Congestion Avoidance Mechanism Research Articles

Formation of Innovative Algorithm for High Speed Protocol using Network Simulator

The effort delivered in this manuscript is grounded on NS-2 (The Network Simulator 2) to implementing the congestion control process of classic TCP (Transmission Control Protocol), with new congestion control mechanism. In this paper, a novel congestion control algorithm is offered, which contains of slow-start and congestion avoidance mechanisms. The proposed slow-start algorithm assumes a duplicating and an interpolating approach to the congestion window (cwnd) for each increment instead of the exponential increment used by other TCP source variants such as Reno, Vega, Tahoe, Newreno, Fack, and Sack. Furthermore, the enhanced congestion avoidance algorithm is built by using an improved Additive Increase Multiplicative Decrease (AIMD) algorithm with multi TCP flow facility, to provide an enhanced congestion control algorithm with some valuable properties to improving TCP routine for high speed protocols.

A Simulation-Based Comparative Study of Controlled Delay (Codel) with Random early Detection (Red) for Network Performance Evaluation

The rising need to use the internet for time/delay-sensitive applications with different Quality of Service (QOS) requirements has made network management and control even more challenging. The current congestion avoidance and control mechanisms for Transport Control Protocol (TCP) are insufficient to offer good service in all circumstances. A few decades ago, the TCP successfully regulated Internet congestion control. However, it is already widely acknowledged that TCP has reached its limits and that new congestion control protocols will be required in the near future. This has prompted a significant amount of research on novel congestion control designs that will meet the demands of the future Internet. With widespread public attention and study, the full buffer problem has not gone away, but rather worsened. As a result, there has been a surge in interest in using Active Queue Management (AQM) in Internet routers to minimize queue latency. The effectiveness of a recently developed AQM, Controlled Delay (CoDel) algorithm, designed to work in today’s network setups and can be deployed as a main part of the bufferbloat solution, is evaluated in this research study. CoDel's effectiveness is evaluated by running simulations in ns-3 and comparing its results to that of Random Early Detection (RED), another promising network queue management technique.

Recommendation of urban vehicle driving routes under traffic congestion: A traffic congestion regulation method considering road network equilibrium

Vehicle travel route selection is the main task of the traveler information service system in the intelligent transportation system. In this study, a dynamic graph convolutional neural network (DGCN) was constructed to perform multi-time-step travel time prediction for each road section of a road network, and vehicle travel route recommendation was performed according to travel demand and in consideration of factors such as avoiding congestion areas and balancing the road network. The road network partitioning was performed by a built weighted network model based on road network structure through the GN (Grivan-Newman) algorithm, which helps to identify the traffic status of congested areas. The results showed that the route selection recommendation for the avoidance of the congested area reduced the congestion equilibrium index of the urban road network. Therefore, considering the congestion avoidance mechanism from the global level of the road network can reduce the overall congestion degree.

An Intelligent Congestion Avoidance Mechanism Based on Generalized Regression Neural Network for Heterogeneous Vehicular Networks

An Intelligent Congestion Avoidance Mechanism Based on Generalized Regression Neural Network for Heterogeneous Vehicular Networks

K-means Clustering, Unsupervised Classification, K-NN, Euclidean Distance, Genetic Algorithm

In recent days, the need to provide reliable data transmission over Internet traffics or cellular mobile systems becomes very important. Transmission Control Protocol (TCP) represents the prevailing protocol that provide reliability to data transferring in all end-to-end data stream services on the Internet and many of new networks. TCP congestion control has become the key factor manipulating the behavior and performance of the networks. TCP sender can regulates the size of the congestion window (CWND) using the congestion control mechanism and TCP dynamically adjust the window size depending on the packets acknowledgment (ACK) or by indicates the packets losses when occur. TCP congestion control includes two main phases, slow-start and congestion avoidance and these two phases even work separately, but the combination of them controls CWND and the packet injection to the network pipe. Congestion avoidance and slow-start are liberated mechanisms and using unlike objectives, but if the congestion happens, they are executed together. This article provides an efficient and reliable congestion avoidance mechanism to enhancing the TCP performance in large-bandwidth low-latency networks. The proposed mechanism also includes a facility to send multiple flows over same connection with a novel technique to estimate the number of available flows dynamically, where the all experiments to approving the proposed techniques are performed over the network simulation NS-2.

