Pedro Sousa

Pedro Sousa
University of Minho · Departamento de Informática (DI)

PhD

About

88
Publications
12,520
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559
Citations
Introduction
Pedro Sousa graduated in Systems and Informatics Engineering at the University of Minho, Portugal, in 1995. He obtained a MSc Degree (1997) and a PhD Degree (2005), both in Computer Science, at the same University. In 1996, he joined the Computer Communications Group of the Department of Informatics at University of Minho, where he is an Assistant Professor and performs his research activities within the Algoritmi R&D Center. For research areas/publications visit: http://marco.uminho.pt/~pns
Additional affiliations
January 1998 - present
University of Minho

Publications

Publications (88)
Conference Paper
This paper aims to tackle the frictions between user applications and the physical infrastructure where they reside. In the face of rising network traffic and stricter application demands, a better understanding is needed on how ISPs should manage their resources, and likewise how applications need to act, so the Internet of the future can run acco...
Conference Paper
Segment Routing (SR) is an implementation of Software-Defined Networking (SDN) for traffic routing. It derives from a source routing paradigm where each node, at the network's periphery, adds a list of labels to the packet's header defining explicitly the path each traffic flow should follow to its destination. Each label is a segment that identifi...
Article
Full-text available
(view only version available at https://rdcu.be/b820L) Traffic engineering approaches are increasingly important in network management to allow an optimized configuration and resource allocation. In link-state routing, setting appropriate weights to the links is an important and challenging optimization task. Different approaches have been put for...
Conference Paper
This paper presents an overview, proof of concept, and a preliminary demonstrative benchmarking study of the Application-Layer Traffic Optimization (ALTO) architecture proposed by the IETF ALTO Working Group. The main ALTO system purpose is to allow applications to get a more complete view of the underlying network infrastructure, allowing for well...
Conference Paper
Precise and efficient monitoring is vital to ensure that a network works according to the intended behaviour, as well as quickly acting in response to possible problems. The task of monitoring a network becomes complex with increasing network size and its heterogeneity. This work explores the development of a Peer-to-Peer (P2P) system to monitor ne...
Conference Paper
The growing adoption of software architectures based on microservices, and consequently the proliferation of the use of containers in environments with hybrid infrastructures (local data centers and public cloud providers), poses several challenges in terms of integrating this new paradigm into already existing solutions. In this context, this arti...
Article
Segment Routing (SR) is a new fertile ground for Traffic Engineering (TE). By decomposing forwarding paths into segments, which specify a list of intermediate delivery points that a packet must visit on its way to the final destination, SR improves TE tasks and enables new solutions for the optimization of network resource utilization. This work pr...
Conference Paper
Internet Service Providers (ISPs) and dedicated inter-Data Center Wide Area Networks have been exploring Software-Defined Networking (SDN) features to achieve a high utilization of the available resources. This work proposes a scalable hybrid IP/SDN routing model, and optimization procedures fostered by Evolutionary Computation algorithms, to achie...
Article
Full-text available
Multicast is a group communication paradigm which aims at reducing, as much as possible, the amount of data generated into the network. Thus, IP Multicast presents itself as a technology that allows data to be distributed in such a way that the least amount of replicas of the same packet is placed into the network. However, the limited deployment o...
Conference Paper
The SDN (Software-defined Nettworking) has introduced a new control paradigm in network infrastructures, thus having a great impact not only on the operation of the network itself, but also on supporting all the development carried out around them (e.g. network and distributed services, Internet applications, etc.). In this context, and in order to...
Conference Paper
This paper presents a P2P Overlay system for network anomaly detection, providing ISP network administrators with a versatile, easily configurable and useful tool to monitor the network infrastructures. In this context, this document describes the system general architecture and the main entities that integrate the proposed overlay system. Some tec...
Conference Paper
The current developments in the Information Technology area, and particularly in Computer Networks related fields, have sustained a considerable scientific and technological progress of the area usually denominated as the Internet of Things (IoT). In this context, this article focuses on the design, implementation and test of a communication protoc...
Conference Paper
A communication infrastructure is not always easy to manage and the level of difficulty increases with the size and number of devices present in the network. Thus, the monitoring of a network is a fundamental process in that it may prevent or detect possible problems, also offering several auxiliary tools for the work of a computer network administ...
Article
Full-text available
Segment Routing (SR) combines the simplicity of Link-State routing protocols with the flexibility of Multiprotocol Label Switching (MPLS). By decomposing forwarding paths into segments, identified by labels, SR improves Traffic Engineering (TE) and enables new solutions for the optimization of network resources utilization. This work proposes an Ev...
Conference Paper
Full-text available
This work explores the optimization of a real-valued parameter, assigned to each network node running the Distributed Exponentially-weighted Flow SpliTting (DEFT) routing protocol, in order to address changes on traffic conditions. This new proposal avoids the need to alter link weights and forwarding paths, by adjusting traffic splitting. In this...
