Computer Network

Wireless body area networks (WBANs) a special type of wireless sensor networks (WSNs) in which sensor nodes to actualize continuous wearable wellbeing observing of patients are able to provide improved healthcare services in a distributed infrastructure less environments. However, the mobile node, due to less battery power, can easily suffer from the problem of energy level when control packets are transfer among nodes—a problem that can occurs by the fact that some sensor nodes may select wrong cluster head with inappropriate path and waste the resources. Although many energy efficient methods have been designed for the traditional sensor networks, there has been limited focus on incorporating WBANs into energy efficient schemes. Therefore, in order to incorporate above issue we revisit the already designed traditional energy efficient methods with cluster head selection protocols and optimal path transformation. Therefore, we encourage researchers to insert WBANs with existing met...

We compare the concept of congestion avoidance with that of ow control and congestion control. A number of possible alternative for congestion avoidance have been identi ed. From these a few were selected for study. The criteria for selection and goals for these schemes ...

A new practical approach to sensitivity analysis of the network parameters of high-frequency structures with commercial full-wave electromagnetic (EM) solvers is proposed. We show that the computation of the linear-network parameter derivatives in the design-parameter space does not require an adjoint-problem solution. The sensitivities are computed outside the EM solver, which simplifies the implementation. We discuss: 1) features of commercial EM solvers which allow the user to compute network parameters and their sensitivities through a single full-wave simulation;

We obtain equivalencies between closed queueing networks with blocking with respect to buffer capacities and the number of customers in the network. These results can be used in approximations, in the buffer allocation problem as well as to explain the behavior of closed queueing networks with finite buffers.

In the view of escalating global threat in security, it is imperative to have an automated detection system that can pick up suspicious patterns of human movement in physical environments. It can give a forewarning before a planned attack happens or an ultimate security is breached. In the past, significant research on the Intrusion Detection was established, but limited to virtual environments like computer networks and operating systems. In this paper, we proposed a general security model for detecting suspicious patterns in physical environment. Suspicious patterns are subtle and we showed that they can be detected via an experiment.

Recent measurements show that BGP peering links can fail as frequently as intradomain links and usually for short periods of time. We propose a new fast-reroute technique where routers are prepared to react quickly to interdomain link failures. For each of its interdomain links, a router precomputes a protection tunnel, i.e. an IP tunnel to an alternate nexthop which can reach the same destinations as via the protected link. We propose a BGP-based auto-discovery technique that allows each router to learn the candidate protection tunnels for its links. Each router selects the best protection tunnels for its links and when it detects an interdomain link failure, it immediately encapsulates the packets to send them through the protection tunnel. Our solution is applicable for the links between large transit ISPs and also for the links between multi-homed stub networks and their providers. Furthermore, we show that transient forwarding loops (and thus the corresponding packet losses) can be avoided during the routing convergence that follows the deactivation of a protection tunnel in BGP/MPLS VPNs and in IP networks using encapsulation.

Ad hoc mobile clouds would be suitable for spontaneous ad hoc networks created in situations where the mobile infrastructures are very pervasive and where the interconnection to an infrastructure network is very costly. The advantages of ad hoc mobile clouds are ubiquity, affordability, availability and spontaneity. The provision of an reliable ad hoc MCC framework has to cope with the specific features of spontaneous networks such as the dynamic topology and the scarcity of mobile device resources. The goal of this paper is to propose a protocol handling the setting up and the management of an ad hoc MCC over mobile ad hoc networks. We show by simulations that our proposal has acceptable overhead and energy consumption especially for small networks. The originality of this work consists in providing seamless communication services to mobile cloud frameworks regarding the underlying ad hoc network technology.

In order to maximize the network's lifetime and ensure the connectivity among the nodes, most topology management practices use a subgroup of nodes for routing. This paper provides an in-depth look at existing topology management control algorithms in Multi-state structure. We suggest a new algorithm based on Geographical Adaptive Fidelity (GAF) and Adaptive Self-Configuring Sensor Networks Topology (ASCENT). The new proposed algorithm outperforms both GAF and ASCENT algorithms.

