{"title":"The response time distribution of a discrete-time queue under a generalized batch arrival process","authors":"S. Galmés, R. Puigjaner","doi":"10.1145/1168117.1168123","DOIUrl":"https://doi.org/10.1145/1168117.1168123","url":null,"abstract":"In this paper we obtain the response time distribution of a single server, discrete-time queue, fed by an aggregate extension of the well-known on/off source. Essentially, at each active slot, we allow for a variable number of units of workload (packets, cells, messages, etc.) to enter the queue. So, the resulting input traffic is a batch-on/off process. The server is deterministic, with a service time corresponding to the transmission of a workload unit. We follow an exact analytical procedure, and we provide an effective algorithm to compute the solution. Moreover, this work has been performed under very general conditions, since no particular distributions are assumed for the random variables characterizing the batch-on/off process: on and off periods, and batch sizes. Also, the fact of obtaining the complete response time distribution, allows for the calculation of other parameters than the mean, such as the jitter, for instance, or higher order moments. This becomes essential when analyzing the performance of finite capacity resources in the context of digital communication systems, especially when real time services are supported. Finally, numerical results are provided.","PeriodicalId":415618,"journal":{"name":"International Latin American Networking Conference","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129036151","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Reliability and maintainability over a wireless Rayleigh radio channel","authors":"Miquel Font, S. Galmés, R. Puigjaner","doi":"10.1145/1168117.1168132","DOIUrl":"https://doi.org/10.1145/1168117.1168132","url":null,"abstract":"Traditionally some system reliability and maintainability parameters are computed with experimental results. This paper analyzes the mean time to failure, mean time to repair, mean time before failure and the availability of a wireless channel. A Markov chain is used to model the characteristics of the physical channel, and three methodologies are established to compute the MTTF, MTTR, MTBF and availability values in terms of the parameters of the channel. Particularly, the Rayleigh fading radio model is considered and analytical results are provided. It proposes a global vision about channel reliability and maintainability parameters.","PeriodicalId":415618,"journal":{"name":"International Latin American Networking Conference","volume":"69 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114210539","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A mathematical programming formulation of optimal cache expiration dates in content networks","authors":"P. Rodríguez-Bocca, H. Cancela","doi":"10.1145/1168117.1168130","DOIUrl":"https://doi.org/10.1145/1168117.1168130","url":null,"abstract":"One of the fundamental decisions in content networks is how the information about the existing contents is deployed and accessed. In particular, there are two main alternatives, either to publish the information when contents are changed, or to search for the contents when a query is received. Even if some networks only use one of these alternatives, in general it is better to employ a mix of both strategies. This implies evaluating the tradeoff between these alternatives, in order to decide the characteristics of the mix. In this work we develop a simplified model of the costs and restrictions associated with cache expiration dates in a cache node in a content network; these expiration dates regulate the proportion of queries which will be answered on the basis of published information, vs. those which will give rise to additional searches in the network backbone. Based on this model, we present a mathematical programming formulation which can be useful to determine the optimal cache expiration dates in order to maximize the total information discovered, while respecting the operational constraints of the network.","PeriodicalId":415618,"journal":{"name":"International Latin American Networking Conference","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134232648","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Admilson R. L. Ribeiro, Fabio Silva, L. C. Freitas, J. H. Costa, C. Francês
{"title":"SensorBus: a middleware model for wireless sensor networks","authors":"Admilson R. L. Ribeiro, Fabio Silva, L. C. Freitas, J. H. Costa, C. Francês","doi":"10.1145/1168117.1168119","DOIUrl":"https://doi.org/10.1145/1168117.1168119","url":null,"abstract":"The use of middleware eases the development of distributed applications by abstracting the intricacies (communication and coordination among software components) of the distributed network environment. In wireless sensor networks, this is even trickier because of their specific issues such as addressing, mobility, number of sensors and energy-limited nodes. This paper describes SensorBus, a message-oriented middleware (MOM) model for wireless sensor networks based on the publish-subscribe paradigm and that allows the free exchange of the communication mechanism among sensor nodes allowing as result the capability of using more than one communication mechanism to address the requirements of larger number of applications. We intend to provide a platform which addresses the main characteristics of wireless sensor networks and also allows the development of energy-efficient applications. SensorBus incorporates constraint and query languages which will aid the development of interactive applications. It intends with the utilization of filters reduces data movement minimizing the energy consumption of nodes.","PeriodicalId":415618,"journal":{"name":"International Latin American Networking Conference","volume":"2007 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128959005","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A proposal to improve network throughput using a QoS building blocks approach at Central University of Venezuela","authors":"M. E. Villapol, Eric Gamess, Neudith Morales","doi":"10.1145/1168117.1168124","DOIUrl":"https://doi.org/10.1145/1168117.1168124","url":null,"abstract":"Central University of Venezuela is the main university of Venezuela and has approximately 60,000 students and 16,000 staff members. The backbone network connects 11 colleges and many non-academic dependencies; some of them are located outside the main campus and even in other regions of the country. The Internet access is centralized and supported by private links at an aggregated data rate of 14.336 Mbps. Users of the institution network can access most of the Internet services with few or non restrictions. In the last few years, there has been an increasing demand on the use of the Internet services provided by the institution. The consequences of the above are degradation of the Internet access services provided by the institution