Abstract: A network design method proceeds by generating cycles, evaluating the economics of building rings on those cycle, and building any economic rings. Generating a cycle involves picking two endpoints between which two disjoint link and node paths are desired—the two nodes selected are thus nodes on the candidate rings. Once a cycle is generated, various combinations of OADM/ADM nodes on the cycle are tried, from rings using three nodes to rings using all of the nodes on the cycle. The network design method considers a sequence of SONET/SDH and DWDM rings on each cycle generated, and compares the cost of carrying demand by SONET/SDH rings, DWDM rings, and an alternative dual-hub benchmark architecture. The ring constraints such as maximum circumference are applied before ring costs are calculated, and rings violating those constraints are eliminated from consideration.

Abstract: To synchronize clock signals in spatially distributed nodes in a large, synchronous electronic, optical, optoelectronic or wireless system, a master node generates two identical pulse trains and propagates them to a plurality of slave nodes via first and second propagation channels, respectively, so that a pair of pulses, one from each pulse train, arrive at each slave node simultaneously, travelling in opposite directions. Each slave node generates a clock signal event when the pair of pulses arrive substantially simultaneous. When the pulses in the two channels do not arrive simultaneously, the slave node adjusts delays in each propagation channel so as to adjust arrival times of subsequent pairs of pulses. The delays may comprise pre-delays upstream of the detection point and post-delays downstream of the detection point, any increment in a pre-delay being compensated by an equal decrement in the post-delay in the same propagation channel.

Abstract: A network and a coupling device for connecting two segments in such a network. The coupling device has means (510 for measuring the slot time configured in the users by means of so-called GAP queries with which active users (201 . . . 206) using the PROFIBUS DP protocol for data transmission cyclically check whether new users have been connected to the network. Based on this slot time, coupling devices obtain information on the extent of the network, which is required for certain monitoring mechanisms. Further, a network and a coupling device for connecting segments in such a network, which has means (63, 64, 73, 78) for detecting corruption of a message by faults on a segment (16) and blocking the onward transmission of messages received on the faulty segment (16). The coupling devices (22, 23) connected to the faulty segment (16) block and reauthorize onward transmission almost simultaneously so that no unidirectional connection is established.

Abstract: The present invention provides a method and structure for allowing more than 16 nodes to be configured in a single SONET BLSR network by utilizing unused portions of the transport overhead of an STS-N frame to expand the node identification field from 4 bits to 8 bits, thereby allowing up to 256 nodes to be present on a single ring.

Abstract: ATM path switched ring switching is based on a ring segment BIP. An ATM VP ring segment is defined as originating at an ATM VP ring input and terminating at an ATM VP ring output. A ring segment BIP is composed of the path BIP error counts of multiple SONET/SDH paths from the ring segment input to the ring segment output.

Abstract: The present invention relates to a method of assigning data from time slots on an input bus to time slots on an output bus comprised of determining the order of time slots of data in a frame, determining whether each time slot of data in an input frame is to be located in the same or later time slot in an output frame, or whether it is to be located in an earlier time slot in an output frame, in the event each time slot of data of the input frame is to be located in the same or later time slot in an output frame, applying each time slot of data of the input frame to the same or a later time slot in the output frame, in the event a time slot of data of the input frame is to be located in an earlier time slot in an output frame, delaying for one time slot internal and then applying each time slot of data of the input frame to the same or a later time slot in the output frame, whereby the order of time slots in a stream of output data is always from an earlier time slot to a later time slot.

Abstract: A method of detecting the network configuration of a communication network in which a plurality of nodes are connected in a ring form, comprises the steps of; enabling a node of the plurality of nodes to store its own node identifier in a specific position of an identifier storing area of a frame, and transmitting said frame along the network in the same direction; enabling each of the plurality of nodes to store its own node identifier in the identifier storing area of said frame and again transmitting said frame in the same direction, and abandoning said frame, according to contents of said frame received from the adjacent node; and enabling each of the plurality of nodes to recognize an arrangement of the plurality of nodes on the communication network, on the basis of contents of the identifier storing area of said frame constantly transmitted and received on the communication network.

