Fault-tolerant Routing Protocol Research Articles

Multipath Fault Tolerant Routing Protocol in MANET

Mobile ad hoc networks (MANETs) consist of a collection of wireless mobile nodes which dynamically exchange data among themselves without the reliance on a fixed base station or a wired backbone network and it the makes the routing a crucial issue to the design of the MANET.Multiple path routing protocols are shown to be performance -effective alternatives over single-path routing for ad hoc networks and it represents a promising routing methodfor wireless mobile ad hoc networks. Multi -path routing achieves load balancing and is more resilient to route failures. .In this paper we propose an energy efficient multipath fault tolerant routing protocol to improve the reliability of data routing in Mobile ad hoc networks. The proposed RFTA is a multi objective routing protocol that meets diverse application requirements by considering the changing conditions of the n etwork. The efficiency of the proposed protocol has been evaluated on different scenarios and there has been a noticeable improvement in the packet delivery ratio and also in the reduction of end -to-end delay comparing toSMR,SMS and MDSR.

Modified GPSR for Fault Tolerant and Energy Efficiency in Mobile Ad Hoc Network

Routing in wireless network is a key research area which establishes path between source and destination node pairs. In this paper, we have designed and evaluated an Energy-efficient and Fault tolerant Greedy Perimeter Stateless Routing (EFGPSR) protocol for wireless ad hoc network. The proposed protocol is divided into four phases: Fault testing phase, Planarization phase, Energy efficient greedy forwarding phase and Energy efficient perimeter forwarding phase. In fault testing phase, all nodes come to know about their fault free neighbours. Next is planarization phase which removes the crossing edges. Next are energy efficient greedy forwarding and perimeter forwarding phases. Both these phases try to maintain balance between the metrics to choose the next hop (i.e. distance from destination in greedy forwarding phase and minimum angle w.r.t the line connecting the forwarding node and destination in perimeter forwarding phase) and selection of node having highest energy among the neighbouring nodes to extend network lifetime. Evaluation and comparison of GPSR and EFGPSR is done through NS-2 simulator. Simulation shows that EFGPSR performs better in terms of increasing the network lifetime, successful packet delivery ratio with insignificant increase in number of hop count.

An Immune Cooperative Particle Swarm Optimization Algorithm for Fault‐Tolerant Routing Optimization in Heterogeneous Wireless Sensor Networks

The fault‐tolerant routing problem is important consideration in the design of heterogeneous wireless sensor networks (H‐WSNs) applications, and has recently been attracting growing research interests. In order to maintain k disjoint communication paths from source sensors to the macronodes, we present a hybrid routing scheme and model, in which multiple paths are calculated and maintained in advance, and alternate paths are created once the previous routing is broken. Then, we propose an immune cooperative particle swarm optimization algorithm (ICPSOA) in the model to provide the fast routing recovery and reconstruct the network topology for path failure in H‐WSNs. In the ICPSOA, mutation direction of the particle is determined by multi‐swarm evolution equation, and its diversity is improved by immune mechanism, which can enhance the capacity of global search and improve the converging rate of the algorithm. Then we validate this theoretical model with simulation results. The results indicate that the ICPSOA‐based fault‐tolerant routing protocol outperforms several other protocols due to its capability of fast routing recovery mechanism, reliable communications, and prolonging the lifetime of WSNs.

Dynamical Jumping Real-Time Fault-Tolerant Routing Protocol for Wireless Sensor Networks

In time-critical wireless sensor network (WSN) applications, a high degree of reliability is commonly required. A dynamical jumping real-time fault-tolerant routing protocol (DMRF) is proposed in this paper. Each node utilizes the remaining transmission time of the data packets and the state of the forwarding candidate node set to dynamically choose the next hop. Once node failure, network congestion or void region occurs, the transmission mode will switch to jumping transmission mode, which can reduce the transmission time delay, guaranteeing the data packets to be sent to the destination node within the specified time limit. By using feedback mechanism, each node dynamically adjusts the jumping probabilities to increase the ratio of successful transmission. Simulation results show that DMRF can not only efficiently reduce the effects of failure nodes, congestion and void region, but also yield higher ratio of successful transmission, smaller transmission delay and reduced number of control packets.