In Wireless Sensor Networks (WSNs), energy consumption is the most challenging issue. The more energy is consumed during captured data transmission than the local data processing at sensor nodes. Because of this reason network lifetime is reduces. Sometimes attacker nodes are also responsible of energy wastage. Data aggregation technique is one of the solutions for this issues of network lifetime and energy loss. In this paper data aggregation technique is used for detecting attack and prevention technique. For collecting the data from the cluster head in the network, system used aggregator Node (AN). If the cluster head (CH) becomes attacker, then AN recover the data from all cluster members, So that the energy in not wasted and packet drop ratio is also minimized. Also, system makes use of the Iterative Filtering (IF) algorithm, which additionally gives trust evaluation to the numerous sources from where the information is aggregated. This IF algorithm is used to detect the Simple...

We developed a networked virtual reality system on which one could have live videoes with high iteractive usage. However, since a client in our system receives both live videoes and computer graphics objects continuously from a server while it is rendering the current frame of the virtual world, a quality of the presentation of the virtual space depends on the current available system resources on the client as well as network resources. In this paper, we discuss the notion of QoS for a networked VR system as an application level QoS which is based on the notion of an importance of presence (IoP) of objects in a virtual space calculated by a distance from a current user's position to the object and an angle from the user's perspective to the object. Then, we show a heuristic mapping mechanism of the application level QoS to a network level QoS which determines the allocation of bandwidth of videos and CG objects to maximize the presentation quality. We adopt bandwidth as a...

new distributed algorithm is presented for dynamically determining weighted shortest paths used for message routing in computer networks. The major features of the algorithm are that the paths .defined do not form transient loops when weights change and the number of steps required to find new shortest paths when network links fail is less than for previous algorithms. Specifically, the worst case recovery time is proportional to the largest number of hops h in any of the weighted shortest paths. For previous loop-free distributed algorithms this recovery time is proportional to h2.

Queueing systems in which arriving customers who find all servers and waiting positions (if any) occupied may retry for service after a period of time are called retrial queues or queues with repeated orders. Retrial queues have been widely used to model many problems in telephone switching systems, telecommunication networks, computer networks and computer systems. In this paper, we discuss some important retrial queueing models and present their major analytic results and the techniques used. Our concentration is mainly on single-server queueing models. Multi-server queueing models are briefly discussed, and interested readers are referred to the original papers for details. We also discuss the stochastic decomposition property which commonly holds in retrial queues and the relationship between the retrial queue and the queue with server vacations.

— In most of the organizations it is highly desirable to perform different tasks on different machines based on their configuration and permissions assigned to the machines for execution of different tasks. This can be achieved by performing a user-machine mapping by stating clearing the list of tasks that can be performed by a particular user on a particular machine. This kind of discipline further enables traffic control, prevents internal DOS (Denial Of Service) attacks for legitimate users and helps in fair resource sharing. The intent of this research is to ena ble the end user performing only the tasks permissible to him/her. In this paper we have developed a network monitor and control tool for monitoring the tasks on a medium sized local area network. To facilitate this, task permissions are assigned to different machines which are stored in XML configuration file which is then parsed using JDOM (Java Document Object Model) Parser. The configuration file contains the details such as machine name, and the list of tasks not permitted on that machine. The list of machines and the list of tasks denied on that machine are configurable by an end user. A background thread will continuously monitor the execution of illegal task on a machine and will abort and report the same in a database. This also facilitates the control of network traffic thereby improving the network performance by aborting illegal tasks. Network monitoring tool is tested for local area network of department of computer studies at SIBER by setting up specific monitors to check status and to carry out specific operations. The tool developed by us requires a small amount of s ystem resources, and it is an open source tool. Presently, the tool generates a report comprising of a list of illegal tasks in a specified time period, which enables network administrator to take corrective measures for the smooth operation of the network.

