Abstract: A cross-bar switch includes a set of input ports for receiving data packets and a set of sink ports coupled to the input ports to accept and forward the data packets. Each sink port includes a multiple entry point FIFO with multiple data inputs for receiving data packets. In one implementation, the multiple entry point FIFO includes a FIFO storage buffer and request logic coupling the multiple entry point FIFO's data inputs to the FIFO storage buffer. The multiple entry point FIFO concurrently maintains separate pointers into the FIFO storage buffer for each data packet being received on the multiple entry point FIFO's data inputs.

Abstract: Each sink port in a cross-bar switch provides for allocating bandwidth among data packets. Packets are assigned priority levels, and the cross-bar switch regulates bandwidth allocation for each priority level. A sink port records traffic volume for packet data of each priority level. The sink port calculates a weighted average bandwidth for each different priority level and determines whether to reject packet data for the priority level. When the packet data collected by a sink port exceeds a threshold, the sink port rejects data packets with priority levels having excessive weighted average bandwidths.

Abstract: A cross-bar switch includes a set of input ports for receiving data packets and a set of sink ports for transmitting the received packets to identified targets. A set of data rings couples the input ports to the sink ports. Each sink port utilizes the set of data rings to accept data packets targeted to destinations supported by the sink port. The cross-bar switch includes a multi-sink port for supporting explicit multicast addressing. The multi-sink port is coupled to each data ring and each sink port. The multi-sink port snoops multicast packets on the cross-bar switch's rings and transfers each packet to a set of sink ports that support the packet's targeted destinations.

Abstract: A cross-bar switch includes a set of input ports to receive data packets and a set of sink ports in communication with the input ports to receive the data packets and forward them onto a communications link. Each sink port is adapted to concurrently receive multiple data packets targeted to the same destination or multiple destinations. For example, one sink port receives a first data packet and a second data packet. The one sink port receives at least a portion of the second data packet during a time period in which the one sink port is receiving the first data packet.

Abstract: This invention provides a new architecture for a communication system between head-ends and end-users which expands bandwidth and reliability of the communication system. A mux-node receives communication signals from a head-end and forwards the received communication signals to one or more mini-fiber nodes. The connection to the head-end is via a small number of optical fibers and the connections to each of the mini-fiber nodes may be via one or more optical fibers that may provide full duplex communication. The head-end may communicate with the mux-node using digital or digital and analog signals. The mini-fiber nodes may combine the signals received from the head-end with loop-back signals used for local media access control prior to forwarding the signals to the end-users. Upstream data are received by the mini-fiber nodes and transmitted to the mux-node.

Abstract: A ring network for transporting data packets between network devices is provided. The ring network includes a number of ring switches. Each ring switch has at least one ring port, at least one local port and at least one table that self learns which network devices are associated with each port of the ring switch based on a selected source identifier from the packets processed by the ring switch. The source and destination identifiers may, for example, be a media access control (MAC) address from an Ethernet packet, an Internet Protocol (IP) address, at least a portion of a hierarchical address, a combination of two or more identifiers at different protocol levels for the data packet, a port number of a universal datagram protocol, or other appropriate identifier. The at least one ring port of each ring switch is coupled to a ring port of another ring switch in the ring network.

Abstract: The Spanning Tree Protocol (STP) chooses a root switch. Each of the other switches has a “root” port and one or more “designated ports(s)” chosen by STP. Packets are transmitted upstream toward the root switch through the root port, and packets designated for downstream switches from the root switch are received by the root port and transmitted through the designated ports. In the invention, an administrator of the core network identifies which switch ports in the core network are boundary ports to customer networks. The administrator designates the boundary ports as “root guard protected” ports (RG ports). The STP then executes as required by the ordinary STP protocol, and if a RG port is selected by the STP to be a root portm then the status of the port is set to “blocked,” and no packets are transmitted through the port.

Abstract: A system and method selectively establishes data communications, such as XDSL services, between data devices and a network switch. Status of the data devices are monitored and active data devices are connected to a data branch for data communications. Data devices which are inactive may remain connected to the data branch, if available, or may be switched to a pilot branch. While disconnected from the pilot branch, the system may detect a signal from the data device indicating that the device is going active. If pilot signals are being used, the pilot signals between a data device and the network switch are monitored to determine when the data device is going active. Once detected, the data device is connected to the data branch. Alternately, if pilot signals are not being used, the system monitors the connection with the data device for any signals, such as a wake-up signal, which indicates that the data device is going active.

