Management of Digital Video Broadcasting Services in Open Delivery Platforms

The future of Digital Video Broadcasting (DVB) is moving towards solutions offering an efficient way of carrying interactive IP multimedia services over digital terrestrial broadcasting networks to handheld terminals. One of the most promising technologies is Digital Video Broadcasting-Handheld (DVB-H), at present under standardisation. Services deployed via this type of DVB technologies should enjoy reliability comparable to TV services and high quality standards. However, the market at present does not provide effective and economical solutions for the deployment of such services over multi-domain IP networks, due to their high level of unreliability. This paper focuses on service management, service level agreement (SLA) and network performance requirements of DVB-H services. Experimental results are presented concerning QoS sensitivity to network performance of DVB-H services delivered over a multi-domain IP network. Moreover, a solution for efficient and cost effective service management via QoS monitoring and control and network SLA design is proposed. The solution gives DVB-H operators the possibility of fully managing service QoS without being tied to third party operators

Monitoring and measurement of computer network performance

Regardless of fast performance improvements in the field of network technologies and their pervasiveness, today’s computer-demanding and service-oriented applications require efficient management of networks. Besides monitoring collision, broadcast and errors, utilization measurement of a local commutated network was carried out by means of a software tool. Measurement was carried out at two different levels of artificially generated continuous workload and by varying workload caused by intensive use of network resources. In our experiments, the monitored network showed that it is resistant to collisions and errors, but also sensitive to workload dynamics characterized by utilization changes. These changes show certain regularity and periodicity and can be considered as a good behavior pattern of a network. The approach proposed enables prediction of accessibility of computer resources by their engagement in complex distributed computer environments.Bez obzira na brzo poboljšanje performansi mrežnih tehnologija i njihove prodornosti, današnji računalno zahtjevni i uslugama usmjereni primjenski programi, zahtijevaju učinkovito upravljanje mrežom. Uz nadzor srazova, prijenosa i pogrešaka, programskim alatom obavljeno je i mjerenje korisnosti. Mjerenje je provedeno na dvije različite razine umjetno generiranog opterećenja, te promjenjivog opterećenja izazvanog intenzivnom uporabom mrežnih resursa. U provedenim eksperimentima, nadzirana mreža pokazala je otpornost na srazove i pogreške, ali i osjetljivost na dinamičnost opterećenja, odnosno promjene korisnosti. Takve promjene pokazuju određenu pravilnost i periodnost, te se mogu smatrati dobrim uzorkom ponašanja mreže. Predloženi pristup omogućava predviđanje dostupnosti računalnih resursa pri njihovom uključivanju u složene raspodijeljene računalne okoline

Herramienta Integrada De Monitoreo De Redes Para Soportar Estudios De Disponibilidad

Esta tesis aborda el problema disponibilidad de redes basada en un monitoreo que ayude a manejar más eficientemente el ancho de banda de la red interna de la organización evitando o minimizando el uso de aplicaciones no permitidas a través de esta. Dicho problema es más critico ya que con el desarrollo de la Internet, el mercado globalizado y crecimiento tecnológico de la empresas, más el gran volumen de información que fluye a través de estas, las organizaciones debes estar más preparadas para asegurar que la información que fluye a través de su red, así como sus aplicaciones, tengan una mayor disponibilidad y performance frente aplicaciones no deseadas que pueden estar circulando por la red. Ante lo mencionado anteriormente, los encargados de IT deben estar constantemente monitoreando y observado cuales son las posibles fallas a presentarse en caso se detecten sobrecargas en la red por aplicaciones no deseadas. Actualmente existen un sin numero de aplicaciones de tipo P2P, chat, juegos en línea, etc., que hacen uso de nuestra interna y si estos no son controlados debidamente pueden llegar a sobre saturar nuestra red causando problemas de de conectividad, performance y disponibilidad de servicios internos. A si mismo si tomamos en cuenta el tipo de información que puede fluir a través de estas aplicaciones como virus informáticos y troyanos, la magnitud del problema puede ser mayor. Es por ello que a partir de este problema, se propone una solución que integres dos módulos de monitoreo, de suceso de eventos (aplicación y sistema); y de tráfico de red en tiempo real, con envío de alertas automático, apenas los umbrales de alerta estándares definidos en la aplicación son sobrepasados. En resumen se propone una herramienta integrada de monitoreo de red que involucra el análisis de eventos y ocurrencias tanto a nivel de servidor como de tráfico de red. Permitiendo visualizar mediante reportes gráficos dichas incidencias en el tiempo y analizarlas para tomar las medidas correspondientes por parte de la gerencia del negocio y el equipo de TI.Tesi