A low-overhead fault-tolerant routing algorithm for mobile ad hoc networks: A scheme and its simulation analysis

The fault-prone nodes in a mobile ad hoc network (MANET) degrade the performance of any routing protocol. Using greedy routing mechanisms that tend to choose a single path every time, may cause major data losses, if there is a breakdown of such a path in a fault-prone environment. On the other hand, using all the available paths causes an undesirable amount of overhead on the system. Designing an effective and efficient fault-tolerant routing protocol is inherently hard, since the problem is NP-complete because of the unavailability of precise path information in adversarial environments [1]. To address the above mentioned problem, we present a fault-tolerant routing algorithm (FTAR), which bases on the ideas of foraging in natural ants [2]. The algorithm is divided into six stages, namely, initialization, path selection, pheromone deposition, confidence calculation, evaporation and negative reinforcement. Simulation results show that FTAR achieves high packet delivery ratio and throughput as compared to some of the key protocols which do not address fault-tolerance at all. Most importantly, FTAR is established to supersede the performance of one of the best fault-tolerant MANET routing schemes [1] known currently, with respect to the amount of routing overhead incurred – it is an important achievement for ad hoc networks.

Fault-tolerant routing in adversarial mobile ad hoc networks: an efficient route estimation scheme for non-stationary environments

Designing routing schemes that would successfully operate in the presence of adversarial environments in Mobile Ad Hoc Networks (MANETs) is a challenging issue. In this paper, we discuss fault-tolerant routing schemes operating in a network with malfunctioning nodes. Most existing MANET protocols were postulated considering scenarios where all the mobile nodes in the ad hoc network function properly, and in an idealistic manner. However, adversarial environments are common in MANET environments, and misbehaving nodes certainly degrade the performance of these routing protocols. The need for fault tolerant routing protocols was identified to address routing in adversarial environments in the presence of faulty nodes by exploring redundancy-based strategies in networks. It turns out that since the nodes are mobile, the random variables encountered are non-stationary, implying that estimation methods for stationary variables are inadequate. Consequently, in this paper, we present a new fault-tolerant routing scheme that invokes a stochastic learning-based weak estimation procedure to enhance a route estimation phase, which, in turn, is then incorporated in a route selection phase. We are not aware of any reported method that utilizes non-traditional estimates to achieve the ranking of the possible paths. The scheme, which has been rigorously tested by simulation, has been shown to be superior to the existing algorithms.

Dcell

A fundamental challenge in data center networking is how to efficiently interconnect an exponentially increasing number of servers. This paper presents DCell, a novel network structure that has many desirable features for data center networking. DCell is a recursively defined structure, in which a high-level DCell is constructed from many low-level DCells and DCells at the same level are fully connected with one another. DCell scales doubly exponentially as the node degree increases. DCell is fault tolerant since it does not have single point of failure and its distributed fault-tolerant routing protocol performs near shortest-path routing even in the presence of severe link or node failures. DCell also provides higher network capacity than the traditional tree-based structure for various types of services. Furthermore, DCell can be incrementally expanded and a partial DCell provides the same appealing features. Results from theoretical analysis, simulations, and experiments show that DCell is a viable interconnection structure for data centers.

A fault-tolerant routing protocol in wireless sensor networks

In this paper, we propose a fault-tolerant routing protocol, called Sensor On-demand Multi-path Distance Vector Reliable (SOMDV-R) routing protocol, for wireless sensor networks to support reliable data delivery. Instead of selecting a shortest path, SOMDV-R takes into account both reliability demand and link quality to determine the number of desired paths. Beside, to improve packet delivery rate upon band channel condition, SOMDV-R supports multipath data delivery. We evaluate our proposed protocol via simulations. The results show that compared with Ad hoc On-demand Multi-path Distance Vector (AOMDV) and AODV, SOMDV-R can achieve higher packet delivery rate, lower routing overhead and lower mean latency, upon different channel conditions.

Octopus: A fault-tolerant and efficient ad-hoc routing protocol

Mobile ad-hoc networks (MANETs) are failure-prone environments; it is common for mobile wireless nodes to intermittently disconnect from the network, e.g., due to signal blockage. This paper focuses on withstanding such failures in large MANETs: we present Octopus, a fault-tolerant and efficient position-based routing protocol. Fault-tolerance is achieved by employing redundancy, i.e., storing the location of each node at many other nodes, and by keeping frequently refreshed soft state. At the same time, Octopus achieves a low location update overhead by employing a novel aggregation technique, whereby a single packet updates the location of many nodes at many other nodes. Octopus is highly scalable: for a fixed node density, the number of location update packets sent does not grow with the network size. And when the density increases, the overhead drops. Thorough empirical evaluation using the ns2 simulator with up to 675 mobile nodes shows that Octopus achieves excellent fault-tolerance at a modest overhead: when all nodes intermittently disconnect and reconnect, Octopus achieves the same high reliability as when all nodes are constantly up.