Abstract: A method and apparatus for the robust implementation and protection of Asynchronous Transfer Mode (ATM) traffic over a Synchronous Optical Network (SONET) unidirectional Path Switched Ring (UPSR). The traditional SONET bridging function is eliminated for the ATM traffic in favor of a selector function. The selector function occurs at the ingress of the ATM traffic to the UPSR and directs the ATM traffic to its destination via a virtual path over the UPSR. The ATM traffic is protected from both SONET failures and ATM failures by means of an Intra-Ring Communication (IRC) protocol. The IRC protocol governs failure detection and the notification of the SONET nodes on the UPSR of the failure and any protection switch that may be necessary.

Abstract: A ring configuring method configures a network in which a plurality of nodes are connected linearly, and performs topology construction for the ring by circulating topology data through the respective nodes and collecting connection information of the respective nodes. The method includes the steps of providing in the topology data a flag indicating whether the connection information is collected in each node; inverting the flag at a terminal station which is an end node of the open ring, and turning the topology data there; causing the topology data to passing through a node other than any terminal station as it is; and adding the connection information to the topology data in each node according to the flag, and performing topology construction.

Abstract: When the operator requests the output of performance data, if all the pieces of performance data in the requested time range could not be acquired, the output control section of each of supervisory control devices M1 to Mn will determine the cause. When the cause that all the pieces of performance data could not be acquired is the execution of zero suppression at nodes N1 to Nn, the data items related to the pieces of performance data that could not be acquired are made zero and the resulting data is outputted.

Abstract: A multi-port LAN switch is provided that enables attached network devices to both communicate directly and to insert into a token-ring network through an attached concentrator. Each port of the multi-port LAN switch has a first transformer, a second transformer, and a switching system. The first transformer has a first winding connected to a first connection of the port. The second transformer has a first winding connected to a second connection of the port. The switching system switches to a port mode or an adapter mode as a function of a mode signal transmitted to the port In the adapter mode, the switching system connects a second winding of the first transformer to a transmitter circuit in the port, and its connects a second winding of the second transformer to a receiver circuit in the port.

Abstract: Provided is a system which automatically determines and assigns an appropriate address for each chip in repeater system. All the ASICs in a system are chained together on a serial data ring for address allocation purposes. A “First On” ASIC in a system initializes the chip address map, assigns itself the first address. The First On ASIC then updates the address map by setting the next address and sends it down the chain to the next ASIC in the system. The second ASIC allocates the incoming address to itself, sets the address for the next ASIC, and passes the address signal on. The process repeats itself until the last ASIC in the chain has an address allocated. The last ASIC the notifies the First On ASIC of its address to close the loop.

Abstract: Methods and apparatus for implementing a technique for inserting and removing a node in a network loop. In a preferred implementation, a hub port includes a detect element which monitors data from the node and from an upstream node. The detect element sets a first flag when a primitive is received at the port, and sets a second flag when a primitive which is a frame termination primitive is received at the port. A frame termination generator generates frame termination primitives and a buffer data generator generates buffer data. A switching element has a control input, an output, and a plurality of data inputs. One data input is connected to each of an output of the node, the upstream node, the frame termination generator, and the buffer data generator. A control element is connected to the detect element and the control input of the switching element.

Abstract: The disclosure relates to apparatus and methods that provide a system interconnect for transporting cells between nodes on a dual counter-rotating ring network, including a link selection register for selecting the shortest path to a destination node, use of a fault tolerant frequency reference to synchronize node clocks, interconnect initialization, multi-ring topologies along with an addressing schema and ring-to-ring couplers. The disclosure also discusses flow control of cells leaving nodes, coupling cells from one ring to another, and use of such an interconnect as a bus replacement.

Abstract: The present invention provides a method and apparatus for removing unwanted data packets from a ring topology communication network having a plurality of nodes. The invention ensures that a data packet is removed from the network if there is a failure of the originating node, or if there is a failure of the node principally responsible for removing the data packet. The invention provides fault-tolerance, without significantly adversely affecting the overall network performance. The invention provides the originating node address in a controlled field of the data packet, with unused data bits within the control field being used as "rouge packet bits." The invention will include one or more nodes designated as "rouge data packet removal nodes" or "rouge removal nodes." A data packet is created at an originating node which will embed its own address in a "Node ID" field of the data packet and will transmit the data packet along the network.

