Cláudia J. Barenco Abbas

Routing Protocols in Wireless Sensor Networks

The applications of wireless sensor networks comprise a wide variety of scenarios. In most of them, the network is composed of a significant number of nodes deployed in an extensive area in which not all nodes are directly connected. Then, the data exchange is supported by multihop communications. Routing protocols are in charge of discovering and maintaining the routes in the network. However, the appropriateness of a particular routing protocol mainly depends on the capabilities of the nodes and on the application requirements. This paper presents a review of the main routing protocols proposed for wireless sensor networks. Additionally, the paper includes the efforts carried out by Spanish universities on developing optimization techniques in the area of routing protocols for wireless sensor networks.

A modular architecture for distributed IDS in MANET

In this paper we propose a distributed and modular architecture for an intrusion detection system (IDS) dedicated to a mobile ad hoc network (MANET) environment. The main feature of our proposition relies on the use, on each node of the MANET, of a local IDS (LIDS) cooperating with other LIDSes through the use of mobile agents. The modular design is needed as a response to the extensibility requirements related to the complex contexts of MANET. The proposed solution has been validated by a proof-of-concept prototype, which is described in the paper. Two different types of attacks are presented and have been implemented, at the network level and at the application level. The detection of such attacks are formally described by specification of data collection, attack signatures associated with such data and alerts generation, emphasizing the relation of each of these detection steps with the modules in the designed architecture. The use of the management information base (MIB) as a primary data source for the detection process is discussed and modules for MIB data extraction and processing are specified and implemented in the prototype. Experiments exhibit fairly good results, the attacks being collaboratively detected in real-time.

A distributed QoS mechanism for ad hoc network

This paper presents a new mechanism of QoS Medium Access in ad hoc IEEE 802.11 network. The Distributed Coordination Function Ad Hoc (DCFAH) offers a fair medium access mechanism and a minimum bandwidth to all stations that ask for Quality of Service (QoS). Also is concerned about the delay and jitter metrics. The DCFAH uses the Enhanced Distributed Channel Access (EDCA) mechanism to provide the difference of QoS services among flows inside a station. The fairness of DCFAH is provided with the use of a distributed control mechanism during the QoS period. The DCFAH also provides the Best Effort (BE) service to applications that do not need QoS.

Load Balancing and Survivability for Network Services Based on Intelligent Agents

This paper describes the functionalities and the implementation of a load balancing scheme with fault tolerance characteristics to guarantee the survivability of a web service using intelligent agents technology. In this proposed model, agents are responsible for the automatic reconfiguration a traffic load balancer for web servers by exchanging information related to availability and workload and using an agent communication language. Besides this feature, with the objective of the network service survival, the intelligent agents monitor the load balancer and may assume its functions in case of failure and thus keeping the network service available.

Survivability for a Network Service and Load Balancing Using Intelligent Agents Software

This paper describes the functionalities and the implementation of a load balancing structure with fault tolerance characteristics to guarantee the survivability of a web service using intelligent agents technology. The developed agents are responsible for the automatic reconfiguration of a traffic load balancer for web servers by exchanging information related to availability and workload and using an ACL (agent communication language). The developed agents also monitor the load balancer and may assume its functions in case of failure and thus keeping the network service available with the objective of the network service survival.

Monitoring of Data Centers using Wireless Sensor Networks

As data center energy densities, measured in power per square foot, increase, energy savings for cooling can be carried out by applying WSN technology and using the gathered information to efficiently manage the data center.

Proposal of a system for searching and indexing heterogeneous vulnerabilities databases

This paper describes the project and implementation of a vulnera-bility search and alert system based on free software. SisBrAV (acronym in Portuguese for Brazilian Vulnerability Alert System), will consist in a spider mechanism that explores several security-related sites for information on vulnerabilities and an intelligent interpreter responsible for analyzing and sorting the relevant data, feeding it into a database. With that information in hands, an email notifier sends out alerts, in Portuguese, about new vulnerabili-ties to registered clients, according to the operating systems and services run in their environment. In addition to the email notifier, a web server will also be implemented, for systems administrators to perform an on-demand custom search in the vulnerabilities database.

A Simulation-Based Performance Analysis of Dynamic Routing Protocols for Mobile Ad Hoc Networks

This work will show a comparative performance analysis of the DSR, AODV, and OLSR dynamic routing protocols for Mobile Ad Hoc Networks (known as MANET). We utilize the Network Simulator (NS) version 2 to simulate a mobile network environment under different circumstances of average node mobility and network traffic volume. This way, we quantitatively evaluated protocols performance.

Network Dependability: An Availability Measure in N-Tier Client/Server Architecture

Published work on computer network reliability frequently uses availability as a dependability measure. However, although several ways of defining availability have been proposed, none capture the overall level of service obtained by client hosts in a modern n-tier client/server architecture. We propose such a measure by calculating the fraction of client hosts receiving complete services from the network. We also extend a published efficient heuristic method for calculating availability to take into account our new proposed measure. The end result is a procedure of polynomial complexity O(n t 4), where n t is the total number of components (hosts, links and interconnection equipment) in the network.

Why not RSVP over DTM

This paper suggests the use of the DTM technology as a solution to the transmission of applications with strict need of bandwidth, instead of the use of the traditional ATM technology. The DTM is a broadband network architecture based on synchronous fast circuit switching solution with a constant delay, perfect to the telephony network which is optimized for the characteristics of voice communication, that is, fixed-sized channels and provision of QoS real-time guarantees. Furthermore, the users require access to new services like audio, video and data which is discussed in this paper by proposing the IETF IntServ and the DTM integration supporting dynamic allocation of resources in a circuit switching network. An overview of the integration of the IntServ guaranteed service/RSVP protocol with the DTM technology on the signalling, reservation and management of the allocated bandwidth before the DTM channel establishment is presented.