Abstract: In a communications network, a request manager simultaneously dispatches a number of requests to servers corresponding to at least one domain of interest that is specified by a client. Multiple responses are received and a single collated response is sent back to the client that initiated the request. A request context table is provided which includes an anchor context and dependent contexts corresponding to each of the servers, and a session count for tracking receipt of all responses for each server. An internal cache of server addresses is also maintained.

Abstract: Method and apparatus for providing a call-tapping point in a switched network with point-to-multipoint functionality. The tapping point is added as an additional destination for data being sent from a source node to a first destination node. The tapping point is also added as a destination for data being sent from the first destination node to the source node. A merge operation is performed for finding and combining common segments of the paths between the source and destination, the source and tapping point, and the destination and tapping point.

Abstract: A system and method are disclosed for routing multicast packets in a subnetwork so as to conserve bandwidth in at least some of the network segments or collision domains of the subnetwork. In particular, multicast packets are only retransmitted in the network segments that are on a path to a host that is a member of the multicast group of hosts to which the multicast packet is destined.

Abstract: A logical representation of a communications network topology has links which represent connections within a network, and models of ports representing elements of devices which form the connections of the network. The logical representation is created and maintained in response to reports from the network, such as new neighbor reports and lost neighbor reports. A new neighbor module creates or changes the logical representation in response to new neighbor reports, based upon whether the reporting port is recently attached and whether the new neighbor port is recently attached. A lost neighbor module changes the logical representation in response to lost neighbor reports, by creating pseudo new neighbor reports, and allowing the pseudo new neighbor reports to be processed following a certain amount of time.

Abstract: A network management system includes a user interface, a virtual network and a device communication manager. The virtual network includes models which represent network entities and model relations which represent relations between network entities. Each model includes network data relating to a corresponding network entity and one or more inference handlers for processing the network data to provide user information. The system can poll or communicate with certain network entities and can infer the status of network connectors and other network entities for which polling is impossible or impractical. The system performs a fault isolation technique wherein the fault status of a network device is suppressed when it is determined that the device is not defective. User displays include hierarchical location views and topological views of the network configuration.

Abstract: An apparatus and method for allocating the performance of applications in a networking chassis among one or more modules in the chassis. In particular, the system acts as a chassis agent for performing network management functions. The agent performs a discovery function whereby each module discovers the location and current utilization of resources and applications for itself and transmits that information to other modules, and wherein each module maintains a slot table of such information for all modules. Based on the information in the slot table, each module performs an election function for allocating applications among the various modules in the chassis. The agent uses Management Information Bases MIBs to gather information about the chassis and to effect control on the chassis, wherein each managed object is registered both locally and remotely in a MIB tree maintained on each module, and the data is maintained locally on the module on which the managed object resides.

Abstract: A method for determining a best path from a source node to a destination node using a breadth first recursive search in parallel. The determination is based upon a plurality of metrics which are set by the system. A path's metrics are compared to respective threshold values and paths are discarded if the metrics values do not each exceed respective thresholds. In addition, if a path has no metric which is better than one of the already completed paths, the path is discarded.

Abstract: An object-oriented architecture for network layer routing is provided which distributes function and system behavior into autonomous router objects. By distributing these functionalities into each object, the services and data normally external to the object are imbedded or accessible within the object itself. In another sense, some objects are distributed across the network; e.g., a separate forwarding engine is provided at each network interface. In a preferred embodiment, each object has: (1) common, protocol-independent functions that are shared by all objects of that class; (2) their own configuration information; (3) accessibility through a router resource object for instantiation and control; (4) automatic persistence in NVRAM; (5) remote management capabilities; and (6) text names for navigation of a resource tree as a file system. These capabilities are in every object regardless of the specific protocol or application.

Abstract: A network management system includes a user interface, a virtual network and a device communication manager. The virtual network includes models which represent network entities and model relations which represent relations between network entities. Each model includes network data relating to a corresponding network entity and one or more inference handlers for processing the network data to provide user information. The system performs a fault isolation technique wherein the fault status of a network device is suppressed when it is determined that the device is not defective. User displays include hierarchical location views and topological views of the network configuration. Network devices are represented on the displays by multifunction icons which permit the user to select additional displays showing detailed information regarding different aspects of the corresponding network device.

