69 results about "Atm switching" patented technology

A novel networking architecture and technique for transmitting both cells and packets or frames across a common switch fabric, effected, at least in part, by utilizing a common set of algorithms for the forwarding engine (the ingress side) and a common set of algorithms for the QoS management (the egress part) that are provided for each I/O module to process packet/cell information without impacting the correct operation of ATM switching and without transforming packets into cells for transfer across the switch fabric.

A two-way cable network offering high-speed broadband communications delivered via virtual private networks over a multi-channel shared media system. Bi-directional transmission of packet to ATM cell based communications is established between a head end communication controller and a number of subscriber terminal units, whereby individual cells are prioritized and routed according to a virtual connection. Virtual connections are organized to support multiple virtual private networks in a shared media CATV system. The virtual private network to which a particular STU belongs is user selectable and has the flexibility of handling multi up/downstream channels with different MAC domains. The present invention can also handle non-ATM MAC domains via the same common ATM switch. To overcome the limited number of addresses inherent to common ATM switches, a mapping/remapping function is implemented in the port cards. Furthermore, downstream as well as upstream traffic are filtered at each STU. In one embodiment, information pertaining to downstream traffic is used to implement predictive scheduling in order to improve the timing associated with the request/grant cycle. In another embodiment, a user has the ability to select a quality of service that best suits the needs of the current application. In a further embodiment, the scheduling function is associated with each of the receivers in order to provide improved scalability.

An ATM switching system architecture of a switch fabric-type is built of, a plurality of ATM switch element circuits and routing table circuits for each physical connection to/from the switch fabric. A shared pool of memory is employed to eliminate the need to provide memory at every crosspoint. Each routing table maintains a marked interrupt linked list for storing information about which ones of its virtual channels are experiencing congestion. This linked list is available to a processor in the external workstation to alert the processor when a congestion condition exists in one of the virtual channels. The switch element circuit typically has up to eight 4-bit-wide nibble inputs and eight 4-bit-wide nibble outputs and is capable of connecting cells received at any of its inputs to any of its outputs, based on the information in a routing tag uniquely associated with each cell.

An ATM switching architecture for a wireless telecommunications network includes two separate units having different functionality. The first unit performs mobility control, wherein a virtual path which contains all virtual channels of a mobile terminal is switched from a first port associated with a first access point, to a second port connected to a first port of the second unit. The second unit performs a switching operation, wherein the virtual channels of the mobile terminal are distributed from the first port of the second unit to different destination ports of the second unit. In one embodiment, the two units may be dedicated hardware components, and in another embodiment, one single hardware component is functionally separated into two separate units connected by a loopback link.

The invention is to use the ability of a switching fabric to set a congestion indicator bit in a segment if any queue through which the segment passes is filled above a lower threshold. The output linecard monitors the field of the congestion indicator bit as it receives segments from the switching fabric. The output linecard periodically calculates the ratio of segments having the congestion bit set to all segments routed to a particular port. The periodically calculated ratio is used as an input parameter to a Random Early Detection (RED) algorithm. The RED algorithm selects a packet for the output linecard to drop, by use of a random selection method. The destination computer then does not receive the packet. The random selection of packets to drop has the effect of helping to prevent undesirable network synchronization of transmission of replacement packets. With adaptive source computers, the network device then does not reach a congested state, thereby maintaining optimum throughput for the computer network. When an ATM switching fabric is used with ATM cells for the segments, then the Explicit Forward Congestion Indication Field (EFCI bit) of a data cell is used to mark a data cell which has passed through a queue which is filled above a lower threshold level. Data cells arriving at the output line card with the EFCI bit set are then counted, and this count is used in the periodic calculation of the ratio used as input to the RED algorithm.