to users, which claim for better response times and throughput. In this paper, we propose a solution to this problem based on the use of congestion control mechanisms and Internet service approaches proposed by the IETF. So, we start the paper given a brief introduction of such mechanisms and service models; then we detail the problem of the campus network and finally we describe the proposed solution. We conclude that the problem of network congestion may be reduced using existing congestion control mechanisms, which can complement a solution based on network over-provision.","PeriodicalId":415618,"journal":{"name":"International Latin American Networking Conference","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130863728","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Solving multiobjective multicast routing problem with a new ant colony optimization approach","authors":"D. Pinto, B. Barán","doi":"10.1145/1168117.1168120","DOIUrl":"https://doi.org/10.1145/1168117.1168120","url":null,"abstract":"This work presents two multiobjective algorithms for Multicast Traffic Engineering. The proposed algorithms are new versions of the Multi-Objective Ant Colony System (MOACS) and the Max-Min Ant System (MMAS), based on Ant Colony Optimization (ACO). Both ACO algorithms simultaneously optimize maximum link utilization and cost of a multicast routing tree, as well as average delay and maximum end-to-end delay, for the first time using an ACO approach. In this way, a set of optimal solutions, know as Pareto set is calculated in only one run of the algorithms, without a priori restrictions. Experimental results show a promising performance of both proposed algorithms for a multicast traffic engineering optimization, when compared to a recently published Multiobjective Multicast Algorithm (MMA), specially designed for Multiobjective Multicast Routing Problems.","PeriodicalId":415618,"journal":{"name":"International Latin American Networking Conference","volume":"51 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128142046","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Developing a functional Tcp/Ip stack oriented towards Tcp connection replication","authors":"J. París, Alberto Valderruten, V. M. Gulías","doi":"10.1145/1168117.1168131","DOIUrl":"https://doi.org/10.1145/1168117.1168131","url":null,"abstract":"Functional languages are not often associated with the development of network stacks, mainly due to the lower performance and lack of support for system programming than more conventional languages such as C. However, there are functional languages that offer features which make it easier to develop network protocols than using a more conventional approach based on an imperative language. Erlang, for instance, offers support for distribution, concurrency and soft real time built-in into the language. All those features are desirable to ease the development of network protocol implementations. It is also possible to implement a reasonably efficient network stack in this language, provided some precautions are taken in the design. By using Erlang distribution it is possible to support fault tolerant distributed TCP connections that take advantage of the distributed nature of the applications implemented in Erlang to provide low cost synchronization, with just some support from the application itself.","PeriodicalId":415618,"journal":{"name":"International Latin American Networking Conference","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129667258","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Network design with node connectivity constraints","authors":"H. Cancela, F. Robledo, G. Rubino","doi":"10.1145/1035662.1035664","DOIUrl":"https://doi.org/10.1145/1035662.1035664","url":null,"abstract":"The Generalized Steiner Problem with Node-Connectivity constraints (GSPNC) consists of determining of a minimum cost subnetwork of a given network where some pairs of nodes are required to satisfy node-connectivity requirements. The GSPNC has applications to the design of low-cost communications networks which can survive failures in the servers as well as in the connection lines. The GSPNC is known to be NP-Complete. In this paper, we introduce an algorithm based on GRASP (Greedy Randomized Adaptive Search Procedure), an effective combinatorial optimization metaheuristic. Experimental results are obtained over a set of problem instances with different characteristics and connectivity requirements, obtaining in all these cases optimal or near-optimal results.","PeriodicalId":415618,"journal":{"name":"International Latin American Networking Conference","volume":"55 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124803080","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Multi-objective scheme over multi-tree routing in multicast MPLS networks","authors":"Y. Donoso, R. Fabregat, Lluís Fàbrega","doi":"10.1145/1035662.1035668","DOIUrl":"https://doi.org/10.1145/1035662.1035668","url":null,"abstract":"This paper proposes a traffic engineering scheme using different distribution trees to several multicast flows. We formulate this problem as one with Non Linear programming with discontinuous derivatives (DNLP). The aim is to combine into a single aggregated metric the following weighting objectives: the maximum link utilization, the hop count, the total bandwidth consumption and the total end-to-end delay. Our proposal solves the traffic split ratio for multiple trees. The proposed approach is applied in MPLS networks by allowing the establishment of explicit routes in multicast events. Furthermore, the results obtained with GAMS tools show that several objectives are decreased; the maximum link utilization is minimized. The main contribution of this paper is the optimization model and the formulation of the multi-objective function.","PeriodicalId":415618,"journal":{"name":"International Latin American Networking Conference","volume":"13 2","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114028718","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A smartcard for authentication in WLANs","authors":"Marc Loutrel, P. Urien, G. Pujolle","doi":"10.1145/1035662.1035673","DOIUrl":"https://doi.org/10.1145/1035662.1035673","url":null,"abstract":"Wireless LANs based on the IEEE 802.11b standard have spread very quickly over the past few years. Nevertheless a lot of security issues remain and stop its deployment in corporations. One of the most important issues is the authentication of a terminal to an Access Point. We propose an interface to integrate the Extensible Authentication Protocol into smartcards and will show that smartcards could constitute the de-facto device for authentication in Wireless LAN as they are for GSM and will be for Universal Mobile Telecommunication System.","PeriodicalId":415618,"journal":{"name":"International Latin American Networking Conference","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122125547","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}