Abstract: A ring switch for a ring network is provided. The ring switch includes at least one ring port that is coupleable to transport data packets in a ring network. Further, the ring switch includes at least one local port that is coupleable to at least one local area network. The ring switch also includes at least one address table that tracks the addresses of network devices associated with each port of the ring switch based on source addresses of data packets received at the ports of the ring switch. Data packets received at the at least one ring port that are not destined for a network device associated with any of the at least one local ports of the ring switch are switched to another ring switch coupled to the at least one ring port based on the at least one address table without the use of a token or encapsulating the packet.

Abstract: A system and method connects a call in a broadband system using the asynchronous transfer mode protocol for switching. Calls are connected over a SONET ring that has SONET multiplexers coupled by SONET paths. The SONET multiplexers are adapted to add calls to, and drop calls from, the SONET ring. An ATM cross connect system that has ATM cross connect devices is coupled to the SONET ring. The ATM cross connect devices provide provisioned ATM connections over the SONET ring. ATM interworking units are coupled to the ATM cross connect system. The ATM interworking units interwork calls with selected ATM connections in response to control messages. The selected ATM connections are provisioned between the ATM interworking units by the ATM cross connect system over the SONET ring. A signaling processor system receives call signaling for the calls, processes the call signaling to select the ATM connections for the calls, and sends the control messages to the selected ATM interworking units.

Abstract: A digital data transfer system transfers digital data along a path in a ring topology. The digital data transfer system comprising a host controller and a digital data transfer subsystem. The host controller generates and receiving digital data and the digital data transfer subsystem receives the digital data from the host controller and transferring the digital data to one or more devices connectable thereto, and further receives digital data from the last of the devices connectable thereto for provision to the host controller, thereby to define the ring data transfer topology. The digital data transfer subsystem comprises an upstream port, a plurality of input/output ports and a port control. The upstream port transfers digital data from an external source to the input of the first input/output port in the series and transfers digital data received from the last input/output port in the series to the host controller.

Abstract: Provided is a system which automatically determines and assigns an appropriate address for each chip in a repeater system. All the ASICs in a system are chained together on a serial data ring for address allocation purposes. A "First On" ASIC in a system initializes the chip address map, and assigns itself the first address. The First On ASIC then updates the address map by setting the next address and sends it down the chain to the next ASIC in the system. The second ASIC allocates the incoming address to itself, sets the address for the next ASIC, and passes the address signal on. The process repeats itself until the last ASIC in the chain has an address allocated. The last ASIC then notifies the First On ASIC of its address to close the loop.

Abstract: An add drop multiplexing (ADM) apparatus has a simple and compact structure. The ADM apparatus has high-order interfaces connected to a high-order network, path setting units each for setting a path for a signal according to path data and inserting or dropping the signal to or from the high-order network, a first path protection switch for selecting one of the signals dropped by the path setting units, low-order interfaces each for receiving the selected signal and transmitting the same to a low-order network, and a second path protection switch for receiving low-order signals from the low-order interfaces and transferring one of them to the path setting units so that the path setting units may insert the signal into the high-order network.

Abstract: A computer system employs a hierarchical ring structure for communication. Computer system elements are configured into modules with ring interface hardware, and the modules are coupled to one or more rings. Bridge modules may be included for transmitting between rings in the hierarchy. The rings are time division multiplexed, and each time slot on a ring carries a frame. According to an address carried within the frame, bridge modules determine whether or not to transmit a frame circulating on a source ring onto a target ring. If the address of the frame indicates a module upon the source ring, the bridge module retransmits the frame on the source ring. Otherwise, the bridge module transmits the frame on the target ring. The bridge module operates in this fashion at any level of the hierarchy. The owner of a time slot on a ring is permitted to release the time slot for use by other modules. To reclaim a time slot, the owner marks the time slot owned.

