A Survey on Handover Management in Mobility Architectures

This work presents a comprehensive and structured taxonomy of available techniques for managing the handover process in mobility architectures. Representative works from the existing literature have been divided into appropriate categories, based on their ability to support horizontal handovers, vertical handovers and multihoming. We describe approaches designed to work on the current Internet (i.e. IPv4-based networks), as well as those that have been devised for the "future" Internet (e.g. IPv6-based networks and extensions). Quantitative measures and qualitative indicators are also presented and used to evaluate and compare the examined approaches. This critical review provides some valuable guidelines and suggestions for designing and developing mobility architectures, including some practical expedients (e.g. those required in the current Internet environment), aimed to cope with the presence of NAT/firewalls and to provide support to legacy systems and several communication protocols working at the application layer

Mobile Computing in Digital Ecosystems: Design Issues and Challenges

In this paper we argue that the set of wireless, mobile devices (e.g., portable telephones, tablet PCs, GPS navigators, media players) commonly used by human users enables the construction of what we term a digital ecosystem, i.e., an ecosystem constructed out of so-called digital organisms (see below), that can foster the development of novel distributed services. In this context, a human user equipped with his/her own mobile devices, can be though of as a digital organism (DO), a subsystem characterized by a set of peculiar features and resources it can offer to the rest of the ecosystem for use from its peer DOs. The internal organization of the DO must address issues of management of its own resources, including power consumption. Inside the DO and among DOs, peer-to-peer interaction mechanisms can be conveniently deployed to favor resource sharing and data dissemination. Throughout this paper, we show that most of the solutions and technologies needed to construct a digital ecosystem are already available. What is still missing is a framework (i.e., mechanisms, protocols, services) that can support effectively the integration and cooperation of these technologies. In addition, in the following we show that that framework can be implemented as a middleware subsystem that enables novel and ubiquitous forms of computation and communication. Finally, in order to illustrate the effectiveness of our approach, we introduce some experimental results we have obtained from preliminary implementations of (parts of) that subsystem.Comment: Proceedings of the 7th International wireless Communications and Mobile Computing conference (IWCMC-2011), Emergency Management: Communication and Computing Platforms Worksho

Model Predictive Control for Building Active Demand Response Systems

The Active Demand Response (ADR), integrated with the distributed energy generation and storage systems, is the most common strategy for the optimization of energy consumption and indoor comfort in buildings, considering the energy availability and the balancing of the energy production from renewable sources. In the paper an overview of basic requirements and applications of ADR management is presented. Specifically, the model predictive control (MPC) adopted in several applications as optimal control strategy in the ADR buildings context is analysed. Finally the research experience of the authors in this context is described

"Always Best Packet Switching" for SIP Services

none3We describe a distributed architecture for the provision of seamless and responsive mobile multimedia services. The architecture allows mobile applications to use concurrently all the wireless Network Interface Cards (NICs) a mobile terminal is equipped with. In particular, it enables the transmission of each datagram through the “most suitable” NIC among those available. We term this operating mode Always Best Packet Switching (ABPS). The ABPS architecture exploits a fixed proxy server, which acts as a relay for the mobile node and enables communications regardless of possible firewalls/NATs, together with a proxy client in the mobile node, responsible for maintaining a multi-path tunnel with the fixed proxy server. Experimental results show the effectiveness of our approach.mixedV. Ghini; S. Ferretti; F. PanzieriGhini, V.; Ferretti, S.; Panzieri, F

The Implementation of Middleware Services for QoS-aware Distributed Multimedia Applications

ABSTRACT In this paper we address issues of design of middleware services that can meet effectively application-level (i.e., end-to-end) QoS requirements of Interact-based, latency-sensitive multimedia applications. In this context, we describe a set of adaptive middleware services that we have developed, based on a commercial middleware platform, in order to support an IP-based telephony application over the Interact; in addition, we summarize the performance results we have obtained from a prototype implementation of these services

Server Consolidation in Clouds through Gossiping

Abstract—The success of Cloud computing, where computing power is treated as a utility, has resulted in the creation of many large datacenters that are very expensive to build and operate. In particular, the energy bill accounts for a significant fraction of the total operation costs. For this reason a significant attention is being devoted to energy conservation techniques, for example by taking advantage of the built-in power saving features of modern hardware. Cloud computing offers novel opportunities for achieving energy savings: Cloud systems rely on virtualization techniques to allocate computing resources on demand, and modern Virtual Machine (VM) monitors allow live migration of running VMs. Thus, energy conservation can be achieved through server consolidation, moving VM instances away from lightly loaded computing nodes so that they become empty and can be switched to low-power mode. In this paper we present V-MAN, a fully decentralized algorithm for consolidating VMs in large Cloud datacenters. V-MAN can operate on any arbitrary initial allocation of VMs on the Cloud, iteratively producing new allocations that quickly converge towards the one maximizing the number of idle hosts. V-MAN uses a simple gossip protocol to achieve efficiency, scalability and robustness to failures. Simulation experiments indicate that, starting from a random allocation, V-MAN produces an almost-optimal VM placement in just a few rounds; the protocol is intrinsically robust and can cope with computing nodes being added to or removed from the Cloud. I