Abstract
The Internet is characterized by the coexistence of two Internet Protocol (IP) versions and multiple autoconfiguration mechanisms which are deployed targeting specific communication scenarios. This heterogeneity requires user pre-configurations, namely with respect to the proper autoconfiguration mechanism to be used at each time. On the other hand, future networks may imply that users own personal networks demanding self-configuration and self-management, and being part of very dynamic scenarios. In this paper we make a survey of the autoconfiguration mechanisms available for IP networks, and argue that a new solution is needed, so that the proper autoconfiguration mechanism can be selected automatically, dynamically and efficiently, and future communication paradigms can be properly addressed. Copyright 2005 ACM.

Abstract
Wireless Mesh Networks (WMNs), which feature infrastructureless broadband network configurations, are attracting attention as an elemental technology when it comes to the extension of current WLAN infrastructures. State of the art solutions addressing WMNs usually assume the use of omnidirectional antennas. In this paper we evaluate the performance improvements obtained when using directional antennas. By using simulations, we analyze the gains in terms of throughput, delay and fairness, considering a grid network topology used to extend an infrastructure network. Simulation results show that by changing the type of antenna in use from omnidirectional to directional, the average throughput of a WMN can increase about 56% and the average network delay can be reduced by approximately 40%, without compromising fairness. © 2010 IEEE.

Abstract
In the Next Generation Networks (NGNs) users will carry multiple devices forming cooperative networks known as Personal Area Networks (PANs). Some existing technologies enable this type of networks, such as Bluetooth or IEEE 802.15.4, but a unified framework capable of self-organizing them dynamically in a full heterogeneous environment populated by these and other technologies still has to be defined. Also, these networks are envisioned to be connecting dynamically to the Internet, and may use two IP versions and their autoconfiguration mechanisms. In this paper we propose a new framework, the Autoconfiguration and Self-management of Personal Area Networks (ASPAN), which enables the automatic and dynamic deployment of PANs in the heterogeneous environments envisioned for NGNs and handles the automatic and dynamic connection of a PAN to the global Internet. Copyright 2006 ACM.

Abstract
Communication networks have been developed based on two networking approaches: bridging and routing. The convergence to an all-Ethernet paradigm in Personal and Local Area Networks and the increasing heterogeneity found in these networks emphasizes the current and future applicability of bridging. When bridging is used, a single active spanning tree needs to be defined. A Minimum Routing Cost Tree is known to be the optimal spanning tree if the probability of communication between any pair of network nodes is the same. Given that its computation is a NP-hard problem, approximation algorithms have been proposed. We propose a new approximation Minimum Routing Cost Tree algorithm. Our algorithm has time complexity lower than the fastest known approximation algorithm and provides a spanning tree with the same routing cost in practice. In addition, it represents a better solution than the current spanning tree algorithm used in bridged networks.

Abstract
The changes in the communication paradigm envisioned for future networks, with peer-to-peer/symmetric attachments gaining momentum and two IP (Internet Protocol) versions coexisting, will pose new challenges to mobile communication networks. Traditional IP auto-configuration mechanisms will not work properly, since they were designed mostly having in mind a client-server/asymmetric attachment model, they assume a single IP version paradigm, and they target the auto-configuration of devices only. The IST Ambient Networks project has introduced a new concept - the Ambient Network - that enables handling every communication entity, either a single device or an entire network, as an Ambient Network (AN). This paper describes a new efficient mechanism, named Basic Connectivity (BC) mechanism, for auto-configuring IP connectivity between attaching ANs. A proof-of-concept prototype, experimental results, and theoretical analysis show that BC suites the future networking paradigm and represents a solution more efficient than the current trial-and-error mechanism for auto-configuring IP connectivity.

Abstract
The changes in the communication paradigm envisioned for next-generation networks (NGNs), with peer-to-peer/symmetric attachments gaining momentum and two Internet Protocol (IP) versions coexisting, will pose new challenges to mobile communication networks. Traditional IP auto-configuration mechanisms will not work properly, since they were designed mostly having in mind a client-server/asymmetric attachment model, they assume a single IP version paradigm, and they target the auto-configuration of devices only. The IST Ambient Networks (ANs) project has introduced a new concept the AN that enables handling every communication entity, either a single device or an entire network, as an AN. This paper describes a new efficient mechanism, named Basic Connectivity (BC) mechanism, for auto-configuring IP connectivity between attaching ANs. A proof-of-concept prototype, experimental results, and theoretical analysis show that BC suites the future networking paradigm and represents a solution more efficient than the current trial-and-error mechanism for auto-configuring IP connectivity. Copyright (C) 2009 John Wiley & Sons, Ltd.