Abstract: A method for dynamically allocating the capacity of a computer network. All users of the network are classified as low or high priority users. High priority users may broadcast a delay message to the low priority users that cause the low priority users to delay before attempting to use the network. The length of delay can be adjusted if the high priority users are not able to utilize the network as required. In addition, if a low priority user does not receive a broadcast delay message within a predetermined amount of time, the delay period is reset to avoid unnecessary slowing of the network.

Abstract: To improve the flexibility in changing a transfer procedure and the efficiency in transferring data when a plurality of sensors transmit detected data to a detected data receiver. The detected data receiver transmits detected data transfer request command RS simultaneously to a plurality of sensors. A detected data transfer request command RS contains information regarding a network using order, to thereby inform respective sensors of a data transferring order. A sensor which has been requested to carry out data transferring by the command RS detects the completion of data transferring by a sensor which has been requested to carry out data transferring immediately preceding the sensor concerned, and then initiates its own data transferring. With this arrangement, a transfer procedure can be flexibly changed by using a request command RS, and useless intervals between data transfers by respective sensors are omitted.

Abstract: Arbitration apparatus is described for arbitrating between a number of jobs, for example for distributing message traffic over a data transmission network. The arbitration apparatus comprises an activity register containing a number of activity bits indicating which of a number of transmission jobs is currently active. The apparatus also includes a two-tier token ring arrangement comprising an outer ring and a number of inner rings. Each ring consists of a number of registers, holding a token which is passed cyclically around the ring. Each register has a bypass path which bypasses the register if a corresponding job or group of jobs is inactive. The positions of the tokens in the rings determines which job is to be scheduled next. Each ring also includes a keeper register for preserving the token if all the jobs are inactive.

Abstract: A system for servicing a plurality of queues containing data cells for transmission over a communication medium. Each queue has an associated queue priority. A queue service sequence is generated in response to the queue priorities and represents a specific order for servicing the plurality of queues. A particular queue is selected for servicing in response to the queue service sequence. When a particular queue has been selected, a data cell is transmitted from the selected queue across the communication medium.

Abstract: A low-power random digit generator for use with existing circuitry samples a changing physical variable. In a communications device, the random digit generator has an A/D converter that repetitively converts a received analog signal at a conversion rate, where a magnitude of the received analog signal changes at a received rate. At least one bit from the conversion is selected, and a random digital signal having a magnitude corresponding to the at least one bit is generated. The communications device preferably taps off an existing A/D converter and uses combinational circuitry to minimize power consumption.

Abstract: A method and system are disclosed for scheduling the assignment and writing of cells from cell sources into a outgoing bitstream transmitted from each device of an ATM communications network. The timeslots are organized into fixed length cycles which cycles each have a sequence of N timeslots, where N is an integer >1. Furthermore, each cycle is divided into at least one round comprising a variable length subsequence of the timeslots of the cycle. During each timeslot of a uniform timeslot clock, at least one subset of the sources is identified. Each subset corresponds to a round. One cell from each subset is assigned to, and written into, a respective timeslot of the corresponding round. During each timeslot of the timeslot clock, each of the sources is assigned a priority state depending on how many cells of that source have been previously assigned to timeslots during the current cycle and whether or not that source has a cell available for assignment to a round during that timeslot.

Abstract: An apparatus for accelerated Fiber Channel protocol handshaking and data exchange involves dividing a Fiber Channel arbitrated loop architecture up into a plurality of arbitrated subloops, each of which arbitrates locally using the same fundamentals as the Fiber Channel arbitration protocol but with some slight modifications which do not affect the compatibility of standard Fiber Channel nodes. Each subloop is coupled to a hub port which contains a state machine which does switching function and fill word generation to implement the accelerated protocol by using a plurality of switching, fill word generation and token passing rules. The state machine in each hub port is coupled to its local subloop and to its neighboring hub ports through a single TDMA bus which has timeslots dedicated to carrying broadcast loop and return loop traffic and control token traffic.

Abstract: A Scalable Multimedia Network providing integrated networking of data, voice, video and image services over a variety of access facilities including metallic loops, fiber/coax or digital fiber is disclosed herein.The SMN establishes customer initiated switched virtual circuits for all traffic types and directs them to the appropriate backbone network. The SMN is based on a distributed switching platform that enables carriers to economically provide service to a small number of customers and add capacity incrementally as the customer base increases. The platform has a protocol adaptation capability which permits communications between customer premises equipment and potentially incompatible backbone networks or network servers.

