An Analytical Model of a Corporate Software-Controlled Network Switch

Implementing the almost limitless possibilities of a software-defined network requires additional study of its infrastructure level and assessment of the telecommunications aspect. The aim of this study is to develop an analytical model for analyzing the main quality indicators of modern network switches. Based on the general theory of queuing systems and networks, generated functions and Laplace-Stieltjes transforms, a three-phase model of a network switch was developed. Given that, in this case, the relationship between processing steps is not significant, quality indicators were obtained by taking into account the parameters of single-phase networks. This research identified the dependencies of service latency and service time of incoming network packets on load, as well as equations for finding the volume of a switch’s buffer memory with an acceptable probability for message loss.

A Statistical Method for Area Coverage Estimation and Loss Probability Analysis on Mobile Sensor Networks

Sensor networks are formed by fixed or mobile sensor nodes and their functions are to capture the events that occur within a certain area and then relay to a central node. Normally, sensor nodes are not able to transmit or receive information over long distances due to the need to use less energy and thus extend their useful life. Therefore, the number of sensor nodes in a given area directly influences the coverage of this area and the ability of information to be relayed by several sensors to the central node. If there are many missed messages, the application will have its performance compromised. In this paper, we use a statistical method based on Monte Carlo approach to estimate the probability of message loss and area coverage. The position and proper motion of the sensors are randomly chosen and from that we estimate how many nodes can communicate with the central node directly or through another sensor working as relay. The free variables in our analysis are node density, node displacement velocity, and sensor quantity. The results obtained are compared analytically with simple cases in order to validate the results obtained by the simulations performed.

An Improved CF-MAC Protocol for VANET

<p>Vehicular Ad hoc Network (VANET) is one of the emerging research areas in the mobile computing field which is considered as future technology and promising topic in computer science and computer networks. Which provides road safety, updated traffic information, and infotainment. VANET consists of a large number of vehicles moving in high speeds while broadcasting important information like safety and control information which must be sent with high priority. Crowded networks like VANET having many vehicles competing to reserve the channel to send critical information which may lead to high collision scenarios, and therefore, there must be a protocol to send this kind of information with high reliability, low data loss and with no collision. In this research a collision-free protocol will be proposed to manage the channel access among competing vehicles to eliminate the collisions which occur rapidly in VANET especially in dense situations, the proposed protocol hereinafter will be called (I-MAC) protocol expected to enhance the channel performance, achieve load balancing, fairness, and decrease message loss and enhance reliability, The evaluation criteria will examine the channel throughput, message delay, and message loss; the results show that the overall channel performance with regard to collision and packet loss ratio is improved.</p>

Adjusting Group Communication in Dense Internet of Things Networks with Heterogeneous Energy Sources

Internet-of-Things (IoT) environments will have a large number of nodes organized into groups to collect and to disseminate data. In this sense, one of the main challenges in IoT environments is to dynamically manage communication characteristics of IoT devices to decrease congestion, traffic collisions, and excessive data collection, as well as to balance the use of energy resources. In this paper, we introduce an energy-efficient and reliable Self Adjusting group communication of dense IoT Network, called SADIN. It configures the communication settings to ensure a dynamic control of IoT devices considering a comprehensive set of aspects, i.e., traffic loss, event relevance, amount of nodes with renewable batteries, and the number of observers. Specifically, SADIN changes the communication interval, the number of data producers, the reliability level of the network. Extensive evaluation results show that SADIN improves system performance in terms of message loss, energy consumption, and reliability compared to state-of-the-art protocol.

Reliable multicast using remote direct memory access (RDMA) over a passive optical cross-connect fabric enhanced with wavelength division multiplexing (WDM)

It has been well studied that reliable multicast enables consistency protocols, including Byzantine Fault Tolerant protocols, for distributed systems. However, no transport-layer reliable multicast is used today due to limitations with existing switch fabrics and transport-layer protocols. In this paper, we introduce a layer-4 (L4) transport based on remote direct memory access (RDMA) datagram to achieve reliable multicast over a shared optical medium. By connecting a cluster of networking nodes using a passive optical cross-connect fabric enhanced with wavelength division multiplexing, all messages are broadcast to all nodes. This mechanism enables consistency in a distributed system to be maintained at a low latency cost. By further utilizing RDMA datagram as the L4 protocol, we have achieved a low-enough message loss-ratio (better than one in 68 billion) to make a simple Negative Acknowledge (NACK)-based L4 multicast practical to deploy. To our knowledge, it is the first multicast architecture able to demonstrate such low message loss-ratio. Furthermore, with this reliable multicast transport, end-to-end latencies of eight microseconds or less (< 8us) have been routinely achieved using an enhanced software RDMA implementation on a variety of commodity 10G Ethernet network adapters.