Dynamic Clustering for Low-Delay Delivery of Video Content Cached in MEC Servers

For the purpose of video caching and low-delay video delivery to the end-users, multiaccess edge computing (MEC) servers are commonly grouped into clusters to efficiently exploit the limited storage resources of the MEC servers. In this article, we first introduce a methodology for analysis of the video delivery delay using the queuing theory. Our analysis shows that the video delivery delay is mainly affected by the arrival rate of the video requests. Furthermore, we show a tradeoff between the ratio of videos found in the MEC servers within the same cluster and the transmission delay of video contents. To reduce the video delivery delay, we propose a dynamic MEC server clustering (DyMECC) algorithm that determines the cluster size at each time interval by solving analytically derived equations considering the actual arrival rate of video requests. It also acts as a congestion avoidance mechanism for the communication interfaces among the MEC servers. Via simulations, we show that the DyMECC reduces the video delivery delay about 15% in light load conditions and by more than five times in heavy load conditions compared to state-of-the-art works while also reduces the load of the communication interfaces among the MEC servers by more than 45%.

A Green Hybrid Congestion Management Scheme for IoT-Enabled WSNs

In the modern era, the Internet of Things (IoT) plays a vital role in connecting physical objects to the Internet. Therefore, an IoT technology can monitor and control any physical object from remote locations. In IoT-based systems, Wireless Sensor Network (WSN) is used to monitor a large number of heterogeneous physical objects. The IoT-enabled WSNs suffer from congestion problems that significantly reduce the network lifetime and performance of the network. This paper present a green hybrid congestion control mechanism for IoT-enabled WSNs. It uses an unequal clustering mechanism which saves the energy of battery-limited sensor nodes and resolves energy hole issues. Furthermore, a novel two-class priority-based congestion avoidance mechanism is proposed which significantly reduces communication delay. Extensive simulations and real-life experiments are performed to demonstrate the effectiveness of the proposed scheme. Experimental result shows that the proposed scheme outperforms the state-of-the-art algorithms in terms of network lifetime, successful packet delivery, average throughput, and other parameters. Furthermore, the proposed scheme is also tested in a real testbed that demonstrates its effectiveness for disaster management in smart city applications.

Analyzing TCP Performance in High Bit Error Rate Using Simulation and Modeling

While Transmission Control Protocol (TCP) works well with a low bit error rate (BER), the performance of TCP degrades significantly if the BER rises above a certain level. A study of the performance of TCP with high BER is required for the efficient design and deployment of such systems. In this paper, we address the problem of TCP performance in high BERs and analyze the issues by investigating the effect of BERs on system performance. We consider TCP Reno in our study to explore the system performance using extensive analysis of simulation and modeling. In the analysis, we consider the amount of datagram sent and retransmitted, mean throughput, link-layer overhead, TCP window size, FTP download response time, packet dropping and retransmission, and the TCP congestion avoidance mechanism. We validate simulation results by setting up a virtualized testbed using Linux hosts and a Linux router. The results obtained show that TCP throughput degrades significantly and eventually collapses at the packet drop probability of 10% (BER = 10−5). The FTP download response time is about 32 times longer than that of a perfect channel (no packet dropping). We found that TCP Reno cannot handle such a high BER to operate in wireless environments effectively. Finally, we provide recommendations for network researchers and engineers confronted with the challenge of operating TCP over noisy channels.

