Mobile Host

MIo-NFS aims at providing disconnected operation for NFS-based file systems. It uses a token-based replica control mechanism that prevents write sharing conflicts though allowing mobile clients to modify their files while disconnected. Files are pre-fetched into the mobile host and, by default, tokens are passed to it on disconnection and given back to the server on connection. The user can override this behaviour with a per-object profile. There is also a weak connection mode that supports low-bandwidth, high-latency lines.

The use of data services from handheld devices has increased exponentially resulting in several challenges. Transactions requiring the same shared data item may simultaneously perform a write operation leading to inconsistency of data items. The generic characteristics of mobile environments like variable bandwidth, disconnections, mobility etc makes transaction management more difficult thereby the traditional Isolation property may not be guaranteed. This paper analyzes and compares various concurrency control strategies in mobile environments proposed in literature. The design requirement for preserving isolation property in mobile environments is also presented.

One of the most recent Internet challenges is to support transparent movement of people along with their computers, data and most of all applications. Therefore, Mobile IP has been developed to provide Internet mobility services. This paper aims at enhancing the IETF Mobile IP standard. The model developed in this paper suggests a new caching mechanism, which is based on the Mobile Information Server (MIS). Actually, the MIS is designed to be part of the border router of any network that supports mobility services. Moreover, the paper suggests a peering technique by which information about mobiles hosts could be shared among different MISs. All the design issues including model components as well as mechanisms for caching and peering are described in details. The simulation results show that the proposed design provides improved performance and better bandwidth utilization. The suggested architecture provides other qualitative advantages such as scalability and transparency.

The past decade has seen significant advancement in the field of consumer electronics. Various ‘intelligent’ appliances such as cellular phones, air-conditioners, home security devices, home theatres, etc. are set to realize the concept of a smart home. They have given rise to a Personal Area Network in home environment, where all these appliances can be interconnected and monitored using a single controller. Busy families and individuals with physical limitation represent an attractive market for home automation and networking. A wireless home network that does not incur additional costs of wiring would be desirable. Bluetooth technology, which has emerged in late 1990s, is an ideal solution for this purpose. This paper describes an application of Bluetooth technology in home automation and networking environment. It proposes a network, which contains a remote, mobile host controller and several client modules (home appliances). The client modules communicate with the host controll...

Notice of Violation of IEEE Publication Principles"A Dynamic Distributed Diagnosis Algorithm for an Arbitrary Network Topology with Unreliable Nodes and Links,"by Pabitra Mohan Khilar and Sudipta Mahapatra,in the Proceedings of the International Conference on Advanced Computing and Communications, 2007. ADCOM, Dec. 2007, pp. 125-130After careful and considered review of the content and authorship of this paper by a duly constituted expert committee, this paper has been found to be in violation of IEEE's Publication Principles.This paper contains significant portions of original text from the paper cited below. The original text was copied without attribution (including appropriate references to the original author(s) and/or paper title) and without permission.Due to the nature of this violation, reasonable effort should be made to remove all past references to this paper, and future references should be made to the following article:"A Distributed Network Connectivity Algorithm,"By E. Procopio Duarte Jr. and A.Weber,The Sixth International Symposium on Autonomous Decentralized Systems, 2003. ISADS 2003 April 2003, pp. 285-292This paper presents a distributed network diagnosis (DND) algorithm for an arbitrary network topology where every node needs to record the status of every other nodes and links assuming the nodes and links are subjected to crash and value faults in a dynamic fault environment (the node's or link's status may change during execution of algorithm). The algorithm operates correctly in each connected component if the network is partitioned due to a set of faulty links or faulty nodes. The worst-case bounds for diagnostic latency is at most O(td) rounds where t is the number of dissemination trees and d is the diameter of the network. The proposed approach uses non-broadcasting method of message dissemination that has similar diagnostic latency with flooding [4] and similar message co- mplexity with Chinese Agent [14] method of message dissemination respectively.

