Abstract:
A method of managing a network application includes identifying a network path for the network application, obtaining network performance measurements along the network path, obtaining application performance information for the network application, and extracting infrastructure specific information for the infrastructure supporting the network application. The method further includes correlating the application performance information, network performance measurements, and the infrastructure specific information to identify a performance issue affecting the network application, and modifying the application behavior, the network behavior, or any combination thereof in response to the performance issue.
Abstract:
A method for producing a summary A of data points in an unaggregated data stream wherein the data points are in the form of weighted keys (a, w) where a is a key and w is a weight, and the summary is a sample of k keys a with adjusted weights wa. A first reservoir L includes keys having adjusted weights which are additions of weights of individual data points of included keys and a second reservoir T includes keys having adjusted weights which are each equal to a threshold value τ whose value is adjusted based upon tests of new data points arriving in the data stream. The summary combines the keys and adjusted weights of the first reservoir L with the keys and adjusted weights of the second reservoir T to form the sample representing the data stream upon which further analysis may be performed. The method proceeds by first merging new data points in the stream into the reservoir L until the reservoir contains k different keys and thereafter applying a series of tests to new arriving data points to determine what keys and weights are to be added to or removed the reservoirs L and T to provide a summary with a variance that approaches the minimum possible for aggregated data sets. The method is composable, can be applied to high speed data streams such as those found on the Internet, and can be implemented efficiently.
Abstract:
A system that incorporates teachings of the present disclosure may include, for example, network device having a controller to combine network data sources enabling simplified database queries across a plurality of data sources, normalize the data from the plurality of data sources, continuously collect routing information between two routers of interest, selectively and automatically extract network data involving network events and routing, determine a temporal correlation among identified network events, determine a spatial correlation among identified network events, and troubleshoot an interactive media service based on a combination of the temporal correlation and the spatial correlation determined between the defined edge routers. Other embodiments are disclosed.
Abstract:
Statistical methods are used to observe packet flow arrival processes and to infer routing changes from those observations. Packet flow arrivals are monitored using NetFlow or another packet flow monitoring arrangement. Packet flow arrivals are quantified by counting arrivals per unit time, or by measuring an inter-arrival time between flows. When a change in packet flow arrivals is determined to be statistically significant, a change in network routing protocol is reported.
Abstract:
The present invention is directed to a method and system for deriving traffic demands for a packet-switched network. A novel model of defining traffic demands as a volume of load originating from an ingress link and destined to a set of egress links enables support for traffic engineering and performance debugging of large operational packet-switched networks.
Abstract:
Methods and apparatus to bound network traffic estimation error for multistage measurement sampling and aggregation are disclosed. An example method disclosed herein comprises determining a hierarchical sampling topology representative of multiple data sampling and aggregation stages, the hierarchical sampling topology comprising a plurality of nodes connected by a plurality of edges, each node corresponding to at least one of a data source and a data aggregation operation, and each edge corresponding to a data sampling operation characterized by a generalized sampling threshold, selecting a first generalized sampling threshold from a set of generalized sampling thresholds associated with a respective set of edges originating at a respective set of descendent nodes of a target node undergoing network traffic estimation, and transforming a measured sample of network traffic into a confidence interval for a network traffic estimate associated with the target node using the first generalized sampling threshold and an error parameter.
Abstract:
The present application relates to methods and devices for providing a reduced risk of free flow from medical devices such as an infusion pump. A medicament containing reservoir (100) is provided with a piston having a sealing portion (121) formed by a material of a first stiffness. The piston further comprises a core member (110) of a material having a stiffness larger than said first stiffness, the core member comprising one or more connective members (111) being adapted to cooperate with said one or more protrusions of the linear actuation member. The one or more connective members being adapted to be substantially rigid in the axial direction while being resilient in a radial direction, thereby forming a releasable snap or friction fit connection with the linear actuation member. Thereby a mechanism is provided which is engageable by a purely axial relative displacement and which is disengageable by retracting the linear actuation member axially relative to the piston by exerting a pulling force greater than a predetermined limit.
Abstract:
Two regularized estimators that avoid the pathologies associated with variance estimation are disclosed. The regularized variance estimator adds a contribution to estimated variance representing the likely error, and hence ameliorates the pathologies of estimating small variances while at the same time allowing more reliable estimates to be balanced in the convex combination estimator. The bounded variance estimator employs an upper bound to the variance which avoids estimation pathologies when sampling probabilities are very small.
Abstract:
An efficient streaming method and apparatus for detecting hierarchical heavy hitters from massive data streams is disclosed. In one embodiment, the method enables near real time detection of anomaly behavior in networks.
Abstract:
The present invention provides apparatus for sampling data flows in a data network in order to estimate a total data volume in the network. Sampling the data flows in the data network reduces the network resources that must be expended by the network to support the associated activity. The present invention enables the service provider of the data network to control sampled volumes in relation to the desired accuracy. The control can be either static or can be dynamic for cases in which the data volumes are changing as a function of time.