Emerging mobile devices are equipped with multiple interfaces allowing users to take advantage of heterogeneous radio technologies (e.g., cellular networks and wireless LANs). To support mobility and quality of service (QoS) for such multi-interface mobile devices, it is important to dynamically determine which interface or interfaces a mobile should use and when to switch from one interface to another. To make such decisions, it is critical for the mobile to compare the "qualities of the interfaces (QoI)", which may be measured by a variety of metrics, in real time so that the mobile can switch from one interface to another without user perceivable interruptions to on-going applications. This paper presents and analyzes new techniques for a mobile device to make rapid comparison of the quality of the interfaces using quickest sequential change detection and sequential two-sample hypotheses tests.

This paper presents a comprehensive framework to develop joint RRM (radio resource management) strategies taking full advantage of the reconfigurable equipment capabilities and the diversity offered by available RATs (radio access technologies) in a multi-radio environment. The envisaged JRRM treatment calls for establishing links with all the entities involved, first at functional level, identifying realistic scenarios in terms of deployment, technologies and services, and managing the emerging complexity with proper algorithms. Then, a fuzzy-neural methodology framework able to cope with the complexities and uncertainties these new scenarios rise is presented. In particular both technical and economical aspects are considered when selecting a particular RAT. Finally some significant examples of the algorithm behaviour are shown.

Current radio access networks are based on tree and star topologies, which have no inherent restorability properties. This paper proposes a heuristic topology enhancement method that adds redundant spans and upgrades existing infrastructure cost-effectively, in order to create partially meshed architectures that can provide the desired level of restorability against single span failures. The algorithm is tested using several different variants of restoration mechanisms. Results show that reasonably good solutions can be achieved in a short time scale. Finally, a service-oriented protection and restoration model is presented. Attributes are defined and used to create differentiated protection classes.

Up to date, most of approaches proposed for bandwidth reservation in MANETs assume cooperativeness among all nodes. However, in a public network where nodes are owned by different self-interested organizations, willingness to cooperate cannot be assumed. Selfishness of network nodes may cause not only failure of reservation but also degradation of overall networking performance. A mechanism of economic incentives is therefore needed to induce selfish nodes to participate in bandwidth reservation. In this paper, we propose a game theoretic framework based on Nash bargaining game from cooperative game theory. The framework solves the selfishness problem when reserving bandwidth in a forwarding node's neighborhood. We describe the network model in which this framework may be applied, as well as the computation of Nash equilibrium point, which can be considered as a pricing scheme that may obtain social optimality in reservation negotiations. Application of our framework can efficiently prevent network nodes from acting selfishly and therefore would improve the overall performance of the network.

The inclusion of multiple metrics in a routing computation is called policy-based routing. Previous work on solutions to this problem have focused on virtual-circuit-based solutions, and have resulted in computationally expensive algorithms. This paper presents a number of advances in the provision of policy-based routing services in networks and internetworks. An integrated policy-based routing architecture is formulated where the general problem is decomposed into a traffic engineering problem of computing routes in the context of administrative traffic constraints, and a quality-of-service (QoS) problem of computing routes in the context of performance-related path constraints. A family of routing algorithms are presented for computing routes in the context of these constraints which achieve new levels of computational efficiency. Lastly, a forwarding architecture is presented that efficiently supports hop-by-hop forwarding in the context of multiple paths to each destination, which is required for policy-based routing.

Energy use is a crucial design concern in wireless ad hoc networks. The design objectives of energy-aware routing include selecting energy-efficient paths and minimizing the protocol overhead incurred in acquiring such paths. To achieve these goals altogether, we present the design of two energy-aware on-demand routing protocols for different network environments. The key idea behind our design is to adaptively select the subset of nodes required to involve in a route-searching process to acquire a high residual-energy path or the degree to which nodes are required to participate in the process of searching for a low-power path for networks wherein nodes can adaptively adjust their transmission power: Analytical and simulation results are given to demonstrate the high performance of the designed protocols in energy-efficient utilization and in reducing the protocol overhead incurred in acquiring energy-aware routes.

