IOSR Journal of Computer Engineering (IOSR-JCE) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of computer engineering and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in computer technology. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
PERFORMANCE EVALUATION OF SELECTED E2E TCP CONGESTION CONTROL MECHANISM OVER ...ijwmn
TCP is one of the main protocols that govern the Internet traffic nowadays. However, it suffers significant
performance degradation over wireless links. Since wireless networks are leading the communication
technologies recently, it is imperative to introduce effective solutions for the TCP congestion control
mechanisms over such networks. In this research four End-to-End TCP implementations are discussed,
they are TCP Westwood, Hybla, Highspeed, and NewReno. The performance of these variants is compared
using LTE emulated environment in terms of throughput, delay, and fairness. Ns-3 simulator is used to
simulate the LTE networks environment. The simulation results showed that TCP Highspeed achieves the
best throughput results. Although TCP Westwood recorded the lowest latency values comparing to others,
it behaved unfairly among different traffic flows. Moreover, TCP Hybla demonstrated the best fairness
behaviour among other TCP variants
International Journal of Engineering Research and Applications (IJERA) is a team of researchers not publication services or private publications running the journals for monetary benefits, we are association of scientists and academia who focus only on supporting authors who want to publish their work. The articles published in our journal can be accessed online, all the articles will be archived for real time access.
Our journal system primarily aims to bring out the research talent and the works done by sciaentists, academia, engineers, practitioners, scholars, post graduate students of engineering and science. This journal aims to cover the scientific research in a broader sense and not publishing a niche area of research facilitating researchers from various verticals to publish their papers. It is also aimed to provide a platform for the researchers to publish in a shorter of time, enabling them to continue further All articles published are freely available to scientific researchers in the Government agencies,educators and the general public. We are taking serious efforts to promote our journal across the globe in various ways, we are sure that our journal will act as a scientific platform for all researchers to publish their works online.
Fault tolerant wireless sensor mac protocol for efficient collision avoidancegraphhoc
In sensor networks communication by broadcast methods involves many hazards, especially collision. Several MAC layer protocols have been proposed to resolve the problem of collision namely ARBP, where the best achieved success rate is 90%. We hereby propose a MAC protocol which achieves a greater success rate (Success rate is defined as the percentage of delivered packets at the source reaching the destination successfully) by reducing the number of collisions, but by trading off the average propagation delay of transmission. Our proposed protocols are also shown to be more energy efficient in terms of energy dissipation per message delivery, compared to the currently existing protocol.
Iaetsd an effective approach to eliminate tcp incastIaetsd Iaetsd
This document proposes an Incast Congestion Control for TCP (ICTCP) scheme to eliminate TCP incast collapse in datacenter environments. TCP incast collapse occurs when multiple synchronized servers send data to the same receiver in parallel, overwhelming the switch buffer and causing packet loss. ICTCP is a receiver-side approach that proactively adjusts the TCP receive window size of connections to control their aggregate burstiness and prevent switch buffer overflow before packet loss occurs. It estimates available bandwidth and uses this as a quota to coordinate receive window increases. For each connection, the receive window is adjusted based on the ratio of the difference between measured and expected throughput. This allows adaptive tuning of receive windows to meet sender throughput needs while avoiding congest
Available network bandwidth schema to improve performance in tcp protocolsIJCNCJournal
The document describes a new congestion control scheme called New General Window Advertising (NGWA) for TCP. NGWA provides information on available network bandwidth to TCP endpoints. It stores the available bytes in router queues in a variable transmitted in IP headers. Receivers extract this value and use it to set the receive window size, indirectly informing senders of network capacity. Simulations show NGWA achieves stable transmission rates and fairness compared to TCP New Reno and standard TCP. An implementation in the Linux kernel proves NGWA's correct operation.
The document describes a proposed Fuzzy-AQM algorithm for congestion control in wireless ad-hoc networks. It begins by summarizing common Active Queue Management (AQM) policies and their issues. It then discusses congestion in ad-hoc networks and how the proposed Fuzzy-AQM algorithm uses fuzzy logic rules based on queue size and neighbor density to dynamically calculate packet drop probability, aiming to improve network performance. Simulation results showed the effectiveness of Fuzzy-AQM for congestion detection and avoidance.
A packet drop guesser module for congestion Control protocols for high speed ...ijcseit
This document summarizes research on congestion control protocols for high-speed networks. It discusses how existing protocols like CUBIC consider every packet drop as congestion and reduce throughput. The document proposes a packet drop guesser module using k-NN to differentiate between packet drops due to congestion versus other factors like noise. It evaluates CUBIC integrated with this module and finds significant performance improvements over CUBIC alone in noisy conditions. Related work on high-speed protocols like BIC, FAST and CUBIC is also summarized.
RED: A HIGH LINK UTILIZATION AND FAIR ALGORITHMEditor IJCATR
Internet and its applications are an integral part of our daily life .These days they are widely used for various purposes such as
communication, public services, entertainments, distant educations, etc., each possessing different quality of service (QoS) requirements.
How to provide finer congestion control for network emerges as a major problem. To prevent the problem of congestion control and
synchronization various active queue management (AQM) techniques are used. AQM algorithms execute on network routers and detect
initial congestion by monitoring some functions. When congestion occurs on the link the AQM algorithms detects and provides signals to
the end systems. Various algorithms have been proposed in recent years but RED is one of the most influential techniques among all the
existing ones. This review paper provides the functioning mechanism of the RED technique with the help of its algorithm & its variants
PERFORMANCE EVALUATION OF SELECTED E2E TCP CONGESTION CONTROL MECHANISM OVER ...ijwmn
TCP is one of the main protocols that govern the Internet traffic nowadays. However, it suffers significant
performance degradation over wireless links. Since wireless networks are leading the communication
technologies recently, it is imperative to introduce effective solutions for the TCP congestion control
mechanisms over such networks. In this research four End-to-End TCP implementations are discussed,
they are TCP Westwood, Hybla, Highspeed, and NewReno. The performance of these variants is compared
using LTE emulated environment in terms of throughput, delay, and fairness. Ns-3 simulator is used to
simulate the LTE networks environment. The simulation results showed that TCP Highspeed achieves the
best throughput results. Although TCP Westwood recorded the lowest latency values comparing to others,
it behaved unfairly among different traffic flows. Moreover, TCP Hybla demonstrated the best fairness
behaviour among other TCP variants
International Journal of Engineering Research and Applications (IJERA) is a team of researchers not publication services or private publications running the journals for monetary benefits, we are association of scientists and academia who focus only on supporting authors who want to publish their work. The articles published in our journal can be accessed online, all the articles will be archived for real time access.
Our journal system primarily aims to bring out the research talent and the works done by sciaentists, academia, engineers, practitioners, scholars, post graduate students of engineering and science. This journal aims to cover the scientific research in a broader sense and not publishing a niche area of research facilitating researchers from various verticals to publish their papers. It is also aimed to provide a platform for the researchers to publish in a shorter of time, enabling them to continue further All articles published are freely available to scientific researchers in the Government agencies,educators and the general public. We are taking serious efforts to promote our journal across the globe in various ways, we are sure that our journal will act as a scientific platform for all researchers to publish their works online.
Fault tolerant wireless sensor mac protocol for efficient collision avoidancegraphhoc
In sensor networks communication by broadcast methods involves many hazards, especially collision. Several MAC layer protocols have been proposed to resolve the problem of collision namely ARBP, where the best achieved success rate is 90%. We hereby propose a MAC protocol which achieves a greater success rate (Success rate is defined as the percentage of delivered packets at the source reaching the destination successfully) by reducing the number of collisions, but by trading off the average propagation delay of transmission. Our proposed protocols are also shown to be more energy efficient in terms of energy dissipation per message delivery, compared to the currently existing protocol.
Iaetsd an effective approach to eliminate tcp incastIaetsd Iaetsd
This document proposes an Incast Congestion Control for TCP (ICTCP) scheme to eliminate TCP incast collapse in datacenter environments. TCP incast collapse occurs when multiple synchronized servers send data to the same receiver in parallel, overwhelming the switch buffer and causing packet loss. ICTCP is a receiver-side approach that proactively adjusts the TCP receive window size of connections to control their aggregate burstiness and prevent switch buffer overflow before packet loss occurs. It estimates available bandwidth and uses this as a quota to coordinate receive window increases. For each connection, the receive window is adjusted based on the ratio of the difference between measured and expected throughput. This allows adaptive tuning of receive windows to meet sender throughput needs while avoiding congest
Available network bandwidth schema to improve performance in tcp protocolsIJCNCJournal
The document describes a new congestion control scheme called New General Window Advertising (NGWA) for TCP. NGWA provides information on available network bandwidth to TCP endpoints. It stores the available bytes in router queues in a variable transmitted in IP headers. Receivers extract this value and use it to set the receive window size, indirectly informing senders of network capacity. Simulations show NGWA achieves stable transmission rates and fairness compared to TCP New Reno and standard TCP. An implementation in the Linux kernel proves NGWA's correct operation.