Abstract: A ring communication network including N nodes and comprising links between the nodes for carrying data in W channels. The network is configured by providing nodes and channels such that N.gtoreq.2 log.sub.2 W-1 where W is a power of 2. No more than W channels are assigned to the transmission of data along any of the links. The nodes are configured such that each channel of a first one of the links adjacent any one of the nodes can be switched to no more than W-1 channels of a second one of the links adjacent any one node.

Abstract: A method and an apparatus for interprocessor communication in which each processor simultaneously outputs a local data subset of a data set and simultaneously receives foreign data subsets of the data set in both directions around a ring of processors. A destination data memory buffer the size of the entire data set is accessed for transmission and reception and uses four data pointers, two input and two output, whose positions in the memory buffer correspond to the data subsets passing into and out of the processor in each direction at that moment and which correspond to a direction of output or input. The processors pass the subsets one-half of the way around the ring in each direction. Each processor knows whether a data subset should be passed on to neighboring processors. Received each foreign data subset received is stored in the data memory buffer in the correct position as designated by the appropriate input data pointer.

Abstract: The present invention provides a network element of a first type for operating in a network including other network elements of such first type and for allowing the other network elements to form part of the network that are not of the first type. Each of the first type of network element has the ability to automatically determine the topology of the network for each network element of such first type and further has the ability to store manually provisioned routing information about the network elements not of the first type when the network elements not of the first type are in the path to a network element of the first type. Each network element of the first type further comprises a circuit for periodically checking the validity of manually provisioned routing information.

Abstract: A system and method for displaying and configuring parameters in a fieldbus configuration system. The fieldbus configuration utility first determines the devices and blocks present in the system, and then determines the parameters of each block. When the parameters are displayed, an object is displayed proximate to certain of the parameters. The object includes a color and/or shape which indicates the type or class of parameter. The user can also configure alarms and trends using the improved graphical interface of the present invention. The user configures alarms and trends by assembling a graphical program or wiring diagram on the screen which comprises a selected one or more block icons and an icon representing the device receiving the trend or alarm. The system also includes a periodic update window which is used to obtain periodically updated values of selected parameters.

Abstract: A method is provided for designing a hierarchical architecture for a synchronous optical network (SONET) given a plurality of demand nodes at which communications traffic originates and at least one destination node at which the communications traffic is collected for transmission to a switch.

Abstract: A loop isolation circuit (LIC) to enable subdivision of a single daisy-chained communication loop (e.g., FC-AL) into smaller loops and to enable joining of smaller loops into a single larger loop. An LIC comprises essentially two multiplexors configured so as to permit controlled subdivision or joining of two loop portions. In a first selected state, the LIC subdivides a communication loop in which it is inserted into two loops. This configuration sacrifices accessibility among some devices previously on the larger loop for the benefit of enhanced bandwidth and reduced overhead due to node count. Bandwidth is enhanced by enabling simultaneous operation of two (or more) loop portions for establishing and communicating over logical circuit connections. However, when a failure of a redundant loop precludes access to devices, the LIC may be set to a second state to rejoin previously subdivided loops into a larger loop. This configuration restores access among all devices sharing common access to the larger loop.

Abstract: A method for selectively modifying an information signal at a remote site in a telecommunications system having a head end and a number of remote sites connected to form a ring. An initiation signal is received at a head end. The initiation signal indicates when to start modifying the information signal. Further, the method retrieves at least one stored modification signal. The method also transmits the modification signal to at least one selected remote site over a packet ring network of the telecommunications system. The packet ring network includes ring switches that self-learn the location of network devices based on addresses in packets processed by the switches and which learn that addresses of network devices associated with other ring switches are reachable out of at least one ring port of the ring switch. The information signal is modified with the modification signal. The method also detects the end of the modification signal and ends the modifying of the information signal.

