Performance and implementation of routing and wireless transport layer connections in micro mobility Ad hoc networks

In mobile ad hoc networks wireless nodes communicate over multi hop links and are capable of movement. This paper evaluates a solution that provide these networks with Internet Access and the capability to roam between different access points. Design and implemenation consideration are discussed that focus on behaviour and criterias for performing handover. Simulation result show that the main factor affecting transport performance during micro mobility are link breaks, where choice of TCP flavour and advanced window freezing behaviours have little effect It is also shown that a new kind of TCP unfairness arise when different TCP flavours compete among each other

Performance of Internet Access Solutions in Mobile Ad Hoc Networks

Although an autonomous mobile ad hoc network (MANET) is useful in many scenarios, a MANET connected to the Internet is more desirable. This interconnection is achieved by using gateways, which act as bridges between a MANET and the Internet. Before a mobile node can communicate with an Internet host it needs to find a route to a gateway. Thus, a gateway discovery mechanism is required. In this paper the MANET routing protocol ad hoc on-demand distance vector (AODV) is extended to achieve the interconnection between a MANET and the Internet. Moreover, the paper investigates and compares three approaches for gateway discovery. The question of whether the configuration phase with the gateway should be initiated by the gateway, by the mobile node or by mixing these two approaches is being discussed. We have implemented and simulated these three methods and we discuss the advantages and disadvantages of the three alternative

Cross layer routing and media access control with channel dependant forwarding in wireless ad-hoc networks

Wireless ad hoc networks have the last 10 years gained a lot of attention within the research community. A wireless ad hoc network is a special type of wireless network where nodes are typically mobile and doesn’t rely on any fixed infrastructure to operate correctly. Much work has been done on developing robust and stable routing algorithms that consider the dynamic nature of an ad hoc network: nodes are very mobile and enter and leave the network in random ways. Much work has also been done on developing medium access control (MAC) algorithms that consider many wireless characteristics such as interference and the hidden terminal problems. Little work has so far been done on developing joint routing and MAC layer solutions that consider the variations of the wireless channel. We present a solution where the routing protocol can cooperate with the MAC layer to provide power control and channel dependent forwarding. By establishing non-disjoint multiple paths between each source and destination, nodes may be able to avoid links that are currently in a deep signal fade by choosing a more beneficial next hop path

Internet connectivity for mobile ad hoc networks

The need for ad hoc networks arises when a number of mobile nodes gather in one particular location and form autonomous networks. Ad hoc networks can be adjoined to the Internet, introducing routing and addressing issues that require new features from ad hoc networking protocols. The Internet Gateway can offer global addressability and bidirectional Internet connectivity to every node in the ad hoc network. This can be done in such a way that mobile wireless nodes can migrate between wireless access points that have direct access to the wired Internet and the wireless ad hoc networks that do not have any such local access point infrastructure. Mobile IP can be employed to make such movement seamless (whenever physically possible), even though it occurs between domains with previously incompatible routing models. We believe that IPv6 and Mobile IPv6 afford important advantages for making such attachments, especially regarding router advertisement and address autoconfiguration. In this paper, we show how general ad hoc networks can be connected to the Internet by Internet Gateways, and then describe our specific experiments with Ad hoc On-Demand Distance Vector Routing (AODV) for IPv6 (AODV6). After demonstrating the basic principles allowing access to the Internet, we then detail our further experiments using Mobile IPv6. Copyright (C) 2002 John Wiley Sons, Ltd

Dynamic combination of multiple host-based anomaly detectors with broader detection coverage and fewer false alerts

The original publication is available at www.springerlink.comTo achieve broader detection coverage with fewer false alarms, a POMDP-based anomaly detection model combining several sate-of-the-art host-based anomaly detectors is proposed in this paper. An optimal combinatorial manner is expected to be discovered through a policy-gradient reinforcement learning algorithm, based on the independent actions of those detectors, and the behavior of the proposed model can be adjusted through a global reward signal to adapt to various system situations. A primarily experiment with some comparative studies are carried out to validate its performance.Zonghua Zhang and Hong She