Abstract: A technique for modifying the IEEE 802.3 standard for selecting transmit-to-transmit interpacket gap (IPG) intervals in a Carrier Sense Multiple Access with Collision Detection (CSMA/CD) network, to provide fairness and good channel utilization in the event that a node has captured the network communication channel. If there is a small number of active nodes on the network, one node may capture the channel and the standard backoff algorithm makes it increasingly unlikely for another node to transmit. The new technique provides for use of a longer interpacket gap (IPG) interval to be used by a node that has been initially unsuccessful in contention for the channel, thereby ensuring that the other node may continue to transmit back-to-back data packets without interruption or collision. After a preselected time interval, the nodes reverse their roles by selecting the opposite IPG intervals. The initial receiver now selects the shorter IPG interval and captures the channel for the preselected time interval.

Abstract: Apparatus and method for realizing a parallel implementation of run length coding. The system encodes control and data information into the respective link control and data streams and merges the same onto the communication link for transmission. In addition, the system separates link data information from control information upon receipt of the information stream and decodes the received link data and control information into the original information.

Abstract: The apparatus stores a manual flag having a stored manual flag logic value, and the manual flag is stored in a first non-volatile memory. The apparatus stores a trusted flag having a stored trusted flag logic value, and the trusted flag is stored in a second non-volatile memory. The apparatus is connected to a computer network for performing a first boot-up operation. The apparatus learns an address of a neighbor apparatus connected through the communications network. The apparatus is responsive: to the manual flag, and to the trusted flag, and to the first boot-up operation, and to learning a neighbor address of the neighbor apparatus, for configuring an address of the apparatus from an identifier stored in a third non-volatile memory, and from the neighbor address, and for changing the stored trusted flag logic value to a second logic value. Also the apparatus chooses, responsive to the manual flag, between using a manually loaded address or performing the configuring an address.

Abstract: A wiring concentrator (160) for Fiber Distributed Data Interface (FDDI) networks employs only two PHY modules (182 and 184) for initialization of all attached stations (174, 176, 178, and 180). A bank of switches (204, 206, 208, and 210) initially switches one of the stations into full-duplex communication with one of the PHY modules (182), with which it performs the initialization process. The attached station (174, 176, 178, or 180) is then switched into a loop formed with the other PHY (184), in which loop the station remains in the active state that it reached as a result of the initialization process. The process is then repeated for each attached station. A separate PHY module thus is not required for every attached station.

Abstract: The concurrency-control mechanisms in a database-management system achieves high concurrency by using a lock-mode set larger than that conventionally employed for multi-granularity locking. In a system of key-valued locking in which locks on key-value ranges are acquired separately from the locks on the key values with which they are associated, the IX lock mode conventionally acquired on a range by update, insert, and delete operations is replaced with three separate lock modes respectively associated with those operations and invoked by them for range locking. In key-valued-locking systems in which ranges are locked commonly with the key-values associated with them, the mode set is further expanded so that each mode represents a different combination of range and key-value locks.

Abstract: Method and apparatus facilitating the processing of a request from a client application for a service, or for access to a resource, in a distributed computing environment. A shared repository is organized in such a manner that binding information, defining how a server is accessed, can be stored in the repository and accessed by multiple clients without their having knowledge of more than the common name for the requested service, or the common name of a specific resource for performing the service. The binding information for each server is stored in a server entry sub-hierarchy of the namespace in the shared repository, and the full names of server entries are stored in a service entry sub-hierarchy of the namespace and a resource entry sub-hierarchy of the namespace.

Abstract: An asynchronous transfer mode (ATM) network device having a receiver portion, the receiver portion capable of receiving ATM cells on virtual circuits (VCs) from an upstream ATM switch, a local memory used to store the ATM cells, managing local memory using queues, assembling ATM cells into packets, transmitting the packets to a host memory, resynchronizing ATM credits, and a transmitter portion, the transmitter portion indicating transmitting of packets to host memory to the upstream ATM switch.

Abstract: A signature system, such as an El Gamal or DSS system, involving the use of a long-term secret number and a per-message secret number generates the per-message secret number without the use of a random number generator or non-volatile storage. The per-message secret number is generated by applying a one-way hash function to a combination of the long-term secret number and the message itself.

Abstract: In a method and system for monitoring the performance of servers across a network and for suggesting an appropriate server to a client requesting a service, a plurality of probes are placed in various clients in the network by a Broker-Performance Mechanism. The probes request that the servers perform various network functions and measure the response times of the servers in satisfying those requests. The Broker-Performance Mechanism retrieves, analyzes, and stores the response time data. The stored data can be made available to a user for system diagnostic purposes. In addition, when a particular client requests a particular service, the Broker-Performance Mechanism examines the analyzed data and determines which server is best suited, at that particular time, to provide the requested service to the requesting client.

Abstract: In the synthesis procedure for circuit design, a convenient notation is used for the insertion of new instances in the consequence portion of a rule having a antecedent form and a consequence portion. The notation is of the form(outputs . . . )=(operator inputs . . . ).The outputs and inputs may be signal names or data base pin access forms. Double quoted strings of characters can represent specific signals in the global design model. Double quoted strings of characters including the % character can be used for local connectivity among logic elements representing multiple equations inserted by the rule. The equations are converted to model instance structures and are inserted into the data base. Creation of database pointers are generated automatically and not by the rule writer, greatly simplifying the rule syntax.

