Network Path Capability Identification and Performance analysis of Mobile Ad hoc Network

The mobile ad hoc networks have gained immense popularity in the current decade due their less costly and rapid deployability, inherent support for mobility and the potential to provide ad hoc connectivity to devices.Routing in mobile ad hoc network is considered as a challenging task due to the drastic and unpredictable changes in the network topology resulting from the random and frequent movement of the nodes and due to the absence of any centralized control.Routing becomes even more complex in hybrid networking scenario where the MANET is combined with the fixed network for covering wider network area with less fixed infrastructure.Although, several routing protocols have been developed and tested under various network environments, but, the simulations of such routing protocols have not taken into account the hybrid networking environments.In this work we have carried out a systematic simulation based performance study and analysis of the two prominent routing protocols: Destination Sequenced Distance Vector Routing (DSDV) and Dynamic Source Routing (DSR) protocols in the hy-brid networking environment under varying node speed.We have analyzed the performance differentials on the basis of three metrics -packet delivery fraction, average end-to-end delay and normalized routing load using NS2 based simulation.

The demand for any time anywhere connectivity has increased rapidly with the tremendous growth of the Internet in the past decade and due to the huge influx of highly portable devices such as laptops, PDAs etc. In order to provide the users with the huge pool of resources together with the global services available from the Internet and for widening the coverage area of the MANET, there is a growing need to integrate the ad hoc networks to the Internet. Due to the differences in the protocol architecture between MANET and Internet, we need gateways which act as bridges between them. The gateway discovery in hybrid network is considered as a critical and challenging task and with decreasing pause time and greater number of sources it becomes even more complex. Due to the scarcity of network resources in MANET, the efficient discovery of the gateway becomes a key issue in the design and development of future hybrid networks. In this paper we have described the design and implementation of the various gateway discovery approaches and carried out a systematic simulation based performance study of these approaches using NS2 under different network scenarios. The performance analysis has been done on the basis of three metrics - packet delivery fraction, average end-to-end delay and normalized routing load.KeywordsAverage end-to-end delaygateway discovery approachesInternetMobile ad hoc networknormalized routing loadpacket delivery fractionperformance study

Experiences on using a workstation cluster to implement a real-time digital transient network analyzer

Optimum network resource utilization and network resource pooling to deal with network congestion in present time is one of the biggest challenges faced by various research, development and monitoring network groups or organisations. IETF research group has proposed various solutions to improve the Quality of Service (QoS) of internet communication. Routing solutions with effective operations can enhance the performance by managing the network resources efficiently, which in turn can enhance the performance of end to end TCP/IP connections. In this paper a comprehensive solution called OSPFxQoS-LSFM, based on OSPF and QoS routing mechanisms has been proposed and presented with an aim to optimize the utilization of network capacity by avoiding network congestion.

Main characteristics of large-scale, geographically distributed grid systems are resource heterogeneity and network latency. In this paper, we use queuing network models to analyze data-parallel grid applications and we show the effects of resource heterogeneity, communications delays, network bandwidths and synchronization overheads on the application-level performance. The proposed models rely on the statistical pattern of computation, communication, and I/O operations in the parallel applications, as well as on measurable infrastructure characteristics. We finally show how the high variability in the execution and communication times must be considered when modeling applications on geographically distributed grid infrastructures

Interconnected networks of today provide a wide variety of services, which consume widely differing amounts of resources. But unlike other computing resources such as disk space and processing power, the network resource is not that much accounted.Internet Engineering Task Force (IETF) internet-accounting working group is currently studying this subject. Their approach to the problem is focused on network accounting but does not cover any real-time controls such as quotas or enforcement.In this paper, a model that increases coordination between accounting mechanisms and access controls is introduced. This model is compatible with the concepts and the architecture introduced by IETF internet-accounting working group. In the proposed model the quota manager is responsible from producing a table of service consumers that have already reached their quotas. This table is formed by using the data accumulated by the accounting system.KeywordsNetwork ManagementNetwork AccountingQuota SystemTCP/IPSNMP.