The document describes a proposed Fuzzy-AQM algorithm for congestion control in wireless ad-hoc networks. It begins by summarizing common Active Queue Management (AQM) policies and their issues. It then discusses congestion in ad-hoc networks and how the proposed Fuzzy-AQM algorithm uses fuzzy logic rules based on queue size and neighbor density to dynamically calculate packet drop probability, aiming to improve network performance. Simulation results showed the effectiveness of Fuzzy-AQM for congestion detection and avoidance.
A packet drop guesser module for congestion Control protocols for high speed ...ijcseit
This document summarizes research on congestion control protocols for high-speed networks. It discusses how existing protocols like CUBIC consider every packet drop as congestion and reduce throughput. The document proposes a packet drop guesser module using k-NN to differentiate between packet drops due to congestion versus other factors like noise. It evaluates CUBIC integrated with this module and finds significant performance improvements over CUBIC alone in noisy conditions. Related work on high-speed protocols like BIC, FAST and CUBIC is also summarized.
RED: A HIGH LINK UTILIZATION AND FAIR ALGORITHMEditor IJCATR
Internet and its applications are an integral part of our daily life .These days they are widely used for various purposes such as
communication, public services, entertainments, distant educations, etc., each possessing different quality of service (QoS) requirements.
How to provide finer congestion control for network emerges as a major problem. To prevent the problem of congestion control and
synchronization various active queue management (AQM) techniques are used. AQM algorithms execute on network routers and detect
initial congestion by monitoring some functions. When congestion occurs on the link the AQM algorithms detects and provides signals to
the end systems. Various algorithms have been proposed in recent years but RED is one of the most influential techniques among all the
existing ones. This review paper provides the functioning mechanism of the RED technique with the help of its algorithm & its variants
Effective Router Assisted Congestion Control for SDN IJECEIAES
This document proposes a new congestion control method called PACEC (Path Associativity Centralized Congestion Control) that works within the Software Defined Networking (SDN) framework. PACEC aims to overcome weaknesses of traditional Router Assisted Congestion Control (RACC) methods by utilizing global network information available in SDN. It calculates an aggregate rate for the entire data path rather than individual links. The controller collects switch utilization data and uses it to determine the path rate (Rp), updating it each control period. Simulation results show PACEC achieves better efficiency and fairness than TCP and RCP.
"Performance Evaluation and Comparison of Westwood+, New Reno and Vegas TCP ...losalamos
Luigi A. Grieco, Saverio Mascolo.
ACM CCR, Vol.34 No.2, April 2004.
This article aims at evaluating a comparison between three TCP congestion control algorithms. A really interesting reading.
IRJET-A Survey on Red Queue Mechanism for Reduce Congestion in Wireless NetworkIRJET Journal
This document summarizes several queue management mechanisms for congestion control in wireless networks, including Random Early Detection (RED) and variants. RED detects congestion by tracking average queue length and dropping packets probabilistically. Variants like Fuzzy Logic RED (FLRED) and Hemi-Rise Cloud Model (CRED) aim to improve RED by addressing its sensitivity to parameters and nonlinearity. Explicit Congestion Control (ECC) and Explicit Non-Congestion Notification (ENCN) modify TCP headers to signal congestion or non-congestion. Three section Random Early Detection (TRED) divides the queue into three sections to calculate dropping probability nonlinearly. These variants aim to more effectively control congestion and improve performance
PERFORMANCE ANALYSIS OF MULTI-PATH TCP NETWORKIJCNCJournal
MPTCP is proposed by IETF working group, it allows a single TCP stream to be split across multiple
paths. It has obvious benefits in performance and reliability. MPTCP has implemented in Linux-based
distributions that can be compiled and installed to be used for both real and experimental scenarios. In this
article, we provide performance analyses for MPTCP with a laptop connected to WiFi access point and 3G
cellular network at the same time. We prove experimentally that MPTCP outperforms regular TCP for
WiFi or 3G interfaces. We also compare four types of congestion control algorithms for MPTCP that are
also implemented in the Linux Kernel. Results show that Alias Linked Increase Congestion Control
algorithm outperforms the others in the normal traffic load while Balanced Linked Adaptation algorithm
outperforms the rest when the paths are shared with heavy traffic, which is not supported by MPTCP.
KALMAN FILTER BASED CONGESTION CONTROLLERijdpsjournal
Facing burst traffic, TCP congestion control algorithms severely decrease window size neglecting the fact
that such burst traffics are temporal. In the increase phase sending window experiences a linear rise which
may lead to waste in hefty proportion of available bandwidth. If congestion control mechanisms be able to
estimate future state of network traffic they can cope with different circumstances and efficiently use
bandwidth. Since data traffic which is running on networks is mostly self-similar, algorithms can take
advantage of self-similarity property and repetitive traffic patterns to have accurate estimations and
predictions in large time scales.
In this research a two-stage controller is presented. In fact the first part is a RED congestion controller
which acts in short time scales (200 milliseconds) and the second is a Kalman filter estimator which do
RTT and window size estimations in large time scales (every two seconds). If the RED mechanism decides
to increase the window size, the magnitude of this increase is controlled by Kalman filter. To be more
precise, if the Kalman filter indicates a non-congested situation in the next large time scale, a magnitude
factor is calculated and given to RED algorithm to strengthen the amount of increase.
This paper proposes a new end-to-end congestion control protocol called ACP that is designed for high bandwidth-delay product networks. ACP aims to achieve high link utilization, fairness among flows, and fast convergence. It does this by estimating the bottleneck queue size upon detecting congestion and decreasing the congestion window by exactly the amount needed to empty the queue. It also uses a "fairness ratio" metric to determine window increases to ensure convergence to a fair share of bandwidth among flows. The paper argues that existing protocols cannot achieve high utilization and fairness due to their inability to accurately measure link load. It claims ACP addresses this through a new congestion window control approach combining queue size estimation and a fairness measure.
Performance Evaluation of UDP, DCCP, SCTP and TFRC for Different Traffic Flow...IJECEIAES
The demand for internet applications has increased rapidly. Providing quality of service (QoS) requirements for varied internet application is a challenging task. One important factor that is significantly affected on the QoS service is the transport layer. The transport layer provides end-to-end data transmission across a network. Currently, the most common transport protocols used by internet application are TCP (Transmission Control Protocol) and UDP (User Datagram Protocol). Also, there are recent transport protocols such as DCCP (data congestion control protocol), SCTP (stream congestion transmission protocol), and TFRC (TCP-friendly rate control), which are in the standardization process of Internet Engineering Task Force (IETF). In this paper, we evaluate the performance of UDP, DCCP, SCTP and TFRC protocols for different traffic flows: data transmission, video traffic, and VOIP in wired networks. The performance criteria used for this evaluation include throughput, end to end delay, and packet loss rate. Well-known network simulator NS-2 used to implement the UDP, DCCP, SCTP, and TFRC protocols performance comparison. Based on the simulation results, the performance throughput of SCTP and TFRC is better than UDP. Moreover, DCCP performance is superior SCTP and TFRC in term of end-to-end delay.
Clustering based Time Slot Assignment Protocol for Improving Performance in U...journal ijrtem
Recently, numerous approaches have been proposed for designing medium access control (MAC)
in underwater acoustic networks (UANs). Some of those works tried to adapt MAC protocols proposed for
terrestrial networks. However, unique environmental characteristics of UANs make the MAC protocols hard to be
used in the UANs and degrade network performance. In order to improve network performance, COD-TS MAC
protocol was proposed. COD-TS focuses on both single hop and multi-hop mode and utilizes CDMA for
exchanging schedule information between cluster heads. COD-TS has shortcomings such as collisions, additional
energy consumption by exchanging schedule information and near-far effect of CDMA. To overcome above
shortcomings, we propose a clustering-based time slot assignment protocol. In the proposed protocol, nodes are
clustered, and each cluster head performs two-hop neighbor cluster discovery operation. And then, a cluster head
obtains its own relative position information. Finally, the cluster head assigns its own time slot for data
transmission based on the information. Simulation results show that the proposed protocol has always better
performance compared to the COD-TS.
Multiple Downlink Fair Packet Scheduling Scheme in Wi-MaxEditor IJCATR
IEEE 802.16 is standardization for a broadband wireless access in network metropolitan area network (MAN). IEEE 802.16
standard (Wi-Max) defines the concrete quality of service (QoS) requirement, a scheduling scheme and efficient packet scheduling
scheme which is necessary to achieve the QoS requirement. In this paper, a novel waiting queue based on downlink bandwidth
allocation architecture from a number of rtps schedule has been proposed to improve the performance of nrtPS services without any
impaction to other services. This paper proposes an efficient QoS scheduling scheme that satisfies both throughput and delay guarantee
to various real and non-real applications corresponding to different scheduling schemes for k=1,2,3,4. Simulation results show that
proposed scheduling scheme can provide a tight QoS guarantee in terms of delay for all types of traffic as defined in WiMax standards.
