Abstract: A method and apparatus for auto-configuring layer 3 intermediate devices in computer networks by extending the Dynamic Host Configuration Protocol (DHCP). The devices generate, transmit and receive DHCP messages having novel options embedded therein. The options permit a layer 3 device to request and receive from a DHCP server a unique, overall IP address that may be assigned to the device. The device may also request and receive one or more IP subnets and corresponding IP addresses for each of its interfaces. The device may further receive the routing protocols to be used on the various subnets. The layer 3 device can thus be auto-configured with IP configuration parameters, including IP subnets, IP addresses and routing protocols without the time-consuming, manual involvement of a network administrator.

Abstract: The present invention relates to a program-development environment that allows developers to seamlessly switch between a visual programming paradigm and a textual programming paradigm, thereby permitting developers to choose the paradigm best suited for creating each aspect of the desired program. A graphical user interface (GUI) may be generated by the program-development environment, and displayed on the screen of a computer system. The GUI has several elements including a form window and a designer window. The form window is configured to receive one or more control objects selected by the developer, and the designer window is configured to display a symbolic representation of those control objects placed in the form window.

Abstract: A system for rapidly switching at least one virtual local area network (VLAN) from a first loop-free topology to a second loop-free topology in response to a failure within the first loop-free topology. Each VLAN has one “logical” VLAN which represents the network entities organized into the VLAN and a set of “physical” VLANs each having its own VLAN designation. For each physical VLAN, a different loop-free topology is defined, although only one physical VLAN is “active” at any given time. Messages associated with the logical VLAN are tagged with the designation of the currently active physical VLAN, and forwarded along its loop-free topology. Upon detecting a failure in the loop-free topology, the logical VLAN is rapidly switched to the loop-free topology defined by a second, back-up physical VLAN. Following the switch messages associated with the logical VLAN are tagged with the designation of this back-up VLAN and are forwarded along its loop-free topology.

Abstract: A system for efficiently organizing data or information into an associative memory device, such as a ternary content addressable memory (TCAM), for subsequent searching divides the TCAM is divided into a plurality of individual stages that are interconnected in a cascading fashion. The data or information that is to be stored into the TCAM for subsequent searching is initially translated into a first Boolean representation, such as a binary decision diagram (BDD), that is partitioned into a plurality of segments. Each segment defines one or more outputs, and the outputs from one segment define the inputs to the next segment. After partitioning the BDD and identifying the resulting outputs, each BDD segment along with its corresponding outputs is mapped into a particular stage of the TCAM.

Abstract: The invention relates to a method and apparatus for efficiently organizing, storing and evaluating access control lists (ACLs) for use by an intermediate network device of a computer network. The intermediate network device includes an ACL converter which, in turn, includes a boolean transformation engine that is operatively coupled to a boolean manipulation engine. The boolean transformation engine is configured to access the ACLs in first format and to translate them into a first boolean representation, such as binary decision diagram (BDD) format. The boolean manipulation engine is configured to perform one or more operations on the ACLs specified for a given interface, including a merge operation, so as to generate a single, unified ACL for the given interface. In order to resolve possibly conflicting actions output by the multiple ACLs, the ACL converter may utilize one or more predefined conflict resolution tables during the merging process.

Abstract: A system within a computer network identifies specific traffic flows originating from a given network entity and requests and applies appropriate policy rules or service treatments to the traffic flows. A network entity includes a flow declaration component that communicates with one or more application programs executing on the entity. The flow declaration component includes a message generator and an associated memory for storing one or more traffic flow data structures. For a given traffic flow, the application program issues one or more calls to the flow declaration component providing it with information identifying the traffic flows. The flow declaration component then opens a flow management session with a local policy enforcer that obtains policy rules or service treatments for the identified flow from a policy server and applies those rules or treatments to the specific traffic flows from the network entity.

Abstract: A portable computer system allows a pilot to efficiently and effectively manage time-oriented and other flight-related tasks. The system preferably includes a microprocessor coupled to a display/input screen. The microprocessor, which includes or is coupled to a timer, preferably executes one or more application programs that are configured to receive information from and display information to the pilot. The application program is preferably hierarchically arranged and menu-driven for navigating among the various displays and thereby retrieving the desired information or initiating the desired functionality.

Abstract: A method and apparatus facilitates and enhances the operation of the spanning tree protocol in bridged computer networks. An intermediate network device in accordance with the present invention includes an enhanced spanning tree engine that is configured to perform certain novel functions. First, the enhanced spanning tree engine is configured to identify and block ports at which messages are looped-back to the transmitting port, thereby avoiding the creation of network loops. In second aspect, the enhanced spanning tree engine rapidly transitions certain ports to a forwarding state to prevent associated applications from timing out and shutting down. Rather than moving the ports through blocking, listening and learning states before reaching the forwarding state, selected ports may be transitioned directly to the forwarding state.