We consider a variation of a constrained Steiner minimal tree problem that is applicable for multicast conferencing. We assume a network having a cost and delay values associated with each edge. Then, we find an optimal shared tree with minimal cost subject to the constraint that the delay between any two nodes of the tree must be bounded by some maximal value. Such a constraint on the delay is appropriate for an application such as a multicast conference that uses a shared tree. We consider a new heuristic algorithm for solving this problem. Our approach is inspired by Lagrangian relaxation techniques. We first develop a novel distance metric on trees, termed delta diameter. Using this metric, our algorithm then uses a Prim-like labeling algorithm coupled with the Takahashi Matsuyama Steiner tree algorithm. Simulation results show how cost and delay can be traded off smoothly. Using simulation, we also compare our heuristic with the optimal achievable. We believe that our approach is practical for dynamically building shared trees to support applications such as real-time video conferencing with delay constraints.

The next steps in signaling (NSIS) IETF working group has been recently created to design a generic IP signaling protocol supporting various signaling applications such as resource reservation and middle box configuration. This paper presents the generic signaling service protocol (GISP) we designed to contribute to the NSIS WG effort taking into consideration the current outputs of the working group. In particular, we focus on the state management and transport mechanisms of GISP.

We analyze the performance of E-limited scheduling in Bluetooth piconets under bursty traffic finite buffer case. We model the joint probability distributions of uplink and downlink queues using M[x]/G/1/K model and derive buffer blocking probabilities at slaves and at the master. Wd also derive access delays at slaves' buffers.

Two main approaches can be identified for QoS management, the first is oriented to infrastructure management and the second deals with alignment of service delivery with business objectives. This paper addresses the main issues arising under the second perspective. A critical issue is to provide an effective way to define and evaluate service level indicators. Two evaluation modes naturally arise: on-line and off-line. On-line methods compute indicators values when a related event occurs whereas off-line methods do at the end of a pre-defined assessment period. This work focuses on techniques for on-line evaluation of service level indicators. It presents an architecture for implementing service quality management (SQM) systems and the details of the mechanisms for on-line evaluation.

We show how integrated planning of wired and wireless infrastructures can be used to build a QoS-aware broadband infrastructure. The outset is a case study of the municipality of Hals, a rural community in Denmark, where the objective is to establish a broadband infrastructure reaching all households and businesses. Two factors are considered particularly important when designing an infrastructure: the chosen technology must allow for sufficient bandwidth, and the physical network structures must allow for independent paths between any pair of nodes. A final solution is obtained by using fiber to the home for primary connections and fixed wireless access for backup. This is implemented over 15 years, during which temporary solutions ensure sufficient QoS and reliability for all users. These temporary solutions form parts of the final solutions.

By constraining the output rate of mobile hosts in a cell via DiffServ configuration mechanisms, it is possible to keep 802.11 networks in a non-saturation state. We present a policy-based management solution for video streaming service provisioning and the system evaluation as a feasible alternative to contribute providing QoS in real time services in wireless environments. A prototype intended for proof of concept has been evaluated in a simulated WLAN making use of real video applications.

The IEEE 802.11 distributed coordination function (DCF) offers only best-effort service. The enhanced DCF (EDCF) scheme supports quality of service by establishing a probabilistic priority mechanism to access the shared wireless medium. EDCF defines four access categories, namely, AC.VO, AC-VI, AC-BE and AC-BK to support voice, video, best-effort and background traffic, respectively. Since DCF and AC_BE of EDCF offer best-effort service, it is desirable that applications demanding such a service, experience comparable delay and, throughput whether they are run on a DCF-compliant or an EDCF-compliant wireless station. In this paper, we show through simulation experiments that DCF-and EDCF-compliant stations do not provide comparable support to best-effort applications while operating together. This is due to different parameter settings in DCF and EDCF which leads to an undesirable service differentiation.