A method for scheduling cell transmissions through a switch with rate and delay guarantees and with low jitter is proposed. The method applies to a classic input-buffered N×N crossbar switch without speedup. The time axis is divided into frames each containing F time-slots. An N×N traffic rate matrix specifies a quantized guaranteed traffic rate from each input port to each output port. The traffic rate matrix is transformed into a permutation with NF elements which is decomposed into F permutations of N elements using a recursive and fair decomposition method. Each permutation is used to configure the crossbar switch for one time-slot within a frame of size F time-slots, and all F permutations result in a Frame Schedule. In the frame schedule, the expected Inter-Departure Time (IDT) between cells in a flow equals the Ideal IDT and the delay jitter is bounded and small. For fixed frame size F, an individual flow can often be scheduled in O(logN) steps, while a complete reconfiguration requires O(NlogN) steps when implemented in a serial processor. An RSVP or Differentiated Services-like algorithm can be used to reserve bandwidth and buffer space in an IP-router, an ATM switch or MPLS switch during a connection setup phase, and the proposed method can be used to schedule traffic in each router or switch. Best-effort traffic can be scheduled using any existing dynamic scheduling algorithm to fill the remaining unused switch capacity within each Frame. The scheduling algorithm also supports multicast traffic.

An Asynchronous Transfer Mode (ATM)-based distributed virtual tandem switching system is provided in which a network of ATM-based devices is combined to create a distributed virtual tandem switch. The system includes an ATM switching network that dynamically sets up individual switched virtual connections. The system also includes a trunk interworking function (T-IWF) device and a centralized control and signaling interworking function (CS-IWF) device. The trunk interworking function device converts end office voice trunks from TDM channels to ATM cells by employing a structured circuit emulation service. The centralized control and signaling interworking function device performs call control functions and interfaces narrowband signaling and broadband signaling for call processing and control within the ATM switching network. Consequently, the ATM based distributed virtual tandem switching system replaces a standard tandem switch in the PSTN.

A method and apparatus for reducing bandwidth usage in an ATM switching network by controlling bandwidth used for IP multicasting through the switching network. Bandwidth usage is controlled by modifying ingress and access modules, such as IP service gateways and access modules that terminate branches of a multicast tree. If a join request is received at an IP service gateway from a sink node served by an access module, the IP service gateway instructs the access module to graft a leaf to the branch to join the sink node to the tree and to merge the multicast packets with other IP packets for the sink node. Consequently, only one connection carrying the multicast traffic is required between the IP service gateway and the access module. Bandwidth usage in the ATM switching network is thereby controlled, and bandwidth usage in service access trunks connecting the access modules to the ATM switching network is reduced.

A method and system including ATM switching equipment provided for switching between a working channel and a protection channel in an ATM network. The method and system include the following processes: In each cell for transmission providing an indication of whether the cell belongs connection currently in a working state via a working channel; cells are duplicated on each connection basis; the duplicated cells are transmitted simultaneously on both a working channel and a protection channel; and valid cells are selected from received cells according to the indication in each cell indicating whether the relevant connection is currently in a working state.

A substitution call control system includes an ATM (Asynchronous Transfer Mode) subscriber network of an ATM communication network. The ATM subscriber network includes a plurality of network terminators respectively connected with a plurality of subscriber terminals, and an ATM subscriber line concentrator, which accommodates VCs (Virtual Connection) to the plurality of network terminators, and is connected with a ATM switching apparatus of the ATM network through a UNI (User-Network Interface). The ATM subscriber line concentrator includes a substitution call control function to substitute for the plurality of network terminators and the subscriber terminals for a call control.

An ATM switching system 1 is provided with an ATM switch 11, a reserved connection memory 12 for storing reserved connection information, a call history memory 13 for maintaining call histories of requests for connection from subscriber's terminal units 2₋₁ to 2_−n, and a call-signal processing section 15. The call-signal processing section 15 generates a request for connection with respect to a trunk ATM switching network 3 by the use of the call histories in the call history memory 13 in the case where no call was issued from the subscriber's terminal units, and stores response results thereof in the reserved connection memory 16. Thereafter, when there was a call from the subscriber's terminal units 2₋₁ to 2_−n, and contents of the request for connection thereof are the same as the reserved connection information, which has been stored in the reserved connection memory 16, processing for connection is executed by the use of the reserved connection information. As a result, an ATM switching system by which response becomes possible in even the case where a large amount of calls are issued at the same time, besides reduction in cost can also be attained is provided.

A transmission apparatus includes a part which sets a resource management information path based on a given network management protocol onto PVC logically set traffic defined in ATM switching so that a customer network management agent process and a user network management system can communicate with each other.