Abstract: A method that rapidly reconfigures a computer network having a plurality of devices executing the spanning tree algorithm. First, one or more devices are configured and arranged so that one port, providing connectivity to the root, is in the forwarding state and the remaining ports, providing connectivity to the root, are in the blocked state. Next, one or more of the blocked ports are designated as back-up ports. Upon detection of a failure at the active forwarding port, one of the back-up ports immediately transitions from blocked to forwarding, thereby becoming the new active port for the device. Following the transition to a new active port, dummy multicast messages are transmitted, each containing the source address of an entity directly coupled to the affected device or downstream thereof. By examining the dummy multicast messages, other devices in the network learn to use to the new forwarding port of the affected device.

Abstract: Iterative information retrieval from a large database of textual or text-containing documents is facilitated by automatic construction of faceted representations. Facets are chosen heuristically based on lexical dispersion, a measure of the number of different words with which a particular search expression co-occurs within a given type of lexical construct (e.g., a noun phrase) appearing in the document set. Words having high dispersion rates represent “facets” that may be used to organize the documents conceptually in accordance with the search expression, effectively providing a concise, structured summary of the contents of a result set as well as presenting a set of candidate terms for query reformulation.

Abstract: The invention relates to a method and apparatus for disseminating Virtual Local Area Network (VLAN) membership information across computer networks defining multiple spanning trees. An intermediate network device configured in accordance with the invention includes a plurality of ports and a plurality of spanning tree engines each associated with one or more VLAN designations defined within the network. The spanning tree engines transition the ports among a plurality of port states, including a forwarding state and a blocked state. For each port, a separate Generic Attribute Registration Protocol (GARP) participant is also established and each GARP participant includes a multiple spanning tree (MST) GARP VLAN Registration Protocol (MST-GVRP) application component and an associated GARP Information Declaration (GID) component.

Abstract: An improved screen basket for use with a centrifuge includes two adjoining screen sections. The first screen section is formed from a wear resistant material and is located proximate to the point at which slurry is introduced into the basket. The length of the first screen section is chosen so that the majority of potential wear caused by the abrasive slurry occurs within the first section of the basket. The second screen section is preferably formed from less expensive materials, such as steel wedge wire. The second screen section smoothly joins the first screen section and provides for further dewatering or separation of the accelerated slurry so that a dry cake is produced by the centrifuge.

Abstract: The present invention is directed to a system and method for centrally coordinating, collecting and storing error, trace, audit and other information in a computer network. Selected applications or processes running at various entities or hosts within the network instantiate one or more “debug” objects that collect particularized information. Each entity also includes at least one logging service layer that communicates with the application or process, and includes a communications resource and one or more state machine engines. In response to collecting error, trace, audit or other information, each debug object passes it to the respective logging service layer, which decides whether or not to forward it to a centralized logging facility disposed within the network. The forwarding of collected information depends on the state of the debug object. If the state of the debug object is enabled, then the logging service layer forwards the collected information to the centralized logging facility.

Abstract: A blowerless air conditioning or heat pump system for use in providing conditioned air includes an outdoor section that is preferably coupled to an indoor section, and is advantageously used with a forced hot air furnace and a corresponding air distribution duct system of a home or building. The two sections are preferably installed along a boundary of the home or building such that outdoor section is outside of the home and the indoor section is inside or below the home and proximate to a forced hot air furnace. Disposed within the outdoor unit are a compressor, an outdoor coil and an outdoor fan. Disposed within the indoor section is an evaporator coil. There is no separate fan or blower disposed within the indoor section. An inlet air tube couples the indoor section to a first point in the air distribution system, and an outlet air tube couples the indoor section to a second point in the air distribution system. The second point is downstream of the first point relative to the furnace.

Abstract: A system within a computer network identifies specific traffic flows originating from a given network entity and requests and applies appropriate policy rules or service treatments to the traffic flows. A network entity includes a flow declaration component that communicates with one or more application programs executing on the entity. The flow declaration component includes a message generator and an associated memory for storing one or more traffic flow data structures. For a given traffic flow, the application program issues one or more calls to the flow declaration component providing it with information identifying the traffic flows. The flow declaration component then opens a flow management session with a local policy enforcer that obtains policy rules or service treatments for the identified flow from a policy server and applies those rules or treatments to the specific traffic flows from the network entity.

Abstract: The invention relates to a mechanism for detecting forks within data flow diagrams corresponding to application programs and for controlling the execution of such application programs. The flow diagram is preferably formed by interconnecting a plurality of symbolic representations of program objects with a plurality of wire constructs. The symbolic representations correspond to program objects having input properties and configured to execute pre-defined functions based on the values of its input properties. The flow diagram preferably represents a logical flow of information used to set the input property values of the program objects. According to the invention, the input properties of the program objects are first invalidated. Next, information is allowed to flow along at least a portion of the diagram, thereby setting one or more of the program objects' input property values. In response to having its input property value set, the program object validates the respective input property.

Abstract: A program object is provided for use in developing application programs through a program-development environment. Using the program-development environment, a developer graphically specifies a flow diagram that represents the logical operation of the application program. The program object, which may have a corresponding symbolic representation for display within the flow diagram, is configured to perform repeating functions and to issue a plurality of ready events, and is preferably used to define loop procedures within the application program. An event handler procedure that is responsive to at least one of the ready events of the repeating program object may be specified by the developer through either graphical inputs or textual inputs to a computer. This event-handler procedure may then be incorporated into the application program for execution at application run-time.