An IoV-PBFT Consensus-Based Blockchain for Collaborative Congestion Avoidance and Simulation Test

This paper proposes a novel Internet of Vehicles (IoV) practical Byzantine fault tolerance (PBFT) consensus mechanism suitable for the distributed vehicle-to-vehicle (V2V) scenario and the V2V collaborative congestion avoidance mechanism based on blockchain. Compared with the traditional PBFT consensus mechanism, the proposed IoV-PBFT consensus mechanism has been improved in three aspects. (1) The authenticated vehicles are divided into three types including common nodes, production nodes, and verification nodes. The vehicles in the same congestion road section are used as the consensus participation nodes, which are divided into the production node and verification node. Since the vehicles in this section are moving slowly or even stopping and the number of newly added and departing nodes are less, the identity of the previous nodes is verified before each round of consensus, which ensures the dynamic tolerance with less additional delay. (2) The verification nodes are grouped based on path loss, and the nodes with good channel quality are selected as the leader nodes. (3) The main node in traditional PBFT is omitted, and the two-stage process is used instead of the traditional three-stage process, which effectively reduces the consensus delay and communication complexity. The theoretical derivation and simulation results show that the proposed IoV-PBFT has greatly improved the V2V link quality compared with traditional PBFT, and the success ratio of links between nodes can reach more than 93%, which has met the requirements of establishing blockchain in IoV.

Load balancing routing algorithm based on extended link states in LEO constellation network

As an important part of satellite communication network, LEO satellite constellation network is one of the hot research directions. Since the nonuniform distribution of terrestrial services may cause inter-satellite link congestion, improving network load balancing performance has become one of the key issues that need to be solved for routing algorithms in LEO network. Therefore, by expanding the range of available paths and combining the congestion avoidance mechanism, a load balancing routing algorithm based on extended link states in LEO constellation network is proposed. Simulation results show that the algorithm achieves a balanced distribution of traffic load, reduces link congestion and packet loss rate, and improves throughput of LEO satellite network.

Towards Stability Analysis of Data Transport Mechanisms: A Fluid Model and Its Applications

The Transmission Control Protocol (TCP) utilizes congestion avoidance and control mechanisms as a preventive measure against congestive collapse and as an adaptive measure in the presence of changing network conditions. The set of available congestion control algorithms is diverse, and while many have been studied from empirical and simulation perspectives, there is a notable lack of analytical work for some variants. To gain more insight into the dynamics of these algorithms, we: (1) propose a general modeling scheme consisting of a set of functional differential equations of retarded type (RFDEs) and of the congestion window as a function of time; (2) apply this scheme to TCP Reno and demonstrate its equivalence to a previous, well known model for TCP Reno; (3) show an application of the new framework to the widely-deployed congestion control algorithm TCP CUBIC, for which analytical models are few and limited; and (4) validate the model using simulations. Our modeling framework yields a fluid model for TCP CUBIC. From a theoretical analysis of this model, we discover that TCP CUBIC is locally uniformly asymptotically stable -- a property of the algorithm previously unknown.

Development of an efficient mechanism for rapid protocols using NS-2 simulator

The delivered effort in this manuscript is grounded on NS-2 (The Network Simulator 2) to implement the congestion control process of classic TCP (Transmission Control Protocol), with new congestion control mechanism. In this paper, a novel congestion control algorithm is offered, which contains of slow-start and congestion avoidance mechanisms. The proposed slow-start algorithm assumes a duplicating and an interpolating approach to the congestion window (cwnd) for each increment instead of the exponential increment used by other TCP source variants such as Reno, Vega, Tahoe, Newreno, Fack, and Sack. Furthermore, the enhanced congestion avoidance algorithm is built by using an improved Additive Increase Multiplicative Decrease (AIMD) algorithm with multi TCP flow facility, to provide an enhanced congestion control algorithm with some valuable properties to improve TCP routine for high speed protocols. The improvement strategy based on merging of slow start, congestion avoidance mechanism that are used in TCP congestion control, to create a new AIMD algorithm with a new relationship between the pair parameters a and b. This paper is also involved in the creation of rapid agent in NS-2 models designed to identify the modified TCP and to configure the NS-2 platform. A fast TCP also includes an innovative scheme to slow the rapid start to help TCP to start faster through the high speed networks and also to postpone the congestion state as much as possible.

