The aim of this paper is to determine the performance enhancement of the network for eliminating congestion through the use of the benefits of algorithms. These algorithms can be used in hindering the congestion which may occur within the network that relies on a Transmission Control Protocol (TCP) protocol. This paper specifically focuses on demonstrating the function of TCP, and most especially the four (slow start, congestion avoidance, fast retransmit and fast recovery algorithms) that are applied in the control of congestion. In the study, the varying effects of connection link from PPP DS1 to PPP DS3 on the network’s performance are investigated.

Growing popularity of Internet demands for the agility as well as the flexibility of computer networks. Traditional networking system is unable to satisfy recent computing needs. Proprietary devices configured manually create an error-prone situation in addition they are incapable to fully utilize the capability of physical network infrastructure. This has resulted in the paradigm shift in the networking industry and it is known as Software defined networking. Advantages such as programmability, task virtualization and easy management of the network can be provided by employing SDN platform, on the other hand POX is defined as a Python based open source OpenFlow SDN Controller mainly used for faster development and prototyping of new network applications basically comes pre-installed with the mininet virtual machine. POX controller can turn dumb OpenFlow devices into hub, switch, load balancer and firewall devices. In this paper Performance metrics such as service Delay, utilized bandwidth, received packets and bytes were measured and recorded using network monitoring tools like iperf and D-ITG in order to analyze the functionality of the POX controller as well as to evaluate the operation performance of POX controller for SDN environment. The results of this research were the recommendation of using POX controller in for rapid development and prototyping of network control systems as well as being the framework for the interaction with Open Flow switches.

Nowadays wireless sensor networks (WSNs) became a modern research theme owing to the various applications range in assorted fields. Clustering considered from the more efficient techniques for solving the WSN drawbacks of energy consumption. The grid-based cluster has definitely done its effectiveness, especially for networks with high dynamic, all nodes in the clusters represented and the values of data are collected from sensor nodes by the cluster head (CH). For balancing the energy consumption with network traffic, the (CH) must be exchanged between all sensor nodes and the cluster size ought to be closely determined at different network parts. The most important issues for WSN is developing an energy-efficient algorithm by Grid-based clustering for improving the network lifetime, reduced cost, and increasing the network reliability. The equipment of the sensor nodes attached with limited power sources, the Grid-Based Clustering algorithm (GBC), therefore efficiently employing the energy of the sensor nodes can preserve a prolongation of the network lifetime. The network Performances of the sensor node are largely based on the application of the routing protocols, three routing protocols OLSR, AODV, and DSR in grid-based cluster WSN are evaluated by using Qualnet simulator. The results show DSR outperforms in the range of throughput, and end to end delay, while the AODV can be considered as the best in the package delivery ratio PDR with compared to others.

In the last few years, there has been a growing interest in the rise of demand for moving from traditional networks towards software-defined networks, this has raised a lot of challenges. Software-defined networks are continually evolving, which include the need to address issues such as scalability, and packet loss, transmission delay and network congestion. accordingly, researchers introduced the concept of multi-controller architectures, although it will not assist to balance the load between them, it will tackle the network congestion issue through the distribution of load between them. the present study proposes a linear multi-controller architecture to explore the impact of increasing the number of controllers connected in a linear style on network performance. The study was based on the generation of simultaneous multi-flows with different sizes using Distributed Internet Traffic Generator(D-ITG). From the outcomes of our investigation, it is possible to conclude that the performance-enhanced uniformly with the number of controllers while preserving the same number of Open Vswitches. as the number of controllers reached four, The Quad-controller architecture recorded the best results related to improving the reduction of average delay and average jitter to 62% and 64% as well as increasing the throughput, bytes received, average packet rate to 32%, 32% and 31.8%.

Traditional load balancer suffers from inflexibility, high cost and the difficulty to manage the network. Software-Defined Network (SDN) gives a promising solution for traditional load balancer limitations through enabling programmability and centralized control over the network, which offers inexpensive and scalable solutions. This paper investigates the impact of increasing the workload requests from 0 up to 180 requests per second (req/sec) in order to explore average network throughput under the deployment of static as well as dynamic load balancing algorithms by the POX controller. The study was based on the utilization of HTTPerf based on the fact that it provides a flexible facility for the generation of various HTTP workloads as well for the measurement of server performance. Our experiments revealed that as the number of requests increases the throughput increases as well. Dynamic least bandwidth-based load balance scheme has shown a remarkable improvement in terms of average network throughput up to 8%, 3.3% and 2.56 %, as compared with static load balancing schemes like random, round-robin and weighted round-robin. However, Dynamic least bandwidth recorded a slight ineffective improvement less than 1 % was recorded when a comparison was carried out dynamic least connections, this directed us to the fact that their performance was almost the same. Based on what dynamic least bandwidth scheme has achieved in terms of average network throughput, more efforts should be driven by the researchers on algorithm development like introducing static weight for each server as well as the application of the algorithm on several POX controllers to avoid a single point of failure.