This process results in maintaining the fairness of allocation and helps to eliminate starvation of lower priority class services. The
authors propose a new efficient and generalized scheduling schemes for IEEE 802.16 broadband wireless access system reflecting the
delay requirements.
A COMPARISON OF CONGESTION CONTROL VARIANTS OF TCP IN REACTIVE ROUTING PROTOC...ijcsit
A widely used TCP protocol is originally developed for wired networks. It has many variants to detect and
control congestion in the network. However, Congestion control in all TCP variants does not show similar
performance in MANET as in wired network because of the fault detection of congestion. In this paper, we
do a performance comparison between TCP variants NEW RENO, SACK and Vegas in AODV and DSR
reactive (On-Demand) routing protocols. Network traffic between nodes is provided by using File Transfer
Protocol (FTP) application. Multiple scenarios are created and the average values of each performance
parameter are used to evaluate the performance. The results show that TCP variants perform better in
terms of throughput and Packet drop with DSR routing protocol compared with AODV routing protocol.
TCP variants show a lower Jitter in AODV compared with DSR.
This document discusses adaptive multistreaming over a network using the Stream Control Transmission Protocol (SCTP). It proposes adapting the number of streams based on estimates of available bandwidth and current congestion window size to improve performance under congestion. The performance of this adaptive streams mechanism is evaluated through computer simulation using the OMNeT++ network simulation tool and INET framework. Simulation results are compared between the proposed adaptive streams approach and normal SCTP streaming.
AdHoc Probe is a tool that estimates the effective end-to-end path capacity in wireless ad hoc networks. It employs a one-way active probing technique called packet pair dispersion that measures the minimum delay between two probing packets to estimate capacity without queueing effects. Simulations and testbed experiments using AdHoc Probe show it can accurately measure path capacity under different conditions such as varying topology, interference, mobility, and transmission rates in both single-hop and multi-hop wireless ad hoc network configurations.
Design, implementation and evaluation of icmp based available network bandwid...IJCNCJournal
We propose a method to measure available network ba
ndwidth using the Internet Control Message
Protocol (ICMP). The recently proposed ImTCP techni
que uses Transmission Control Protocol (TCP) data
packets and the corresponding acknowledgement respo
nses to measure the available bandwidth between
sender and receiver. Since ImTCP needs to change th
e sender’s TCP implementation, it needs
modifications to sender’s operating system kernel.
Moreover, ImTCP cannot measure available bandwidth
accurately if the receiver sends delayed acknowledg
ments. These problems stem from the use of TCP. In
this paper, we discuss an ICMP-based method that ov
ercomes these limitations. We evaluate the
performance of the proposed method in an experiment
al network and show that it generates less
measurement traffic and requires less time for band
width measurement than PathLoad. We also show that
proposed method can measure the available bandwidth
even if the bandwidth changes during
measurement
Comparative Analysis of Drop Tail, Red and NLRED Congestion Control Algorithm...EvaObinna
Congestion in a network may occur when the load on the network is greater than the capacity of the network and consequently, performance degrades. Congestion control is a technique and mechanisms that can either prevent congestion before it happens, or remove congestion after it has happened. This work presents a comparative analysis of Drop Tail, RED and NLRED congestion control algorithm and performed a simulation experiment to show their relative effectiveness. The experiment was done using NS2 simulator on the basis of End-to-End Delay, Throughput, Packet Drop, and Packet Delivery Ratio in a wired network. The simulation result showed that NLRED performs best in high congestion network, while in low cohesive network, Drop Tail gives a good result. Drop Tail, RED and NLRED was also analysed in real audio traffic and the entire results showed that in congested network, NLRED and RED are better while in low congested network Drop Tail is better. This is because in heavy congested network, congestion avoidance mechanism aids the network to gain better performance while in low congested network unnecessary computation avoidance mechanisms degrades the performance of the network. If parameters are set effectively in RED, it will be the best queuing mechanism for that particular network. However, it is of great importance to know which congestion control mechanism is suitable for each network and traffic.
This document proposes a new dynamic approach to congestion control in TCP that determines congestion based on round trip time rather than packet loss. It suggests using the estimated round trip time as a threshold and increasing the congestion window linearly as long as the sample round trip time is below the threshold. If the sample round trip time exceeds the estimated time, the congestion window would be halved, and if it exceeds the estimated time plus four times the deviation round trip time, the window would be reset to one MSS. This approach aims to avoid the bottleneck problem of TCP by not including a slow start phase and responding earlier to potential congestion based on network delays.
ANALYSIS AND EXPERIMENTAL EVALUATION OF THE TRANSMISSION CONTROL PROTOCOL CON...IRJET Journal
This document analyzes and experimentally evaluates several TCP congestion control algorithms (variants) - TCP cubic, TCP hybla, TCP scalable, TCP Vegas, and TCP Westwood - in a wireless multihop environment. It aims to understand the throughput performance of each variant as the number of nodes increases. The analysis provides insights into how well different variants can adapt to dynamic multihop wireless networks. It experimentally tests the variants in a simulation using Network Simulator 2 and compares their throughput performance under varying node counts. The goal is to help develop more robust TCP algorithms that can effectively manage congestion in challenging wireless network conditions.
VEGAS: Better Performance than other TCP Congestion Control Algorithms on MANETsCSCJournals
The document analyzes the performance of six TCP congestion control algorithms (BIC, Cubic, Compound, Vegas, Reno, and Westwood) on mobile ad hoc networks (MANETs) using network simulator 2 (NS2). Simulation results show that the Vegas algorithm provided better and more stable throughput than the other algorithms over the entire simulation time, both with and without node mobility. While BIC achieved the highest throughput after 75 seconds, Vegas was the only algorithm that maintained almost constant throughput from the start to end of the 200 second simulations. Therefore, the document concludes that Vegas is the most suitable algorithm for MANET scenarios.
Comparative Analysis of Different TCP Variants in Mobile Ad-Hoc Network partha pratim deb
The document analyzes the performance of different TCP variants (New Reno, Reno, Tahoe) with MANET routing protocols (AODV, DSR, TORA) through simulation. It finds that in scenarios with 3 and 5 nodes, AODV has better throughput than DSR and TORA for all TCP variants. Throughput decreases for all variants as node count increases. New Reno provides multiple packet loss recovery and is the best choice for AODV in MANETs due to its consistent performance with changes in node count. Further analysis of additional protocols and TCP variants is recommended.
Transmission Control Protocol (TCP) is a fundamental protocol of the Internet Protocol Suite. TCP complements the Internet Protocol (IP), therefore it is common to refer to the internet protocol suit as TCP/IP. TCP is used for error detection, detection of packet loss or out of order delivery of data. TCP requests retransmission, rearranges data and helps with network congestion.
Several congestion control algorithms have been developed, over the last years, to improve TCP's performance over various technologies and network conditions.
The purpose of this assignment is to present TCP, network congestion, congestion algorithms and simulate different algorithms in different network conditions to measure their performance. For this assignment's needs, OPNET IT Guru Academic Edition software was used to accomplish the reproduction of projects that have been already published and gave the wanted results.
This document proposes a new dynamic approach to congestion control in TCP that determines congestion based on round trip time rather than packet loss. It suggests using the estimated round trip time as a threshold and increasing the congestion window linearly as long as the sample round trip time is below the threshold. If the sample round trip time exceeds the estimated time, the congestion window would be halved, and if it exceeds the estimated time plus four times the deviation round trip time, the window would be reset to one MSS. This approach aims to avoid the bottleneck problem of TCP by not including a slow start phase and responding earlier to potential congestion based on network delays.
This document proposes a new dynamic approach to congestion control in TCP that determines congestion based on round trip time rather than packet loss. It suggests using the estimated round trip time as a threshold and increasing the congestion window linearly as long as the sample round trip time is below the threshold. If the sample round trip time exceeds the estimated time, the congestion window is halved, and if it exceeds the estimated time plus four times the deviation round trip time, the window is reset to one MSS. This approach aims to overcome issues with TCP Reno and Tahoe like the bottleneck problem by avoiding an exponential increase in window size. The document discusses advantages like preventing network congestion and disadvantages like ambiguity in measured sample round trip
Effective Router Assisted Congestion Control for SDN IJECEIAES
This document proposes a new congestion control method called PACEC (Path Associativity Centralized Congestion Control) that works within the Software Defined Networking (SDN) framework. PACEC aims to overcome weaknesses of traditional Router Assisted Congestion Control (RACC) methods by utilizing global network information available in SDN. It calculates an aggregate rate for the entire data path rather than individual links. The controller collects switch utilization data and uses it to determine the path rate (Rp), updating it each control period. Simulation results show PACEC achieves better efficiency and fairness than TCP and RCP.
"Performance Evaluation and Comparison of Westwood+, New Reno and Vegas TCP ...losalamos
Luigi A. Grieco, Saverio Mascolo.
ACM CCR, Vol.34 No.2, April 2004.
This article aims at evaluating a comparison between three TCP congestion control algorithms. A really interesting reading.
