Abstract: First-order effects of hypothesized fault conditions are determined by propagating discrete test packets between select nodes and noting the change of path, if any, taken by the test packet under each condition relative to the fault-free path. Tools are provided to create classes of node pairs of interest, and test packets are created only for select classes. The network is analyzed to identify fault conditions that are likely to impact system performance, and only these fault conditions are simulated. By providing a methodology for selecting classes of node pairs to test, and prioritizing the faults to simulate, a first-order survivability analysis of large networks can be performed efficiently and effectively. The efficiency of this technique is also enhanced by providing test packets that are representative of a wide range of possible source-destination combinations, and by evaluating only the source-destination combinations that may be directly affected by each fault condition.

Abstract: The invention presented herein provides methods and compositions for the prevention and treatment of bacterial infections. The methods are based on the discovery that depletion of bioavailable iron stimulates surface motility in bacteria thus inhibiting the ability of a bacterial population to develop into a biofilm.

Abstract: The present system includes a system, method and device for inferring connectivity between unconnected network segments. In operation, unconnected network segments are identified. Configuration data related to the unconnected network segments may be examined to facilitate inferring configuration data for an external network connected between the unconnected network segments. The inferred configuration data may be rendered, such as exported or visualized. The inferred configuration data may be related to a communication protocol and/or may be related to network bandwidth. The examined configuration data may be captured directly from one or more of the unconnected network segments and/or may be retrieved from a configuration data file, such as a network configuration model.

Abstract: Network survivability is quantified in such a way that failure cases can be compared and ranked against each other in terms of the severity of their impact on the various performance measures associated with the network. The degradation in network performance caused by each failure is quantified based on user-defined sets of thresholds of degradation severity for each performance measure. Each failure is simulated using a model of the network, and a degradation vector is determined for each simulated failure. A comparison function is defined to map the degradation vectors into an ordered set, and this ordered set is used to create an ordered list of network failures, in order of the network degradation caused by each failure.

Abstract: A network configuration is processed to identify each policy and the criteria associated with each policy. The criteria of the policies are processed to identify a non-overlapping set of ranges of the criteria parameter, each range being associated with a particular policy or set of policies. In a preferred embodiment, the criteria include the protocol, the source and destination IP addresses, and the source and destination ports, and a default range is defined for each criteria parameter.

Abstract: A sub-system is provided to a discrete event simulator (DES) to expedite simulation execution by first detecting a non-quiescent steady-state condition in the simulated system, and when the steady-state condition is detected, the simulator determines a state, and subsequently simulates the system at a skip-ahead time using this determined state, or a predicted state based on the determined state. Convergence analysis is used to determine whether the system is at, or approaching, a steady-state condition. This convergence skip-ahead process achieves faster analysis by avoiding the computation that would conventionally be required to simulate the system behavior during the time interval that is skipped.

Abstract: A method and system for flow propagation analysis uses ‘tracers’ that are iteratively propagated through a simulated network between source and destination elements. These tracers are structured to contain traffic flow information from source to destination, and to reflect changes as the flow is affected by each element along the path from source to destination. The resultant flow information at the destination corresponds to the effective throughput from the source to the destination, and the flow information at the output of each intermediate element in the network corresponds to the potentially achievable throughput through that element for the given source-to-destination flow.

Abstract: A method and system for flow propagation analysis uses ‘tracers’ that are iteratively propagated through a simulated network between source and destination elements. These tracers are structured to contain traffic flow information from source to destination, and to reflect changes as the flow is affected by each element along the path from source to destination. The resultant flow information at the destination corresponds to the effective throughput from the source to the destination, and the flow information at the output of each intermediate element in the network corresponds to the potentially achievable throughput through that element for the given source-to-destination flow.

Abstract: A sub-system is provided to a discrete event simulator (DES) to expedite simulation execution by first detecting a non-quiescent steady-state condition in the simulated system, and when the steady-state condition is detected, the simulator determines a state, and subsequently simulates the system at a skip-ahead time using this determined state, or a predicted state based on the determined state. Convergence analysis is used to determine whether the system is at, or approaching, a steady-state condition. This convergence skip-ahead process achieves faster analysis by avoiding the computation that would conventionally be required to simulate the system behavior during the time interval that is skipped.