As internet network developed rapidly in the past ten years, and its operating environment is constantly changing along with the development of computer and communication technology, the congestion problem has become more and more serious. Since TCP is the primary protocol for transport layers on the internet, the data transmitted via the transport protocol utilizes Vegas Transmission Control Protocol (TCP) as the congestion control algorithm, where it uses increasing in delay round trip time (RTT) as a signal of network congestion. However, this congestion control algorithm will attempt to fill network buffer, which causes an increase in (RTT) determined by Vegas, thereby reducing the congestion window, and making the transmission slower, Therefore Vegas has not been widely adopted on the Internet. In this paper, an improved algorithm called TCP Vegas-A is proposed consist of two parts: the first part is sending the congestion window used by the algorithm for congestion avoidance along with the TTL (Time To Live) mechanism that limits the lifetime of a packet in the network. While the second part of the algorithm is the priority-based packet sending strategy, and jitter is used as a congestion signal indication. The combination of the two is expected to improve the efficiency of congestion detection. A mathematical model is established, and the analysis of the model shows that the algorithm has better effects on controlling congestion and improving the network throughput, decreasing packet loss rate and increasing network utilization, the simulation is done using NS-2 network simulation platform environment and the results support the theoretical analysis.
Portable devices such as smartphones, tablet PCs, and PDAs are a useful combination of hardware and software turned toward the mobile workers. While they present the ability to review documents, communicate via electronic mail, appointments management, meetings, etc. They usually lack a variety of essential security features. To address the security concerns of sensitive data, many individuals and organizations, knowing the associated threats mitigate them through improving authentication of users, encryption of content, protection from malware, firewalls, intrusion prevention, etc. However, no standards have been developed yet to determine whether such mobile data management systems adequately provide the fundamental security functions demanded by organizations and whether these functions have been securely developed. Therefore, this paper proposes a security framework for mobile data that combines core security mechanisms to avoid these problems and protects sensitive information without spending time and money deploying several new applications.
Ad-hoc routing algorithm has always been a core problem in research of ad-hoc networks. In order to be able to deal with various routing protocol problems on an ad-hoc network like poor validity and large control overhead, this paper classify and compare ad-hoc network routing protocols through OPNET simulation tool and focus on testing two routing protocols' performance namely, table-driven and on-demand routing protocol. The Destination Sequenced Distance Vector routing protocol is the most used table-driven routing protocols, While AODV and DSR routing protocols are the two most used on-demand routing protocols. The performance of these three protocols is simulated with a variety of packet delivery functions, average end-to-end delays, and routing loads. These protocols are also analyzed and compared. The simulation results show that for a high mobility environment, the on-demand routing protocol is the best option.
To minimize the network congestion problem, a multi-constraint optimization mathematical model is established and a hybrid particle swarm algorithm based on the Tabu search algorithm is proposed. The algorithm integrates Tabu search into particle swarm algorithm, which can prevent the algorithm from falling into the local optimal solution, and gives a better initial individual for Tabu search, so it can speed up the algorithm convergence and improve the quality of the solution. The simulation was done using Matlab and the results show that the optimization algorithm reduces the end-to-end delay and packet loss rate, thereby avoiding network congestion and optimizing the utilization of network resources.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.