Abstract: A method of identifying the current route of paths on communications MS-SPRINGs is described. The method comprises the steps of providing the network manager with information relating to the Nominal Route of the at least one path; and providing the management system with information of current status of the at least one network element, and being characterized by comprising the steps of processing the information provided through steps a) and b) so as to calculate the current route of the at least one path. The invention further concerns a network manager able to carry out the various steps of the method.

Abstract: A data transferring apparatus includes a ring bus, which circularly transfers data by holding in a slot to one direction and a plurality of nodes connected to the ring bus. Each of the plurality of nodes includes a detector and a controller. The detector detects whether or not data destined for a self-node is held in a slot arrived to another node connected to an upstream side of the self-node. The controller captures the data destined for the self-node from the slot when the detector detects presence of the data destined for the self-node and the slot arrives to the self-node.

Abstract: Methods and apparatus for Fibre Channel interconnection is provided between a plurality of private loop devices through a Fibre Channel private loop device interconnect system. In the preferred embodiments, the Fibre Channel private loop device interconnect system is a fabric or an intelligent bridging hub. In one aspect of this invention, a Fibre Channel private loop device is connected to two or more Arbitrated Loops containing, or adapted to contain, one or more private loop devices. Preferably, the interconnect system includes a routing filter to filter incoming Arbitrated Loop physical addresses (ALPAs) to determine which Fibre Channel frames must attempt to be routed through the fabric. Numerous topologies of interconnect systems may be achieved.

Abstract: A switch, switched architecture and process for transferring data through an FCAL switch is disclosed. The switch uses multiple switch control circuits each coupled to one FCAL network and all connected to a crossbar switch. The switch control circuits are coupled together by a protocol bus for coordination purposes. Local conversations can occur on each FCAL loop and crossing conversations through the switch can occur concurrently. The OPN primitive is used to establish the connection before any data is transferred thereby eliminating the need for buffer memory in the switch control circuits. The destination address of each OPN is used to address a lookup table in each switch control circuit to determine if the destination node is local. If not, the destination is looked up and a connection request made on the protocol bus. If the remote port is not busy, it sends a reply which causes both ports to establish a data path through the backplane crossbar switch.

Abstract: A system and a method of operating the system for non-disruptively inserting a node into the operations of an ATM ring uses the ring operations to update topology information and routing tables at the existing nodes to include therein the new node and one or more virtual paths associated with the new node. Basically, the node to be inserted establishes communications with a ring hub node over an established intra-ring management channel. The node and the ring hub node then exchange information over the management channel and the node performs its initializing routines in order that the node may operate to pass through traffic on the existing virtual paths. The new node next requests from the hub node the assignment of one or more virtual paths for directing traffic between that node and other nodes on the network. In response to the request, the hub node assigns one or more virtual paths to the requesting node and establishes a signaling channel to the node over one of the virtual paths.

Abstract: A method for rate matching in equipment used as part of, or in communication with, a radio access network implementing FLO (Flexible Layer One) so as to provide retransmission with incremental redundancy, the method using a rate-matching algorithm based on determining a starting parameter eini, the method characterized by: a step (21) of providing a retransmission parameter R controlled by the RLC protocol layer and having typically a value of one for a first retransmission and a next higher value for each subsequent transmission; a step (24) of determining a characteristic distance D related to the average distance between either punctured bits or between transmitted bits, depending on the value of the average distance between punctured bits; and a step (25) of determining a new value of eini based on a cycling term having a value depending on R but modulated by D so as to never exceed D?1.

Abstract: A communications network having two complementary optical networks each connectable to a headend, each optical network comprising a plurality of periodic interleaving filters serially connected by optical waveguides such that an output port of one periodic interleaving filter is couple to an input port of another periodic interleaving filter, and wherein an input or output node of the network is formed by a non-serially connected input or output port of a periodic interleaving filter.

Abstract: Normal 802.3 Ethernet requires a tree topology. If a ring or a loop exists, then packets will be forwarded around the ring indefinitely. If the ring is broken, then there is no possibility of packets being propagated forever. This invention shows how to quickly impose a virtual break in the ring such that all nodes can communicate with each other, and how to remove the virtual break when a real failure occurs. This is accomplished by placing intelligent nodes on the ring that work together to virtually break and restore the ring. An embodiment is disclosed that handles a unidirectional break in a communication link. This abstract is provided as an aid to those performing prior art searches and not a limitation on the scope of the claims.

Abstract: A WDM ring network and method for distributing within such ring network for feeding in data and for distributing both working signals and protection signals on different transmission paths and in oppositely directed transmission directions, and for forwarding data from subscribers and for distributing the working signals to the subscribers.