IRJET-A Survey on Red Queue Mechanism for Reduce Congestion in Wireless NetworkIRJET Journal
This document summarizes several queue management mechanisms for congestion control in wireless networks, including Random Early Detection (RED) and variants. RED detects congestion by tracking average queue length and dropping packets probabilistically. Variants like Fuzzy Logic RED (FLRED) and Hemi-Rise Cloud Model (CRED) aim to improve RED by addressing its sensitivity to parameters and nonlinearity. Explicit Congestion Control (ECC) and Explicit Non-Congestion Notification (ENCN) modify TCP headers to signal congestion or non-congestion. Three section Random Early Detection (TRED) divides the queue into three sections to calculate dropping probability nonlinearly. These variants aim to more effectively control congestion and improve performance
PERFORMANCE ANALYSIS OF MULTI-PATH TCP NETWORKIJCNCJournal
MPTCP is proposed by IETF working group, it allows a single TCP stream to be split across multiple
paths. It has obvious benefits in performance and reliability. MPTCP has implemented in Linux-based
distributions that can be compiled and installed to be used for both real and experimental scenarios. In this
article, we provide performance analyses for MPTCP with a laptop connected to WiFi access point and 3G
cellular network at the same time. We prove experimentally that MPTCP outperforms regular TCP for
WiFi or 3G interfaces. We also compare four types of congestion control algorithms for MPTCP that are
also implemented in the Linux Kernel. Results show that Alias Linked Increase Congestion Control
algorithm outperforms the others in the normal traffic load while Balanced Linked Adaptation algorithm
outperforms the rest when the paths are shared with heavy traffic, which is not supported by MPTCP.
KALMAN FILTER BASED CONGESTION CONTROLLERijdpsjournal
Facing burst traffic, TCP congestion control algorithms severely decrease window size neglecting the fact
that such burst traffics are temporal. In the increase phase sending window experiences a linear rise which
may lead to waste in hefty proportion of available bandwidth. If congestion control mechanisms be able to
estimate future state of network traffic they can cope with different circumstances and efficiently use
bandwidth. Since data traffic which is running on networks is mostly self-similar, algorithms can take
advantage of self-similarity property and repetitive traffic patterns to have accurate estimations and
predictions in large time scales.
In this research a two-stage controller is presented. In fact the first part is a RED congestion controller
which acts in short time scales (200 milliseconds) and the second is a Kalman filter estimator which do
RTT and window size estimations in large time scales (every two seconds). If the RED mechanism decides
to increase the window size, the magnitude of this increase is controlled by Kalman filter. To be more
precise, if the Kalman filter indicates a non-congested situation in the next large time scale, a magnitude
factor is calculated and given to RED algorithm to strengthen the amount of increase.
This paper proposes a new end-to-end congestion control protocol called ACP that is designed for high bandwidth-delay product networks. ACP aims to achieve high link utilization, fairness among flows, and fast convergence. It does this by estimating the bottleneck queue size upon detecting congestion and decreasing the congestion window by exactly the amount needed to empty the queue. It also uses a "fairness ratio" metric to determine window increases to ensure convergence to a fair share of bandwidth among flows. The paper argues that existing protocols cannot achieve high utilization and fairness due to their inability to accurately measure link load. It claims ACP addresses this through a new congestion window control approach combining queue size estimation and a fairness measure.
Performance Evaluation of UDP, DCCP, SCTP and TFRC for Different Traffic Flow...IJECEIAES
The demand for internet applications has increased rapidly. Providing quality of service (QoS) requirements for varied internet application is a challenging task. One important factor that is significantly affected on the QoS service is the transport layer. The transport layer provides end-to-end data transmission across a network. Currently, the most common transport protocols used by internet application are TCP (Transmission Control Protocol) and UDP (User Datagram Protocol). Also, there are recent transport protocols such as DCCP (data congestion control protocol), SCTP (stream congestion transmission protocol), and TFRC (TCP-friendly rate control), which are in the standardization process of Internet Engineering Task Force (IETF). In this paper, we evaluate the performance of UDP, DCCP, SCTP and TFRC protocols for different traffic flows: data transmission, video traffic, and VOIP in wired networks. The performance criteria used for this evaluation include throughput, end to end delay, and packet loss rate. Well-known network simulator NS-2 used to implement the UDP, DCCP, SCTP, and TFRC protocols performance comparison. Based on the simulation results, the performance throughput of SCTP and TFRC is better than UDP. Moreover, DCCP performance is superior SCTP and TFRC in term of end-to-end delay.
Clustering based Time Slot Assignment Protocol for Improving Performance in U...journal ijrtem
Recently, numerous approaches have been proposed for designing medium access control (MAC)
in underwater acoustic networks (UANs). Some of those works tried to adapt MAC protocols proposed for
terrestrial networks. However, unique environmental characteristics of UANs make the MAC protocols hard to be
used in the UANs and degrade network performance. In order to improve network performance, COD-TS MAC
protocol was proposed. COD-TS focuses on both single hop and multi-hop mode and utilizes CDMA for
exchanging schedule information between cluster heads. COD-TS has shortcomings such as collisions, additional
energy consumption by exchanging schedule information and near-far effect of CDMA. To overcome above
shortcomings, we propose a clustering-based time slot assignment protocol. In the proposed protocol, nodes are
clustered, and each cluster head performs two-hop neighbor cluster discovery operation. And then, a cluster head
obtains its own relative position information. Finally, the cluster head assigns its own time slot for data
transmission based on the information. Simulation results show that the proposed protocol has always better
performance compared to the COD-TS.
Multiple Downlink Fair Packet Scheduling Scheme in Wi-MaxEditor IJCATR
IEEE 802.16 is standardization for a broadband wireless access in network metropolitan area network (MAN). IEEE 802.16
standard (Wi-Max) defines the concrete quality of service (QoS) requirement, a scheduling scheme and efficient packet scheduling
scheme which is necessary to achieve the QoS requirement. In this paper, a novel waiting queue based on downlink bandwidth
allocation architecture from a number of rtps schedule has been proposed to improve the performance of nrtPS services without any
impaction to other services. This paper proposes an efficient QoS scheduling scheme that satisfies both throughput and delay guarantee
to various real and non-real applications corresponding to different scheduling schemes for k=1,2,3,4. Simulation results show that
proposed scheduling scheme can provide a tight QoS guarantee in terms of delay for all types of traffic as defined in WiMax standards.
This process results in maintaining the fairness of allocation and helps to eliminate starvation of lower priority class services. The
authors propose a new efficient and generalized scheduling schemes for IEEE 802.16 broadband wireless access system reflecting the
delay requirements.
A COMPARISON OF CONGESTION CONTROL VARIANTS OF TCP IN REACTIVE ROUTING PROTOC...ijcsit
A widely used TCP protocol is originally developed for wired networks. It has many variants to detect and
control congestion in the network. However, Congestion control in all TCP variants does not show similar
performance in MANET as in wired network because of the fault detection of congestion. In this paper, we
do a performance comparison between TCP variants NEW RENO, SACK and Vegas in AODV and DSR
reactive (On-Demand) routing protocols. Network traffic between nodes is provided by using File Transfer
Protocol (FTP) application. Multiple scenarios are created and the average values of each performance
parameter are used to evaluate the performance. The results show that TCP variants perform better in
terms of throughput and Packet drop with DSR routing protocol compared with AODV routing protocol.
TCP variants show a lower Jitter in AODV compared with DSR.
This document discusses adaptive multistreaming over a network using the Stream Control Transmission Protocol (SCTP). It proposes adapting the number of streams based on estimates of available bandwidth and current congestion window size to improve performance under congestion. The performance of this adaptive streams mechanism is evaluated through computer simulation using the OMNeT++ network simulation tool and INET framework. Simulation results are compared between the proposed adaptive streams approach and normal SCTP streaming.
AdHoc Probe is a tool that estimates the effective end-to-end path capacity in wireless ad hoc networks. It employs a one-way active probing technique called packet pair dispersion that measures the minimum delay between two probing packets to estimate capacity without queueing effects. Simulations and testbed experiments using AdHoc Probe show it can accurately measure path capacity under different conditions such as varying topology, interference, mobility, and transmission rates in both single-hop and multi-hop wireless ad hoc network configurations.
Design, implementation and evaluation of icmp based available network bandwid...IJCNCJournal
We propose a method to measure available network ba
ndwidth using the Internet Control Message
Protocol (ICMP). The recently proposed ImTCP techni
que uses Transmission Control Protocol (TCP) data
packets and the corresponding acknowledgement respo
nses to measure the available bandwidth between
sender and receiver. Since ImTCP needs to change th
e sender’s TCP implementation, it needs
modifications to sender’s operating system kernel.