Disclosed herein is a method for summarizing a default address of a PNNI (Private Network-Network Interface) lowest level node in an ATM (Asynchronous Transfer Mode) switching system. In the method, first, a database for storing prefix information, node information and reachable address information is constructed. Parameters inputted for creating an internal prefix is arranged to be adaptable to the system, a prefix information is generated by checking the validation and address system of the parameters inputted for creating the internal prefix, and the prefix information is registered in the prefix information database. An ATM end system address is generated by checking the validation and address system of parameters inputted for creating the node information. The node address of the node information is summarized up to the bit length of the internal prefix and the summarization of a default reachable address is performed by defining the internal prefix as the default reachable summarization address.

A method for cross connecting an ATM network and a telecommunication switch includes receiving ATM cells from the ATM network at a packet sorter and extracting data packets comprising address data and payload data from the ATM cells. Translated addresses are generated based on the address data, and new data packets are created based on the payload data and the translated addresses to create new ATM cells with the new data packets. The new ATM cells are scheduled to be transmitted from the packet sorter to an ATM switch in compliance with an ATM service contract. The new ATM cells are forwarded from the ATM switch to at least one distributed SAR, which converts the new ATM cells into TDM signals and transmits the TDM signals from to the telecommunication switch via at least one TDM port.

The present invention relates to a multicasting network apparatus and method for an ATM switching system having a banyan network and a route network which includes a header encoder part for generating a header, a boolean splitter network for copying a cell routed from the banyan network to thereby transmit the same to a route network. The boolean splitter network includes a plurality of boolean splitters, each of the boolean splitters includes the step of dividing the destination addresses of a cell into an upper group and a lower group and selecting an active port to thereby route the same. As described above, any extra translation table is not required owing to a cell copying operation according to the present invention, whereby the number of hardware components can be reduced, and an expansion can be easily performed.

The present invention is directed to a high performance broadband ATM switching system comprised of concentrator, non-recirculating sort-trap and queuing stages. The concentrator stage concentrates cells entering the switch by discarding idle inputs thereto. Cells arriving at the non-recirculating sort-trap stage during a time slot are sorted based upon destination address and priority. Cells having a unique address for the time slot are placed in a corresponding output queue while cells having non-unique destination addresses are re-routed to a trap buffer which ages the cell until a subsequent time slot in which the destination address is unique.

A method for sub-port multicasting in an Asynchronous Transfer Mode (ATM) switching system, including inserting multicast fan-out port information for sub-ports of each of a plurality of switch ports into a multicast cell at an ingress port card, transmitting the multicast cell to an egress port card, reading the multicast fan-out port information from the multicast cell at the egress port card, and performing multicasting for the sub-ports corresponding to the multicast fan-out port information.

An apparatus and method for analyzing the performance of an ATM switch, and an ATM switching system employing the same. The apparatus includes a traffic detecting portion for detecting traffic of constant bit rate connection type data and available bit rate connection type data input to the ATM switch installed in a communication network for processing a data circuit switching, and a performance analyzing portion for calculating a performance of processing the constant bit rate connection type data and the available bit rate connection type data according to information related to the detected traffic of the constant bit rate connection type data and the available bit rate connection type data. According to the apparatus and method, and an ATM switching system employing the same, performance of the ATM switch can be analyzed and the analyzed result can be used in designing the ATM switch.

The system of this invention for extending address on UTOPIA and the method thereof can extend the single PHY on the ATM switching chip bus to many PHY ports easily without increasing too much cost, and thus increase the application flexibility of corresponding ATM switching chips. Evidently, there would be still many other embodiments of the invention, the people skilled in the art can make a variety of corresponding changes and transformations in accordance with the invention without departing from its spirit and essential, but these corresponding changes and transformations should also be in the protection range of the claims of this invention.

An ATM switching system includes a plurality of (m) small-scale nxn ATM switch modules, and a coupling module for coupling the ATM switch modules to one another to implement a large-scale ATM switching system. The coupling module includes m concentrators corresponding to the m ATM switch modules. Each concentrator has a multiplexing block for multiplexing mxn signal sequences into n signal sequences, concentration buffer block including a nxn banyan network for specifying one of ATM switch modules for each effective cell based on a destination signal and a plurality of buffers. The concentrator operates at slow transfer rate in a large-scale ATM system so that the performance of the concentrator does not restrict the scale of the ATM system.