This article presents a novel, end-to-end, quality-aware optimization framework for multimedia clouds, where path selection mechanisms are exploited in conjunction with media optimization in order to support multimedia delivery in a quality-aware manner. As wireless data traffic worldwide is characterized by exponential growth, with the most prominent part being multimedia services, consumers get in the challenging position to compete for the limited wireless network resources. Cloud technologies and especially Software-Defined Networking is the perfect candidate technology in order to provide an elastic, dynamic provisioning of network resources that adapt to a highly changing environment, where application requirements and data volumes vary over time. This work combines the selection of the optimum path in the core network with quality-aware media adaptation based on the current conditions of the wireless access network. Thus the proposed framework achieves efficient network resources utilization in an end-to-end fashion.

Mobile Ad hoc Networks (MANETs) are considered as a new paradigm of infrastructure-less mobile wireless communication systems. MANETs are being widely studied and it is the technology that is attracting a large variety of applications. Routing in MANETs is considered a challenging task due to the unpredictable changes in the network topology, resulting from the random and frequent movement of the nodes and due to the absence of any centralized control [1][2]. In this paper, we evaluate the performance of reactive routing protocols, Ad hoc On demand Distance Vector (AODV) and Dynamic Source Routing (DSR) and proactive routing protocol Destination Sequenced Distance Vector (DSDV). The major goal of this study is to analyze the performance of well known MANETs routing protocol in high mobility case under low, medium and high density scenario. Unlike military applications, most of the other applications of MANETs require moderate to high mobility. Hence it becomes important to study the impact of high mobility on the performance of these routing protocols. The performance is analyzed with respect to Average End-to-End Delay, Normalized Routing Load (NRL), Packet Delivery Fraction (PDF) and Throughput. Simulation results verify that AODV gives better performance as compared to DSR and DSDV.

A mobile ad hoc network (MANET) is a group of nodes constituting a network of mobile nodes without predefined and pre-established architecture where mobile nodes can communicate without any dedicated access points or base stations. In MANETs, a node may act as a host as well as a router. Nodes in the network can send and receive packets through intermediate nodes. However, the existence of malicious and selfish nodes in MANETs severely degrades network performance. The identification of such nodes in the network and their isolation from the network is a challenging problem. Therefore, in this paper, a simple reputation-based scheme is proposed which uses the consumption and contribution information for selfish node detection and cooperation enforcement. Nodes failing to cooperate are detached from the network to save resources of other nodes with good reputation. The simulation results show that our proposed scheme outperforms the benchmark scheme in terms of NRL (normalized routing load), PDF (packet delivery fraction), and packet drop in the presence of malicious and selfish attacks. Furthermore, our scheme identifies the selfish nodes quickly and accurately as compared to the benchmark scheme.

As multimedia IP services become more popular, commercial service providers are under pressure to maximise their utilisation of network resources whilst still providing a satisfactory service to the end users. The present work examines user opinions of quality and acceptability for video streaming material under different network performance conditions. Subjects provided quality and acceptability opinions for typical multimedia material presented under different network conditions. The subjective test showed that increasing loss levels results in poorer user opinions of both quality and acceptability. Critically, for a given percentage packet loss, the test found that increasing the packet burst size produced improved opinions of quality and acceptability. These results suggest that user-perceived Quality of Service can be improved under network congestion conditions by configuring the packet loss characteristics. Larger bursts of packet loss occurring infrequently may be preferable to more frequent smaller-sized bursts.

