Robust Energy Management for Green and Survivable IP Networks

Despite the growing necessity to make Internet greener, it is worth pointing out that energy-aware strategies to minimize network energy consumption must not undermine the normal network operation. In particular, two very important issues that may limit the application of green networking techniques concern, respectively, network survivability, i.e. the network capability to react to device failures, and robustness to traffic variations. We propose novel modelling techniques to minimize the daily energy consumption of IP networks, while explicitly guaranteeing, in addition to typical QoS requirements, both network survivability and robustness to traffic variations. The impact of such limitations on final network consumption is exhaustively investigated. Daily traffic variations are modelled by dividing a single day into multiple time intervals (multi-period problem), and network consumption is reduced by putting to sleep idle line cards and chassis. To preserve network resiliency we consider two different protection schemes, i.e. dedicated and shared protection, according to which a backup path is assigned to each demand and a certain amount of spare capacity has to be available on each link. Robustness to traffic variations is provided by means of a specific modelling framework that allows to tune the conservatism degree of the solutions and to take into account load variations of different magnitude. Furthermore, we impose some inter-period constraints necessary to guarantee network stability and preserve the device lifetime. Both exact and heuristic methods are proposed. Experimentations carried out with realistic networks operated with flow-based routing protocols (i.e. MPLS) show that significant savings, up to 30%, can be achieved also when both survivability and robustness are fully guaranteed

Energy management in communication networks: a journey through modelling and optimization glasses

The widespread proliferation of Internet and wireless applications has produced a significant increase of ICT energy footprint. As a response, in the last five years, significant efforts have been undertaken to include energy-awareness into network management. Several green networking frameworks have been proposed by carefully managing the network routing and the power state of network devices. Even though approaches proposed differ based on network technologies and sleep modes of nodes and interfaces, they all aim at tailoring the active network resources to the varying traffic needs in order to minimize energy consumption. From a modeling point of view, this has several commonalities with classical network design and routing problems, even if with different objectives and in a dynamic context. With most researchers focused on addressing the complex and crucial technological aspects of green networking schemes, there has been so far little attention on understanding the modeling similarities and differences of proposed solutions. This paper fills the gap surveying the literature with optimization modeling glasses, following a tutorial approach that guides through the different components of the models with a unified symbolism. A detailed classification of the previous work based on the modeling issues included is also proposed

Recognizing Emergencies and Multi-User Behavior Patterns Using Imperfect Data From Distributed Access Points. A Non-Intrusive Proof of Concept

This paper presents a privacy-preserving proof of concept for assessing human behavior in emergency scenarios using aggregated data from multiple WiFi access points. The proposed method focuses on preserving individual privacy by avoiding tracking and metadata analysis, while still achieving effective multi-user activity recognition. To implement our approach, raw data from the Eduroam WiFi network at Polytechnique Montreal was collected and analyzed using standard supervised and anomaly detection techniques. The initial test was on recognizing patterns of academic activity, serving as the foundation for our investigation. Subsequently, the same methodology was applied during an evacuation drill scenario to recognize anomaly situations. Through our research, we demonstrate the potential to assess human situations effectively while safeguarding privacy, providing a critical capability for the early detection of emergency situations

OSPF optimization via dynamic network management for green IP networks

none4In this paper we present a novel experimental platform for network management able to dynamically optimize the energy consumption of backbone IP networks operating with OSPF. The idea is to efficiently adjust link weights to put to sleep idle devices. The framework relies on multiple precomputed sets of link weights that are applied to the considered network domain according to real time measurements on the link utilization. The management module exploits the Simple Network Management Protocol (SNMP) to collect the load measurements and modify the link weights. The pre-computed link weights are calculated by running a state-of-the-art algorithm for off-line energy-aware traffic engineering based on predicted traffic matrices. The modules of the platforms have been implemented for Linux based environments and tested using emulated networks of virtual machines. Experimental results showed a significant reduction in terms of network resources required to route traffic demands, demonstrating how, in average, 20% of nodes and 40% of links, can be put to sleep without compromising network performance and stability.A. Capone; C. Cascone; L.G. Gianoli; B. SansoCapone, Antonio; Cascone, Carmelo; Gianoli, LUCA GIOVANNI; B., Sans

A robust optimization approach for energy-aware routing in MPLS networks

A robust multi-period model is proposed to minimize the energy consumption of IP networks, while guaranteeing the satisfaction of uncertain traffic demands. Energy savings are achieved by putting into sleep mode cards and chassis. The study of the solution robustness shows that there is a trade-off between energy consumption and the solutions conservatism degree. The model allows this trade-off to be tuned by simply modifying a single parameter per link. The multi-period optimization is constrained by inter-period limitations necessary to guarantee network stability. Both, exact and heuristic methods are proposed. Results show that up to 60% of the energy savings can be achieved for realistic test scenarios in networks operated with flow-based routing protocols (i.e. MPLS) and with a good level of robustness to traffic variations

On the Design of Fault-Tolerant Logical Topologies In Wavelength-Routed Networks supporting Packet Datagrams

In this paper we present a new methodology for the design of fault-tolerant logical topologies in wavelengthrouted optical networks supporting IP datagram flows. Our design approach generalizes the "design protection" concepts, and relies on the dynamic capabilities of IP to reroute datagrams when faults occur, thus achieving protection and restoration, and leading to high-performance costeffective fault-tolerant logical topologies. In this paper for the first time we consider resilience properties during the logical topology optimization process, thus extending the optimization of the network resilience also to the space of logical topologies. Numerical results clearly show that our approach outperforms previous ones, being able to obtain very effective survivable logical topologies with limited computational complexity