Abstract: An application module (A) running on a host computer in a computer network is failure-protected with one or more backup copies that are operative on other host computers in the network. In order to effect fault protection, the application module registers itself with a ReplicaManager daemon process (112) by sending a registration message, which message, in addition to identifying the registering application module and the host computer on which it is running, includes the particular replication strategy (cold backup, warm backup, or hot backup) and the degree of replication associated with that application module. The backup copies are then maintained in a fail-over state according to the registered replication strategy. A WatchDog daemon (113), running on the same host computer as the registered application periodically monitors the registered application to detect failures.

Abstract: A method wherein a verification tool checks the properties of a system model by performing a partial search of the system-model state space. A partial search is a search wherein the verification tool inputs, at each state of the system-model state space, only a subset or fraction of the complete set of inputs that would have been used during a conventional search. Performing a partial search, instead of a conventional search, reduces the total number of inputs that the verification tool will input to the system model during a search of the system-model state space, thus reducing the amount of computational resources and/or time needed by the verification tool to verify given properties of the system model. Moreover, performing a partial search, instead of a conventional search, does not substantially reduce the ability of the verification tool to identify errors in the system-model.

Abstract: An improved PIN photodiode provides enhanced linearity by confining the light absorption region of the diode wholly within the depletion region. The photodiode exhibits improved linearity over prior art designs because the thickness of the absorption region is no longer a function of changes in the size of the depletion region during device operation. Keeping the absorption region wholly within the depletion region ensures that the charge carriers generated by incident illumination will increase the conductivity of the semiconductor material.

Abstract: Call center functions are provided to a plurality of remotely located customer service representatives (CSRs) via a data network, such as the Internet. Each CSR station includes a telephone and a computer. Separate log-in procedures for the computer and the telephone improve system security. Incoming calls are routed to an available CSR. A call control server provides call control pages that include a set of clickable commands (e.g., transfer, hold, conference, speed-dial buttons, and the like) and telephone digits to CSR computers that allow CSRs to remotely control telephone calls. A merchant server can also provide a merchant application page to CSR computers to allow CSRs to process customer calls.

Abstract: A method and apparatus for defining a system design specification by using a finite set of templates that have a format for accepting a set of system expression such that a selected template, when filled with the system expressions, defines an intended behavioral attribute of the system. In one illustrative embodiment, each template has a set of qualifiers and a set of entry blanks, wherein each qualifier is associated with an entry blank. In such an embodiment, the set of entry spaces may comprise a fulfilling condition entry space for accepting a system expression that defines a required or assumed event of the system model, an enabling condition entry space for accepting a system expression that defines a precondition for starting a check of the required or assumed event, and a discharging condition entry space for accepting a system expression that defines a condition after which said fulfilling condition is no longer required or assumed by the system model.

Abstract: The invention presents a method and apparatus for forming a restricted model from a system model to reduce the computational resources required to formally verify the system design, without substantially reducing the ability to test all system model functions, or properties. In general, the restricted model is formed by restricting the range of assumable values of system model variables and system model inputs to a restricted set of values, based on the values assumed by the system model variables and system model inputs during a partial search of the system model. The restricted model can then be fully searched by a conventional verification tool to identify system design errors. Advantageously, the restricted model requires less computational resources to verify the system design (i.e. through a full search) than the original system model.

Abstract: A unique time slot is assigned to each of a plurality of wavelengths emitted by a single, centralized wavelength division multiplexed optical source to provide a "bit interleaved" WDM signal. In accordance with an illustrative embodiment of the present invention, the thus-developed bit-interleaved WDM signal is replicated in cascaded stages of amplification and power splitting before data is encoded for respective frequency dependent receivers as, for example, a plurality of passive optical networks. Because the output of the optical source need not be encoded with data for the respective receivers until after many stages of splitting and amplification, a small number of time division multiplexing (TDM) modulators synchronized to the source may be used to deliver data to potentially tens of thousands of subscribers.