The tremendous growth of the Internet has introduced a number of interoperability problems for distributed multimedia applications. These problems are related to the heterogeneity of client devices, network connectivity, content formats, and user's preferences. The purpose of this paper is to present a framework for transcoding multimedia streams. The proposed infrastructure takes into consideration the profile of communicating devices, network connectivity, exchanged content format, context description, and available customization services to find a chain of services that could be applied to adapt the content to the required needed format. Part of the framework is a QoS-based selection algorithm that finds the best sequence of adaptation services which can maximize users' satisfaction with the delivered content.

3D character animation, as it applies to telling entertaining stories, requires a large amount data, but the need for the data is temporal, meaning it can be progressively loaded. The Internet transmission bottleneck may cause hesitation and pausing while that data is being transmitted, which lowers the perceived quality and possibly interrupts the story narrative. In this paper, we remove the hesitations by determining a ''preload time'' and transmitting the "important" data first heuristically, using "precedence lists".

A layered architecture for advanced collaborative environments has been developed to map the definition of a collaboration task from the requirements needed, to accomplish the task to the collaboration services that can be used to satisfy those needs, and to the technologies on which the services can be delivered. The architecture takes into account the users' goals and needs in configuring the services required for a collaboration task. By understanding and designing for users' needs and requirements, we can ensure a high quality of experience (QoE). The architecture was used to create a prototype system that is currently being tested through user studies.

This paper presents the design patterns and architecture of a testbed for the evaluation of quality of service (QoS) provisioning in WCDMA (wideband code division multiple access) based third generation wireless networks. The testbed allows for the evaluation of QoS adaptation techniques that supercedes to the traditional power control in the radio resource manager (RRM). It handles classes of service defined for the Universal Mobile Telecommunication System (UMTS), as well as mobility and handoffs.

With the increasing demands of mobile users for fast transmission of high quality multimedia over wireless networks, R&D on QoS for wireless multimedia has received a great deal of attention. Recently, we have developed an efficient request TDMA/CDMA protocol for wireless multimedia traffic support. In this paper, we generalize the analysis of the hybrid TDMA/CDMA protocols, and introduce several QoS factors such as non-constant user block rates and non-constant system timeout lengths. We also investigate the effect of QoS and scheduling on the generalized hybrid TDMA/CDMA protocol.

The IP Multimedia Subsystem (IMS) defined by the 3rd Generation Partnership Projects (3GPP and 3GPP2) represents today the global Service Delivery Platform (SDP) standard for providing multimedia applications in Next Generation Networks (NGN). It defines an overlay service architecture that merges the paradigms and technologies of the Internet with the cellular and fixed telecommunication worlds. The architecture enables the efficient provision of an open set of potentially highly integrated multimedia services, combining Web browsing, email, instant messaging, presence, VoIP, video conferencing, application sharing, telephony, unified messaging, multimedia content delivery, etc., on top of possibly different network technologies. Also interworking with the Internet and legacy networks is supported. As such the IMS enables various business models for providing seamless business and consumer multimedia applications. Knowing that the full potential of the IMS can only be revealed by the early nondiscriminant provision of IMS know how and related technologies to the different market players the Fraunhofer Institute FOKUS has launched the "Open IMS Playground" in July 2004 as part of the German 3G beyond national testbed. This paper introduces the IMS standard and provides an overview of the "Open IMS playground @ FOKUS".

The introduction of advanced features, provided by the emerging next generation networks based on the Generalized Multiprotocol Label Switching (GMPLS) protocol framework in grid computing systems, promises to significantly improve the performance of distributed applications and services. An accurate experimental analysis of the main GMPLS features, such as the different reliability solutions, is then required. In this paper, we present the experimental implementation of different reliability solutions in the Metrocore/VESPER field trial, the high-performance network infrastructure located in Pisa, Italy. Protection and restoration schemes are investigated both at the IP/MPLS and physical layer.