Moreover, ImTCP cannot measure available bandwidth
accurately if the receiver sends delayed acknowledg
ments. These problems stem from the use of TCP. In
this paper, we discuss an ICMP-based method that ov
ercomes these limitations. We evaluate the
performance of the proposed method in an experiment
al network and show that it generates less
measurement traffic and requires less time for band
width measurement than PathLoad. We also show that
proposed method can measure the available bandwidth
even if the bandwidth changes during
measurement
Comparative Analysis of Drop Tail, Red and NLRED Congestion Control Algorithm...EvaObinna
Congestion in a network may occur when the load on the network is greater than the capacity of the network and consequently, performance degrades. Congestion control is a technique and mechanisms that can either prevent congestion before it happens, or remove congestion after it has happened. This work presents a comparative analysis of Drop Tail, RED and NLRED congestion control algorithm and performed a simulation experiment to show their relative effectiveness. The experiment was done using NS2 simulator on the basis of End-to-End Delay, Throughput, Packet Drop, and Packet Delivery Ratio in a wired network. The simulation result showed that NLRED performs best in high congestion network, while in low cohesive network, Drop Tail gives a good result. Drop Tail, RED and NLRED was also analysed in real audio traffic and the entire results showed that in congested network, NLRED and RED are better while in low congested network Drop Tail is better. This is because in heavy congested network, congestion avoidance mechanism aids the network to gain better performance while in low congested network unnecessary computation avoidance mechanisms degrades the performance of the network. If parameters are set effectively in RED, it will be the best queuing mechanism for that particular network. However, it is of great importance to know which congestion control mechanism is suitable for each network and traffic.
This document proposes a new dynamic approach to congestion control in TCP that determines congestion based on round trip time rather than packet loss. It suggests using the estimated round trip time as a threshold and increasing the congestion window linearly as long as the sample round trip time is below the threshold. If the sample round trip time exceeds the estimated time, the congestion window would be halved, and if it exceeds the estimated time plus four times the deviation round trip time, the window would be reset to one MSS. This approach aims to avoid the bottleneck problem of TCP by not including a slow start phase and responding earlier to potential congestion based on network delays.
ANALYSIS AND EXPERIMENTAL EVALUATION OF THE TRANSMISSION CONTROL PROTOCOL CON...IRJET Journal
This document analyzes and experimentally evaluates several TCP congestion control algorithms (variants) - TCP cubic, TCP hybla, TCP scalable, TCP Vegas, and TCP Westwood - in a wireless multihop environment. It aims to understand the throughput performance of each variant as the number of nodes increases. The analysis provides insights into how well different variants can adapt to dynamic multihop wireless networks. It experimentally tests the variants in a simulation using Network Simulator 2 and compares their throughput performance under varying node counts. The goal is to help develop more robust TCP algorithms that can effectively manage congestion in challenging wireless network conditions.
VEGAS: Better Performance than other TCP Congestion Control Algorithms on MANETsCSCJournals
The document analyzes the performance of six TCP congestion control algorithms (BIC, Cubic, Compound, Vegas, Reno, and Westwood) on mobile ad hoc networks (MANETs) using network simulator 2 (NS2). Simulation results show that the Vegas algorithm provided better and more stable throughput than the other algorithms over the entire simulation time, both with and without node mobility. While BIC achieved the highest throughput after 75 seconds, Vegas was the only algorithm that maintained almost constant throughput from the start to end of the 200 second simulations. Therefore, the document concludes that Vegas is the most suitable algorithm for MANET scenarios.
Comparative Analysis of Different TCP Variants in Mobile Ad-Hoc Network partha pratim deb
The document analyzes the performance of different TCP variants (New Reno, Reno, Tahoe) with MANET routing protocols (AODV, DSR, TORA) through simulation. It finds that in scenarios with 3 and 5 nodes, AODV has better throughput than DSR and TORA for all TCP variants. Throughput decreases for all variants as node count increases. New Reno provides multiple packet loss recovery and is the best choice for AODV in MANETs due to its consistent performance with changes in node count. Further analysis of additional protocols and TCP variants is recommended.
Transmission Control Protocol (TCP) is a fundamental protocol of the Internet Protocol Suite. TCP complements the Internet Protocol (IP), therefore it is common to refer to the internet protocol suit as TCP/IP. TCP is used for error detection, detection of packet loss or out of order delivery of data. TCP requests retransmission, rearranges data and helps with network congestion.
Several congestion control algorithms have been developed, over the last years, to improve TCP's performance over various technologies and network conditions.
The purpose of this assignment is to present TCP, network congestion, congestion algorithms and simulate different algorithms in different network conditions to measure their performance. For this assignment's needs, OPNET IT Guru Academic Edition software was used to accomplish the reproduction of projects that have been already published and gave the wanted results.
This document proposes a new dynamic approach to congestion control in TCP that determines congestion based on round trip time rather than packet loss. It suggests using the estimated round trip time as a threshold and increasing the congestion window linearly as long as the sample round trip time is below the threshold. If the sample round trip time exceeds the estimated time, the congestion window would be halved, and if it exceeds the estimated time plus four times the deviation round trip time, the window would be reset to one MSS. This approach aims to avoid the bottleneck problem of TCP by not including a slow start phase and responding earlier to potential congestion based on network delays.
This document proposes a new dynamic approach to congestion control in TCP that determines congestion based on round trip time rather than packet loss. It suggests using the estimated round trip time as a threshold and increasing the congestion window linearly as long as the sample round trip time is below the threshold. If the sample round trip time exceeds the estimated time, the congestion window is halved, and if it exceeds the estimated time plus four times the deviation round trip time, the window is reset to one MSS. This approach aims to overcome issues with TCP Reno and Tahoe like the bottleneck problem by avoiding an exponential increase in window size. The document discusses advantages like preventing network congestion and disadvantages like ambiguity in measured sample round trip
This summary provides an overview of the document in 3 sentences:
The document proposes a fuzzy-logic-based sending rate adaptation scheme called FSR to smooth the sending rate of TFMCC and avoid excessive decreases. FSR introduces five actions - additive increase, additive decrease, multiplicative increase, and multiplicative decrease - based on feedback information from receivers to determine how to adjust the sending rate. Simulation results show that FSR has better smoothness and TCP-friendliness compared to TFMCC.
EFFICIENT ADAPTATION OF FUZZY CONTROLLER FOR SMOOTH SENDING RATE TO AVOID CON...ijcsit
ABSTRACT
This paper prefers a fuzzy-logic-based sending rate adaption scheme named FSR(Fuzzy Sending Rate) intending to improve the evenness of TCPFriendly Multicast Congestion Control (TFMCC). To mitigate fluctuation of sending rate for TFMCC sender, FSR intends, five actions and link utilization for tuning sending rate and uses a fuzzy controller to determine which operation should be reaped according to the feedback information from CLR (current limiting receiver). Asymmetrical membership functions and biased fuzzy inference rules make FSR as friendly to TCP flows as TFMCC. Simulation results show that FSR has exceptional smoothness and fine TCP Friendliness.
Abstract - The Transmission Control Protocol (TCP) is
connection oriented, reliable and end-to-end protocol that support
flow and congestion control, with the evolution and rapid growth
of the internet and emergence of internet of things IoT, flow and
congestion have clear impact in the network performance. In this
paper we study congestion control mechanisms Tahoe, Reno,
Newreno, SACK and Vegas, which are introduced to control
network utilization and increase throughput, in the performance
evaluation we evaluate the performance metrics such as
throughput, packets loss, delivery and reveals impact of the cwnd.
Showing that SACK had done better performance in terms of
numbers of packets sent, throughput and delivery ratio than
Newreno, Vegas shows the best performance of all of them.
A Packet Drop Guesser Module for Congestion Control Protocols for High speed ...ijcseit
Different high speed Transport layer protocols have been designed and proposed in the literature to
improve the performance of standard TCP on high BDP links. They are mainly different in their increase
and decrease formulas of their respective congestion control algorithm. Most of these high speed protocols
consider every packet drop in the network as an indication of congestion and they immediately reduce their
congestion window size. Such an approach will usually result in under utilization of available bandwidth in
case of noisy channel conditions. We take CUBIC as a test case and have compared its performance in
case of normal and noisy channel conditions. The throughput of CUBIC was drastically degraded from
50Mbps to 0.5Mbps when we introduced a random packet drops with 0.001 probability. When the
probability of the packet drops increases then the throughput gets decreases. Indeed, we need to
complement existing congestion control algorithms with some intelligent mechanisms that can differentiate
whether a certain packet drop is because of congestion or channel error thus avoid unnecessary window
reduction. In order to distinguish between packets drops, we have developed a k-NN based module to guess
whether the packet drops are due to the congestion or any other reasons. After integrating this module with
CUBIC algorithm, we have observed significant performance improvement.
This document summarizes a survey on congestion control mechanisms. It discusses how congestion control plays an important role in computer networks and modern telecommunications to prevent network congestion. It categorizes major congestion control mechanisms and algorithms, including black box approaches like TCP that rely only on binary feedback and grey/green box approaches that use more network information. Common goals for congestion control algorithms are discussed like efficiency, fairness and smooth convergence.