Modeling Upper Layer Reaction to QoS Degradation as a Congestion Avoidance Mechanism

Modeling Upper Layer Reaction to QoS Degradation as a Congestion Avoidance Mechanism

Proactive coordination for low-congestion multi-path datacenter networks

Abstract Modern datacenters involve a rich mix of workloads, each of which puts forward different service-level objective, including high throughput, low latency, etc. Currently, most datacenters introduce statistical multiplexing technology and oversubscription to the network design to lower the total cost, which can easily lead to the occurrence of network congestion, especially when the network is highly occupied by throughput-intensive workloads. This paper describes ProCAM, a proactive congestion avoidance mechanism for datacenter networks. As throughput-intensive flows are the chief culprit of network congestion, ProCAM adapts the multi-path routing to control transmission bandwidth and utilizes the predictability of throughput-intensive flows to prearrange optimal coordinate scheme (desynchronize the sending time of concurrent long-flows) beforehand as a proactive manner, by solving the low-congestion transmission model which minimizes network-wide host-to-host transmission latency from a global perspective. In this way, queue length in buffers can be kept at a low level and the performance of latency-sensitive flows can be guaranteed. In the evaluation experiments based on simulation with Mininet and SDN controller Ryu, the extensive simulations show that the proposed ProCAM can achieve high throughput with nearly zero packet loss and low latency when the network is highly occupied.

Smart-RED: A Novel Congestion Control Mechanism for High Throughput and Low Queuing Delay

We consider the scenario in which several TCP connections share the same access point (AP) and a congestion avoidance/control mechanism is adopted with the aim of assigning the available bandwidth to the clients with a certain fairness. When UDP traffic with real-time requirements is present, the problem becomes even more challenging. Very well-known congestion avoidance mechanisms are the Random Early Detection (RED) and the Explicit Congestion Notification (ECN). More recently, the Smart Access Point with Limited Advertised Window (SAP-LAW) has been proposed. Its main idea is that of computing the maximum TCP rate for each connection at the bottleneck, taking into account the UDP traffic to keep a low queue size combined with a reasonable bandwidth utilization. In this paper, we propose a new congestion control mechanism, namely, Smart-RED, inspired by SAP-LAW heuristic formula. We study its performance by using mean field models and compare the behaviours of ECN/RED, SAP-LAW, and Smart-RED under different scenarios. We show that while Smart-RED maintains some of the desirable properties of the SAP-LAW, it solves the problems it may have in case of bursty UDP traffic or TCP connections with very different needs of bandwidth.

A congestion avoidance mechanism in multimedia transmission over MANET using SCTP multi-streaming

Congestion is a challenging problem in Mobile Ad hoc Networks (MANETs) because of resource constraints, and dynamic routing. Congestion control is a big concern in achieving fairness between optimal network resource utilization and end-to-end flow control. In MANETs, with shared resources, when multiple senders contend for the same link bandwidth, data rate by each sender must be adjusted to avoid network overload which causes Quality of Service compromises. Strict ordering of data transmission in Transmission Control Protocol (TCP) causes poorer performance during data transmission in MANETs. Unlike TCP, Stream Control Transmission Protocol (SCTP) has a built-in multi-streaming feature to alleviate this issue caused by strict data ordering when using a single data stream within a transport connection. In this paper, we propose a Congestion Avoidance Mechanism over MANET routing based on Data Priority and Streaming Delay Weights (SDWs) which also utilizes SCTP multi-streaming (namely CAM-SCTP). Our proposal implements a Priority Manager (PM) to effectively select a stream to transmit data based on the data priority and by dynamically computing an SDW value per node. Experimental evaluation of the CAM-SCTP is performed for three different data types. The results show improvement in throughput for all data types while maintaining lower jitter, loss, and overhead.

