13,172 research outputs found
Evaluation Study for Delay and Link Utilization with the New-Additive Increase Multiplicative Decrease Congestion Avoidance and Control Algorithm
As the Internet becomes increasingly heterogeneous, the issue of congestion
avoidance and control becomes ever more important. And the queue length,
end-to-end delays and link utilization is some of the important things in term
of congestion avoidance and control mechanisms. In this work we continue to
study the performances of the New-AIMD (Additive Increase Multiplicative
Decrease) mechanism as one of the core protocols for TCP congestion avoidance
and control algorithm, we want to evaluate the effect of using the AIMD
algorithm after developing it to find a new approach, as we called it the
New-AIMD algorithm to measure the Queue length, delay and bottleneck link
utilization, and use the NCTUns simulator to get the results after make the
modification for the mechanism. And we will use the Droptail mechanism as the
active queue management mechanism (AQM) in the bottleneck router. After
implementation of our new approach with different number of flows, we expect
the delay will less when we measure the delay dependent on the throughput for
all the system, and also we expect to get end-to-end delay less. And we will
measure the second type of delay a (queuing delay), as we shown in the figure 1
bellow. Also we will measure the bottleneck link utilization, and we expect to
get high utilization for bottleneck link with using this mechanism, and avoid
the collisions in the link
Improvements in DCCP congestion control for satellite links
We propose modifications in the TCP-Friendly Rate Control (TFRC) congestion control mechanism from the Datagram Congestion Control Protocol (DCCP) intended for use with real-time traffic, which are aimed at improving its performance for long delay (primarily satellite) links. Firstly, we propose an algorithm to optimise the number of feedback messages per round trip time (RTT) rather than use the currently standard of at least one per RTT, based on the observed link delay. We analyse the improvements achievable with proposed modification in different phases of congestion control and present results from simulations with modified ns-2 DCCP and live experiments using the modified DCCP Linux kernel implementation. We demonstrate that the changes results in improved slow start performance and a reduced data loss compared to standard DCCP, while the introduced overhead remains acceptable
Comparative Study Of Congestion Control Techniques In High Speed Networks
Congestion in network occurs due to exceed in aggregate demand as compared to
the accessible capacity of the resources. Network congestion will increase as
network speed increases and new effective congestion control methods are
needed, especially to handle bursty traffic of todays very high speed networks.
Since late 90s numerous schemes i.e. [1]...[10] etc. have been proposed. This
paper concentrates on comparative study of the different congestion control
schemes based on some key performance metrics. An effort has been made to judge
the performance of Maximum Entropy (ME) based solution for a steady state
GE/GE/1/N censored queues with partial buffer sharing scheme against these key
performance metrics.Comment: 10 pages IEEE format, International Journal of Computer Science and
Information Security, IJCSIS November 2009, ISSN 1947 5500,
http://sites.google.com/site/ijcsis
FAST TCP: Motivation, Architecture, Algorithms, Performance
We describe FAST TCP, a new TCP congestion control algorithm for high-speed long-latency networks, from design to implementation. We highlight the approach taken by FAST TCP to address the four difficulties which the current TCP implementation has at large windows. We describe the architecture and summarize some of the algorithms implemented in our prototype. We characterize its equilibrium and stability properties. We evaluate it experimentally in terms of throughput, fairness, stability, and responsiveness
Analysis of Multiple Flows using Different High Speed TCP protocols on a General Network
We develop analytical tools for performance analysis of multiple TCP flows
(which could be using TCP CUBIC, TCP Compound, TCP New Reno) passing through a
multi-hop network. We first compute average window size for a single TCP
connection (using CUBIC or Compound TCP) under random losses. We then consider
two techniques to compute steady state throughput for different TCP flows in a
multi-hop network. In the first technique, we approximate the queues as M/G/1
queues. In the second technique, we use an optimization program whose solution
approximates the steady state throughput of the different flows. Our results
match well with ns2 simulations.Comment: Submitted to Performance Evaluatio
SSthreshless Start: A Sender-Side TCP Intelligence for Long Fat Network
Measurement shows that 85% of TCP flows in the internet are short-lived flows
that stay most of their operation in the TCP startup phase. However, many
previous studies indicate that the traditional TCP Slow Start algorithm does
not perform well, especially in long fat networks. Two obvious problems are
known to impact the Slow Start performance, which are the blind initial setting
of the Slow Start threshold and the aggressive increase of the probing rate
during the startup phase regardless of the buffer sizes along the path. Current
efforts focusing on tuning the Slow Start threshold and/or probing rate during
the startup phase have not been considered very effective, which has prompted
an investigation with a different approach. In this paper, we present a novel
TCP startup method, called threshold-less slow start or SSthreshless Start,
which does not need the Slow Start threshold to operate. Instead, SSthreshless
Start uses the backlog status at bottleneck buffer to adaptively adjust probing
rate which allows better seizing of the available bandwidth. Comparing to the
traditional and other major modified startup methods, our simulation results
show that SSthreshless Start achieves significant performance improvement
during the startup phase. Moreover, SSthreshless Start scales well with a wide
range of buffer size, propagation delay and network bandwidth. Besides, it
shows excellent friendliness when operating simultaneously with the currently
popular TCP NewReno connections.Comment: 25 pages, 10 figures, 7 table
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