Sharif Digital Repository

Energy-Aware routing is a promising technique for reducing energy consumption in future networks. Under this scheme, traffic loads are aggregated over a subset of the network links, allowing other links to be turned off to save energy. Since the capacity of links is the main limiting constraint in this problem, to further improve energy saving, the idea of using redundancy elimination (RE) in energy-Aware routing has been proposed. As performing RE in routers consumes some energy, it should be specified, which routers should perform RE and which links should be deactivated so that the total energy consumption of the network is minimized. As a result, the problem of energy-Aware routing with... 

Wireless sensor networks (WSNs) comprise a large number of small sensor nodes scattered across limited geographical areas. The nodes in such networks carry sources of limited and mainly unchangeable energy. Therefore, it is necessary that these networks operate under energy efficient protocols and structures. Energy efficient clustering algorithms have been developed to reduce the networks energy consumption and extend its lifetime. This paper presents an innovative cluster-based communication protocol for WSNs. In order to reduce communication overhead, the authors propose an Energy Aware Clustering Hierarchy Protocol that creates a multi-level hierarchical structure to adequately route and... 

Wireless sensor networks consist of a large number of nodes which are distributed sporadically in a geographic area. The energy of all nodes on the network is limited. For this reason, providing a method of communication between nodes and network administrator to manage energy consumption is crucial. For this purpose, one of the proposed methods with high performance, is clustering methods. The big challenge in clustering methods is dividing network into several clusters that each cluster is managed by a cluster head (CH). In this paper, a centralized genetic-based clustering (CGC) protocol using onion approach is proposed. The CGC protocol selects the appropriate nodes as CHs according to... 

The Internet of Things (IoT) presents a new paradigm of the future internet that intends to provide interactive communication between various processing object via heterogeneous networks. The routing protocol in the IoT environment is Routing Protocol for Low-Power and Lossy Networks (RPL). The current RPL specification defines primary security modes; therefore it is vulnerable to topological attacks. In this paper the RPL routing mechanism, its topological vulnerabilities and two important topological attacks namely version number attack and rank spoofing attack are analyzed. To counter the mentioned attacks, a lightweight Identity Based Offline–Online Signature based scheme is proposed.... 

The increasing trend in the number of smart connected devices has turned the routing procedure as one of the major challenges in IoT infrastructures. The Routing Protocol for Low Power and Lossy Networks (RPL) was introduced to satisfy different IoT application requirements through Objective Functions (OF). Although there have been several studies on introducing new OFs in order to fulfill specific IoT characteristics, e.g., energy and delay efficiency, reliability, and stability, but still there is a lack of novel OFs which fulfill the IoT application requirements in terms of both, the performance and the power consumption simultaneously. In this paper, we have proposed PEDAL, an OF which... 

The increasing trend in the number of smart connected devices has turned the routing procedure as one of the major challenges in IoT infrastructures. The Routing Protocol for Low Power and Lossy Networks (RPL) was introduced to satisfy different IoT application requirements through Objective Functions (OF). Although there have been several studies on introducing new OFs in order to fulfill specific IoT characteristics, e.g., energy and delay efficiency, reliability, and stability, but still there is a lack of novel OFs which fulfill the IoT application requirements in terms of both, the performance and the power consumption simultaneously. In this paper, we have proposed PEDAL, an OF which... 

Energy consumption is a major challenge in IoT devices, which was aimed to be improved by employing energy-efficient objective functions (OFs) in the structure of the RPL routing protocol. Meanwhile, the majority of the existing OFs mainly perform the parent selection based on the gathered information from the routing layer. Nevertheless, based on our investigations, there exists a series of transmission operations in the medium access control (MAC) layer, which significantly affects the energy consumption in IoT devices. Therefore, in this article, we propose ELITE, an energy-efficient cross-layer OF, which introduces a novel routing metric, called strobe per packet ratio (SPR). SPR... 

The standardized IPv6 Routing Protocol for Low-power and Lossy Networks (RPL) has enabled efficient communications between thousands of smart devices, sensors, and actuators in a bi-directional, and end-to-end manner, allowing the connection of resource constraint devices in multi-hop IoT infrastructures. RPL is designed to cope with the major challenges of Low-power and Lossy Networks (LLNs), specifically their energy-efficiency. However, RPL is facing with severe congestion and load balancing problems, leading to a low Packet Delivery Ratio (PDR) in the network. For the first time since the declaration of RPL, in this paper we explain that ignoring the specifications of the reception and... 

Reliability of routing mechanisms in wireless networks is typically measured with Packet Delivery Ratio (PDR). Basically, PDR is reported with an optimistic assumption that the topology is fully constructed, and the nodes have started their packet transmission. This is despite the fact that prior to being able to transmit packets, nodes must first join the network, and then try to keep connected as much as possible. This is a key factor in the overall reliability provided by the routing protocols, especially in mobile IoT applications, where disconnections occur frequently. Nevertheless, there is a lack of appropriate metrics, which could evaluate the routing mechanisms from this... 