Abstract: A personal reach system includes a network, a personal reach unit, a cellular network, and a landline telephone station. The personal reach unit is coupled to the cellular network and the landline telephone through the network. When a first party pages a second party through the personal research unit, the first party is connected to the second party by either the personal reach unit through the landline telephone station or the cellular network through the cellular phone.

Abstract: A method for performing centralized billing for transactions conducted over the Internet between a user and an Internet Service Provider (ISP) (106) through an Internet Access Provider (IAP) (104) is disclosed. Upon connection of the user's terminal (101) to the IAP, the IAP transmits to a billing platform (108) a message that associates the user's identity and the temporary Internet Protocol (IP) address that is assigned by the IAP to the user's session for use by to that user's terminal. In response to a chargeable transaction with an ISP, the ISP transmits to the billing platform the IP address of the user making the transaction and the charge for the transaction. The charges for all such transactions are accumulated by a transaction server (109) and stored in an account on an associated database (110) identified with the IP address of the requesting terminal.

Abstract: The invention presents a method and apparatus for forming a restricted model from a system model to reduce the computational resources required to formally verify the system design, without substantially reducing the ability to test all system model functions, or properties. In general, the restricted model is formed by restricting the range of assumable values of system model variables and system model inputs to a restricted set of values, based on the values assumed by the system model variables and system model inputs during a partial search of the system model. The restricted model can then be fully searched by a conventional verification tool to identify system design errors. Advantageously, the restricted model requires less computational resources during a fall search than the original system model.

Abstract: Billing for information and/or interactive services provided to a user over the Internet by an information service provider (ISP) is arranged by the user by placing a virtual billing telephone call to a 900 telephone number associated with the ISP for such billing purposes. The cost to the user for the 900 number billing telephone call, which is determined by the ISP, represents the charge for receiving the information and/or interactive services from the ISP, and is billed to the user's telephone number account. The ISP's 900 number account is credited by the telephone company for the call and thus for the information and/or interactive services provided.

Abstract: A system and method is disclosed for performing centralized billing for transactions conducted by a user on a terminal (101) connected on an Intranet (103) with an Internet Service Provider (ISP) (115) connected to the Internet (104). A Firewall Gateway (105) interconnects the Intranet and the Internet and removes the terminal's IP address from packets transmitted by the user's terminal to the ISP on the Internet. A Session Manager (116) stores in a database (117) the associations between the IP address of the user's terminal and the user's identity, and between the IP address and the Connection ID of the connection established between the Firewall Gateway and the ISP for an ongoing transaction between the user and the ISP. A Billing Platform (120) receives a signal indicating the cost of the transaction and the Connection ID associated with the transaction from the ISP.

Abstract: When a cable or equipment failure interrupts delivery of data services being transmitted to subscriber clients located in a first access area on a modulated RF carrier signal over a hybrid fiber-coaxial cable network, at least one channel within the roll-off spectrum above the passband of the coaxial amplifiers in the network is used as a protection data channel to supply these data services to the affected subscriber clients via an alternate signal path through an adjoining second access area. The data channel within the passband is upconverted to the roll-off spectrum and transmitted through the adjoining second access area which is interconnected to the first access area through a plurality of protection units. Each protection unit interconnects a side leg within each access area.

Abstract: A temporary multimedia ELAN is formed on top of one or more existing ELANs between those end-stations (121-1, 121-2, 111-1) participating in a multimedia session, such as a video conference, at the time of initiating the session. At the end of the session the temporary ELAN is torn down. When the temporary ELAN is created an available LAN Emulation Server (LES) (241) and an available Broadcast and Unknown Server (BUS) (243) are allocated to serve those end-stations participating in the multimedia session. The BUS also serves as a multicast server to multicast a multimedia stream from one end-station to each other end-station on the temporary ELAN. The initiator of a session accesses a Multimedia Session Manager (401), which oversees and manages the session and coordinates the necessary resources.