Abstract: A technique for modifying the IEEE 802.3 standard for selecting backoff times in a Carrier Sense Multiple Access with Collision Detection (CSMA/CD) network, in the event that a collision is sensed by a node that has captured the network communication channel. If there is a small number of active nodes on the network, one node may capture the channel and the standard backoff algorithm makes it increasingly unlikely for another node to transmit. The new technique provides for less aggressive, i.e. longer, backoff times before at least the first retransmission attempt made by a node that has captured the channel, and in addition provides for the use of a stopped backoff algorithm. Three specific examples of methods to choose a backoff time and two methods of using a stopped backoff algorithm are disclosed.

Abstract: A digital message routing network has at least some nodes at which messages are monitored for accounting purposes. Such a node contains means for generating and compressing accounting digests, each of which consists of a key K representing the nature and route of the message and a value V associated with the message. For each message, a digest is produced in register 30, and copied into a location in a first memory 22D at a location determined by hashing its key; further digests with the same key are compressed into the digest already in that location. A second memory 23D is operated as a cyclic buffer with head and tail counters HDCT 40 and TLCT 41. The address of the head of the buffer, ie the valid area of memory 23D, is included as an index I in each digest in the first memory 22D as that digest is created. Each time a digest is created or changed in the first memory 22D, it is copied into the second memory at the location in the second memory determined by its index.

Abstract: A method of scheduling a conversation between a designated transmitter adapter card and a designated receiver adapter card, comprising the steps of selecting a first slot having a free channel, selecting a second slot having the designated transmitter adapter card free, selecting a third slot having the designated receiver adapter card free, assigning a connection between the designated transmitter adapter card and the designated receiver adapter card in the free channel in the first slot, resolving any conflict between the designated transmitter adapter card and any other conversation by swapping conversations between the first slot and the second slot, resolving any conflict between the designated receiver adapter card and any other conversation by swapping conversations between the first slot and the third slot.

Abstract: A technique for modifying the IEEE 802.3 standard for selecting transmit-to-transmit interpacket gap (IPG) intervals in a Carrier Sense Multiple Access with Collision Detection (CSMA/CD) network, in the event that a node has captured the network communication channel. If there is a small number of active nodes on the network, one node may capture the channel and the standard backoff algorithm makes it increasingly unlikely for another node to transmit. The new technique provides for less aggressive, i.e. longer, interpacket gap (IPG) intervals to be used by a node that has captured the channel, thereby increasing the likelihood that another node will gain access.

Abstract: A technique for compensating for frequency distortion in a band-limited communication channel, using a random-access memory (RAM) to store successive samples of a signal pulse, the samples having been precalculated to perform an equalization function prior to transmission of the pulse. The signal samples are retrieved, converted to analog form, and filtered to produce a precompensated analog pulse signal. In one embodiment of the invention, equalized profiles of a limited number of pulses of different shapes are stored in the RAM, and are retrieved as needed for transmittal through the band-limited channel. Thus the invention can perform its equalization function while facilitating encoding of the signal into a different form, such as modified duobinary code.

Abstract: Method and apparatus for automatically switching an Ethernet station interface to choose between two protocols and, possibly, two external connector configurations, to adapt the station automatically to the correct one of two communication media types, such as the twisted-pair medium served by the 10BASE-T protocol, and other media types, served by the attachment unit interface (AUI). The invention continually tests for proper operation in the currently selected protocol, and switches to the other protocol upon failure of a test. If one of two available external connectors is used to connect the station to a network, the invention chooses between the connectors automatically, such that manual switching between them is not required.

Abstract: A binary signal encoding technique for reducing the amount of electromagnetic interference (EMI) caused by the transmission of high-speed binary signals over an unshielded twisted pair of conductors. Duobinary modulation, combined with low-pass filtering to confine the signals' frequency spectrum, and stop-band filtering to reduce critically high spectral lines, results in an acceptably low level of electromagnetic emission from the twisted pair. Moreover, duobinary modulation and stop-band filtering to reduce spectral lines avoids the need for signal scrambling to reach acceptable radiation levels by spreading the signal energy across the frequency spectrum.

Abstract: Loop-back detection and signalling is achieved on any DS-0 channel that conforms to 56 kbps operation such as DDS in a DS-1 digital data transmission system. A standard DS-1 chip set (line interface unit, framer, and link layer controller) is used, coupled to 24 transmit and receive buffer means in the customer main memory. The framer detects control bits by using Channel Associate Signalling, (designed for digitising voice in-band signalling and not normally used for data transmission), in the incoming signal and interrupts the customer CPU, which determines from the framer which channel caused the interrupt, changes the mode of the relevant channel, checks that channel's receive buffer means for loop-back codes, and, if enough successive loop-back codes are found, copies the receive buffer means into the transmit buffer means (with code mapping) for as long as the loop-back condition exists.

Abstract: A packet data communication network employs a local switch, router or bridge device functioning to transfer packets between segments of a larger network. When packets enter this device, an address translation is performed to generate local source and destination addresses which are much shorter than the globally-unique addresses contained in the packet as dictated by the protocol. These local addresses are inserted in a header that is added to the packet, in addition to any header already contained in the packet. This added header travels with the packet through the local switch, router or bridge device, but then is stripped off before the packet is sent out onto another network segment. The added header may also contain other information, such as a local name for the source and destination segment (link), as well as status information that is locally useful, but not part of the packet protocol and not necessary for transmission with the packet throughout the network.

Abstract: An assembly for mounting fiber optic transceivers. A front wall having a plurality of holes is provided. A plurality of mounting members are attached to the rear of the front wall and extend perpendicularly from each of the plurality of holes. The mounting members include a base, a pair of side walls and rear wall coupled to the base, and a flexible clamp member attached to the rear wall. The flexible clamp member includes a pair of short wall portions impressed at each end to provide securing dimples and an integral back wall portion to seat the fiber optic transceiver.