In the last few years, video streaming facilities over TCP or UDP, such as YouTube, Facetime, Daily-motion, Mobile video calling have become more and more popular. The important
challenge in streaming broadcasting over the Internet is to spread the uppermost potential quality,
observe to the broadcasting play out time limitation, and efficiently and equally share the offered
bandwidth with TCP or UDP, and additional traffic types. This work familiarizes the Streaming
Media Data Congestion Control protocol (SMDCC), a new adaptive broadcasting streaming
congestion management protocol in which the connection’s data packets transmission frequency is
adjusted allowing to the dynamic bandwidth share of connection using SMDCC, the bandwidth share
of a connection is projected using algorithms similar to those introduced in TCP Westwood. SMDCC
avoids the Slow Jump phase in TCP. As a result, SMDCC does not show the pronounced rate
alternations distinguishing of modern TCP, so providing congestion control that is more appropriate
for streaming broadcasting applications. Besides, SMDCC is fair, sharing the bandwidth equitably
among a set of SMDCC connections. Main benefit is robustness when packet harms are due to
indiscriminate errors, which is typical of wireless links and is becoming an increasing concern due to
the emergence of wireless Internet access. In the presence of indiscriminate errors, SMDCC is also
approachable to TCP Tahoe and Reno (TTR). We provide simulation results using the ns3 simulator
for our protocol running together with TCP Tahoe and Reno.
IRJET-A Survey on congestion control with TCP networkIRJET Journal
This document summarizes various mechanisms for congestion control in computer networks. It begins with an introduction to congestion and its impacts. It then classifies congestion control schemes into several categories such as window-based vs. rate-based, unicast vs. multicast, and end-to-end vs. router-supported. Several popular congestion control protocols are described, including TCP, RAP, TFRC, and TEAR. Window-based multicast congestion control approaches like RLA and MTCP are also summarized. The document provides an overview of different congestion control techniques in computer networks.
Towards Seamless TCP Congestion Avoidance in Multiprotocol EnvironmentsIDES Editor
In this paper we explore the area of congestion
avoidance in computer networks. We provide a brief overview
of the current state of the art in congestion avoidance and also
list our extension to the TCP congestion avoidance mechanism.
This extension was previously published on an international
forum and in this paper we describe an improved version which
allows multiprotocol support. We list preliminary results
carried out in a simulation environment.
New introduced approach called Advanced Notification
Congestion System (ACNS) allows TCP flows prioritization
based on the TCP flow age and priority carried in the header
of the network layer protocol. The aim of this approach is to
provide more bandwidth for young and high prioritized TCP
flows by means of penalizing old greedy flows with a low
priority. Using ACNS, substantial network performance
increase can be achieved.
This document discusses a proposed congestion control mechanism called Network Border Protocol (NBP) that aims to prevent congestion collapse and unfairness in networks. NBP works by having edge routers monitor and control the ingress rates of individual flows to prevent packets from entering the network faster than they can leave. It uses feedback exchanged between ingress and egress routers to inform them of flow rates. While adding complexity to edge routers, NBP's approach aims to isolate this within the network borders and not require changes to end systems or transport protocols. The key components of NBP include its rate control algorithm, use of leaky bucket algorithms at ingress routers, and feedback control between edge routers.
Improved SCTP Scheme To Overcome Congestion Losses Over ManetIJERA Editor
Transmission control conventions have been utilized for data transmission process. TCP has been pre-possessed
for information transmission over wired correspondence having diverse transfer speeds and message delays over
the system. TCP gives correspondence utilizing 3-handshake which sends RTS and ACK originate from server
end and information message has been transmitted over the data transmission gave. This does not give security
over flooding assault happened on the system. TCP gives correspondence between distinctive hubs of the wired
correspondence however when multi-spilling happens in a system TCP does not gives legitimate throughput of
the framework which is significant issue that happened in the past framework. In the proposed work, to beat this
issue SCTP and Improved SCTP transmission control convention has been executed for the framework
execution of the framework. SCTP gives 4-handshake correspondence in the message transmit and improved
SCTP gives the performance when the queue length comes to its full value then it divides the message to other
nodes because of which security element get expansions and this likewise gives correspondence administrations
over multi-spilling and multi-homing. Numerous sender and recipients can impart over wired system utilizing
different methodologies of correspondence through same routers, which debases in the TCP convention. In last
we assess parameters for execution assessment. Here, we composed and actualized our proving ground utilizing
Network Simulator (NS-2.35) to test the execution of both Routing conventions.
IMPACT OF CONTENTION WINDOW ON CONGESTION CONTROL ALGORITHMS FOR WIRELESS ADH...cscpconf
TCP congestion control mechanism is highly dependent on MAC layer Backoff algorithms that
predict the optimal Contention Window size to increase the TCP performance in wireless adhoc
network. This paper critically examines the impact of Contention Window in TCP congestion
control approaches. The modified TCP congestion control method gives the stability of
congestion window which provides higher throughput and shorter delay than the traditional TCP. Various Backoff algorithms that are used to adjust Contention Window are simulatedusing NS2 along with modified TCP and their performance are analyzed to depict the influence of Contention Window in TCP performance considering the metrics such as throughput, delay, packet loss and end-to-end delay
1 improvement of tcp congestion window over ltetanawan44
This document discusses improving the performance of TCP congestion control over LTE-Advanced networks. It proposes a new congestion avoidance mechanism that uses the available bandwidth of the connection to better detect the network path capacity and improve congestion avoidance. The mechanism is tested using the NS-2 network simulator to model LTE-Advanced traffic. The document provides background on LTE-Advanced network architecture and existing TCP congestion control mechanisms. It aims to develop an enhanced TCP variant that can efficiently transfer high data rates over the large bandwidth, low latency links of LTE-Advanced networks.
This document summarizes an Active Congestion Control (ACC) mechanism that uses active networking technology to make feedback congestion control more responsive to network congestion. ACC includes programs in data packets that allow routers to react to congestion without incurring round trip delay. When congestion is detected, the congested router calculates and sends a new congestion control state to endpoints to synchronize distributed states. Simulations show ACC TCP can achieve up to 18% higher throughput than standard TCP under bursty traffic conditions by reacting more quickly to congestion. ACC and TCP perform comparably under stable network conditions.
TCP INCAST AVOIDANCE BASED ON CONNECTION SERIALIZATION IN DATA CENTER NETWORKSIJCNCJournal
In distributed file systems, a well-known congestion collapse called TCP incast (Incast briefly) occurs
because many servers almost simultaneously send data to the same client and then many packets overflow
the port buffer of the link connecting to the client. Incast leads to throughput degradation in the network. In
this paper, we propose three methods to avoid Incast based on the fact that the bandwidth-delay product is
small in current data center networks. The first method is a method which completely serializes connection
establishments. By the serialization, the number of packets in the port buffer becomes very small, which
leads to Incast avoidance. The second and third methods are methods which overlap the slow start period
of the next connection with the current established connection to improve throughput in the first method.
Numerical results from extensive simulation runs show the effectiveness of our three proposed methods.
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It also offers an in-depth guide on how to configure the WSL interpreter and files within the PyCharm environment. This is essential for ensuring that the debugging process is set up correctly and that the program can be run effectively within the WSL terminal.
Additionally, the document provides guidance on how to set up breakpoints for debugging, a fundamental aspect of the debugging process which allows the developer to stop the execution of their code at certain points and inspect their program at those stages.
Finally, the document concludes by providing a link to a reference blog. This blog offers additional information and guidance on configuring the remote Python interpreter in PyCharm, providing the reader with a well-rounded understanding of the process.
Software Engineering and Project Management - Introduction, Modeling Concepts...Prakhyath Rai
Introduction, Modeling Concepts and Class Modeling: What is Object orientation? What is OO development? OO Themes; Evidence for usefulness of OO development; OO modeling history. Modeling
as Design technique: Modeling, abstraction, The Three models. Class Modeling: Object and Class Concept, Link and associations concepts, Generalization and Inheritance, A sample class model, Navigation of class models, and UML diagrams
Building the Analysis Models: Requirement Analysis, Analysis Model Approaches, Data modeling Concepts, Object Oriented Analysis, Scenario-Based Modeling, Flow-Oriented Modeling, class Based Modeling, Creating a Behavioral Model.
CHINA’S GEO-ECONOMIC OUTREACH IN CENTRAL ASIAN COUNTRIES AND FUTURE PROSPECTjpsjournal1
The rivalry between prominent international actors for dominance over Central Asia's hydrocarbon
reserves and the ancient silk trade route, along with China's diplomatic endeavours in the area, has been
referred to as the "New Great Game." This research centres on the power struggle, considering
geopolitical, geostrategic, and geoeconomic variables. Topics including trade, political hegemony, oil
politics, and conventional and nontraditional security are all explored and explained by the researcher.