Network resources and traffic priorities can be utilized to distribute requested tasks across edge nodes at the edge layer. However, due to the variety of tasks, the edge nodes have an impact on data accessibility. Resource management approaches based on Virtual Machine (VM) migration, job prioritization, and other methods were used to overcome this problem. A Minimized Upgrading Batch VM Scheduling (MSBP) has recently been developed, which reduces the number of batches required to complete a system-scale upgrade and assigns bandwidth to VM migration matrices. However, due to poor resource sharing caused by suboptimal VM utilization, the MSBP was unable to effectively ensure the global best solutions. In order to distribute resources and schedule tasks optimally during VM migration, this paper proposes the MSBP with Multi-objective Optimization of Resource Allocation (MORA) method. The major goal of this proposed methodology is to take into account different objectives and solve the Pareto-front problem to enhance lifetime of the fog-edge network. First, it formulates an NP-hard challenge for MSBP by taking into account a variety of factors such as network sustainability, path contention, network delay, and cost-efficiency. The Multi-objective Krill Herd optimization (MoKH) algorithm is then used to address the NP-hard issue using the Pareto optimality rule and produce the best solution. First, it introduces an NP-hard challenge for MSBP by accounting in network sustainability, path contention, network latency, and cost-efficiency. The Pareto optimality rule is then implemented to overcome the NP-hard problem and provide the optimum solution employing the Multi-objective Krill Herd optimization (MoKH) algorithm. This increases network lifetime and improves resource allocation cost efficiency. Finally, the simulation results show that the MSBP-MORA distributes resources more efficiently and hence increases network lifetime when compared to other traditional algorithms.

In conventional TCP/IP networks, there is a differentiated service architecture for providing different levels of services. Similarly in Delay Tolerant Networks (DTNs), we need to provide differentiated services where the network resources are limited, particularly in buffer size. Since DTNs have their own network characteristics, such as multiple copy routings, and intermittently connection, the traditional differentiated service architecture does not apply. In this paper, we propose two simple schemes to provide a packet forwarding assurance in DTNs. The two proposed schemes are an absolute differentiation scheme, and a relative differentiation scheme. These schemes have a prioritization process when a packet is dropped from the local buffer at each node to provide a high priority to Assured Forwarding (AF) packet and a low priority to Best Effort packet. We show that the proposed algorithms can dynamically find the appropriate target delivery ratio for AF packets, which can provide forwarding assurance for AF packets while avoiding starvation of BE packets, without any global information even though network conditions are changing. We believe that our study is the initial step toward exploiting differentiation services in DTNs.

Epidemic Routing is an original and effective multicopy routing algorithm in disruption tolerant networks. However, its performance degrades significantly when network resources are limited. In this paper, we proposed a new routing scheme, called Weighted Epidemic Routing (WER). WER appropriately arranges the priority of messages for forwarding or deleting through assigning a weight for each of them when the buffer size of nodes and contact duration are limited. The weight of a message is determined by TTL and replications density that is a novel metric to estimate the amount of copies around an infected node. Meanwhile, an ACK vector exchange mechanism is employed by WER to purge the redundant messages. Simulation results show that WER outperforms Epidemic with Drop-tail and FIFO drop policy by a factor of about 6.8 and 0.66 respectively when buffer size is low.

Quantum aided efficient resource control for connected support in IRS assisted networks

The evolution of the World Wide Web service has incorporated new distributed multimedia conference applications, powering a new generation of e-learning development and allowing improved interactivity and prohuman relations. Groupware applications are increasingly representative in the Internet home applications market, however, the Quality of Service (QoS) provided by the network is still a limitation impairing their performance. Such applications have found, in multicast technology, an ally contributing for their efficient implementation and scalability. Additionally, considering QoS as a design goal at the application level becomes crucial for groupware development, enabling QoS productivity to applications. The applications’ ability to adapt themselves dynamically according to the resources availability can be considered a quality factor. Tolerant real-time applications, such as video conferences, are in the frontline to benefit from QoS adaptation. However, not all include adaptive technology able to provide both end-system and network quality awareness. Adaptation, in these cases, can be achieved by introducing a multiplatform middleware layer responsible for tutoring the applications’ resources (enabling adjudication or limitation) based on the available processing and networking capabilities. Congregating these technological contributions, an adaptive platform has been developed integrating public domain multicast tools, applied to a Web-based distance learning system. The system is user-centered (e-student), aiming at good pedagogical practices and proactive usability for multimedia and network resources. The services provided, including QoS adapted interactive multimedia multicast conferences (MMC), are fully integrated and transparent to end-users. QoS adaptation, when treated systematically in tolerant real-time applications, denotes advantages in group scalability and QoS sustainability in heterogeneous and unpredictable environments such as the Internet.