An essential function for achieving security in computer networks is reliable authentication of communicating parties and network components. Such authentication typically relies on exchanges of cryptographic messages between the involved parties, which in turn implies that these parties be able to acquire shared seeret keys or certified public keys. Provision of authentication and key distribution functions in the primitive and msmwce-constrained environments of low-function networking mechanisms, portable, or wireless devices presents challenges in terms of resouree usage, system management, ease of use, etBciency, and flexibility that are beyond the capabilities of previous designs such as Kerberos or X.509. This paper presents a family of lightweight authentication and key distribution protocols suitable for use in the low layers of network architectures. All the protocols are built around a common two-way authentication protocol. The paper argues that key distribution may require substantially different approaches in different network environments and shows that the proposed family of protocols offers a flexible palette of compatible solutions addressing many different networking scenarios. The mechanisms are minimal in cryptographic processing and message size, yet they are strong enough to meet the needs of secure key distribution for network entity authentication. Tbe protocols presented have been implemented as part of a comprehensive security subsystem prototype called KryptoKnight, whose software and implementation aspeets are discussed in [16], and which is the basis for the recently announced IBM Network Seeurity Program product. 1. INTROD(JCTION T HE STEADILY growing use of computer networks is fostering increasing concerns about network security. One of the main issues is effective control of access to network components and resources by expanding populations of users, some of which cannot always be trusted to use the network properly. An essential requirement for implementing suitable access controls is a mechanism for reliable authentication of communicating entities and network users. State-of-the-art authentication protocols typically rely on exchanges of cryptographic messages between entities wanting to authenticate one another prior to or during actual communication. Such exchanges in turn demand that the communicating parties be able to acquire cryptographic keys Manuscript

The area of visualization has ,always been one of the ,most attractive sections of network management,technology. Successful management,tools must not only fulfill objective management needs but also be aestheticallyappealing. Consequently, the seemingly mundane task of presenting information to the user has become,almost a true art. The application proposed in this paper is a vehicle for the presentation of network ,management ,data using interactive graphs. By using ,the Scalable Vector Graphics markup ,language ,(SVG) [1] and Asynchronous ,Javascript and XML (AJAX) [2], it strives to aid the rapid development of visually impressive management applications that are accessible through the use of a ,web browser. These highly interactive and versatile applications can respond to user actions and present data which is organized into layers and is retrieved and refreshed on demand. ,The data of these ,layers is generated ,by network management,tools that plug in to the application thro...

An electronic voting system makes it possible for the voters to cast their ballots over the computer network. Hence, voters 11 can participate in elections without having to go to the polling places, which is more convenient and efficient. To design a 12 practical voting scheme, Mu and Varadharajan have recently proposed an anonymous secure electronic voting scheme to be 13 applied over the network. It does not only protect voters' privacy and prevent double voting, but also suits large-scale elections. 14 However, the scheme has a weakness in security; that is, some voters may still double vote without being detected and may 15 even reveal information they should not. In this paper, we shall show this weakness and improve the scheme to increase the 16 protection against fraudulence. 17 D 2002 Published by Elsevier Science B.V. 18 19 23

Ethernet is a branching broadcast communication system for carrying digital data packets among locally distributed computing stations. The packet transport mechanism provided by Ethernet has been used to build systems which can be viewed as either local computer networks or loosely coupled multiprocessors.

The work culture in libraries has changed due to the growth of computer networks and the World Wide Web. The growth of interest in knowledge management (KM) has essentially been contemporary with that of intranets/extranets. It is no longer sufficient for libraries to depend solely on having sufficient access to internal and external information resources but to efficiently exploit what the system actually knows-not only what it owns. The successful implementation of KM is that people will share what they know and reuse the know how of others; from this perspective, paper examines the changing role and core competencies required for information professionals specially as a chief knowledge officer (CKO). It also focuses on the vision, strategy and appropriate mind set required for successful implementation without which knowledge management can become an empty slogan.