Using Mackinder's Heartland, Spykman Rimland, and Hegemonic Stability theories, examines China's role
in Central Asia. This study adheres to the empirical epistemological method and has taken care of
objectivity. This study analyze primary and secondary research documents critically to elaborate role of
china’s geo economic outreach in central Asian countries and its future prospect. China is thriving in trade,
pipeline politics, and winning states, according to this study, thanks to important instruments like the
Shanghai Cooperation Organisation and the Belt and Road Economic Initiative. According to this study,
China is seeing significant success in commerce, pipeline politics, and gaining influence on other
governments. This success may be attributed to the effective utilisation of key tools such as the Shanghai
Cooperation Organisation and the Belt and Road Economic Initiative.
CHINA’S GEO-ECONOMIC OUTREACH IN CENTRAL ASIAN COUNTRIES AND FUTURE PROSPECT
Recital Study of Various Congestion Control Protocols in wireless network
1. IOSR Journal of Computer Engineering (IOSR-JCE)
e-ISSN: 2278-0661,p-ISSN: 2278-8727, Volume 17, Issue 2, Ver. V (Mar – Apr. 2015), PP 129-138
www.iosrjournals.org
DOI: 10.9790/0661-1725129138 www.iosrjournals.org 129 | Page
Recital Study of Various Congestion Control Protocols in wireless
network
Mehta Ishani1
, UditNarayan Kar2
, Dr. Atul Gonsai3
1
(PG Student, Computer Science, GardiVidyapith,Rajkot,Gujarat, India)
2
(Research Scholar,Computer Science, Saurastra University,Rajkot, Gujarat, India)
3
(Associate Professor, Computer Science, Saurastra University,Rajkot, Gujarat, India)
Abstract: Congestion control in packet switching networks became a high priority in network design and
research due to ever-growing network bandwidth and intensive network applications. Dozens of various
congestion control strategies have been proposed, and more are forthcoming. Based on control theory concepts
congestion control can be viewed as control policy to achieve prescribed goals (e.g., round-trip delay or
throughput) in a distributed network environment. This paper discusses the advantages, disadvantages and the
applications of various congestion control protocols for wireless networks. It explores the motivation behind the
design of congestion control protocols which is suitable to large scale wireless network and abolish drawbacks
of the most widely accepted two algorithms of TCP and RCP.
Keywords: TCP- Transmission Control Protocol, RCP- Rate Control Protocol
I. Introduction
The use and demand of wireless network has increased significantly in past years. Wireless
environment is more flexible, easy to deploy and scalable than traditional wired setup. Besides that in wireless
network air is used as access medium it is also more sensitive to inferences and to congestion. The developed
congestion control protocols like Transmission Control Protocol (TCP) and Rate Control Protocols (RCP) do
not take into account the problems and particularities of wireless network. TCP is the most widely accepted and
used congestion protocol in internet. It used window based Additive Increase Multiplicative Decrease (AIMD)
strategy for congestion control [1]. However, TCP proved to be unsuitable for dynamic environment of wireless
network where nodes are mobile and frequently participate and departure from the flow. RCP is built on rate
based congestion control strategy. It relay on network interaction modules such as routers for congestion
control. Also it is proved that RCP performs better than TCP [6]. The above described protocols are also proved
heavy for implementation into light devices with the reference of OS, Processing, and Memory Requirement and
Power consumption. They perform complex computation which is consuming power, requiring more memory
for storing per packet states, heavy for Hot Spot Tethering and might get hang with heavy processing [3]. Some
of these performance problems led to the development of new congestion control protocols. In this paper we
present performance comparison of TCP, RCP+ and our proposed model Enhanced RCP in wireless network.
The paper organizes as follows. The next section II, III and IV describes the mechanism of different congestion
control protocols, TCP, RCP and RCP+.Section V briefly introduced our proposed approach and section VI
presents implementation and evaluation results. Finally section VII provides conclusion.
II. TCP
The TCP achieves two important functions: (1) Reliable and ordered delivery and (2) Congestion
control. Congestion can be detected by Packet loss or Packet delay. Solution of this problem is limiting sender‟s
transmission rate. Now question arise, at what rate should the data be sent for the current network path? [5].
Congestion control mechanism given in [1] is shown in figure 1.
Congestion control mechanism given in [1] is shown in Fig 1. Each TCP connection initiate with a pre-
configured small congestion window no larger than 4 Maximum Segment Size (MSS).The goal of Slow-Start is
to keep a new sender from overflowing network buffers, while at the same time increasing the congestion
window fast enough and avoiding performance loss while the connection is operating with a small
window.Slow-Start increases the congestion window by one MSS for each new acknowledgment received,
which results in the window doubling after each window‟s worth of data is acknowledged. With this exponential
increase, RTT log2W (where RTT stands for round-trip time) time is required to reach a window of size W.
2. Recital Study of Various Congestion Control Protocols in wireless network
DOI: 10.9790/0661-1725129138 www.iosrjournals.org 130 | Page
Figure 1: TCP‟s congestion control mechanism [1]
A connection enters Slow-Start on newly starting or on experiencing a packet retransmission timeout,
and exits Slow-Start when it detects a packet loss or when the congestion window has reached a dynamically
computed threshold, ssthresh. More specifically, ssthresh is set to half of the current congestion window when
packet loss was detected. TCP exits Slow-Start to enter the Congestion Avoidance phase, where it continues to
probe for available bandwidth, but more cautiously than in Slow-Start. During periods when no packet losses
are observed, TCP performs an Additive Increase of the window size, by 1 MSS each time a full window is
acknowledged (i.e., increases the congestion window as:
cwnd = cwnd +1 (1)
on receiving each acknowledgment packet). And when Congestion occurs it decreases the window size by half
as given in equation below
cwnd=cwnd*
1
2
(2)
III. RCP
Researchers of paper [6, 7] have proposed Rate Control Protocol (RCP). In RCP, a router assigns a
single rate, R (t), through which all flows pass. Here, the basic idea is: If there is spare capacity available, then
share it equally among all flows. Furthermore if there is a queue building up, then the link capacity is
insufficient and the flow rate is decreased evenly. they have tried to minimize Flow completion time (FCT).
FCT is time from when the first packet of a flow is sent (in TCP, this is the SYN packet) until the last packet is
received. To minimize FCT for each router a well-known method is to use processor-sharing (PS) i.e. a router
divides outgoing link bandwidth equally among ongoing flows. Also they have proposed an equation for RCP:
R(t) = R(t - d0) +
α ∁−y t −β
q t
d0
N(t)
(3)
where,
d0 = a moving average of the RTT measured across all flows,
R(t−d0) = last updated rate,
C = link capacity,
y(t) = measured input traffic rate during the last update interval (d0 in this case),
q(t) = instantaneous queue size,
N(t) = router‟s estimate of the number of ongoing flows (i.e., number of flows actively sending traffic) at time t
α, β = parameters chosen for stability and performance.
Simulation results show that RCP performs better than TCP in terms of FCT and link utilization in
wired network [9]. It is also taken account that RCP possess routing overhead on network also due to having
complex computation and involving routers. Researchers of paper [8] have introduced two limitations of RCP:
(1) RCP will need to operate alongside existing non-RCP traffic, such as TCP and UDP, without adversely
affecting or being affected by the other traffic; and (2) RCP will need to operate in a network where some
routers are not RCP-enabled.
3. Recital Study of Various Congestion Control Protocols in wireless network
DOI: 10.9790/0661-1725129138 www.iosrjournals.org 131 | Page
IV. RCP+
Authors [2] described a simple congestion control algorithm called RCP+ which reduces flow
completion time for diverse flow types to large extend for broad range of traffic conditions and network
situations. In RCP+, unlike XCP, RCP they are not following feedback mechanism but they are adapting the
ancient congestion window based congestion control mechanism. The reason behind sticking to the congestion
window for congestion control is that, while each second new flow are entering and moving out of network, it is
tough to obtain exact number of flows at particular RTT. This inspired us to stay with congestion window based
mechanism instead of feedback based mechanism. We set the ‗cwnd„ value completely based on the rate
computation, but that doesn„t impose any overhead over the router. In addition, we are setting the value of
‗maxcwnd„ to obtain the better start for our optimum data rate calculation at the initial stage.
RCP+ wins upon existing congestion control algorithm with three characteristics, 1) RCP+ is more
flexible to be implemented on wireless networks in comparison of RCP. 2) It allows multiple variants of TCP to
co-exist in the same networks with RCP+ and work with each other smoothly. 3) And it performs well in Large
scale wireless networking scenario too.The equation of RCP+ can be given as:
N(t) * R(t) = (α*C - α*y(t) – (β*q(t)/d)) (4)
Where,
d = moving average of RTT per interval,
R(t) = last updated rate,
y(t) = existing traffic observed in network,
q(t) = the instantaneous queue size,
C = link capacity and
N(t) = number of flows.
α (alpha) is a stability parameter and β (beta) is a performance parameter added to the equation to make the
rate stable and not aggressive.
Thus, the equation gives us the desired aggregate rate change in presence of traffic in the next interval.