Article
This paper presents an automated optimization framework able to provide network administrators with resilient routing configurations for link-state protocols, such as OSPF or IS-IS. In order to deal with the formulated NP-hard optimization problems, the devised framework is underpinned by the use of computational intelligence optimization engines,...
Article
Full-text available
IP networks are nowadays well established technolo- gies being used to support a myriad of applications and services, thus assuming a crucial role in todays telecommunication sys- tems. Nevertheless, such infrastructures usually require network administrators to perform a wide set of complex planning and management tasks trying to attain adequate n...
Chapter
Peer-to-Peer (P2P) is nowadays a widely used paradigm underpinning the deployment of several Internet services and applications. However, the management of P2P traffic aggregates is not an easy task for Internet Service Providers (ISPs). In this perspective, and considering an expectable proliferation in the use of such applications, future network...
Conference Paper
Link State routing protocols, such as Open Shortest Path First (OSPF), are widely applied to intra-domain routing in todays IP networks. They provide a good scalability without lost of simplicity. A router running OSPF distributes traffic uniformly over Equal-cost Multi-path (ECMP), enabling a better distribution of packets among the existent links...
Article
Full-text available
Abstract—Nowadays, many P2P applications proliferate in the Internet. The attractiveness of many of these systems relies on the collaborative approach used to exchange large resources without the dependence and associated constraints of centralized approaches where a single server is responsible to handle all the requests from the clients. As conse...
Conference Paper
Traffic Engineering (TE) approaches are increasingly important in network management to allow an optimized configuration and resource allocation. In link-state routing, the task of setting appropriate weights to the links is both an important and a challenging optimization task. A number of different approaches has been put forward towards this aim...
Article
IP networks are currently the major commu- nication infrastructure used by an increasing number of applications and heterogeneous services, including voice ser- vices. In this context, the session initiation protocol (SIP) is a signaling protocol widely used for controlling multimedia communication sessions such as voice or video calls over IP netw...
Article
Full-text available
Abstract. The advent of Cloud Computing opened new opportunities in several areas, namely in the application development processes. As consequence, nowadays, PaaS (Platform-as-a-Service) service model allows simpler and flexible deployment strategies of applications, avoiding the need for dedicated networks, servers, storage, and other services. Wi...
Conference Paper
P2P applications are nowadays commonly used in the Internet for the development of distinct services. As consequence, Internet Service Providers (ISPs) are facing some coexistence problems with P2P applications due to the unpredictable dynamics of such applications, causing traffic to traverse the network links in an unforeseeable way. As a contrib...
Conference Paper
Nowadays, P2P applications are commonly used in the Internet being an important paradigm for the development of distinct services. However, the dissemination of P2P applications also entails some important challenges that should be carefully addressed. In particular, some of the important coexistence problems existing between P2P applications and I...
Article
Full-text available
The increasing use of Peer to Peer (P2P) applications, usually ruled by selfish behaviors, is posing new challenges to the research community. As contributions of this work we firstly devise a general framework underpinning the development of highly reconfigurable P2P trackers. Following that, a novel tracker architecture is proposed and several il...
Article
The electronic mail (email) is nowadays an essential communication service being widely used by most Internet users. One of the main problems affecting this service is the proliferation of unsolicited messages (usually denoted by spam) which, despite the efforts made by the research community, still remains as an inherent problem affecting this Int...
Conference Paper
In current network infrastructures, several management tasks often require significant human intervention and can be of high complexity, having to consider several inputs to attain efficient configurations. In this perspective, this work presents an optimization framework able to automatically provide network administrators with efficient and robus...
Chapter
Cloud Computing has emerged as a new paradigm for services delivering over the Internet. In this growing market, PaaS (Platform-as-a-Service) service model has been the subject of great interest from several organizations allowing a straightforward deployment of applications without the need for a dedicated infrastructure, dependencies installation...
Conference Paper
Nowadays, P2P applications proliferate in the Internet with distinct utilization contexts, being also an attractive model for the deployment of advanced Internet services. However, there are several undesirable effects that are caused by such applications, raising coexistence problems with Internet Service Providers (ISPs). In this context, using a...
Conference Paper
Open Shortest Path First (OSPF) is a widely used routing protocol that depends on weights assigned to each link to make routing decisions. If traffic demands are known, the OSPF weight setting (OSPFWS) problem can be defined to seek a set of weights that optimize network performance, typically by minimizing a congestion measure. The OSPFWS problem...
Article
O Cloud Computing tem emergido como sendo um novo paradigma para entrega de serviços através da Internet. Neste mercado em expansão, o serviço de PaaS (Platform-as-a-Service) tem sido objeto de grande interesse por parte das mais variadas organizações permitindo o fácil deployment de aplicações sem necessidade de uma infra-estrutura dedicada, insta...