This paper proposes a new approach for reducing average call delivery cost and location server's load of wireless mobile networks. It uses caches whose up-todate information is responsible for dropping these costs and these caches are updated not only during call arrival moment from the calling Mobile Hosts (MHs) but also during call receiving moment to those MHs. To achieve load balancing among replicated Home Location Registers (HLRs), hashing technique is also used and this load is also affected by up-to-date cache information. The analytical model and experimental results show that our proposed method prepares the cache with up-to-date information more frequently with the increase of average call arrival rate as well as average call receiving rate. This increases probability of finding MH's location as well as hit ratio of the cache. As a result, both the average call delivery cost and load on a particular HLR are minimized considerably than all other previous approaches.

Mobile ad-hoc networks (MANETs) consist of special kind of wireless mobile nodes which form a temporary network without using any infrastructure or centralized administration. MANETs can be used in wide range of future applications as they have the capability to establish networks at anytime, anywhere without aid of any established infrastructure. It is a challenging task to find most efficient routing due to the changing topology and the dynamic behavior of the nodes in MANET. It has been found that ant colony optimization (ACO) algorithms can give better results as they are having characterization of Swarm Intelligence (SI) which is highly suitable for finding the adaptive routing for such type of volatile network. ACO algorithms are inspired by a foraging behavior of group of ants which are able to find optimal path based upon some defined metric which is evaluated during the motion of ants. ACO routing algorithms use simple agents called artificial ants which establish optimum paths between source and destination that communicate indirectly with each other by means of stigmergy. Keeping in view of the above, in this paper we provide a taxonomy of various ant colony algorithms with advantages and disadvantages of each others with respect to various metrics.

The future for WiMAX-based mobile wireless access is so bright. With the increasing popularity of WiMAX, it is gaining a great position in the next generation of wireless networks. Due to the evolution of new technologies wireless is not secured as like others networking technologies. On the other side the trend is towards converged network in which the same networking infrastructure is used for both data and voice transmission. A lot of security concerns are needed to secure a converged network. This paper aims to review the study of WiMAX and converged network and security considerations for both the technologies. WiMAX security in converged network is studied. The security threats that can occur in converged network to WiMAX and countermeasures that can be taken against these threats are reviewed.

Abstract: Education can benefit from the use of technology in the teaching process. This has been done in the past using various technologies. In recent years, computers, information systems, multimedia and hypertext systems have been used to develop self-learning ...

With the rapid advance of mobile computing, high speed Wireless Local Area Networks (LAN) attracts a lot of research interests in recent years. A new international stander IEEE 802.11 on wireless LAN has been established. Its physical transmission is realized by either spread spectrum communication or non-directive infrared. The medium access control of IEEE 802.11 is using carrier sense multiple access with collision avoidance (CSMA/CA) as the basic level access. Continuing from the study of, we shall analyze IEEE 802.11 CSMA/CA performance with or without RTS/CTS in this paper. We have improved the simulation by including RTS/CTS exchanges, which is part of the CSMA/CA protocol. Using this methodology, we hoped to increase the number of successful transmissions and decrease the number of collisions within the WLAN. This particular aspect of the simulation is demonstrated in the Analysis section of this work. Additionally, the simulation makes sure that once an RTS/CTS handshake is completed; all other nodes not included in the data exchange remain silent. This is done to prevent nodes from getting into a continuous cycle of RTS/CTS exchanges.

ABSTRACT This article deals with the role of server operating systems (SOS) in sustaining availability and reliability of contemporary E-business. A framework that can be used in identifying the most critical SOS functions and selecting appropriate SOS platform is presented.

Context awareness has been a vital field of ubiquitous computing research. Numerous methods for capturing, interring external context and providing necessary service have been developed and relevant projects have been performed. However, user's internal context is more valuable than the external one. Thus, more searches on internal context are needed. This paper confines its research domain to the internet based information system (IS) in order to infer the internal context of user. For inferring internal context in this IS domain, one of the computer network techniques, packet sniffing technique, is utilized. This is effective and efficient in acquiring the information of the user's demand. Also, inference algorithm which is integrated with the acquired user's information is proposed. Furthermore, this paper demonstrates that the prototype system adopts the suggested technique and algorithm in order to prove its validity. The proposed prototype system is the basis of providing IS user with ubiquitous services and enhances the convenience and efficiency during business hour of IS user. In this fashion, this paper presents a new pattern of context acquisition and inference in implementing the ubiquitous computing based-IS along with the direction of internal context awareness research.

