Abstract: In a network that includes static bandwidth and dynamic bandwidth links, traffic flow at the OSI network layer is simulated at a traffic-flow level at interfaces to fixed bandwidth links, and simulated at a discrete-packet level at interfaces to dynamic bandwidth links. The resultant discrete-packet reception events at the receiving interface(s) of the dynamic bandwidth link are processed to determine the effective bandwidth/throughput of the link, as well as the allocation of this bandwidth among the individual flows through the link. The discrete-packet level receptions are used to reconstruct the parameters of the traffic flow at the network layer of the receiving interface, and this determined traffic flow is simulated accordingly at the next link, depending upon whether the next link is a static or dynamic bandwidth link.

Abstract: A network analysis system invokes an application specific, or source-destination specific, path discovery process. The application specific path discovery process determines the path(s) used by the application, collects performance data from the nodes along the path, and communicates this performance data to the network analysis system for subsequent performance analysis. The system may also maintain a database of prior network configurations to facilitate the identification of nodes that are off the path that may affect the current performance of the application. The system may also be specifically controlled so as to identify the path between any pair of specified nodes, and to optionally collect performance data associated with the path.

Abstract: A hybrid approach to populating forwarding tables in a virtual network obtains forwarding data both by simulating routing protocol behavior in the virtual network to build forwarding tables, and by importing operational forwarding data from corresponding physical nodes in a physical network. The use of operational forwarding data improves the fidelity of the simulation by closely conforming forwarding behavior in the simulation to that which occurs in the physical network.

Abstract: A hybrid approach to populating forwarding tables in a virtual network obtains forwarding data both by simulating routing protocol behavior in the virtual network to build forwarding tables, and by importing operational forwarding data from corresponding physical nodes in a physical network. The use of operational forwarding data improves the fidelity of the simulation by closely conforming forwarding behavior in the simulation to that which occurs in the physical network.

Abstract: A network analysis system invokes an application specific, or source-destination specific, path discovery process. The application specific path discovery process determines the path(s) used by the application, collects performance data from the nodes along the path, and communicates this performance data to the network analysis system for subsequent performance analysis. The system may also maintain a database of prior network configurations to facilitate the identification of nodes that are off the path that may affect the current performance of the application. The system may also be specifically controlled so as to identify the path between any pair of specified nodes, and to optionally collect performance data associated with the path.

Abstract: Disclosed are, inter alia, methods, apparatus, and means for stateful switching between reliable transport modules for communicating with an external peer without losing the transport layer connection. Primary and standby reliable transport protocol modules each maintain state concerning the reliable transport connection (e.g., data, segmentation, acknowledgements) such that if the primary or standby reliable transport protocol module fails, the other can resume by itself such that the communication with the peer transport application does not need to be restarted. Also, by the communications subsystem of a device providing copies of received reliable transport protocol messages directly to both the primary and standby reliable transport protocol modules, upon failover, the communications subsystem does not need to be reconfigured for resuming operations as, for example, the standby reliable transport protocol module will already be receiving these packets.

Abstract: A network analysis system invokes an application specific, or source-destination specific, path discovery process. The application specific path discovery process determines the path(s) used by the application, collects performance data from the nodes along the path, and communicates this performance data to the network analysis system for subsequent performance analysis. The system may also maintain a database of prior network configurations to facilitate the identification of nodes that are off the path that may affect the current performance of the application. The system may also be specifically controlled so as to identify the path between any pair of specified nodes, and to optionally collect performance data associated with the path.

Abstract: A network analysis system invokes an application specific, or source-destination specific, path discovery process. The application specific path discovery process determines the path(s) used by the application, collects performance data from the nodes along the path, and communicates this performance data to the network analysis system for subsequent performance analysis. The system may also maintain a database of prior network configurations to facilitate the identification of nodes that are off the path that may affect the current performance of the application. The system may also be specifically controlled so as to identify the path between any pair of specified nodes, and to optionally collect performance data associated with the path.

Abstract: Channel access delays and reception uncertainty are modeled as protocol-independent generic processes that are optimized for improved simulation performance. The generic process components are designed such that each different protocol can be modeled using an arrangement of these components that is specific to the protocol. In this way, speed and/or accuracy improvements to the generic process components are reflected in each of such protocol models. If an accurate analytic model is not available for the generic process component, a prediction engine, such as a neural network, is preferably used. The prediction engine is trained using the existing detailed models of network devices. Once trained, the prediction engine is used to model the generic process, and the protocol model that includes the generic component is used in lieu of the detailed models, thereby saving substantial processing time.

Abstract: Traffic flows through an administered network from an off-network source and/or to an off-network destination are simulated and analyzed by selecting an ingress and/or egress node within the administered network, the ingress node capable of collecting traffic from an off-network source, and the egress node capable of routing traffic to an off-network destination. Traffic flow is mapped from the source or ingress node through the administered network to the egress node. The traffic flow may be simulated and analyzed. The ingress and/or egress nodes may be selected in a variety of ways.

