An integrated bandwidth allocation and admission control framework for the support of heterogeneous real-time traffic in class-based IP networks

The support of real-time traffic in class-based IP networks requires the reservation of resources in all the links along the end-to-end paths through appropriate queuing and forwarding mechanisms. This resource allocation should be accompanied by appropriate admission control procedures in order to guarantee that newly admitted real-time traffic flows do not cause any violation to the Quality of Service (QoS) experienced by the already established real-time traffic flows. In this paper we initially aim to highlight certain issues with respect to the areas of bandwidth allocation and admission control for the support of real-time traffic in class-based IP networks. We investigate the implications of topological placement of both the bandwidth allocation and admission control schemes. We show that the performance of bandwidth allocation and admission control schemes depends highly on the location of the employed procedures with respect to the end-users requesting the services and the various network boundaries (access, metro, core, etc.). Based on our results we conclude that the strategies for applying these schemes should be location-aware, because the performance of bandwidth allocation and admission control at different points in a class-based IP network, and for the same traffic load, can be quite different and can deviate greatly from the expected performance. Through simulations we also try to provide a quantitative view of the aforementioned deviations. Taking the implications of this “location-awareness” into account, we subsequently present a new Measurement-based Admission Control (MBAC) scheme for real-time traffic that uses measurements of aggregate bandwidth only, without keeping the state of any per-flow information. In this scheme there is no assumption made on the nature of the traffic characteristics of the real-time traffic flows, which can be of heterogeneous nature. Through simulations we show that the admission control scheme is robust with respect to traffic heterogeneity and measurement errors. We also show that our scheme compares favorably against other admission control schemes in the literature

Prototipo para la Evaluación de Calidad de Servicio Mediante Técnicas de Encolamiento en Ambientes de Backbone

The cost in infraestructure and access to emerging technologies on telecommunications networks, made necessary to have a mechanisms the quality of service assessment using queuening based. Objective in this article was evaluate different technical modeled various scenes of campus backbone network, in order to compare his performance using the tool of simulation OPNET. The evaluation aimed to the measurement of keys variables in the performance networks like delay, packet loss and jitter, among others. Are show here the results once these were gotten from utilization mechanism when granting differentiation to sensitive traffics to present factors of congestion in IP networks, such like traffic in real time; collecting a significant improvement in the network performance.El costo en infraestructura y acceso a tecnologías emergentes en redes de telecomunicaciones, hizo necesario disponer de un planteamiento de evaluación de Calidad de Servicio utilizando mecanismos de encolamiento basado en simulación. El objetivo en este artículo fue evaluar diferentes técnicas de encolamiento modeladas bajo diversos escenarios de campus de redes backbone, para comparar su desempeño usando la herramienta de simulación OPNET. La evaluación apuntó hacia la medición de variables claves en el desempeño de la red como retraso, pérdida de paquetes y variación del retraso (jitter), entre otras. Son presentados aquí los resultados obtenidos en la utilización de éstos mecanismos al momento de otorgar diferenciación a tráficos sensibles a factores de congestión presentes en las redes IP, tales como tráfico en tiempo real; obteniendo un significativo mejoramiento en el desempeño de la red