Recent attention to Cyber Physical Systems (CPS) is driven by the need for deeper integration of design disciplines that dominate physical and computational domains. Consequently, heterogeneity is the norm as well as the main challenge in CPS design: components and systems are modeled using multiple physical, logical, functional and non-functional modeling aspects. The scope of relevant design domains includes (1) physical domains, such as structure, mechanical dynamics, thermal, propulsion, fluid, electrical, acoustics/vibration and (2) computational/networking domains, such as system control, sensors, health management, mission management, communication. However, the practice of multi-modeling-using established domain-specific modeling languages and tools independently in the design process-is insufficient. Modeling and analyzing cross-domain interactions among physical and computational/networking domains and understanding the effects of heterogeneous abstraction layers in the design flow are fundamental part of CPS design theories. I will cast this challenge as a model integration problem and discuss solutions for capturing interdependencies across the modeling domains using constructs for meta-model composition and integration.

The digital revolution that has been taking place for the past two decades propelled by major breakthroughs in the ICT field has changed the way we communicate, work, travel, live-and even the way we use public space. Our cities are increasingly moving from a collection of static buildings and infrastructures to dynamic and evolving smart ecosystems known as, Intelligent Cities. In this article we analyze an intelligent city from the electronic information and communication perspective and offer examples of variants of its implementation. An intelligent city lays its foundation on a digital-city infrastructure which connects a local community and drives growth, efficiency, productivity, and competitiveness. The high level architecture of an intelligent city ecosystem, key enabling technologies, and the necessary policy framework for the establishment of digital cities worldwide are introduced. Business models for this new ecosystem bridging the physical and virtual worlds are briefly discussed.

8th International Conference on Computer Networks & Data Communications (CNDC 2021) will provide an excellent international forum for sharing knowledge and results in theory and applications of Computer Networks and Data Communications. The Conference looks for significant contributions to the Computer Networks and Communications for wired and wireless networks in theoretical and practical aspects. Original papers are invited on Networks, wireless and Mobile, Protocols and wireless networks and security. The aim of the conference is to provide a platform to the researchers and practitioners from both academia as well as industry to meet and share cutting-edge development in the field.

The technologies, architectures, and methodologies traditionally used to develop distributed applications exhibit a variety of limitations and drawbacks when applied to large scale distributed settings (e.g., the Internet). In particular, they fail in providing the desired degree of configurability, scalability, and customizability. To address these issues, researchers are investigating a variety of innovative approaches. The most promising and intriguing ones are those based on the ability of moving code across the nodes of a network, exploiting the notion of mobile code. As an emerging research field, code mobility is generating a growing body of scientific literature and industrial developments. Nevertheless, the field is still characterized by the lack of a sound and comprehensive body of concepts and terms. As a consequence, it is rather difficult to understand, assess, and compare the existing approaches. In turn, this limits our ability to fully exploit them in practice, and to further promote the research work on mobile code. Indeed, a significant symptom of this situation is the lack of a commonly accepted and sound definition of the term "mobile code" itself.

This paper presents an extension of MOVICAB-IDS, a Hybrid Intelligent Intrusion Detection System characterized by incorporating temporal control to enable real-time processing and response. The original formulation of MOVICAB-IDS combines artificial neural networks and case-based reasoning within a multiagent system to perform Intrusion Detection in dynamic computer networks. The contribution of the anytime algorithm, one of the most promising to adapt Artificial Intelligent techniques to real-time requirements; is comprehensively presented in this work.