Conference Paper
The fast growing of mobile Internet users with the ability of using a wide diversity of access technologies such as Wi-Fi, WiMAX and UMTS/LTE, and the increasing proliferation of mobile devices with heterogeneous network interfaces, require versatile mobility mechanisms providing seamless roaming across those access technologies. Mobility agents su...
Article
Full-text available
Many of the current approaches used in teaching and learning in engineering education are not the most appropriate to prepare students for the challenges they will face in their professional careers. The active involvement of students in their learning process facilitates the development of the technical and professional competencies they need as p...
Article
This article presents three methods to forecast accurately the amount of traffic in TCP/IP based networks: a novel neural network ensemble approach and two important adapted time series methods (ARIMA and Holt-Winters). In order to assess their accuracy, several experiments were held using real-world data from two large Internet service providers....
Conference Paper
This work presents a symbiotic filtering approach enabling the exchange of relevant word features among different users in order to improve local anti-spam filters. The local spam filtering is based on a Content- Based Filtering strategy, where word frequencies are fed into a Naive Bayes learner. Several Evolutionary Algorithms are explored for fea...
Article
Full-text available
The fast growing of mobile Internet users with the ability of using a wide diversity of access technologies such as Wi-Fi, WiMAX and UMTS/LTE, and the increasing proliferation of mobile devices with heterogeneous network interfaces, require versatile mobility mechanisms providing seamless roaming across those access technologies. Mobility agents su...
Article
This paper presents a novel spam filtering technique called Symbiotic Filtering (SF) that aggregates distinct local filters from several users to improve the overall performance of spam detection. SF is an hybrid approach combining some features from both Collaborative (CF) and Content-Based Filtering (CBF). It allows for the use of social networks...
Conference Paper
Full-text available
Nowadays, network planning and management tasks can be of high complexity, given the numerous inputs that should be considered to effectively achieve an adequate configuration of the underlying network. This paper presents an optimization framework that helps network administrators in setting the optimal routing weights of link state protocols acco...
Conference Paper
Full-text available
Evolutionary Algorithms (EAs) have been used to develop methods for Traffic Engineering (TE) over IP-based networks in the last few years, being used to reach the best set of link weights in the configuration of intra-domain routing protocols, such as OSPF. In this work, the multiobjective nature of a class of optimization problems provided by TE w...
Article
In this work, a novel optimization framework is proposed that allows the improvement of Quality of Service levels in TCP/IP based networks, by configuring the routing weights of link-state protocols such as OSPF. Since this is a NP-hard problem, some algorithms from Evolutionary Computation were considered, working over a mathematical model that al...
Article
Full-text available
Electronic mail is nowadays one of the most important Internet networking services. However, there are still many challenges that should be faced in order to provide a better e-mail service quality, such as the growing dissemination of unsolicited e-mail (spam) over the Internet. This work aims to foster new research efforts giving ground to the de...
Conference Paper
Full-text available
Spam is serious problem that affects email users (e.g. phishing attacks, viruses and time spent reading unwanted messages). We propose a novel spam email filtering approach based on network-level attributes (e.g. the IP sender geographic coordinates) that are more persistent in time when compared to message content. This approach was tested using t...
Conference Paper
The fast growing of mobile Internet users with the ability of using a wide diversity of access technologies such as Wi-Fi, WiMAX and UMTS/LTE, and the increasing proliferation of mobile devices with heterogeneous network interfaces, require versatile mobility mechanisms providing seamless roaming across those access technologies. Mobility agents su...
Conference Paper
Decentralized architectures have been proposed using functional hierarchies of several middle-level managers with delegation of management activities. However, no management applications have been implemented and widely used that could sanction this approach for real use. Also, current frameworks or mechanisms in network management do not directly...
Conference Paper
This work introduces and proposes the concept of context aware programmable trackers for the next generation Internet. The proposed solution gives ground for the development of advanced applications based on the P2P paradigm and will foster collaborative efforts among several network entities (e.g. P2P applications and ISPs). The proposed concept o...
Conference Paper
Unsolicited e-mail (spam) is a severe problem due to intrusion of privacy, online fraud, viruses and time spent reading unwanted messages. To solve this issue, Collaborative Filtering (CF) and Content-Based Filtering (CBF) solutions have been adopted. We propose a new CBF-CF hybrid approach called Symbiotic Data Mining (SDM), which aims at aggregat...
Conference Paper
This paper focuses on the development of solutions able to enhance the peer selection semantics supported by P2P based applications. The proposed framework relies on the concept of a flexible P2P tracker able to support multiple versatile peer selection procedures that might be activated and configured during the application lifetime. The devised f...