Abstract: A method and apparatus for accessing a communication system relies on the use of varying access probabilities for subscribers or messages of varying priority. A serving infrastructure entity (e.g., a base station) determines access probabilities (e.g., p.sub.hi and p.sub.lo where there are two classes of subscribers) in response to known system parameters like the current rate of access attempts for each priority class of user/message. Values representative of these access probabilities are then transmitted to the subscriber unit(s), for example by use of a system broadcast channel or control channels. These values are then used by the subscriber units in determining when to access an uplink channel. A temporal and/or proportional priority distribution approach is preferably used in determining the access values. As a result of this contention-based prioritization, an expedited access is achieved by higher priority units/traffic, thus increasing their throughput.

Abstract: A communication system and communication method having protocols used are to priorly process real-time data without delay. Information of a protocol header of data to be sent or received is used as priority decision information to decide whether or not the data should be priorly send- or receive-processed. The information to be priorly processed of combination of the priority decision information is registered and managed as priority data information before being stored. The data send or receive process fetches the priority decision information from the send or receive data before deciding whether or not the data are registered as the priority data information. If so, the data are send- or receive-processed prior to the data that are not registered.

Abstract: A dual priority switching apparatus for making input port to output port connections on a requested basis quickly and dynamically, in a standard mode from any one of the input ports to a fixed number of subsets of multiple output ports simultaneously, or in a broadcast mode from any one of the input ports to all output ports simultaneously. The apparatus permits multiple broadcasts to be queued at the individual switching apparatus which resolves the broadcast contention on a synchronous priority driven basis that permits one broadcast to follow the other at the earliest possible moment and the quickest possible speed. The apparatus permits multiple multi-cast operations to occur simultaneously within the network. The multi-cast function permits subsets of nodes assigned to the same tasks to communicate among themselves without involving other nodes that are not in its own subset. Hardware circuitry detects and corrects deadlock conditions in the multi-stage network.

Abstract: An apparatus and associated method employ the concept of a central busy list for coordinating the receipt of incoming calls to a subscriber subscribing to the calling services of separate first and second communication networks. The central busy list apparatus cooperates with the networks to register a current call by a subscriber serviced by the first network, to receive a request for interruption of the call serviced by the first network to allow the subscriber to receive an incoming call to be serviced by the second network, to send a request to disconnect to the first network when a priority of the current call is lower than the priority of the incoming call, and to deny interruption of the current call by the incoming call when the priority of the current call is higher.

Abstract: A downward compatible full-duplex ethernet transceiver associated with either the hub or the remote node in an ethernet local area network (LAN) includes generator circuitry for generating a full-duplex-capability signal indicating its full-duplex capability for transmission over a link of the LAN and detector circuitry for detecting transmission of such a signal from the transceiver with which it is communicating across the link of the LAN. The detector circuitry responds to the full-duplex-capability signal by sending a full-duplex enable signal to an ethernet controller configured according to the present invention. An ethernet controller contains circuitry responsive to the full-duplex-enable signal to disable transmission deferral in response to a carrier-sense signal generated by the transceiver. The full-duplex-capability indicator portion may comprise an extra pulse following an Nth link-integrity pulse after a delay of from about 2 to about 7 microseconds.

Abstract: A data processing system for regulating access to a communication network is disclosed herein. The data processing system employs a component that can be implemented in hardware logic or software. The component regulates access to the priority queue or transmit channel that is attached to the shared medium local area network section. All access to the priority queue or transmit channel must pass through this component, thus subjecting all communication transactions to rejection or tracking by the component. The component allocates a frame size based on the information to be transmitted and the priority to assure the transmission will be completed in line with the quality of service required. The component monitors the rate and size of messages to assure that an application's actual throughput does not exceed its negotiated throughput. The component, moreover, is capable of operating in correction mode where throughput and frame size violations are prevented and reported.

Abstract: A method provides for priority data transmission utilizing medium access control protocol with a fair cell-access scheme having a two-level priority for access in a local area network having a unidirectional looped bus and a plurality of network stations coupled to the bus for asynchronous cell transmissions from one network station to other network stations. A-head-of-bus is used to generate continuously time slots to the bus. Each of the time slots includes a busy bit, a high priority slot reserved bit, a low priority slot reserved bit, a high priority slot reservation bit, and a low priority slot reservation bit. The method further extends the two-level cell access to n-level cell access. Each of the time slots thus includes a busy bit, n priority slot reserved bits, and n priority slot reservation bits.