Abstract: A method of managing connectivity of a cluster of bridging-devices including a plurality of links. The method includes pre-designating at least one of the links as a redundant link which is blocked when all the other links are operative and connected in accordance with a predetermined scheme, determining connectivity data on the connectivity of the links of the cluster, and activating or blocking the pre-designated redundant at least one link responsive to the connectivity data.

Abstract: A method of processing internal operations in a network switch includes the steps of constructing a lookup table in system memory by snooping a communication channel in a network switch for lookup table information. Upon detection of lookup table information on the communication channel, the lookup table information is transmitted to a remote system memory, thereby constructing a lookup table in the remote system memory. DMA operations are performed by providing a DMA descriptor including a reload field therein. The DMA descriptor is processed, and a location of a next DMA descriptor is identified based upon a condition of the reload field. The lookup table in remote system memory enables CPU access to the lookup table without requiring communication on the communication channel. The condition of the reload field enables flexible DMA descriptor handling. A network switch also includes elements associated with this method.

Abstract: A network switch routes switch packets among nodes with input and output ports. The nodes are connected together in a loop by two buses. One bus sends packets in a clockwise direction around the loop of nodes, while the other bus sends packets in a counter-clockwise direction around the loop. Each bus is divided into links between adjacent nodes, which examine and forward the packets to the next node in the loop. A packet is duplicated and injected onto both buses from a source node, reaching half of the nodes in one direction, and the other nodes in the opposite direction. A distance value in the packet header is set to half of the number of nodes so that the packet is removed after traveling half-way around the loop. A bit-mask in the header indicates nodes to receive the packet, or source-monitoring can remove packets half-way around the loop.

Abstract: A computer system may include a processor, at least one memory coupled to the processor and having a plurality of scattered memory locations each having a pointer associated therewith, and a receiver interface circuit coupled to the at least one memory. The receiver interface circuit may include a scatter pointer queue for storing available pointers corresponding to available scattered memory locations. The scatter pointer queue may also store unavailable pointers corresponding to unavailable scattered memory locations. The receiver interface circuit may also include a receiver for receiving the data and writing the received data to the available scattered memory locations based upon the available pointers in the scatter pointer queue.

Abstract: An orderwire controller and orderwire control system which provide enhanced capabilities of flexible orderwire signaling to improve usability and maintainability. A network system involves multiple ring networks, each of which comprises a plurality of network elements interconnected in a ring topology. An orderwire controller, implemented in a network element, comprises a plurality of mixers and a combination controller. The mixers add up orderwire signals from local and remote sources. The combination controller controls how to associate the mixers with the rings, to provide flexible connections among the rings so that they can share their orderwire signals.

Abstract: In the node device of a network of performing communication while changing the communication channel, a plurality of packets are transmitted to a terminal device in a different order from the reception order of a plurality of received packets without rearranging the packets in the terminal device. In addition, the packets are transmitted to the terminal device with traffic characteristics based on traffic characteristics used to transmit a plurality of packets.

Abstract: The present invention provides a mechanism for supporting high digital bandwidth in a multi-drop bus system. A first device of the system encodes multiple bits in a symbol and drives the encoded symbol onto the multi-drop bus. Multiple receiving devices are linked to the bus through electromagnetic couplers. A receiving device samples the encoded symbol through the electromagnetic coupler and recovers the encoded bits from the sampled symbol.

Abstract: A method of operating a network device in a communication system for the transmission of data packets which include network addresses identifying sources and destinations of data, the network device being capable of both bridging and routing decisions and including a forwarding database by means of which a packet including network address data can be forwarded to at least one port and thereby to at least one network path identified by a network address, and packets can be forwarded to at least one port in response to a media access control address. The method comprises establishing a data table which contains entries comprising a network address of an end station to which a packet is destined, a respective media access control address and an identification of at least one port to which the packet will be directed within the device. The table is accessed in response to network addresses and media access control addresses, whereby the same table can be used for both routing and bridging decisions.

Abstract: A packet switching fabric includes means forming a data ring, means forming a control ring, and means forming a plurality of data communication network links each having at least one network node coupled thereto. The fabric further includes a plurality of output queuing controlled switching devices coupled together by the data ring means and the control ring means so that the network links can be selectively communicatively coupled. Each of the output queuing controlled switching devices includes control ring processing means operative to develop, transmit and receive control messages to and from adjacent ones of the devices via the control ring means.

