8 research outputs found

    Accurate and efficient SLA compliance monitoring

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    Multi-Tier Diversified Service Architecture for Internet 3.0: The Next Generation Internet

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    The next generation Internet needs to support multiple diverse application contexts. In this paper, we present Internet 3.0, a diversified, multi-tier architecture for the next generation Internet. Unlike the current Internet, Internet 3.0 defines a new set of primitives that allows diverse applications to compose and optimize their specific contexts over resources belonging to multiple ownerships. The key design philosophy is to enable diversity through explicit representation, negotiation and enforcement of policies at the granularity of network infrastructure, compute resources, data and users. The basis of the Internet 3.0 architecture is a generalized three-tier object model. The bottom tier consists of a high-speed network infrastructure. The second tier consists of compute resources or hosts. The third tier consists of data and users. The “tiered” organization of the entities in the object model depicts the natural dependency relationship between these entities in a communication context. All communication contexts, including the current Internet, may be represented as special cases within this generalized three-tier object model. The key contribution of this paper is a formal architectural representation of the Internet 3.0 architecture over the key primitive of the “Object Abstraction” and a detailed discussion of the various design aspects of the architecture, including the design of the “Context Router-” the key architectural element that powers an evolutionary deployment plan for the clean slate design ideas of Internet 3.0

    Non-Intrusive Measurement in Packet Networks and its Applications

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    PhDNetwork measurementis becoming increasingly important as a meanst o assesst he performanceo f packet networks. Network performance can involve different aspects such as availability, link failure detection etc, but in this thesis, we will focus on Quality of Service (QoS). Among the metrics used to define QoS, we are particularly interested in end-to-end delay performance. Recently, the adoption of Service Level Agreements (SLA) between network operators and their customersh as becomea major driving force behind QoS measurementm: easurementi s necessaryt o produce evidence of fulfilment of the requirements specified in the SLA. Many attempts to do QoS based packet level measurement have been based on Active Measurement, in which the properties of the end-to-end path are tested by adding testing packets generated from the sending end. The main drawback of active probing is its intrusive nature which causes extraburden on the network, and has been shown to distort the measured condition of the network. The other category of network measurement is known as Passive Measurement. In contrast to Active Measurement, there are no testing packets injected into the network, therefore no intrusion is caused. The proposed applications using Passive Measurement are currently quite limited. But Passive Measurement may offer the potential for an entirely different perspective compared with Active Measurements In this thesis, the objective is to develop a measurement methodology for the end-to-end delay performance based on Passive Measurement. We assume that the nodes in a network domain are accessible.F or example, a network domain operatedb y a single network operator. The novel idea is to estimate the local per-hop delay distribution based on a hybrid approach (model and measurement-based)W. ith this approach,t he storagem easurementd ata requirement can be greatly alleviated and the overhead put in each local node can be minimized, so maintaining the fast switching operation in a local switcher or router. Per-hop delay distributions have been widely used to infer QoS at a single local node. However, the end-to-end delay distribution is more appropriate when quantifying delays across an end-to-end path. Our approach is to capture every local node's delay distribution, and then the end-to-end delay distribution can be obtained by convolving the estimated delay distributions. In this thesis, our algorithm is examined by comparing the proximity of the actual end-to-end delay distribution with the estimated one obtained by our measurement method under various conditions. e. g. in the presence of Markovian or Power-law traffic. Furthermore, the comparison between Active Measurement and our scheme is also studied. 2 Network operators may find our scheme useful when measuring the end-to-end delay performance. As stated earlier, our scheme has no intrusive effect. Furthermore, the measurement result in the local node can be re-usable to deduce other paths' end-to-end delay behaviour as long as this local node is included in the path. Thus our scheme is more scalable compared with active probing

    Monitoring middleware for distributed applications

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    With growing maturity Internet services are proving integral to the provision of computer services. To provide consistent end-user experiences these services are increasingly augmented with some notion of 'Quality-of-Service' (QoS), which typically requires the management of computing resources to maintain a predictable level of service performance. It is difficult to guarantee consistent servIce provision In dynamic and open environments such as the Internet. However service monitoring can be used to inform compensatory actions by collecting meaningful service performance data from strategic points in an active service environment. Due to the unpredictable nature of the Internet distributed monitoring mechanisms face challenges with respect to the various communication protocols, application languages, and monitoring requirements associated with a service environment. With the growing popularity of Internet services creation of monitoring solutions on a per- service basis becomes time-consuming and misses opportunities to re-use existing logic. Ideally monitoring solutions would be domain-agnostic, automatically generated and automatically deployed. This thesis progresses these ambitions by providing a generic, distributed monitoring and evaluation framework based on Metric Collector (MeCo) components. These components can transparently gather measurement data across a range of service technologies as used within E-Commerce service environments. MeCo components form part of a framework which can interpret Service Level Agreements (SLAs) to automatically provide tailored service monitoring. The evaluation paradigms of the Meeo Framework are re-appropriated for use in Distributed Virtual Environments (DYEs). Quantifiable QoS requirements are established for Interest Management mechanisms (which limit message production based on object localities within a DYE). These are then incorporated into a DVE Simulator application. This application allows DYE application developers to evaluate Interest Management configurations for their suitability. Extensions to the DVE Simulator are exhibited in the Evolutionary Optimisation Simulator (EOS), which provides automated optimisation capabilities for DVE configurations through utilisation of genetic algorithm techniques.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

    A Scalable Monitoring Approach for Service Level Agreements Validation

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    In order to detect violations of end-to-end service level agreements (SLA) and to isolate trouble links and nodes based on a unified framework, managers of a service provider network need to gather Quality of Service (QoS) measurements from multiple nodes in the network. For a network carrying over thousands of flows with end-toend SLAs, the information exchanged between network nodes and a central network management system (NMS) could be substantial. Moreover, in situations where only a small number of flows violate their respective SLAs, simple polling mechanisms can lead to huge unnecessary overhead in identifying these ill-behaved flows. In this work, we propose an algorithm called ARM (Aggregation and Refinement based Monitoring) to reduce the amount of information exchange. ARM uses a histogram-based dynamic QoS data aggregation/refinement technique at each network node and a reasoning engine at the NMS to minimize the amount of data exchange between network nodes and NMS. ARM not only reduces unnecessary reporting through selective refinement, it also performs well across a wide range of traffic loads. Our simulation results show that ARM is at least an order of magnitude more efficient than a simple polling scheme. It also outperforms two centralized, highly optimized schemes that cannot be implemented in practice.
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