Implementation of secure email server in cloud environment

In the recent virtual communication world, the email services play a vital role as a basic content of heterogeneous networking infrastructure. Whereby, multiple platforms are connecting each other. Mail Server refers to computer performing Mail Transfer Agent functions. MTA is software that delivers electronic mail messages from one computer to another, by using client-server application architecture. MTA implements both sender and receiver portions of SMTP (Simple Mail Transfer Protocol). Postfix is a free and open-source MTA which is fast, easy-to-administrator and provide secure communication over Internet. In this paper we focus on the problem of email contents disclosure, and establish a secure mail server by using Postfix in Linux platform and then implement it into a cloud service provider as IaaS (Infrastructure as a Service). Security is provided by tuning a Transport Layer Security (TLS), and SMTP-AUTH which use Simple Authentication and Security Layer (SASL) as a security mechanism and platform

Energy-efficient intrusion detection in wireless sensor network

The use of Wireless Sensor Networks (WSNs) has developed rapidly in the last decade. Deploying tiny sensors with limited battery power in open and unprotected environment and dynamic topology in WSNs raises security issues in this kind of networks. Attacks can occur from any direction and any node in WSNs, so one crucial security challenge is to detect networks' intrusion. There are several algorithms for building Intrusion Detection Systems (IDS) based on different WSN routing protocol classifications with respect to energy-efficient manner. This paper provides an overview of the research on IDS in WSNs, focusing on routing protocol classification depending on network structure with respect to energy consumption as a crucial parameter in these kinds of networks. In addition, some simulation manners are reviewed

Co-channel interference mitigation techniques in multi-cell OFDMA Relay-Based Cellular Networks: a survey

Orthogonal Frequency Division Multiplexing Access (OFDMA) technology along with cooperative relay networks are generally described as an appropriate applicant for developed cellular networks because of the improvements to system performance through flexible resource allocation schemes. In these networks interference-aware resource allocation or interference coordination, represents an important role in raising resource utilization as well as enhancing cell throughput. This paper focuses on existing co-channel interference mitigation methods in multi-cell OFDMA Relay Based Cellular Networks (RBCNs). It aims to utilize the advantages of relay stations while reducing the negative effects of introduced interference. This research first presents the general system model scenarios of interference in RBCNs and provides an overview of the problem. It then compares the potential interference scenarios in these systems. Our study examines the techniques based on the frequency reuse factor they use and shows that even by maintaining the frequency reuse at one; we can maximize the system throughput

Mobility and handover technique in heterogeneous wireless networks

The management techniques for Mobile IPv6 between different wireless technologies are very important to complete the handover process with the least possible delay. In the fast handover, when a mobile node moves to another network, it needs to do handover operations. These operations have a severe impact on the handover latency. This paper proposes an Enhanced Advanced Duplicate Address Detection (EA-DAD) method in a heterogeneous mobile environment with the support of the MIH services. The proposed method quickly provides a unique Ipv6 address for MNs. At the same time, the binding updates to home agent and correspondent node are to be performed from old access router. We can see through results that by optimizing network layer, EA-DAD quickly presents unique Ipv6 addresses for MNs with a minimum handover latency and packet loss even at high speed movements

Communication requirements of wide area control in smart grid

Wide Area Control is a new technology to maintain the power system stability; however, it requires the support of short-latency communication. The existing communication technology does not have the abilities to provide this support. It highlights the demand for new and short-latency communication technologies. The aim of this paper is to provide communication challenges of the wide area control system, to understand the communication requirements of the future energy system and to realize the existing network technologies that are applicable to energy management

A discrete event framework for OFDMA relay-based cellular networks

The cooperation of Relay-Based Cellular Network (RBCN) and Orthogonal Frequency-Division Multiple Access (OFDMA) techniques provide rich of promising solutions especially in terms of Radio Resource Management (RRM). However, the main challenge of this cooperation is managing the resources in a dynamic system in the midst of co-channel interference. Allocating of the RRM associated schemes have been developed to overcome these interferences and to operate the relays in a dynamic and opportunistic manner. The deployments of these RRM schemes have enormous matrices of combination analyzing these performances are of vital essence. There are different simulator tools to address these needs such as NS2, OPNet, OMNet++, etc. An effort to enrich these repositories of simulators is to provide a discrete customization of analyzing the main aim of the study. A discrete event simulation for RBCN evaluation using a general-purpose programming language has been solved. The performance analysis orientation is on Signal-to Interference-plus-Noise Ratio (SINR) algorithm with specific focus on the transmission reliability of relays for channel fading in terms of spectral efficiency for downlink of OFDMA relay-based cellular networks. The developed simulator has been extensively tested and has proven to be a valid and substantial simulator