Abstract: A communication system between head-ends and end-users is provided which expands bandwidth and reliability. A concentrator receives communication signals from a head-end and forwards the received communication signals to one or more fiber nodes and/or one or more mini-fiber nodes. The concentrator demultiplexes/splits received signals for the mini-fiber nodes and the fiber nodes and forwards demultiplexed/split signals respectively. The mini-fiber nodes may combine signals received from the head-end with loop-back signals used for local medium access control prior to forwarding the signals to the end-users. Upstream data are received by the mini-fiber nodes and/or fiber node and transmitted to the concentrator. The concentrator multiplexes/couples the mini-fiber node and the fiber node upstream signals and forwards multiplexed/coupled signals to the head-end.

Abstract: The present invention is directed to a synchronous I/O interface buss system. The system includes a master-buss controller that generates a system timing signal. The master-buss controller transmits a time-division multiplexed (TDM) slave output data signal and receives a time-division multiplexed (TDM) slave input data signal. The TDM slave output data signal and the TDM slave input data signal are synchronous relative to the system timing signal. A buss is coupled to the master-buss controller. The buss propagates the system timing signal, the TDM slave output data signal, and the TDM slave input data signal. At least one slave device is coupled to the buss. The at least one slave device is in synchronicity with the system timing signal. The at least one slave device demultiplexed slave device output data in device-ready format from the TDM slave output data signal during a predetermined output data signal time slot.

Abstract: Method for interconnecting a number of RPR rings in a wide area RPR network which provides for creating a hierarchical tree of RPR rings. Communications between different RPR rings in the network are allowed only according to the hierarchical tree architecture, through suitable ring identifiers assigned to the RPR rings according to the hierarchical tree structure.

Abstract: A cross-bar switch includes a set of input ports for receiving data packets and a set of sink ports for transmitting the received packets to identified targets. A set of data rings couples the input ports to the sink ports. Each sink port utilizes the set of data rings to simultaneously accept multiple data packets targeted to the same destination—creating a non-blocking cross-bar switch. Sink ports are also each capable of supporting multiple targets—providing the cross-bar switch with implicit multicast capability.

Abstract: A cross-bar switch includes a set of input ports for receiving data packets and a set of sink ports for transmitting the received packets to identified targets. A set of data rings couples the input ports to the sink ports. Each sink port utilizes the set of data rings to simultaneously accept multiple data packets targeted to the same destination—creating a non-blocking cross-bar switch. Sink ports are also each capable of supporting multiple targets—providing the cross-bar switch with implicit multicast capability.

Abstract: Cross-bar switch includes a set of input ports for receiving data packets and a set of sink ports for transmitting the received packets to identified targets. A set of data rings couples the input ports to the sink ports. Each sink port utilizes the set of data rings to simultaneously accept multiple data packets targeted to the same destination—creating a non-blocking cross-bar switch. Sink ports are also each capable of supporting multiple targets—providing the cross-bar switch with implicit multicast capability.

Abstract: An optical network includes interconnected via an N×N WDM router. The nodes are connected to an optical waveguide ring having a duplex structure. A first set of optical waveguides connects the transmitters in the nodes and a second set of optical waveguides connects the receivers in the nodes. The N×N wavelength router is connected across the ring between the first set of optical waveguides and the second set of optical waveguides. Each of the nodes is able to communicate with any other of the nodes on a respective wavelength channel via the router.

Abstract: A switching unit and a method for operating the same as well as a device for use in the switching unit, where the switching unit comprises a ring-shaped bus for transporting the data packets and a daisy-chain type bus for transporting controlling device information for use in a later switching routing. The two busses are driven synchronously. This systolic nature of the busses ensures optimal bandwidth of the switching.

Abstract: In a communication network, a ring network is formed with switches connected to a number of parallel channels. Terminal devices are also connected to the parallel channels and supply an input signal. The switches receive the input signal from each of the channels and output it to other channels. The network is configured so that the input signal passes through the switches not less than twice before the signal reaches a destination terminal device. A signal passed through a switch once will reach its destination if that switch designates a channel. Instead, that signal is output using an arbitrary channel in place of being output using the designated channel. Once the signal has made its journey around the ring once, it is output by designating a channel. Since the last switch receives the signal from an arbitrary channel, a broad communication band can be assured.