In this paper, we present an energy-efficient manycast routing and spectrum assignment (EEM-RSA) algorithm in elastic optical networks supporting cloud computing applications. The proposed EEM-RSA is adapted for both static and dynamic scenarios. First, an integer linear programing formulation is derived for energy-efficient manycasting and spectrum assignment; then, the corresponding heuristic methods are proposed. To reduce the energy consumption, inactive (idle) elements are turned off, and in the proposed energy-efficient manycasting heuristic, the number of activated elements are minimized. The power consumption of network elements is modeled by considering a constant overhead for the... 

Wireless Sensor Networks (WSNs) are prone to faults due to battery depletion of nodes. A node failure can disturb routing as it plays a key role in transferring sensed data to the end users. This paper presents a Fault-Tolerant and Energy-Aware Mechanism (FTEAM), which prolongs the lifetime of WSNs. This mechanism can be applied to cluster-based WSN protocols. The main idea behind the FTEAM is to identify overlapped nodes and configure the most powerful ones to the sleep mode to save their energy for the purpose of replacing a failed Cluster Head (CH) with them. FTEAM not only provides fault tolerant sensor nodes, but also tackles the problem of emerging dead area in the network. Our... 

Wireless sensor networks (WSNs) usually consist of many tiny sensor nodes and a sink. Problems and characteristics like resources' severe constraints, low reliability and fault tolerance, low throughput, and insecure operational environments, significantly degrade their overall performance. One significant solution against these problems is multipath routing. However, the existing multipath routing protocols have weaknesses like high overhead and algorithmic-computational complexity, security vulnerabilities, low scalability, and permanent usage of optimal paths and resources' severe exhaustion. As a result, this paper proposes a statistical distributed multipath routing protocol for... 

Several unicast and multicast routing protocols have been presented for MPSoCs. Multicast protocols in NoCs are used for cache coherency in distributed shared memory systems, replication, barrier synchronization, or clock synchronization. Unicast routing algorithms are not suitable for multicast, as they increase traffic, congestion and deadlock probability. Famous multicast schemes such as tree-based and path-based schemes have been proposed originally for multicomputers and recently adapted to NoCs. In this paper, we propose a switch tree-based multicast scheme, called STBA. This method supports tree construction with a minimum number of routers. Our evaluation results reveal that, for... 

Wireless Sensor Networks (WSNs) have developed in recent years and are used in many different applications such as fire detection, military operations, and healthcare. Sensor nodes have the ability to sense an environment, sending and receiving information and forwarding packets from source nodes to a sink. These tasks consume large amounts of energy. In many WSN applications, delay and reliability of data delivery and the energy consumption of nodes are important design metrics. Network protocols such as medium access control (MAC) and routing should be designed to improve these metrics. In this article, we propose a new cross layer algorithm that improves the performance of WSN networks... 

With the widespread use of Internet of Things (IoT) in every aspect of human's daily life, communications of such an enormous amount of existing embedded devices in these systems arise many new challenges from power consumption, performance, and reliability perspectives. Communications in an IoT infrastructure are managed by a set of policies which are determined by Objective Functions (OFs). Thus, OFs are the most important contributors in facing with the mentioned challenges. In this paper, due to the lack of information on how OFs affect the primary properties of an IoT infrastructure, we have compared three well-known OFs (OF0, MRHOF, and OFFL) from power consumption, performance, and... 

The emergence of mobile IoT applications in recent years and the challenge of routing in their infrastructures have motivated scholars to propose appropriate routing mechanisms for such systems. Meanwhile, the IPv6 Routing Protocol for Low Power and Lossy Networks (RPL) is the standard routing protocol for IoT infrastructures. Nevertheless, RPL was mainly designed to comply with the primitive requirements of static IoT applications and it behaves poorly in confronting with the severe alterations in mobile conditions. The most important factor for such a poor behavior in mobile applications is the inappropriate design of OFs, which determine RPL's routing policies in the network. Therefore,... 

Ad hoc wireless networks are power constrained since nodes operate with a limited battery energy. To maximize the lifetime of these networks, transactions through mobile nodes must be controlled such that the power dissipation rates of all nodes are rarely the same. This paper presents a fuzzy extension to Ad hoc On demand Distance Vector routing protocol with power considerations. The path selected by conventional AODV routing protocol is not the optimal path because AODV selects the first path that has been found which is not necessarily the best. Routing optimality affects the network performance, especially when the load is high. Longer route consumes more bandwidth, produces more delay,... 

This research aims to represent a novel approach to detect malicious nodes in Ad-hoc On-demand Distance Vector (AODV) within the next-generation smart cities. Smart city applications have a critical role in improving public services quality, and security is their main weakness. Hence, a systematic multidimensional approach is required for data storage and security. Routing attacks, especially sinkholes, can direct the network data to an attacker and can also disrupt the network equipment. Communications need to be with integrity, confidentiality, and authentication. So, the smart city and urban Internet of Things (IoT) network, must be secure, and the data exchanged across the network must...