Conference Paper
Full-text available
Resumo — O serviço de correio electrónico assume uma crescente importância na sociedade actual e, em particular, no âmbito dos serviços de comunicação que hoje em dia são alvo preferencial de utilização por parte dos utilizadores da Internet. No entanto, são ainda muitos os desafios que se colocam a este serviço, nomeadamente no que diz respeito à...
Conference Paper
Full-text available
This paper presents an OSPF routing optimization framework taking into account a set of multiconstrained QoS requirements of the networking domain. The proposed optimization approach, based on Evolutionary Computation, is able to handle network scenarios with both unicast and multicast traffic, providing high quality configurations for single-topol...
Conference Paper
Full-text available
By improving Internet traffic forecasting, more efficient TC P/IP traf- fic control and anomaly detection tools can be developed, lea ding to economic gains due to better resource management. In this paper, Neural Networks (NNs) are used to predict TCP/IP traffic for 39 links of the UK educat ion and research network, under univariate and multivari...
Conference Paper
In multiservice networks, admission control (AC) is a convenient means of assuring high quality communications by safeguarding enough availability for customer traffic. This can be particularly useful to preserve the quality of services such as IP telephony and video conferencing, and to ensure acceptable throughput to elastic flows. This paper tac...
Conference Paper
Full-text available
A number of Traffic Engineering (TE) approaches have been rec ently proposed to improve the performance of network routing protocols, both developed over MPLS and intra-domain protocols such as OSPF. In this work, a TE approach is proposed for routing optimization in scenarios where unicast and multicast demands are simultaneously present. Evolutio...
Conference Paper
Full-text available
The use of Internet as an ubiquitous communication platform puts a strong demand on service providers regarding the assurance of multiple service levels consistently. Designing flexible and simple service-oriented management strategies is crucial to support multiconstained applications conveniently and to obtain a deployable and sustainable service...
Conference Paper
Full-text available
Forecasting Internet traffic is receiving an increasing attention from the computer networks domain. Indeed, by improving this task efficient traffic engineering and anomaly detection tools can be developed, leading to economic gains due to better resource management. This paper presents a Neural Network (NN) approach to predict TCP/IP traffic for...
Conference Paper
Full-text available
In this work, the main goal is to develop and evaluate a num- ber of optimization algorithms in the task of improving Quality of Service levels in TCP/IP based networks, by configuring the routing weights of link-state protocols such as OSPF. Since this is a complex problem, some meta-heuristics from the Evolutionary Computation arena were consid-...
Article
Full-text available
This paper presents a contribution for the de- velopment of network management tools able to auto- matically provide QoS aware routing configurations. In this perspective, a traffic engineering framework able to provide near-optimal OSPF configurations is presented. The devised solution takes into account the multiconstrained QoS demands of a given...
Conference Paper
Full-text available
This paper discusses the problematic of QoS monitoring, suggesting the use of on-line multipurpose active monitoring in multiclass networks as a powerful tool to eciently assist and enhance the control of multiple service levels. To im- prove the simultaneous estimation of one-way QoS metrics, we propose a flexible probing source able to adjust pro...
Conference Paper
Full-text available
This paper proposes a novel traffic engineering framework able to automatically provide near-optimal OSPF routing configurations for QoS con- strained scenarios. Within this purpose, this work defines a mathematical model able to measure the QoS compliance in a class-based networking domain. Based on such model, the NP-hard optimization problem of...
Conference Paper
Full-text available
This paper presents a traffic engineering framework able to optimize OSPF weight setting administrative procedures. Using the proposed framework, enhanced OSPF configurations are now provided to network administrators in or- der to effectively improve the QoS performance of the corresponding network do- main. The envisaged NP-hard optimization prob...
Conference Paper
Full-text available
The forecast of Internet traffic is an important issue that has received few attention from the computer networks field. By improving this task, efficient traffic engineering and anomaly detection tools can be created, resulting in economic gains from better resource management. This paper presents a neural network ensemble (NNE) for the prediction...
Conference Paper
Full-text available
OSPFOSPF is the most common intra-domain routing protocol in Wide Area Networks. Thus, optimizing OSPF weights will produce tools for traffic engineering with Quality of Service constraints, without changing the network management model. Evolutionary Algorithms (EAs) provide a valuable tool to face this NP-hard problem, allowing flexible cost funct...
Article
This article presents a modular scheduler with powerful semantics able to differentiate simultaneously multiple QoS metrics in classbased IP networks. In opposition to traditional scheduling mechanisms, this scheduler encompasses rate, loss and delay differentiation capabilities in a flexible way. This behaviour stems from new relative and mixed di...
Article
O aparecimento ea crescente utilização das tecnologias de comunicação sem fios tem vindo a potenciar o desenvolvimento de inúmeros serviços avançados no âmbito das redes de comunicação. Neste sentido, o protocolo IP, globalmente aceite como um dos principais protocolos de rede que possibilita a convergência e integração de diferentes tecnologias, f...