Abstract: In order to be able to transmit continuous and/or discontinuous data streams in a hybrid telecommunication system, particularly a “ISDN⇄DECT-specific RLL/WLL” system, given minimal technical outlay, for example with respectively separate data ports (data inputs and data outputs), a plurality of second telecommunication channels (for example, DECT channels) adapted to the analyzed data transmission situation is respectively set up dependent on the analysis of the data transmission situation on a first telecommunication channel or, respectively, channels (for example, the ISDN B-channel or, respectively, B-channels).

Abstract: A ring-bus transition 100 is provided which for switching signals between inputs 140-144 and outputs 180-85. First, signals are received at a number of inputs 140-144. Each input is coupled to a demod 130-134. Each demod is coupled to a communication ring 151-160 which is in turn coupled to a bridge 190. Signals received at the inputs 140-144 are demodulated at the demods 130-134 and then sent via the communication rings 151-160 to the bridge 190. The bridge relays the signals to a communication bus 195 which in turn relays the signals to output processors 170-175. Each output processor 170-175 may receive and stores signals destined for it in a memory queue 230. The signals may then be output in the order they arrive or in some other order based on a priority signal. Additionally, each communication ring 151-160 may be closed by connecting the bridge 190 to the first input on each loop.

Abstract: An integrated circuit has a data transfer system which is simple in switching control and timing extraction of transfer. A bus provided between four modules has a bit width the same as number of bits consisting a transfer data. The bus is divided into a plurality of fractions respectively lying between a plurality of modules. Respective divided fractions are connected by adapters. The adapter includes a lip-flip or the like temporarily holds data to be transmitted from one fraction of the transmission path and outputs to another fraction of the transmission path to form a ring transmission path. Since data flows in a predetermined direction on the bus, control can be simple. Also, since a plurality of modules can perform transmission and reception of data at the same timing, transfer efficiency can be improved significantly.

Abstract: A data network hub unit is stackable with other such units to constitute a hub in which each of the units can supply data packets to network data destinations and receive data packets from network data sources, and to form a closed data transmission ring which enables packets received at any unit to be transmitted from any other unit. The hub unit includes arbitration control means responsive to packet headers circulating on said ring.

Abstract: Apparatus and a method for interfacing between the Internet and the Telephone Network. A time slot interchange is enhanced by the addition of a supplementary memory for storing data for accumulating Internet packets. When a packet has been accumulated, the appropriate header is inserted into the packet under the control of a routing processor, and the packet can then be sent as a group of adjacent PCM samples over a connection to the Internet. In other embodiments, information is sent to the Internet over a direct data pipe for transmitting ATM cells or Ethernet packets. A Vocoder signal processor can be inserted between the TSI memory, and the supplementary memory to convert PCM voice samples into vocoded voice samples for transmission over the Internet. A modem signal processor can be interposed between the TSI memory and the supplementary memory to convert between analog data (representing for example, shift key analog signals) and binary data for transmission within packets over the Internet.

Abstract: A layer 3 forwarding method for layer 3 forwarding an individual packet from a station I to a station II wherein the packet's layer 2 destination includes a router within the network which is reachable from a network element A via which stations I and II are connected to the network, the router storing ARP information, the method including providing network element A with a capability to perform layer 3 forwarding of a packet from station I to station II, wherein the providing step includes learning, on the part of network element A, of forwarding information used by the router to forward packets from station I to station II, by reading the ARP information of the router and performing layer 3 forwarding on the individual packet, at network element A.

Abstract: A computer chip includes a data transfer network. The data transfer network comprises a backbone bus, a plurality of communication ports and a plurality of devices or modules each coupled to the backbone bus. Each of the devices includes or is coupled to one or more communication ports. Some of communication ports are operable to transmit and receive data on the backbone bus. Furthermore, the communication ports are interconnected in a ring topology forming a circular bus or a semi-circular bus. A subset of the communication ports may transmit and receive data on the circular bus or semi-circular bus. For the semi-circular bus, the communication ports are not coupled to form a complete ring topology. The communication ports may be operable to communicate with each other over the backbone bus and/or the circular bus. Each of the communication ports includes backbone bus interface logic, circular bus interface logic, one or more data transfer buffers and/or control logic.