Abstract: Apparatus and method for establishing "virtual connections" through a packet switched data communications network, the network including a plurality of end systems and switches connected by links. Each end system has a unique physical layer address and each switch has a connection database of valid connections between different ports on the switch and a switching mechanism for establishing temporary connections. Each switch is registered with a connection server such that, prior to transmission of a connectionsless datagram from a first end system to a second end system, a path of valid remains as a connectionless datagram. In other aspects, an improved method is provided for allocating bandwidth among competing devices requesting access to a bandwidth limited shared resource (e.g., the previously defined switch), and to a search method for making a best path determination through the network based on a number of constraints.

Abstract: Apparatus and method for establishing "virtual connections" through a packet switched data communications network, the network including a plurality of end systems and switches connected by links. Each end system has a unique physical layer address and each switch has a connection database of valid connections between different ports on the switch and a switching mechanism for establishing temporary connections. Each switch is registered with a connection server such that, prior to transmission of a connectionless datagram from a first end system to a second end system, a path of valid connections through one or more switches from the first end system to the second end system is determined by configuring the connection table of each switch on the path with a connection identifier identified by the physical layer addresses of the first and second end systems, and wherein the data packet remains as a connectionless datagram.

Abstract: A network management system includes a user interface, a virtual network and a device communication manager. The virtual network includes models which represent network entities and model relations which represent relations between network entities. Each model includes network data relating to a corresponding network entity and one or more inference handlers for processing the network data to provide user information. The system performs a fault isolation technique wherein the fault status of a network device is suppressed when it is determined that the device is not defective. User displays include hierarchical location views and topological views of the network configuration. Network devices are represented on the displays by multifunction icons which permit the user to select additional displays showing detailed information regarding different aspects of the corresponding network device.

Abstract: A flexible modular interconnect system is provided which utilizes a backplane having a plurality of module receiving slots and a plurality of circuit modules, selected ones of the circuit modules being mounted in at least selected ones of the slots. The modules may be of a variety of different types. First and second switches are provided for each circuit module with selected lines from module logic being connected to each of the switches. The first and second switches for each module are interconnected and the first switch for the selected modules are connected to the switch for adjacent modules. Selected information concerning each module is provided to each adjacent module and control logic is provided which is responsive at least in part to the received information concerning the adjacent module for controlling the state of an appropriate switches. The switches may also be controlled from an external source. By selectively controlling the state of the switches, the modules may be flexibly interconnected.

Abstract: A network management system includes a user interface, a virtual network and a device communication manager. The virtual network includes models which represent network entities and model relations which represent relations between network entities. Each model includes network data relating to a corresponding network entity and one or more inference handlers for processing the network data to provide user information. The system performs a fault isolation technique wherein the fault status of a network device is suppressed when it is determined that the device is not defective. User displays include hierarchical location views and topological views of the network configuration. Network devices are represented on the displays by multifunction icons which permit the user to select additional displays showing detailed information regarding different aspects of the corresponding network device.

Abstract: Methods and apparatus, including a concentrator, for operating a station coupled to a ring in a token ring network. The ring carries signal at an active monitor clock rate. The method includes the steps of generating a local clock at an accelerated clock rate that is equal to or greater than the active monitor clock rate, operating the station at the accelerated clock rate when the station is a standby monitor, operating the station at the active monitor clock rate when the station is the active monitor, operating the station at its own clock rate when the station is in loopback mode, and receiving signal from the ring and transmitting signal to the ring at the active monitor clock rate. The station operates at the accelerated clock rate of the local clock except when the station is the active monitor or is in loopback mode.

Abstract: A network management system includes a user interface, a virtual network and a device communication manager. The virtual network includes models which represent network entities and model relations which represent relations between network entities. Each model includes network data relating to a corresponding network device and one or more inference handlers for processing the network data to provide user information. The system performs a fault isolation technique wherein the fault status of a network device is suppressed when it is determined that the device is not defective. User displays include hierarchical location views and topological views of the network configuration. Network devices are represented on the displays by multifunction icons which permit the user to select additional displays showing detailed information regarding different aspects of the corresponding network device.

Abstract: A flexible modular interconnect system is provided which utilizes a backplane having a plurality of module receiving slots and a plurality of circuit modules, selected ones of the circuit modules being mounted in at least selected ones of the slots. The modules may be of a variety of different types. First and second switches are provided for each circuit module with selected lines from module logic being connected to each of the switches. The first and second switches for each module are interconnected and the first switch for the selected modules are connected to the second switch for adjacent modules. Selected information concerning each module is provided to each adjacent module and control logic is provided which is responsive at least in part to the received information concerning the adjacent module for controlling the state of an appropriate switch. The switches may also be controlled from an external source.