A mobile ad hoc network (MANET) is a temporary infrastructureless network, formed by a set of mobile hosts that dynamically establish their own network on the fly without relying on any central administration. Mobile hosts used in MANET have to ensure the services that were ensured by the powerful fixed infrastructure in traditional networks, the packet forwarding is one of these services. The resource limitation of nodes used in MANET, particularly in energy supply, along with the multi-hop nature of this network may cause new phenomena which do not exist in traditional networks. To save its energy a node may behave selfishly and uses the forwarding service of other nodes without correctly forwarding packets for them. This deviation from the correct behavior represents a potential threat against the quality of service (QoS), as well as the service availability, one of the most important security requirements. Some solutions have been recently proposed, but almost all these solutions rely on the watchdog technique as stated in S. Marti et al. (2000) in their monitoring components, which suffers from many problems. In this paper we propose an approach to mitigate some of these problems, and we assess its performance by simulation.

Abstract This paper considers distributed algorithms for distributed mobile systems. Many distributed algorithms have been designed for distributed systems consisting of static computers only. But most of them cannot be directly applied to mobile systems. This paper ...

A wireless MANET is a collection of wireless mobile hosts that dynamically create a temporary network without a fixed infrastructure. The topology of the network may change unpredictably and frequently. Therefore, multicast routing in ad hoc networks is a very challenging problem. This paper proposes a multi-constrained QoS multicast routing method using the genetic algorithm. The proposal will be flooding-limited using the available resources and minimum computation time in a dynamic environment. By selecting the appropriate values for parameters such as crossover, mutation, and population size, the genetic algorithm improves and tries to optimize the routes. Simulation results indicate its better performances compared to other methods.

TCP is a protocol which performs well with networks that are physically linked and hosts are stationary. However, TCP/IP protocols work independently of the physical layer. In wireless environments, mobile hosts are subject to change their attachment point during communication. When a user moves towards a new network domain during communication, the TCP packet loss is increased. Our approach provides a solution that minimizes the TCP packet loss when handover occurs. This paper introduces a solution for mobility management in the transport layer which improves the TCP performance throughout the handover process

A crucial aspect of effective networking on the battlefield is choosing the correct networking architecture. Multi-hop wireless networks provide the best model for tactical networking because of their ability to self-organize and rapidly adapt to change. We focus on a multi-hop wireless network model that is highly dynamic and that consists of mobile base stations and mobile hosts. In this model, there are two key requirements for enabling an effective networking infrastructure for the battlefield: the support of highly mobile nodes and the scalability to a large number of nodes. We present some of the system-level challenges encountered in highly dynamic multi-hop wireless networks. In particular, we address the topology model, the location model, and the routing model in light of the aforementioned challenges

Transaction support is crucial in mobile data management. Specific characteristics of mobile environments (e.g. variable bandwidth, disconnections, limited resources on mobile hosts) make traditional transaction management techniques no longer appropriate. Several models for mobile transactions have been proposed but it is difficult to have an overview of all of them. This paper analyzes and compares several contributions to mobile transactions. The analysis distinguishes two groups of models. The first group includes proposals where transactions are completely or partially executed on mobile hosts. In this group we focus on ACID properties support. The second group considers transactions requested by mobile hosts and executed on the wired network. In this case, ACID properties are not compromised and focus is on supporting mobile host movements during transaction execution. Discussions pointing out limitations, interesting solutions and research perspectives complete this paper.

In mobile computing and wireless communication, proxies are mainly used to overcome the three major problems of these networks: throughput and latency differences between the wired and the wireless links, host mobility, and limited resources of the mobile hosts (MH). This report aims to present a general classification of proxy-based approaches, describe the most frequent functions assigned to proxies, discuss

Abstract—This paper investigates differentiated services in wireless packet networks using a fully distributed approach that supports service differentiation, radio monitoring and admission control. While our proposal is generally applica- ble to distributed wireless access ...