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 switch that has a plurality of inputs in which cells are received at these inputs. Each cell received at the inputs of the switch contain routing information. A routing means is employed to route the cells received at the inputs of the switch to outputs using routing information in which a number of the cells are misrouted by the routing means during the process of routing the cells to the outputs. Bus means is employed to route a cell to the destination in which the bus means is connected to the routing means. The bus means routes misrouted cells that are misrouted from the destination by some selected amount.

Abstract: A method for common transmission of digital source and control data between data sources and sinks being connected through data lines, includes transmitting the source and control data in a format specifying a clocked sequence of individual bit groups of equal length. In these bit groups, certain bit positions are each reserved for the source and control data and the bit positions reserved for the source data form a cohesive region within one bit group. The region of a bit group reserved for the source data is subdivided into a plurality of partial bit groups of equal length. The source data assigned to each partial bit group are allocated to a certain data source/data sink as a function of the control data.

Abstract: In the prior art, the storing of subscriber-related data ensues in the peripheral installations of the communication system. This requires a great deal of memory space. In order to minimize this, the subscriber-related data is stored, per interface to a subscriber connection network, in only one of the peripheral installations, or, if redundancy is required, in two of them.

Abstract: A high speed circular data bus system having a plurality of input buffers connected to uplink demodulator units associated with a plurality of data receivers. The input buffers are connected to each other in a daisy chain configuration with each input buffer connected to the next sequential input buffer in the daisy chain configuration and connected to an associated output buffer slice. Data received from each uplink demodulator unit is sequentially circulated through each input buffer so that each input buffer sequentially sees the data received from each uplink demodulator unit. In the preferred embodiment, each input buffers consists of an input buffer node having a primary input buffer and an associated redundant input buffer. Each pair of input buffers also being connected in a daisy chain circular configuration and cross-linked to each other.

Abstract: An optical communications network includes a plurality of passive optical networks (PONs) connected in a ring in PON address order, in which communication channels between terminals are wavelength multiplexed. Each optical link between adjacent PONs includes a tunable wavelength filter, and a common wavelength allocation database is arranged dynamically to select wavelengths for a connection and to provide corresponding control signals to the appropriate filters such that the allocated wavelengths for a connection can pass over only the transmission path between the terminals. Thus the same wavelengths can be re-used for another connection whose transmission path does not overlap with any existing transmission path involving those wavelengths.

Abstract: A non-blocking switching network for routing packets from a plurality of inputs to a plurality of outputs includes a reservation ring mechanism for resolving conflicts among inputs contending for access to specified ones of said outputs. This reservation ring performs a sequence of step and compare operations in top-to-bottom ring-like order during at least one arbitration cycle for granting contending inputs access to said specified outputs in a top-to-bottom order that is also consistent with the order required by self-clocked weighted fair queueing or, alternatively, virtual clock, with up to a maximum permissible plural number of contenders being given access to such an output on each of the arbitration cycles.

Abstract: A local area network switch includes a set of input ports each receiving and storing incoming packets from a corresponding network station, a set of output ports each forwarding packets to a corresponding network station, and a switching system for routing packets from the input ports to the output ports. The output ports are interconnected to form an output token passing ring and the input ports are interconnected to form an input token passing ring. Whenever an idle output port receives the output token, it holds the output token and signals the input ports to start an input token passing cycle. During an input token passing cycle, an input port storing a packet destined for an output token holder terminates the input token passing cycle when it receives the input token and signals the switching system to establish a connection to the output token holder. To fairly distribute arbitration priority, input and output ports starting positions are rotated for successive input and output token passing cycles.

Abstract: A data communication system, such as a local area network, is provided with a capability of transmitting isochronous data. Preferably the system conveys both isochronous data and non-isochronous data by time-multiplexing the data into a recurring frame structure on a four-bit nibble basis. An efficient encoding scheme permits transmission of both isochronous and non-isochronous data over existing media, such as twisted pair, without degrading bandwidth previously achieved for non-isochronous data over the same media, such as using an ethernet system. Bandwidth available for a particular isochronous source/sink is selectable and sustainable with a predefined granularity. The arriving data is de-multiplexed at the hub into separate channels for handling the separate streams by appropriate hardware. Preferably, the present invention can be implemented in a fashion that is transparent to already-installed media access controllers.