Abstract: The entry polling (EP) method (900) of the present invention primarily incorporates two types of polling: contention based and standard polling. The present invention provides several advantages over present polling approaches. EP slots allow multi-priority users to compete for access into the standard polling scheme. The reservation channel is efficiently used by dynamically adjusting the frequency of contention slots based on system dynamics and dynamically changing the number of contention minislots for each service category within a contention slot with the case of sending only one minislot per slot. The channel is assigned primarily to active users. Pipeline polling is also incorporated, thus providing full use of the upstream channel. Since the local state information is provided by the user, the central controller may allow multiple variable length packets to be sent.

Abstract: A method of managing communication on an unstable error-prone channel is disclosed, having particular applicability to transceiver nodes in a high frequency radio network. The method achieves highly reliable, efficient communication through the exchange of headers within control frames in accordance with a selected suite of protocols. An orderly link establishment is achieved by the exchange of headers indicating specific link establishment states of the nodes. One node having message data to transmit to another sends a herald header, and if the data is to be accepted by the other node, it responds with a herald acknowledgment header. The herald conveys parameters of the proposed transmission to the receiving node, permitting the parameters to be varied by the transmitting node for changing channel conditions. The issuance of a herald acknowledgment depends on message priorities exchanged by the nodes, so that higher priority messages can preempt lower priority ones.

Abstract: An apparatus and method in a data processing system for sending a data packet from a source node to a destination node. The data processing system includes a multi-segment network having at least two segments, wherein the source node and the destination node are located within different segments. Communication of a data packet from one segment to another segment is provided by an agent node. When a receiving node, which may be either an agent or a destination node, cannot accept a packet, it places a reservation tag of "A" or "B" in an echo packet. The retried packet then uses this reservation tag to gain priority for any available buffers in the agent or destination node. The receiving node toggles between accepting all the outstanding "A" packets (when the receiving node is in the "receiving A" state) and accepting all the outstanding "B" packets (when the receiving node is in the "receiving B" state) assuming that the receiving node has a free, unoccupied buffer for accepting the packet.

Abstract: A data communications system has nodes provided with data processing apparatus disposed at a number of points which are mutually separated at a distance with optical transmission cables and which are provided with a FDDI (fiber distributed data exchange interface) for optical local area networks for transmitting/receiving at either high-speed or low-speed, data between the data processing apparatus, control apparatus and peripheral apparatus.

Abstract: A transmit-receive station connected to a high speed ring bus carrying data signals that may be received from and sent to each station on the ring bus has two sources of transmit clocking signals. One source is based on the frequency and phase of data signals received on the ring bus from another station and the other source is a local crystal oscillator having essentially the same frequency as the first source but in an indeterminate phase. When changing the source of clocking signals for transmission of data originating at the station, bit slippage may be minimized by providing the local oscillator output signal in four phases and using the phase most nearly aligned with the other clocking signal when the change is made. Control of access to transmit by a station employs a token having a message field of seven bits and a access control bit.

Abstract: A transmit-receive station connected to a high speed ring bus carrying data signals that may be received from and sent to each station on the ring bus has two sources of transmit clocking signals. One source is based on the frequency and phase of data signals received on the ring bus from another station and the other source is a local crystal oscillator having essentially the same frequency as the first source but in an indeterminate phase. When changing the source of clocking signals for transmission of data originating at the station, bit slippage may be minimized by providing the local oscillator output signal in four phases and using the phase most nearly aligned with the other clocking signal when the change is made. Control of access to transmit by a station employs a token having a message field of seven bits and a access control bit.

Abstract: A method for allocating access to a shared limited resource among a plurality of users who require access to the resource, the allocation being made such that each user is granted access to the resource at a minimum guaranteed rate associated with each user and such that the resource is available for use by any user exceeding its minimum guaranteed rate only if the resource is available, the method comprising the steps of: assigning tokens to each user at a rate determined by the minimum guaranteed rate associated with each user; storing tokens assigned to each user in a bank associated with each user, each bank having a finite capacity associated with each user; storing tokens assigned to a user whose associated bank has reached its capacity in a bank assigned to another user whose bank is below its capacity; and allowing a user requesting access to the resource to have access to the resource if the user has a predetermined number of tokens in its associated bank and otherwise denying access to the resource.