Abstract: A system controls the configuration of a Token Ring network port having a first mode of operation and a second mode of operation. The system includes a mode selector having a first state associated with the first mode of operation and a second state associated with the second mode of operation. A switching device is coupled to the mode selector and the network port. The switching device has a first configuration associated with the first mode of operation and a second configuration associated with the second mode of operation. The network port may include multiple signal wires that are coupled in different configurations by the switching device based on the switching device configuration. Additionally, the switching device may be coupled to receive a phantom current in the first configuration and coupled to transmit a phantom current in the second configuration. A detector can be coupled to the switching device to detect a phantom current in the first mode of operation.

Abstract: A distributed telecommunications switching subsystem (100) receives and distributes data packets passed between a plurality of switching subsystems or channel banks (102, 104, 106) and a data packet switch (110). Each channel bank (102) has a stored list of addresses. When a channel bank (102) receives a data packet, it compares the address of the data packet to its stored list of addresses, and transmits the data packet to another channel bank (104) if the address of the data packet does not correspond to any of the addresses in its stored list of addresses. The data packet is passed on until it reaches a channel bank (106) with a matching address or else it is appropriately handled by a last channel bank (106) in the chain. If the address of data packet matches an address in its stored list of addresses, the channel bank (102) passes the data packet through a subscriber interface card (120) to a customer premises equipment unit (108) corresponding to the address of the data packet.

Abstract: A data mover which provides guaranteed transfer of data between two locations. The data mover includes a pair of data packet memories for input, a pair of data packet memories for output, and a controller which alternately switches each of the paired data packet memories between a data loading mode and a data unloading mode. The controller enables one of the paired data packet memories in the data loading mode and enables the other one of the paired data packet memories in the data unloading mode. The controller switches the modes of the paired data packet memories upon receiving an acknowledgement of moved data.

Abstract: A connection switching circuit is disposed in each node of a ring system in which a first ring and a second ring are provided with two communication lines which allow data to flow in a different direction respectively and is connected with a currently used passage and preliminary passage. The connection switching circuit comprises an alarm correction reading part for generating a control signal, an alarm monitor part for outputting respective alarm detection signals, a currently used/and preliminary alarm recognition part, and a switching control signal generation part for generating a control signal for selecting a passage, wherein either the currently used passage or the preliminary passage is selected by monitoring the alarm of the data which flows on the currently used passage or the preliminary passage to connect the first ring and the second ring with each other.

Abstract: A method and apparatus for analyzing a telecommunications network and providing data based on such analysis first receives physical topology data for the network based on nodes and their connections in the network. Thereafter, the method and apparatus identify several inter-node configurations in the network. Preferably, the method and apparatus identify six inter-node configurations: stranded network non-rings, non-ring network spurs, stranded network rings, spur nodes with path diversity, network segments with pass-through nodes, and network segments without pass-through nodes. From these six identified inter-node configurations, the method and apparatus identify failure spans or maximum lengths in a network that can be singularly restored.

Abstract: The IP addresses of network elements are generated based on the ID numbers of nodes within a network having a predetermined configuration. After producing the configuration information including an interconnection relationship among the network elements, the respective IP addresses are determined such that the ID number of each node is used to determine an IP address of each network element according to the interconnection relationship between the node and the network element. A node IP address is determined based on the ID number of the node, and another IP address of each of the network elements other than the nodes is determined based on the sum of the total number of nodes and the ID number of the node.

Abstract: A technique for initializing a communications network having a ring topology chooses a ring master for each ring. The ring master communicates with all network nodes to assign each node a unique number. Upon power up, after all system clocks become stable, the ring master asserts a line that is normally used to delineate slots by holding the line for a predetermined amount of time. When a node is ready for operation, i.e. it has performed an internal reset procedure, and receives the asserted signal, it forwards such signal. Subsequent receipt of the asserted signal by the ring master indicates that the ring is operating properly.

Abstract: A node device for performing packet communication using a transmission line composed of a plurality of channels is connectable to a network having a plurality of node devices, each of the plurality of node devices connecting the transmission line to a sub-transmission line. The node device a has packet processor for processing a packet, first, second, and third devices for outputting a packet, a memory device and a transmitter. The first device corresponds to each of the plurality of channels and outputs a packet input on a predetermined one of the plurality of channels to a side of the sub-transmission line or a side of the transmission line. The second device corresponds to each of the plurality of channels and outputs a packet transmitted through the sub-transmission line to the transmission line side or the packet processor side. The third device outputs a packet supplied thereto from the packet processor to the sub-transmission line side.

