Enrique Vázquez

Anomaly-based network intrusion detection: Techniques, systems and challenges

The Internet and computer networks are exposed to an increasing number of security threats. With new types of attacks appearing continually, developing flexible and adaptive security oriented approaches is a severe challenge. In this context, anomaly-based network intrusion detection techniques are a valuable technology to protect target systems and networks against malicious activities. However, despite the variety of such methods described in the literature in recent years, security tools incorporating anomaly detection functionalities are just starting to appear, and several important problems remain to be solved. This paper begins with a review of the most well-known anomaly-based intrusion detection techniques. Then, available platforms, systems under development and research projects in the area are presented. Finally, we outline the main challenges to be dealt with for the wide scale deployment of anomaly-based intrusion detectors, with special emphasis on assessment issues.

A Simulation Tool for Dimensioning and Performance Evaluation of the UMTS Terrestrial Radio Access Network

The efficient support of multiple traffic classes with different quality of service requirements (end-to-end delay, jitter, loss) poses an extraordinary complexity in the design of third-generation mobile networks. This task becomes especially critical for the access network, where radio and transmission resources are usually scarce. In this paper we present a simulation model of the ATM-based UMTS (Universal Mobile Telecommunications System) terrestrial radio access network. The simulator aims to provide a test bed for conducting further research studies on several topics of potential interest. In particular, we intend to use the tool for dimensioning ATM links, for evaluating performance under different mixes of traffic classes, and for investigating quality of service mechanisms. This wide range of applications has led us to develop a very flexible simulation model that captures many low level details. Some preliminary results obtained with the simulator are presented in order to illustrate its capabilities.

Simulation of quality of service mechanisms in the UMTS terrestrial radio access network

Supporting multiple traffic classes with different QoS (quality of service) constraints in third generation mobile systems is not a straightforward problem. This issue becomes critical at the access network interfaces, where transmission resources are usually expensive. One of the most important interfaces is the one that connects each base station with its controller, because there can be many instances of it. We have approached the dimensioning of this interface from the perspective of simulation, concretely for the UMTS (Universal Mobile Telecommunications System) access network. We have developed a simulation model capable of representing multi-service scenarios inside this particular UTMS interface. This tool can be fed with traffic of different types, representing the different traffic classes defined for UMTS, and is able to simulate traffic differentiation both at the ATM (Asynchronous Transfer Mode) and the AAL2 (ATM Adaptation Layer 2) level. We present simulation results showing how the simulator can aid us in the task of access network dimensioning with QoS constraints.

Performance modeling of web access over HSPA networks

HSPA (High Speed Packet Access) technologies have become an attractive solution for broadband wireless Internet access. This article evaluates the quality of service experimented by one HSPA user in the presence of multiple terminals sharing the cell capacity. The study focuses on Web traffic and includes analytical and simulation results, providing a basis for dimensioning and admission control in HSPA networks given the intended user quality of experience. The results show that the downlink channel capacity can be shared by several tens of Web users with a satisfactory quality. This is possible because the activity factor of this application (i.e. the time spent in downloading pages compared to the time spent in reading them) is low. However, the results also indicate that the page download time is penalized by the delay associated with the initial procedure for allocating resources on the traffic channels. This problem can be alleviated by an adequate configuration of the timers associated to the resource allocation procedures in HSPA.

Io: An Estelle Simulator for Performance Evaluation

Abstract This paper describes a performance simulation tool based on Estelle. Estelle is a Formal Description Technique designed to specify the behavior of concurrent systems, in particular communication protocols. It is based on a state machine model extended with Pascal-like data structures and statements. Currently, Estelle is an International Standard of the International Standards Organization (ISO), and several development tools such as syntax-directed editors, compilers, and debuggers are available in the research community. The main objective of the tool described here is to integrate the evaluation of performance with other aspects of protocol development (validation, rapid-prototyping, etc) using common protocol models and tools for all of them. The paper deals with practical aspects of simulation with Estelle, such as the use of the language to write simulation models, the tool features and its current status. A theoretical discussion about the applicability of formal description techniques to performance simulation, although important, is considered outside the scope of this paper.

Smart CEI Moncloa: An IoT-based Platform for People Flow and Environmental Monitoring on a Smart University Campus

Internet of Things platforms for Smart Cities are technologically complex and deploying them at large scale involves high costs and risks. Therefore, pilot schemes that allow validating proof of concepts, experimenting with different technologies and services, and fine-tuning them before migrating them to actual scenarios, are especially important in this context. The IoT platform deployed across the engineering schools of the Universidad Politécnica de Madrid in the Moncloa Campus of International Excellence represents a good example of a test bench for experimentation with Smart City services. This paper presents the main features of this platform, putting special emphasis on the technological challenges faced and on the solutions adopted, as well as on the functionality, services and potential that the platform offers.

Network Convergence over MPLS

Multiprotocol Label Switching (MPLS) is emerging as a flexible technology that can transport voice, IPv4, IPv6, layer 2 services (Frame Relay, ATM, Ethernet, etc.), and even PDH and SDH/SONET circuits over a single packet infrastructure, in a new attempt to solve the old problem of network convergence. MPLS traffic engineering, quality of service support (in combination with DiffServ), and fast restoration capabilities can be used to provide each service with strict service-level agreements (SLAs) in a cost- efficient way. Several standardization and industry organizations are contributing to this goal. This article reviews current activities in the IETF, MPLS/Frame Relay Alliance, and ITU-T related to transport over MPLS, comparing their approaches, identifying overlaps, and open issues.

Experiences with middleware and mobile agents in an e-commerce European project

This paper presents several experiences and conclusions about the usage of the J2EE middleware platform in an e-commerce mediation framework, and introduces mobile agent possibilities within the same environment. The main conclusions are taken from the Smart-EC project, where J2EE and mobility are considered as a value added in its architecture. Other advanced technologies such as XML based multi-device publishing and the utilisation of e-commerce ontologies to handle static and dynamic aspects of complex services or to control their transactional properties, are also considered in the project.

Performance Evaluation of a Buffered ATM Connectionless Server

In an ATM-based network it is foreseen that connectionless traffic will be handled by Connectionless Servers (CLSs) interconnected to each other and to the users via semi-permanent connections, forming a Connectionless Overlay Network. This paper discusses the necessity of frame-level buffering in the CLSs in order to meet the connectionless service requirements, in particular the maximum allowed frame loss ratio, with a reasonable utilization of network resources. The frame loss and delay performance of a buffered CLS are evaluated both by analysis and by simulation, showing the utilization improvements that can be achieved with properly dimensioned CLS buffers.

Modelling and formal specification of the real-time manufacturing automation protocol

This paper describes the application of the standard formal description technique Estelle to the modelling and specification of the manufacturing automation protocol three-layer architecture (real-time MAP). The paper discusses the real-time requirements that must be met by communication protocols operating in manufacturing plants, and shows how the Estellle language can be used to specify such protocols formally, including aspects that are crucial in real-time environments, e.g. time constraints, priorities, etc. The formal specification presented here includes the SDA (send data with acknowledgement) service and a deterministic access method for a field bus using token-passing (IEEE 802.4). It has been developed with the Estelle workstation, a set of Estelle-based tools developed in the Esprit Project Sedos Estelle Demonstrator (ESPRIT P1265). The use of Estelle and its associated tools allows not only the formalization of a protocol (uncovering possible ambiguities, logical errors, etc), but also the automatic prototyping, testing, and, eventually, implementation of the protocol. Not less important, the formal specification provides a flexible framework to design new functions, analyze different system configurations or design choices, etc.<<ETX>>