Application of congestion avoidance mechanism in multimedia transmission over mesh networks

The unreliable nature and shared multi-media of multi-hop communications cause the deployment of multi-media applications in wireless mesh network (WMN) a thorny problem. For instance, video is usually compressed into a group of frames before transmission, resulting in unrecoverable destruction during the display process. The importance of different frames' type is quite different. However, they are considered as same in most existing WMNs. In this paper, we propose a novel Congestion Avoidance Mechanism for multimedia transmission over 802.11e mesh networks. In our mechanism, we added priority for video packets. According to the significance of frames, we proposed an adaptive mechanism involves the mapping of H.264 video packets to appropriate access categories in IEEE 802.11e standard. Simulation results show that our mechanism improves quality of service (QoS) of multimedia transmission.

Congestion Control Techniques in WSNs: A Review

Congestion control has a great importance in wireless sensor network (WSN), where efficient application of congestion control mechanisms can prolong the network lifetime. Thus, proper examination is needed to improve more refine way to address the congestion occurrence and resolution. While designing congestion control techniques, the maximum output can be achieved by efficient utilization of required resources within WSN. From last few years several approaches have been brought in, that consist of routing protocols which provide support with congestion control, congestion prevention, and reliable data routing. In old schemes the topology reset and extent traffic drop take place because sink node executes the congestion avoidance. Therefore, node level congestion avoidance, detection, congestion preventing, and resolution mechanisms have been proposed during past few years. Our paper provides a brief overview and performance comparison of centralized and distributed congestion control algorithms in WSN.

Efficient evacuation in a multi-exit environment: an agent-based decision support model

A majority of research work carried out in crowd evacuation rely on simulation due to non-availability of real and realistic trial data. In this paper, an agent-based simulation study of an evacuating crowd is presented. The model is based on the microscopic behavioural rules formulated through small-scale empirical evidence in conjunction with crowd behavioural theories. In particular, the study focuses on the possibility of efficient evacuation from the environment with limited perceptions. Extending Moore's neighbourhood model, local congestion avoidance mechanism capable of detecting the relative displacement and orientation of the all the individuals in its neighbourhood is considered. Other strategies based on exit capacity and exit population are also modelled and tested. A probabilistic exit selection strategy is also designed that considers a sensitivity of an exit as a deciding factor. The simulation results show that the enhanced exit selection strategies make the proposed system more robust and increase the evacuation efficiency substantially.

Development of an efficient mechanism for rapid protocols using NS-2 simulator

The delivered effort in this manuscript is grounded on NS-2 (The Network Simulator 2) to implement the congestion control process of classic TCP (Transmission Control Protocol), with new congestion control mechanism. In this paper, a novel congestion control algorithm is offered, which contains of slow-start and congestion avoidance mechanisms. The proposed slow-start algorithm assumes a duplicating and an interpolating approach to the congestion window (cwnd) for each increment instead of the exponential increment used by other TCP source variants such as Reno, Vega, Tahoe, Newreno, Fack, and Sack. Furthermore, the enhanced congestion avoidance algorithm is built by using an improved Additive Increase Multiplicative Decrease (AIMD) algorithm with multi TCP flow facility, to provide an enhanced congestion control algorithm with some valuable properties to improve TCP routine for high speed protocols. The improvement strategy based on merging of slow start, congestion avoidance mechanism that are used in TCP congestion control, to create a new AIMD algorithm with a new relationship between the pair parameters a and b. This paper is also involved in the creation of rapid agent in NS-2 models designed to identify the modified TCP and to configure the NS-2 platform. A fast TCP also includes an innovative scheme to slow the rapid start to help TCP to start faster through the high speed networks and also to postpone the congestion state as much as possible.