Abstract: A system for configuring a process control system, e.g., a Fieldbus network, having intelligent field mounted devices coupled to a data communications bus. A software representation of the process control system to be configured is first designed on a computer. Using the system, a user selects representations of the various field mounted devices to be included in the actual control system. The user then specifies which function blocks of each field mounted device are to be used and how those function blocks are to be linked. The computer is then coupled to the communications bus of the actual control system via an interface device and the configuration and link data are downloaded to the field mounted devices of the control system. The computer can act as a bus master of the communications bus of the control system with the field mounted devices acting as slaves.

Abstract: A novel transport architecture and network elements use nodes in a ring or virtual ring configuration. Information is exchanged among the nodes in a continuous series of containers carried in a superframe. A container is assigned to a destination node and is divided into partitions which are allocated for source nodes. Therefore, when a container destined to a particular destination node arrives at a node and if this node has information to send to the destination node, it fills the allocated partition within the container with information destined to the destination node. The sizes of the superframe, containers and partitions are all variable dynamically or statically.

Abstract: A wiring scheme for providing loop-back capability for individual failed channels around a ring network composed of nodes with limited space-switching. With this invention each node has a switch for interconnecting channels between incident links of the node. Each secure channel i has a backup channel B(i). In the normal mode of operation, the switch is configured so that the ports for channel B(i) of the incident links are connected to each other. Upon failure of channel i in one of the incident links of the node, the port for channel i of the failed link is connected to the port for channel B(i) on the other incident link of the node. With this invention when there is a failure of channel i on one of the links, the connection using this failed channel can be restored by switch configurations at only two nodes of the ring since the backup channels at the other nodes are already connected to each other.

Abstract: This is a method and system of communicating on a data and computer communications network.

Abstract: A hierarchial bus structure having at least three dimensions provides improved interconnect flexibility between nodes located on one or more levels of the structure. Nodes are defined on at least first and second "horizontal" (or "H") rings, the rings being coupled by at least one "vertical" (or "V") ring. Each node is identified in terms of its (H,V) coordinates in the hierarchial interconnect structure, and an M-dimensional structure will provide an M-way multiplex unit at each node. For an M=3, e.g., three-dimensional structure, each multiplex unit has three-inputs, a Localout, a Vin, and an Hin input, and couples one of these inputs to an output port in response to a Local select arbitration signal. The output signal is coupled to Hout and Vout, and to Localin. Nodes on the same horizontal level will drive their Hin signal to Vout and Hout, whereas all other nodes receive the Vin signal.

Abstract: A means for transferring circuit switched data (CSD) and packet switched data (PSD) in an open, high speed, high bandwidth, expandable telecommunications system having a plurality of switching and non-switching nodes. The network may carry any type of information present in the system including voice, data, video, multimedia, control, configuration and maintenance, and the bandwidth of the network may be divided or shared across various information types. The network provides each node with essentially direct access to information (e.g., circuit switched data, packet switched data, etc.) originating from any port associated with any node served by the network. Different packet structures are provided for communicating circuit switched data, packet switched data, maintenance and control information, and the like. In one method, each node transmits one or more packets, each having an "empty" payload, which is received by other nodes that determine the source of the received packet and the packet's status.

Abstract: A system and method for communication and management of an aggregate is provided including a plurality of separate entities, each entity residing in a separate environment. The system includes a data path which is provided as a common medium. Each of the entities is connected to the data path for exciting the medium with a signal. All entities connected to the common medium receive the signal. A mapping path is also provided. The mapping path is implemented as a multitude of point-to-point connections such that each entity is connected directly to another entity via a point-to-point connection or connected to a first entity by a point-to-point connection and connected to a second entity by a point-to-point connection. The connections provide a known topology, allowing identification of all entities adjacent to a given entity to establish mapped adjacent entities. From these mapped adjacent entities all entities adjacent to the mapped adjacent entities are mapped until all entities of the aggregate are mapped.