On Monitoring and Controlling QoS Network Domains

We design an integrated distributed monitoring, TCP-friendly traffic conditioning, and flow control system for securing network domains. Edge routers monitor (using tomography techniques) a network domain to detect quality of service (QoS) violations-- possibly caused by underprovisioning-- as well as bandwidth theft and denial of service (DoS) attacks. To bound the monitoring overhead, the router only verifies service level agreement (SLA) parameters such as delay, loss, and throughtput when anomalies are detected. The marking component of the router uses TCP flow characteristics to protect "fragile" flows. The edge routers may also regulate unresponsive flows. Ingress routers propagate congestion information to upstream domains. Preliminary simulation results indicate that this design increases application-level throughput of data applications such as large FTP transfers; achieves low packet delays and response times for Telnet and WWW traffic; and detects trafficintensive attacks and service violations

Monitoring and Controlling QoS Network Domains £

Increased performance, fairness, and security remain important goals for service providers. In this work, we design an integrated distributed monitoring, traffic conditioning, and flow control system for higher performance and security of network domains. Edge routers monitor (using tomography techniques) a network domain to detect quality of service (QoS) violations – possibly caused by underprovisioning – as well as bandwidth theft attacks. To bound the monitoring overhead, a router only verifies service level agreement (SLA) parameters such as delay, loss, and throughput when anomalies are detected. The marking component of the edge router uses TCP flow characteristics to protect “fragile ” flows. Edge routers may also regulate unresponsive flows, and may propagate congestion information to upstream domains. Simulation results indicate that this design increases application-level throughput of data applications such as large FTP transfers; achieves low packet delays and response times for Telnet and WWW traffic; and detects bandwidth theft attacks and service violations

Monitoring and controlling QoS network domains: An edge -to -edge approach

This research studies and designs techniques for coordinated network monitoring, traffic conditioning, and flow control as integral components of the edge routers in a network domain. The enhanced edge routers yield secure network domains, and achieve better performance in terms of high data throughput, low delay, and low loss rates. The potential performance gain from the proposed techniques is critical for the current and emerging network services such as multimedia applications. Using simulation, we evaluate the edge router for data intensive applications such as FTP and delay sensitive applications such as Telnet and Web. The contributions of this thesis can be summarized as follows: (1) Network Monitoring. Continuous monitoring of network activity is required to maintain confidence in the security of networks with quality of service (QoS) support. The flows are monitored for possible service level agreement violations and bandwidth theft attacks. We design and evaluate tomography-based and overlay-based network monitoring methodologies for efficient and scalable network monitoring. These schemes infer the internal characteristics of a network domain without involving the core routers. Our results show that we can monitor a network domain with O(n) probes, where n is the number of edge routers. Monitoring mechanism can be used to detect denial of service (DoS) attacks at an early stage. A quantitative comparison among schemes to defeat DoS attacks is conducted, in which, we highlight the merits of each scheme and estimate the processing and communication overhead introduced by it. The comparison provides guidelines for selecting the appropriate scheme based on the requirements and how much overhead can be tolerated. (2) Policy Enforcement. To improve the QoS, we enforce policy on the incoming flows and focus on congestion and unfairness in network resource allocation problems. We design an adaptive conditioner that considers congestion window size, round trip time (RTT), retransmission time-out, and explicit congestion notification information to mark and shape a flow. The conditioner also improves the fairness among long and short-RTT flows. (3) Flow Control. We use the differentiated services framework and network tomography to detect the unresponsive flows. The flow detection mechanism is scalable, and it requires very low overhead. An adaptive congestion control framework is designed that follows TCP-like congestion control algorithm and regulates the unresponsive flows to alleviate the congestion