The complexity of today's data communication networks necessitates complete, realistic and sophisticated testing grounds for verifying and validating their functionality. Network testing grounds are restricted to laboratories and environments isolated from real life scenarios. Testing in production and commercial networks is typically forbidden since they present a high degree of risk factors for service availability. Additionally, the majority of today's communication network testbeds lack the scale and flexibility needed to properly represent a true networking environment. Before deploying live networks there is a need to have a network testing environment scalable and flexible enough where issues such as: network design, vendor interoperability, endurance, multiprotocol layer interconnectivity, a vendor's specific implementations of standards and network design viability have been verified to meet the requirements. In this paper a design and implementation of a next generation network is described, where both testing and production traffic coexist. NCIT*net 2 is an optical transmission network supporting end-to-end services over technologies such as Ethernet, SONET, MPLS and DWDM. The paper also discusses key technology aspects related to the functionality of equipment and network from a service point of view. These include the physical layer and network operation, as well as architecture and control. The testbed network is used for the deployment of networking services over the above technologies in order to verify service implementation, provisioning and assurance of quality of service requirements. This network also allows testing and evaluating systems, subsystems and components from different vendors in various interconnections. The paper goes further to describe, as an example, the tests designed and implemented for the analysis of MPLS based services over next generation networks.

People interested in Cultural Heritage constitute a community of users characterized by a high degree of mobility. Users visiting cultural sites hosted by local institutions expect to access information pertaining to cultural/artistic heritage from anywhere at anytime, as they can through the desk at their own homes or offices. The Ecumene Web Information System, developed in the groundwork of the Ecumene Project, offers a framework for accessing the artistic and cultural information through a Web application. In this paper, we expose the underlying communication network architecture, based on the IPv6 protocol and investigate the benefits of its adoption, in terms of mobility and security support. Indeed, the need of granting different access rights to different user classes enforces the security requirements of the system. Lastly, the open issues related to the practical integration of an experimental testbed with Mobile IPv6 and IPSec support are detailed and possible solutions are presented.

The CREATE-NET testbed is a long term project aiming at implementing a best state-of-the-art infrastructure able to link together research centers, both from academia and industrial bodies, in order to create a fruitful collaborative environment to help generating new ideas for advanced applications and services, developing new protocols, testing and integrating different vendor equipments. This testbed is aimed to be unique as it covers novel topics such as optical and wireless integration and WiMAX experimentation for offering broadband access to rural communities. In this paper we present both the technical design issues and a general outline of the implementation process.

The National Institute of Information and Communications Technology of Japan completed a real-life testbed, called the "ubiquitous home", for home context-aware service experiments in 2004. From the viewpoint of sensor ubiquity, the Ubiquitous Home is superior to other similar testbeds. At the Ubiquitous Home, experimenters can collect real-life data as if living in their own house, not in a laboratory. This paper introduces an overview and detailed sensor arrangement of the Ubiquitous Home. Two cases from several progressing experiments are also presented. The first case is on connecting networked appliances; the second concerns the combination of wearable devices and the Ubiquitous Home sensors to record user behavior.

Core to ubiquitous computing environments are adaptive software systems that adapt their behavior to the context in which the user is attempting the task the system aims to support. This context is strongly linked with the physical environment in which the task is being performed. The efficacy of such adaptive systems is thus highly dependent on the human perception of the provided system behavior within the context represented by that particular physical environment and social situation. However, effective evaluation of human interaction with adaptive ubiquitous computing technologies has been hindered by the cost and logistics of accurately controlling such environmental context. This paper describes TATUS, a ubiquitous computing simulator aimed at overcoming these cost and logistical issues. Based on a 3D games engine, the simulator has been designed to maximize usability and flexibility in the experimentation of adaptive ubiquitous computing systems. We also describe how this simulator is interfaced with a testbed for wireless communication domain simulation.