Mobile IP: state of the art report

Due to roaming, a mobile device may change its network attachment each time it moves to a new link. This might cause a disruption for the Internet data packets that have to reach the mobile node. Mobile IP is a protocol, developed by the Mobile IP Internet Engineering Task Force (IETF) working group, that is able to inform the network about this change in network attachment such that the Internet data packets will be delivered in a seamless way to the new point of attachment. This document presents current developments and research activities in the Mobile IP area

Service discovery using Bloom filters

A protocol to perform service discovery in adhoc networks is introduced in this paper. Attenuated Bloom filters are used to distribute services to nodes in the neighborhood and thus enable local service discovery. The protocol has been implemented in a discrete event simulator to investigate the behavior in case of a multihop mobile ad-hoc network with nodes that all have services to offer. Methods to optimize the used bandwidth, which is a scarce resource in wireless networks, are investigated. Experiments performed with the simulator suggest that the proposed service discovery system enables users to find local services in a multihop ad-hoc network efficiently. The costs for advertising can be kept low, whereas the additional costs for queries set due to so-called false positives are moderate

Context discovery using attenuated Bloom filters in ad-hoc networks

A novel approach to performing context discovery in ad-hoc networks based on the use of attenuated Bloom filters is proposed in this paper. In order to investigate the performance of this approach, a model has been developed. This document describes the model and its validation. The model has been implemented in Matlab, and some results are also shown in this document. Attenuated Bloom filters appear to be a very promising approach for context discovery in ad hoc networks

Providing Delay Guarantees in Bluetooth

Bluetooth polling, also referred to as Bluetooth MAC scheduling or intra-piconet scheduling, is the mechanism that schedules the traffic between the participants in a Bluetooth network. Hence, this mechanism is highly determining with respect to the delay packets experience in a Bluetooth network. In this paper we present a polling mechanism that provides delay guarantees in an efficient manner and we evaluate this polling mechanism by means of simulation. It is shown that this polling mechanism is able to provide delay guarantees while saving as much as possible resources, which can be used for transmission of best effort traffic or for retransmission

Design and evaluation of a connection management mechanism for an ATM-based connectionless service

The Asynchronous Transfer Mode (ATM) has been developed as a connection-oriented technique for the transfer of fixed-size cells over high-speed networks. Many applications, however, require a connectionless network service. In order to provide such a technique, one can built a connectionless service on top of the connection-oriented service. In doing so, the issue of connection management comes into play. In this paper we propose a new connection management mechanism that provides for low bandwidth usage (as compared to a permanent connection) and low delays (as compared to a connection-per-packet approach). We model the new mechanism under two workload scenarios: an ordinary Poisson process and an interrupted Poisson process. We use Markovian techniques as well as matrix-geometric methods to evaluate the new connection management mechanism. From the evaluations it turns out that the proposed mechanism is superior to older approaches (which can be seen as limiting cases)

Providing over-the-horizon awareness to driver support systems

Vehicle-to-vehicle communications is a promising technique for driver support systems to increase traffic safety and efficiency. A proposed system is the Congestion Assistant [1], which aims at supporting drivers when approaching and driving in a traffic jam. Studies have shown great potential for the Congestion Assistant to reduce the impact of congestion, even at low penetration. However, these studies assumed complete and instantaneous availability of information regarding position and velocity of vehicles ahead. In this paper, we introduce a system where vehicles collaboratively build a so-called TrafficMap, providing over-the-horizon awareness. The idea is that this TrafficMap provides highly compressed information that is both essential and sufficient for the Congestion Assistant to operate. Moreover, this TrafficMap can be built in a distributed way, where only a limited subset of the vehicles have to alter it and/or forward it in the upstream direction. Initial simulation experiments show that our proposed system provides vehicles with a highly compressed view of the traffic ahead with only limited communication

Mobile IP

The Internet is growing exponentially, both in the amount of traffic carried, and in the amount of hosts connected. IP technology is becoming more and more important, in company networks (Intranets), and also in the core networks for the next generation mobile networks. Further, wireless access to IP networks is becoming mature (e.g., IEEE 802.11 networks, Irda, Bluetooth). At the same time, the existing generation of mobile (cellular) networks is evolving from voice services to networks with a rich mixture of services (e.g., GPRS and 3rd generation networks). These developments demand for mobility in IP-based networks. A first solution to this problem has been proposed as Mobile IP. This solution makes use of Home Agents and Foreign Agents to allow mobile hosts to move freely between subnetworks while communicating.\ud \ud The tutorial will describe and explain the approaches taken to provide mobility for hosts in the Internet and IP-based networks. The tutorial will start with expanding on the need for Mobile IP. It will briefly explain the main Internet principles relevant to Mobile IP. The problems Mobile IP is trying to solve will be explained. After an overview of the general operation of Mobile IP, the principal mechanisms will be discussed in more detail. The tutorial will describe the operation of advertising care-of addresses, mobile host registration, tunneling, and proxy- and gratuitous ARP. Special attention will be paid to the main problems related to Mobile IP, such as triangle routing and smooth hand-off. The tutorial will finally explain how mobility can be supported in IPv6.\u

Exploring Space – towards high-capacity inter-vehicular communications

This presentation discusses the question “Are there still research challenges in inter-vehicular communications”. The premise is that these may come from autonomous, or rather coordinated driving. I will start with a few results from an earlier project, Connect & Drive, where a system for cooperative adaptive cruise control was researched, designed, and prototyped. We project that for coordinated driving, important challenges are in the area of reliable consensus for coordinated manoeuvres, and high-rate beaconing for increased situational awareness of vehicles. I show that current systems do not suffice for these challenges. In order to increase the scalability of inter-vehicular communications, I propose to explore spatial reuse, by using cheap large-scale antenna arrays and beamforming receivers. This way, a vehicle can be equipped with a large number of receivers, each receiving from a specific (dynamically reconfigurable) direction. Given this idea, I point at important research questions, and argue that for a good understanding, the use of good analytical performance models is of paramount importance

A Distributed Routing Algorithm for Internet-wide Geocast

Geocast is the concept of sending data packets to nodes in a specified geographical area instead of nodes with a specific address. To route geocast messages to their destination we need a geographic routing algorithm that can route packets efficiently to the devices inside the destination area. Our goal is to design an algorithm that can deliver shortest path tree like forwarding while relying purely on distributed data without central knowledge. In this paper, we present two algorithms for geographic routing. One based purely on distance vector data, and one more complicated algorithm based on path data. In our evaluation, we show that our purely distance vector based algorithm can come close to shortest path tree performance when a small number of routers are present in the destination area. We also show that our path based algorithm can come close to the performance of a shortest path tree in almost all geocast situations

Performance evaluation of MPEG-4 video streaming over UMTS networks using an integrated tool environment

Universal Mobile Telecommunications System (UMTS) is a third-generation mobile communications system that supports wireless wideband multimedia applications. This paper investigates the video quality attained in streaming MPEG-4 video over UMTS networks using an integrated tool environment, which comprises an MPEG-4 encoder/decoder, a network simulator and video quality evaluation tools. The benefit of such an integrated tool environment is that it allows the evaluation of real video sources compressed using an MPEG-4 encoder. Simulation results show that UMTS Radio Link Control (RLC) outperforms the unacknowledged mode. The latter mode provides timely delivery but no error recovery. The acknowledged mode can deliver excellent perceived video quality for RLC block error rates up to 30% utilizing a playback buffer at the streaming client. Based on the analysis of the performance results, a self-adaptive RLC acknowledged mode protocol is proposed