Fault-tolerant and deadlock-free routing in 2-D meshes using rectilinear-monotone polygonal fault blocks

We propose a deterministic fault-tolerant and deadlock-free routing protocol in 2-dimensional (2-D) meshes based on Wu's fault-tolerant odd–even turn model and Wang's rectilinear-monotone polygonal fault block model. The fault-tolerant odd–even turn protocol, also called extended X–Y routing, was originally proposed to achieve fault-tolerant and deadlock-free routing among traditional, rectangular fault blocks. It uses no virtual channels. The number of faults to be tolerated is unbounded as long as nodes outside fault blocks are connected in the mesh network. The recently proposed rectilinear-monotone polygonal fault blocks (also called minimal-connected-components or MCCs) are of the polygonal shapes, and are a refinement of rectangular fault blocks. The formation of MCCs depends on the relative locations of source and destination, and MCCs include far fewer healthy nodes in resultant fault blocks. In this paper, we show that with a simple modification, the extended X–Y routing can also be applied to 2-D meshes using extended MCCs.

Dynamically configurable message flow control for fault-tolerant routing

Fault-tolerant routing protocols in modern interconnection networks rely heavily on the network flow control mechanisms used. Optimistic flow control mechanisms, such as wormhole switching (WS), realize very good performance, but are prone to deadlock in the presence of faults. Conservative flow control mechanisms, such as pipelined circuit switching (PCS), ensure the existence of a path to the destination prior to message transmission, achieving reliable transmission at the expense of performance. This paper proposes a general class of flow control mechanisms that can be dynamically configured to trade-off reliability and performance. Routing protocols can then be designed such that, in the vicinity of faults, protocols use a more conservative flow control mechanism, while the majority of messages that traverse fault-free portions of the network utilize a WS like flow control to maximize performance. We refer to such protocols as two-phase protocols. This ability provides new avenues for optimizing message passing performance in the presence of faults. A fully adaptive two-phase protocol is proposed, and compared via simulation to those based on WS and PCS. The architecture of a network router supporting configurable flow control is also described.

Configurable flow control mechanisms for fault-tolerant routing

Fault-tolerant routing protocols in modern interconnection networks rely heavily on the network flow control mechanisms used. Optimistic flow control mechanisms such as wormhole routing (WR) realize very good performance, but are prone to deadlock in the presence of faults. Conservative flow control mechanisms such as pipelined circuit switching (PCS) insures existence of a path to the destination prior to message transmission, but incurs increased overhead. Existing fault-tolerant routing protocols are designed with one or the other, and must accommodate their associated constraints. This paper proposes the use of configurable flow control mechanisms. Routing protocols can then be designed such that in the vicinity of faults, protocols use a more conservative flow control mechanism, while the majority of messages that traverse fault-free portions of the network utilize a WR like flow control to maximize performance. Such protocols are referred to as two-phase protocols, where routing decisions are provided some control over the operation of the virtual channels. This ability provides new avenues for optimizing message passing performance in the presence of faults. A fully adaptive two-phase protocol is proposed and compared via simulation to those based on WR and PCS. The architecture of a network router supporting configurable flow control is described, and the paper concludes with avenues for future research.

A family of fault-tolerant routing protocols for direct multiprocessor networks

Our goal is to reconcile the conflicting demands of performance and fault-tolerance in interprocessor communication. To this end, we propose a pipelined communication mechanism-pipelined circuit-switching (PCS)-which is a variant of the well known wormhole routing (WR) mechanism. PCS relaxes some of the routing constraints imposed by WR and as a result enables routing behavior that cannot otherwise be realized. This paper presents a new class of adaptive routing algorithms-misrouting backtracking with m misroutes (MB-m). This class of routing algorithms is made possible by PCS. We provide an analysis of the performance and static fault-tolerant properties of MB-m. The results of an experimental evaluation of PCS and MB-3 are also presented. This methodology provides performance approaching that of WR, while realizing a level of resilience to static faults that is difficult to achieve with WR. >