Abstract: A system and method optimize a fiber optic network arrangement in terms of load balancing and equipment placement at network sites. The present invention accomplishes this optimization by transforming a network of rings into a directed graph of nodes and arcs. The two parameters, which are load balancing and equipment placement, are set up as state variables in a mathematical algorithm for optimization. Following the transformation, descriptive linear equations are derived from the directed graph. The linear equations are then optimized for load distribution and equipment placement at network sites. The present invention may be applied to equipment placement and load distribution in new networks, as well as new load accommodation in existing networks by equating a state variable, corresponding to equipment placement, to a constant value.

Abstract: Methods and systems for determining the address of the nearest downstream reconfiguration unit in a dual ring communication system. In a dual ring communication system having a plurality of reconfiguration units one of the reconfiguration units determines if a Reconfiguration Unit Monitor is active on the system. If a Reconfiguration Unit Monitor is not active the reconfiguration unit requests and stores address information from the remaining reconfiguration units in the ring and assembles a ring sequence reconfiguration unit ring map. The reconfiguration unit transmits the reconfiguration unit ring map to the remaining reconfiguration units in the ring. Reconfiguration units receive the reconfiguration unit ring map from the Reconfiguration Unit Monitor and extracts the address of the nearest downstream reconfiguration unit from the reconfiguration unit ring map.

Abstract: A token ring network performs address to port mapping by taking advantage of the abilities of the port switched modules and the neighbor notification process, in order to perform address to port mapping on each individual module. Ring monitors are switched from an upstream side of a port to a downstream side of a port when the neighbor notification process enters the port domain. The processor on the module records all the addresses received on the downstream side of the port, when the neighbor notification process is in the domain of that port. If it appears that the neighbor notification process is in the domain of two adjacent ports, the present invention only records addresses from the most downstream of the two adjacent ports, since such a situation is an indication that the upstream ports do not conform to MAC protocol.

Abstract: Various methods and associated apparatuses are provided for communicating data from a central station to a remote station over some form of communications path. The data, which together form at least one title, are stored on at least one storage device. The data forming that title are then retrieved as data blocks, from storage. Each data block is a sequential segment of the data. Finally, the retrieved data blocks are transmitted from the central station to the remote station. According to preferred embodiments, two types of storage devices are provided. The first type, preferably formed as an array of playback units, allows the data to be stored as data blocks and distributed accordingly over a plurality of storage devices. The second type, preferably formed as ring structures composed of solid state elements, provides a plurality of access points coupled to the storage medium, each of which is able to retrieve the data independently of other access points.

Abstract: The eligibility of all bidirectional links interconnecting a plurality of nodes in a network is determined based on the free bandwidths in both directions of the links and the bandwidth required for transmitting messages between a source node and a destination node in the network. The determination is exercised as to both ends of a link. Then, the link is determined whether or not it is eligible to become part of the shortest route. The determined eligibility of the links may provide a rapid shortest route selection, which will be executed later, because the route selection steps are not executed for ineligible links.

Abstract: A procedure for establishing a scalable spanning tree over a network composed of nodes and links in which the resources for each node is independent of the size of the network. The procedure involves the selection of a set of states, a set of messages, state transition rules as well as a completion rule to thereby detect the the setting up of the spanning tree. One established, data may be distributed over the spanning tree so that coordination of data is maintained over all the nodes in the network.

Abstract: A protocol for use in a system including a first node, a second node and, in some instances, a third node, each of the first, second and third nodes coupled to each other of the first, second and third nodes by a point to point packet-based communication system defines transactions for transferring variable amounts of data from one node to another. A GET transaction allows an instigator node to send a packet to a partner node. The packet specifies data length, and an address in the partner node's resource. A PUT transaction similarly allows an instigator node to send a packet specifying a response port identifier, a data length and an address in a partner node's resource to which data is to be written. A PROXY transaction is disclosed which allows an instigator node to cause a source partner node to send data to a target (destination) partner node. Other transactions are also disclosed. In each instance, port identifiers accompany packets in order to associate received data with a particular transaction.