Abstract: A system for resolving address conflicts in a network. In an illustrative embodiment, the system includes an address-configuration module that is adapted to assign addresses to one or more devices. The one or more devices are connected to the network via device interfaces. An interface-monitoring module communicates with the address-configuration module. The interface-monitoring module is adapted to determine when an address conflict involving plural addresses occurs and to provide a signal in response thereto. A conflict-resolution module is adapted to selectively terminate one or more device interfaces associated with the plural addresses in response to the signal and based on the addresses and one or more predetermined precedence rules. In a more specific embodiment, the system further employs a user interface for facilitating selectively adjusting the precedence rules.

Abstract: Methods and apparatus for substantially minimizing single points of failure for circuit paths in networks with mixed protection schemes are disclosed. According to one aspect of the present invention, a method for routing circuit paths between a source and a destination of a network includes identifying a first available circuit path between the source and the destination. The first available circuit path includes a first plurality of links which each have an associated protection type. The method also includes determining a number protection changes associated with the first plurality of links, and assigning a first metric to the first available path that is based on the number of protection changes. Finally, the method includes identifying a selected available path to be used to pass information between the source and the destination based at least in part on the first metric.

Abstract: A simulation method and system partitions network traffic into background traffic and explicit traffic, wherein explicit traffic is processed in detail, and background traffic is processed at a more abstract level. The packets of explicit traffic are modeled in complete detail, so that precise timing and behavior characteristics can be determined, whereas large volumes of traffic are modeled more abstractly as background flows, and only certain aspects, such as routing through the network, are simulated. Tracer packets are used to model the background traffic and carry a number of characteristics of interest for generating simulation results. In this manner, the effect of the background traffic on the explicit traffic can be modeled at each network element. The abstract processing of background traffic is facilitated by techniques that include multi-variate table look-up, neural networks, and the like.

Abstract: A method and system for representing a low-order connection and a high-order connection as a single circuit are disclosed. The method includes creating a low-order listener object and a low/high listener object at each end point of the low-order connection and creating a high-order listener object at each end point of the high-order connection. The low/high listener objects are matched with the high-order listener objects to create a link and represent the connections as a single circuit.

Abstract: Disclosed are, inter alia, methods, apparatus, and means for stateful switching between reliable transport modules for communicating with an external peer without losing the transport layer connection. Primary and standby reliable transport protocol modules each maintain state concerning the reliable transport connection (e.g., data, segmentation, acknowledgements) such that if the primary or standby reliable transport protocol module fails, the other can resume by itself such that the communication with the peer transport application does not need to be restarted. Also, by the communications subsystem of a device providing copies of received reliable transport protocol messages directly to both the primary and standby reliable transport protocol modules, upon failover, the communications subsystem does not need to be reconfigured for resuming operations as, for example, the standby reliable transport protocol module will already be receiving these packets.

Abstract: In a network that includes static bandwidth and dynamic bandwidth links, traffic flow at the OSI network layer is simulated at a traffic-flow level at interfaces to fixed bandwidth links, and simulated at a discrete-packet level at interfaces to dynamic bandwidth links. The resultant discrete-packet reception events at the receiving interface(s) of the dynamic bandwidth link are processed to determine the effective bandwidth/throughput of the link, as well as the allocation of this bandwidth among the individual flows through the link. The discrete-packet level receptions are used to reconstruct the parameters of the traffic flow at the network layer of the receiving interface, and this determined traffic flow is simulated accordingly at the next link, depending upon whether the next link is a static or dynamic bandwidth link.

Abstract: Channel access delays and reception uncertainty are modeled as protocol-independent generic processes that are optimized for improved simulation performance. The generic process components are designed such that each different protocol can be modeled using an arrangement of these components that is specific to the protocol. In this way, speed and/or accuracy improvements to the generic process components are reflected in each of such protocol models. If an accurate analytic model is not available for the generic process component, a prediction engine, such as a neural network, is preferably used. The prediction engine is trained using the existing detailed models of network devices. Once trained, the prediction engine is used to model the generic process, and the protocol model that includes the generic component is used in lieu of the detailed models, thereby saving substantial processing time.

Abstract: A hybrid approach to populating forwarding tables in a virtual network obtains forwarding data both by simulating routing protocol behavior in the virtual network to build forwarding tables, and by importing operational forwarding data from corresponding physical nodes in a physical network. The use of operational forwarding data improves the fidelity of the simulation by closely conforming forwarding behavior in the simulation to that which occurs in the physical network.

Abstract: Devices and methods for modeling and analysis of services provided over a common network include a processor configured to track services connected to the common network through nodes and links; run service models associated with the services under selected conditions, the selected conditions including failure and repair of one of the nodes or links; and propose corrective action and/or change of network resources of the common network to minimize impact of the failure. The processor may also run Network model(s). The models may be executed successively or simultaneously, and outputs of one model may be used as input to other models, including any necessary conversions for compatibility.

Abstract: Traffic flows through an administered network from an off-network source and/or to an off-network destination are simulated and analyzed by selecting an ingress and/or egress node within the administered network, the ingress node capable of collecting traffic from an off-network source, and the egress node capable of routing traffic to an off-network destination. Traffic flow is mapped from the source or ingress node through the administered network to the egress node. The traffic flow may be simulated and analyzed. The ingress and/or egress nodes may be selected in a variety of ways.