Andrea Zanardi

A distributed network monitoring framework for wireless networks

Multi-hop wireless networks are emerging as a viable alternative for building access networks in areas where conventional solutions (cellular, fiber) are neither feasible nor attractive from an economical standpoint. The management of such networks represents an overly complex task because of the time-varying nature of the radio channel, the mobility of users and the presence of adaptive, self-configuration features. Various solutions are currently being researched, whereby network management functionalities are performed autonomously at the network nodes themselves. Such approaches require a monitoring framework able to bring network-level information to the relevant decision points in an effective and robust manner. In this paper, we present a distributed network monitoring framework, specifically developed for wireless multi-hop networks. The system architecture and the protocols are presented together with results obtained using a prototypical implementation over a real-world testbed. Experimental results show that the framework generates a limited amount of traffic, and that the system is able to consistently recover from node failures.

YAMATO: The First SDN Control Plane for Independent, Joint, and Fractional-Joint Switched SDM Optical Networks

The deployment of space division multiplexed (SDM) optical networks hinges on this technology being able to offer a beneficial ratio between the expected capacity gains and the resulting cost increase. In order to keep the cost of SDM low, several integrated devices have been proposed to perform the functions of transmission, reception, amplification, and switching; however, little or no work has been carried out in creating a network model to represent their behavior, and in actually managing and controlling them, especially with respect to those devices that are able to jointly switch multiple spatial dimensions. This paper describes YAMATO, the first control plane designed to handle any type of SDM fiber and switching paradigm. To do so, we present a network model capable of encoding any SDM link and node, and describe the design and functions of our network controller, which is based on the OpenDaylight framework. Furthermore, we investigate the additional complexity faced by optical restoration schemes for SDM compared to standard optical networks. We experimentally evaluate the proposed system via an emulated testbed, and report some performance measurements of our implementation.

Toward a control and management system enabling cognitive optical networks

Cognition represents one of the ingredients to make up the future high-capacity heterogeneous optical networks. This paper provides three main contributions for a preliminary study of a Control and Management System (CMS) able to support the cognitive entity, named Cognitive Decision System (CDS). First of all, two architectural approaches to realize a cognitive optical network are presented. Secondly, the focus is set on the description of a centralized GMPLS-based CMS architecture and on the interactions between its modules and the CDS. In particular, the CDS decisions rely on a database updated by CMS protocols (i.e., by OSPF - TE) to grasp information about network configuration and resources availability. Unfortunately, OSPF - TE may not be able to timely update the CDS-database. To address this issue, the paper presents two CDS-database updating policies and compares their performance through simulations. Finally, a set of open issues and challenges is detailed in order to provide an input for a deep analysis of the presented CMS architecture.

Network topology visualization and monitoring for multi-hop wireless networks

Multi-hop wireless systems represent a viable means for deploying access networks covering medium-size areas with limited investment, making use of commodity hardware and freely available software suites. At the same time, management of such networks represent an overly complex task, due to the joint effect of the time-varying nature of the radio channel, user mobility and the inherently distributed nature of the system.

NICER: A distributed dynamic shared-backup path-allocation procedure for transmission-impaired WDM optical networks

Survivability in transparent optical networks is a critical concern for network operators. Current survivability techniques for shared protection are mainly based on a centralized off-line pre-planning of the lightpaths. In addition, the presence of Physical Layer Impairments (PLIs) and multi-channel effects must be accurately considered. In this paper we propose a distributed on-line procedure called NICER to allocate shared backup capacity in transmission-impaired optical transparent networks. To this account, we present the on-line algorithms useful to setup the Label Switched Paths (LSPs) in a Generalized MPLS (GMPLS) controlled network and to choose the wavelengths to be eventually shared by the backup lightpaths, given the information about the PLIs distributed in the network. Furthermore, through some simulations we show the performance of the proposed survivability procedure.