Abstract: Multiple LAN emulation servers (LESs) and broadcast and unknown servers (BUSs) are employed to serve a single emulated LAN (ELAN). The LAN emulation clients (LECs) are assigned to sub-ELANs, each of which includes several LECs of the ELAN, e.g., those that are geographically close. Each such sub-ELAN includes its own LES and BUS. The LESs and BUSs of the sub-ELANs are connected so that the sub-ELANs form a single ELAN. The LESs/BUSs can be interconnected in any pattern that allows each LES/BUS to communicate with each other LES/BUS via at least one path, which need not be direct. The LES and BUS of each sub-ELAN presents themselves as proxy-LECs of the other sub-ELANs to which they are connected. The ELAN can include a LAN Emulation Configuration Server (LECS) for downloading the connection topology and forwarding rules to all the sub-ELANs. The topology and rules are downloaded each time the ELAN is configured, e.g.

Abstract: A system and method for processing telephone calls to a personal telephone number, such calls being of the type in which a call to a called party's personal telephone number results in a page to a pager of a called party and the caller's call is held in the network to be bridged to a return telephone call of the called party, employs type-ahead for faster perceived system response while not permitting free paging. In particular, although type-ahead is permitted, the page is not immediately initiated upon receipt of the last character of a valid command string prior to the end of the announcement that is played to the caller upon his call reaching a bridging and signaling unit. Instead, the bridging and signaling unit is arranged to respond so that it appears to have accepted and executed the command, and moves into the next phase of operation, e.g., music on hold.

Abstract: On the Internet, different caches may contain copies of objects that have been copied from originating servers when they were accessed by users. Interconnected caches may have different objects stored thereon that might at some time be requested by a client terminal that is connected to a cache other than the one on which the object is stored. Rather than awaiting a request for a particular object and then querying each neighbor cache to determine whether a copy of the requested object is stored thereon, and then downloading the requested object if it is found, information about the contents of the neighbor caches is exchanged between these caches so that when a request for an object is received, the object can be retrieved from the cache in which it is stored. In the alternative, the object may be retrieved from the originating server if, for example, the object stored in a cache is stale based on the date and time it was last modified in the cache.

Abstract: The invention provides an on-demand real-time video conefrencing system in a circuit switched communications network. The on-demand real-time video conferencing system includes at least one video conference control system that receives an on-demand request for a video conference from a user and, in real-time, allocates video conferencing resources and connects the user with at least one other video conference participant through the circuit switched communications network. Each of the at least one video conference control system includes a video conference connection unit and a voice response unit. The video conference connection unit includes a plurality of video ports coupled to the circuit switched communications network.

Abstract: A communications system uses a World Wide Web (Web) server to provide multimedia messaging functions over the Internet. Multimedia workstations are interconnected via the public switched telephone network (PSTN). Parties are provided with multimedia mailboxes on message servers that are connected to the PSTN and the Internet. In order to identify the message server on which a called party's mailbox is located, the Web server provides the multimedia number of the called party's message server when a call is made. In addition, the Web server provides the multimedia number of the called party. When a multimedia call is unanswered, the system uses the multimedia number of the message server and the called party multimedia number provided by the Web server to record and store a message for the called party in the called party's mailbox.

Abstract: We have recognized that in the prior art, to insure that there is at least some communication between the calling and called parties, when the called party is unavailable to take a call, the calling party may be connected to an alternate destination, e.g., a voice messaging system, and the caller's telephone call is considered completed. If the called party thereafter becomes available, the called party is not connected to the caller's telephone call. However, in accordance with the principles of the invention, this problem is overcome by, in response to receipt of an indication that the called party is available for a caller's telephone call after the caller's telephone call has already been connected to an alternate destination, a) disconnecting the caller's telephone call from the alternate destination and, instead, b) connecting it the called party, thus interrupting the connection between the caller and the alternate destination.