Here, Rate kept same for each flow. “cwnd‟ congestion window value is having proportionate relationship with
the rate and so, “cwnd‟ value is set on the bases of the Rate computed. RCP+ is very acute to packet loss. This
equation was obtained by manipulating Rate equation of RCP [5]
V. Proposed Approach
Our proposed approach is based Improved AIMD and RCP+ algorithm. In our proposed approach we
use congestion window mechanism of Improved AIMD algorithm to use the spare capacity of congestion
window after occurrence of congestion event. The limitation of AIMD is that the algorithm does not include the
different arrival time of flows.[1]. So we have used modified equation of RCP+ algorithm.
RCP+ algorithm is implemented based on the theory of RCP. RCP+ is having the added advantage of
coexistence with other wired and wireless TCP, XCP, RCP and DCCP protocols. RCP+ is flexible like TCP and
so is expected to have wide implementation over current demands of Internet. [2]. In the theory of RCP there is
a concept of queue. RCP was originally implemented in wired network. In wireless network the essential point
is traffic is in bursty nature. Hence it is difficult to use queue concept while going to practical simulation. So we
modified the equation of rate change.
Here we come up with a new proposal of congestion control scheme enhanced RCP. Here we use
Improved AIMD mechanism as well as modified rate change equation of RCP+. Our aim is to gain benefits of
both schemes by eliminating each other‟s demerits.
Initially we defined congestion window size 4 MSS and start data transfer. If acknowledgment is
received means no congestion and increase congestion windows size by +1 and transfer data
If acknowledgment is not received then congestion would likely to be occurred then decrease
congestion window size by equation:
Cwnd = (cwnd *1/2) + K (5)
Where, k is the increment in congestion window size (w) in t cycles or epoch
Calculate the rate change by equation:
Rate = (α*C - α*y(t) )/N(t) (6)
Again check if rate is greater then congestion window size then increase congestion window size
otherwise transfer data.
4. Recital Study of Various Congestion Control Protocols in wireless network
DOI: 10.9790/0661-1725129138 www.iosrjournals.org 132 | Page
Algorithm
1) Initially set congestion window size 4 MSS
2) Data transfer
3) If acknowledgement is received increase congestion window size by cwnd = cwnd +1 and repeat step 2
4) Otherwise decrease congestion window size by equation Cwnd = (cwnd *1/2) + K
5) Calculate the rate change by equation Rate = (α*C - α*y(t) )/N(t)
6) If rate >cwnd then go to step 2
7) Otherwise transfer data
Below figure shows the flow chart for the same.
Figure2 Flow chart for proposed algorithm
VI. Implementation
We have implemented proposed model in NS-2 simulator and version is 2.35 [10].Following are the
steps for modification we have done in C++ file of TCP to implement RCP++
Step 1: Go to the location where tcp.cc is located. There, under the class definition of Tcp agent, bind two
variables for its usability under the procedure of bind.
bind("bw_",&bw_);
bind("flow_",&flow_);
Step 2: Modify TcpAgent::window procedure
5. Recital Study of Various Congestion Control Protocols in wireless network
DOI: 10.9790/0661-1725129138 www.iosrjournals.org 133 | Page
if (frto_ == 2)
{
return (force_wnd(2) <wnd_ ?
force_wnd(2) : (int)wnd_+4);
}
Step 3: Modify TcpAgent::slowdown procedure
double win, halfwin, decreasewin, k;
k = (windowd() / 2) -1;
if (cwnd_ <ssthresh_)
slowstart = 1;
if (precision_reduce_)
{
halfwin = (windowd() / 2)+k;
}
else
{
int temp;
temp = (int)((window() / 2)+k);
halfwin = (double) temp;
}
Step 4: Modify TcpAgent::processQuickStart procedure
Define following variables
intapp_rate, bw_=400000, flow_=4;
float alpha = 0.1, yt = 0.005;
Step 5: Add following lines to the procedure of processQuickStart
qs_requested_ = 0;
qs_approved_ = 0;
if (qsh->flag() == QS_RESPONSE &&qsh->ttl() == ttl_diff_ &&qsh->rate() > 0) {
app_rate = (int)((alpha*TcpAgent::bw_ - alpha*yt) )/TcpAgent::flow);
Step 6: Give the computed rate to qs_cwnd defined under the procedure of processQuickStart
if (app_rate>initial_window())
{
qs_cwnd_ = app_rate;
qs_approved_ = 1;
}
else
{ // Quick Start rejected
}
Step 7: Once the changes in tcp.cc are made, save and exit the editor. Next step is to open the terminal and
under super user, type following commands one by one.
./configure
Make clean
Make
Make Install
Once you have done this your TCP agent will become RCP enabled now run the tcl scripts and
obtained the results.Following table 1.1 present the configuration details of the simulation. We have created a
wireless network and
Table 1 Configuration Table
Layer Parameter Values
Application FTP FTP over TCP agent and RCP+
Configuration No of nodes 10 to 50 incremental
6. Recital Study of Various Congestion Control Protocols in wireless network
DOI: 10.9790/0661-1725129138 www.iosrjournals.org 134 | Page
Mobility Maximum Speed 10 Mbps
Pause time 2 s
Simulation time 500 s
Traffic Type TCP/CBR
Rate 4.0 Mbps
Routing Protocol AODV
MAC Mac 802_11
PHY Propagation model Two ray ground
Antenna Omni
System OS Ubuntu 12.10
Processor Intel(R) Core(TM) i5
The values of throughput, packet delivery ratio and routing load for TCP, RCP+ and proposed model
are given in tables bellow. From these values graphs are plotted and performance of each protocol can be
evaluated.
Throughput: In general terms, throughput is the rate of production or the rate at which something can be
processed. When used in the context of communication networks, throughput or network throughput is the rate
of successful message delivery over a communication channel. The data these messages belong to may be
delivered over a physical or logical link, or it can pass through a certain network node. Throughput is usually
measured in bits per second (bit/s or bps), and sometimes in data packets per second or data packets per time
slot.It is clearly shown that after 20 nodes the packer delivery ratio stated decreasing so that is the bottleneck
area and after that congestion occurs.
Table 2 Throughput Statistics
Throughput
Nodes TCP RCP+ Proposed
10 210.17 215.22 232.22
20 458.35 446.3 460.95
30 633.91 599.13 569.76
40 646.97 588.9 633.41
50 585.45 576.54 618.02
Graph 1 Throughput graph
Packet Delivery Ratio:The ratio of the number of delivered data packet to the destination. ∑ Number of packet
receive / ∑ Number of packet send. This illustrates the level of delivered data to the destination. The greater
value of packet delivery ratio means the better performance of the protocol. It is observed that proposed model
have greater values of Packet Delivery Ratio than existing protocols.
7. Recital Study of Various Congestion Control Protocols in wireless network
DOI: 10.9790/0661-1725129138 www.iosrjournals.org 135 | Page
Table 3 Packet Delivery Ratio Statistics
Packet Delivery Ratio
Nodes TCP RCP+ Proposed
10 0.8858 0.908 0.9803
20 0.991 0.9636 0.9961
30 0.9386 0.8871 0.8453
40 0.7242 0.6587 0.7106
50 0.5357 0.6457 0.5654
Graph 2 Packet Delivery Ratio graph
Routing load: Routing load is the ratio of data packets or receiving packets and routing packets. Greater value
of routing load indicates more impact of router overhead on the performance of the protocol. From below
statistics Routing load of proposed model is less than other protocols.
Table 4 Routing load Statistics
Routing load
nodes TCP RCP+ Proposed
10 0.155 0.11 0.08
20 0.194 0.184 0.102
30 0.282 0.501 0.484
40 0.753 0.939 0.744
50 1.453 1.637 1.244
8. Recital Study of Various Congestion Control Protocols in wireless network
DOI: 10.9790/0661-1725129138 www.iosrjournals.org 136 | Page
Graph 3 Routing load graph
Link Utilization: Link utilization is an important parameter to evaluate in congestion control protocols. It can
be given as portion of link is used in transmitting and receiving packets. We have also obtained the percentage
of link is utilized with respect to node and with respect to time.
Table 5 link utilization with respect to nodes
link utilization %
nodes TCP RCP+ Proposed
10 26.13 26.76 28.88
20 57 55.5 57.32
30 78.83 74.51 70.85
40 80.46 73.23 78.77
50 72.81 71.7 76.86
Graph 4 Link utilization with respect to nodes
10. Recital Study of Various Congestion Control Protocols in wireless network
DOI: 10.9790/0661-1725129138 www.iosrjournals.org 138 | Page
Thesis:
[8]. NanditaDukkipati, “Rate Control Protocol (RCP): Congestion Control to make Flows Complete Quickly”, Ph.D. Thesis, Stanford
University, Stanford, California. 2007
Technical Reports:
[9]. NanditaDukkipati& Nick McKeown, “Processor Sharing Flows in the Internet”, Stanford HPNG Technical Report, Stanford
University, Stanford, California. 2007.
Books:
[10]. Book “Introduction to Network Simulator NS2” springer, 2009