomy for congestion control algorithms in VANETs is presented
based on three classes, namely, proactive, reactive and hybrid. Finally, we
have found the criteria in which fulfill prerequisite of a good congestion
control algorithm
Multimedia congestion control: circuit breakers for unicast RTP sessions
The Real-time Transport Protocol (RTP) is widely used in telephony, video conferencing, and telepresence applications. Such applications are often run on best-effort UDP/IP networks. If congestion control is not implemented in these applications, then network congestion can lead to uncontrolled packet loss and a resulting deterioration of the user's multimedia experience. The congestion control algorithm acts as a safety measure by stopping RTP flows from using excessive resources and protecting the network from overload. At the time of this writing, however, while there are several proprietary solutions, there is no standard algorithm for congestion control of interactive RTP flows. This document does not propose a congestion control algorithm. It instead defines a minimal set of RTP circuit breakers: conditions under which an RTP sender needs to stop transmitting media data to protect the network from excessive congestion. It is expected that, in the absence of long-lived excessive congestion, RTP applications running on best-effort IP networks will be able to operate without triggering these circuit breakers. To avoid triggering the RTP circuit breaker, any Standards Track congestion control algorithms defined for RTP will need to operate within the envelope set by these RTP circuit breaker algorithms
Design and analysis for TCP-friendly window-based congestion control
The current congestion control mechanisms for the Internet date back to the early 1980’s and were
primarily designed to stop congestion collapse with the typical traffic of that era. In recent years the
amount of traffic generated by real-time multimedia applications has substantially increased, and the
existing congestion control often does not opt to those types of applications. By this reason, the Internet
can be fall into a uncontrolled system such that the overall throughput oscillates too much by a single
flow which in turn can lead a poor application performance. Apart from the network level concerns,
those types of applications greatly care of end-to-end delay and smoother throughput in which the
conventional congestion control schemes do not suit. In this research, we will investigate improving the
state of congestion control for real-time and interactive multimedia applications. The focus of this work
is to provide fairness among applications using different types of congestion control mechanisms to get
a better link utilization, and to achieve smoother and predictable throughput with suitable end-to-end
packet delay
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