[show abstract][hide abstract] ABSTRACT: The issue of breaking cycles in communication networks is an important topic for several reasons. For instance, it is required when trans- parent bridges are filling the forwarding tables. It is also needed to prevent the occurrence of deadlocks caused by certain routing protocols. Furthermore, most of the techniques used to work with communication networks can only be applied if the network topology is free of cycles. We present a distributed protocol which, applied to any network topology, provides a cycle-free topology. Our approach is based on the prohibition of only certain turns in the network. In contrast to previous proposals, our protocol is fully distributed, and thus does not require nodes to have knowledge of the global network topology. Furthermore, it allows multiple nodes to initiate the protocol in an independent manner. This feature can be used to cope with new nodes entering the system, as well as with nodes leaving it (voluntarily or due to a failure). We provide a detailed description of our proposal, formal proof of correctness, and an analysis of its performance. � 2007 Elsevier B.V. All rights reserved.
[show abstract][hide abstract] ABSTRACT: Wireless sensor networks (WSNs) are commonly used for continuously monitoring applications. Data gathering and in-network processing are techniques to efficiently gather the information from sensor nodes. Usually, these techniques have been analyzed taking into account a global knowledge of the system in order to select the best path to gather the information or to establish a routing function. In this paper we propose a novel distributed data gathering algorithm for wireless networks and evaluate the effect of having a different number of cluster heads transmitting to the base station. We focus the attention on uniformly distributed nodes in a given area to evaluate the effects on the energy consumption. Our proposal distributes uniformly the energy consumption between the complete set of sensors in the system resulting in a similar longevity for all sensors in the system.
16th Euromicro Conference on Parallel, Distributed and Network-Based Processing (PDP 2008). 01/2007;
[show abstract][hide abstract] ABSTRACT: This paper shows a new distributed algorithm for deadlock detection and resolution under the single-resource request model that highly improves the complexity measurements of previous proposals. The algorithm has a communication cost of 2n - 1 messages and a latency of n · T for a deadlock cycle of n processes, where T is the inter-site communication delay. The algorithm achieves this improvement even verifying the strongest correctness criteria considered in previous works: it resolves all deadlocks in finite time and does not resolve false deadlocks.
14th Euromicro International Conference on Parallel, Distributed and Network-Based Processing (PDP 2006), 15-17 February 2006, Montbeliard-Sochaux, France; 01/2006
[show abstract][hide abstract] ABSTRACT: Leader election is a fundamental problem in distributed computing and it has been studied assuming various computation models and network topologies. This paper analyzes the algorithms for leader election in complete networks using asynchronous communication channels. We present a novel algorithm that reduces the information necessary to select a leader compared with other leader election algorithms for complete networks. In this paper, the algorithm works without sense of direction. And, it does not require to know the number of nodes in the system. Our proposal requires O(n) messages and O(n) time, where n is the number of nodes in the system, to elect a leader.
13th Euromicro Workshop on Parallel, Distributed and Network-Based Processing (PDP 2005), 6-11 February 2005, Lugano, Switzerland; 01/2005
[show abstract][hide abstract] ABSTRACT: We present a novel distributed algorithm which provides QoS by only enabling free-of-cycles routes which are known to ensure
network stability. Network stability is synonymous of QoS as allows to deterministically bound maximum delays and backlogs.
Cycles are avoided by disabling the use of pair of input-output links around a node (turns). This method improves network
utilization compared to previous solutions, which avoids cycles by forbidding the use of whole links.
The algorithm can be applied in joint with any routing algorithm as does not require knowledge of the whole network topology,
reducing the communication overhead compared to centralized approaches.
The performance of the proposed algorithm has been compared against a centralized optimization solution. Even though the centralized
solution exhibits a lower percentage of prohibited turns, the difference is quite moderate. We have also shown how our protocol
can be enhanced to be able to tolerate fail-stop node crashes without the necessity of having to start from the beginning.
Quality of Service in the Emerging Networking Panorama: Fifth International Workshop on Quality of Future Internet Services, QofIS 2004 and First Workshop on Quality of Service Routing WQoSR 2004 and Fourth International Workshop on Internet Charging and QoS Technology, ICQT 2004, Barcelona, Catalonia, Spain, September 29 - October 1, 2004, Proceedings; 01/2004
[show abstract][hide abstract] ABSTRACT: This work has been focused on the design of a VoD parameter-measuring tool. This tool works as a video client and additionally
provides a set of measurements used to define different user parameters in different network conditions.
Web Engineering, International Conference, ICWE 2003, Oviedo, Spain, July 14-18, 2003, Proceedings; 01/2003