Cloud computing enables a transparent access to information technology (IT) services such that the users do not need to know the location and characteristics of the relevant resources. While IT resource virtualization and service abstraction have been widely investigated, data transport within the cloud and its efficient control have not received much attention in the technical literature. In fact, connectivity is, itself, a service that contributes to the overall performance of the cloud. This paper introduces a novel classification of the Network as a Service (NaaS) such that it can be orchestrated with other cloud services. Then, it proposes a network virtualization platform (NVP) as the mediation layer able to provide NaaS to cloud computing by exploiting the functionality provided by control plane (CP)-enabled networks. In particular, the proposed NVP maps the end-point addresses and perceived Quality of Service parameters of a NaaS requests in the parameters characterizing the connectivity as viewed by transport networks using the information obtained from the CP at the boundary of the network. The NVP uses these parameters to fulfill connectivity requests to the CP. Finally, this paper presents a complete design from both the software implementation and network signaling perspective of two use cases in which NaaS is involved as stand-alone facility for the connectivity service provisioning or is combined with other cloud services for a storage service provisioning.

The Internet and computer networks are exposed to an increasing number of security threats. With new types of attacks appearing continually, developing flexible and adaptive security oriented approaches is a severe challenge. In this context, anomaly-based network intrusion detection techniques are a valuable technology to protect target systems and networks against malicious activities. However, despite the variety of such methods described in the literature in recent years, security tools incorporating anomaly detection functionalities are just starting to appear, and several important problems remain to be solved. This paper begins with a review of the most well-known anomaly-based intrusion detection techniques. Then, available platforms, systems under development and research projects in the area are presented. Finally, we outline the main challenges to be dealt with for the wide scale deployment of anomaly-based intrusion detectors, with special emphasis on assessment issues.

Modeling computer networks is a complex task, as their behavior depends from several variables. Focusing on a single communication device, ISO/OSI and TCP/IP layered protocol stacks provide interoperability and fast deployment of networking solutions, but they limit the control on the interaction among protocols operating at different layers. As a consequence, the need is emerging to develop appropriate models to capture and evaluate the interaction of protocols within a single communication device in order to underline such forms of "indirect" interaction-since they may lead to unforeseen performance degradations. The proposed work aims at using the game theory for capturing the interactions within the protocol stack of a single node, with the goal of allowing to determine the "steady state" or the operating point of the system in a given scenario. As a result, a scalable and modular framework is presented, that enables characterization and analysis of crosslayer interactions starting from the protocols' specifications.

Stochastic simulation is an important aid for the design and performance engineering of computer networks. The credibility of simulative results can, however, be seriously affected by human errors (e.g., inconsistencies in the parameter selection, poor initialization of random generators, bugs in the scripts used for post-processing), which become more and more likely and numerous as the dimension of the set of simulated scenarios (simulation campaign) increases. The occurrence of such errors can be limited by using reliable automation tools, i.e. tools which take care of the above mentioned tasks by using state-of-the-art methodologies. This work describes ANSWER (Automated NS-2 Workflow managER), a simulation workflow automation tool for the Network Simulator (ns-2), explicitly designed for facilitating large-scale simulation campaigns, i.e. those involving many factors. Our framework reduces the space for errors when defining scenarios, controls the execution of a large number of scenarios, and reduces the time overhead required for output data analysis.

We introduce a compact graph-theoretic representation for multi-party game theory. Our main result is a provably correct and efficient algorithm for computing approximate Nash equilibria in one-stage games represented by trees or sparse graphs.

The Reference Model of Open Distributed Processing (RM -ODP) was a joint effort by the international standards bodies ISO and ITU-T to develop a coordinating framework for the standardisation of open distributed p~ocessing (ODP). The ~odel describes an architecture within which support of distribution, interworking, interoperability and portability can be integrated. The RM-ODP framework defines ODP concerns using five "viewpoints" (abstractions), namely enterprise, 'information, computational, engineering, and technology. This tutorial introduces the reference model, describing the viewpoints and some of the ODP functions and transparencies. 1.1. The Goals and Deliverables of RM-ODP RM-ODP aims to achieve: portability of applications across heterogeneous platforms interworking between ODP systems, i.e. meaningful exchange of information and convenient use of functionality throughout the distributed system distribution transparency, i.e. hide the consequences of distribution from both the applications programmer and user K. Raymond et al. (eds.), Open Distributed Processing