Abstract: A highly available communications system capable of circuit reestablishment and tear-down without manual intervention. The communications system includes a plurality of nodes interconnected by a plurality of communications paths to form at least one communications network. The nodes forward control packets on the network by way of a signaling protocol employing an out-of-band control technique. At least a portion of the nodes comprises a software configuration including a topology manager and a protocol manager. The protocol manager is operative to determine whether a control path is operational and whether a data transmission channel along a corresponding data path is established. In the event the control path is not operational, the protocol manager maintains the data transmission channel along the data path so long as the channel is established.

Abstract: A method of joint data transmission of digital source data and control data is provided between data sources and data sinks which are subscribers of a uni-directionally operated communication network having a ring configuration, in which source data and control data are transmitted in a format which prescribes a clocked sequence of individual bit groups of the same bit width which are transmitted in a continuous data stream, in each case specific bit positions predetermined by the format are reserved, in which the subscribers sample data in each case with a first sampling frequency and the communication network samples data with a second sampling frequency, which is an integral multiple of the first sampling frequency, in which, within each bit group, at least one contiguous region with a predetermined number of bit positions can be reserved for source data and the contiguous region(s) in each case have a beginning and a defined length and are in each case assigned to a subscriber address, in which at least o

Abstract: The present invention is a communications protocol which provides for voice and data priority channels in order that both voice and data information have equal opportunity to transmit over a communications network. This is achieved by splitting the 25 millisecond FCC dwell time into two 12.5 millisecond halves, and dedicating one half to voice packets and the other half to data frames. In the voice priority channel, the frequency hopping interval is doubled. Additionally, both channels operate independently, each maintaining independent bidding, data transmission, acknowledgement and retransmission. Pad packets are used to insure voice channel connectivity.

Abstract: A system for using an under-utilized data channel for carrying additional data, in a network mode. One such channel is the D-channel in the ISDN system. In one implementation, a group of telephone call centers share data, using the D-channel, about the lengths of time incoming callers must wait before being answered. Using the shared data, the call centers collectively route incoming calls to call centers having smaller waiting times.

Abstract: A contention priority control circuit which receives data of two priority classes from a plurality of input ports, and arbitrates contention between output requests for outputting these data to a bus on the basis of the priority classes and priorities determined for the respective input ports includes a plurality of arbiters which are arranged at a plurality of input ports for receiving data of the two priority classes, and receive data output requests for each of the two priority classes, a forward high-priority ring for connecting the plurality of arbiters in a forward direction, a forward low-priority ring for connecting the plurality of arbiters in the forward direction, and a backward high-priority ring for connecting the plurality of arbiters in a backward direction opposite to the forward direction.

Abstract: A method and system for providing a customer network with high speed access to a carrier network is provided. The system comprises an access device for providing a communication path for the customer network, a first concentrator device that is operable to establish a communication path with the carrier network, and a second concentrator device that is operable to establish a communication path with the carrier network. The access device is operable to receive data traffic from the customer network and to forward the data traffic within the system. The access device and the first concentrator device cooperate to form a first virtual channel for allowing data traffic to flow from the customer network to the carrier network and from the carrier network to the customer network and wherein the first virtual channel is the primary communication channel for the customer network.

Abstract: A network (100) includes a hub device (110) and at least one unattached peripheral device (120). The unattached peripheral device (120) transmits an attach request to the hub device (110) with a selected address, receives a new address from the hub device to identify the unattached peripheral device (120), and communicates with the hub device (110) using the new address.

Abstract: Systems and methods consistent with this invention allow for each node within one or more rings to obtain connection and topology information from other nodes within these rings. In such a system, each node is able to maintain connection table and topology tables for each node and each ring within a ring network. In particular, such information can be kept current because this scheme allows for dynamic updating of connection and topology information in real time. With such current information, a node is able to utilize this information to execute such operations as squelching connections on a protect line and timeslot interchange. In addition, by supporting timeslot interchange, the ring can be managed as more than a single logical entity as well as can have better bandwidth management utilization.

Abstract: A method for controlling virtual connections between endpoints over a unidirectional ring network. The network includes a number of network elements coupled together to form segments of the ring network. The method receives a request to create a virtual connection between first and second endpoints on the ring network. The method identifies the segments of the ring network that would be affected by the addition of the connection between the first and second endpoints. Further, the method retrieves data that represents the currently allocated capacity for each affected segment. For each affected segment, the method determines whether adding the requested virtual connection would exceed the capacity for the segment. The method transmits signals over the ring to establish the virtual connection when adding the virtual connection does not exceed the capacity for any of the affected segments.

Abstract: In an illustrative method for providing enhanced SONET network analysis, data related to the structure of a SONET network is identified, for example, in a database. The data comprises details regarding the network elements that form the SONET network as well as data regarding how the network elements are interconnected to form the SONET network. From the identified data, the nodes comprised in the SONET network are identified. Similarly, the plurality of communication links located between the identified nodes are retrieved from the data. Using the information identifying the nodes and plurality of communication links, a graphical representation of the SONET network is generated. In the graphical representation of the SONET network, nodes may be represented, for example, with a plurality of lines extending radially from a common point. Communication links between nodes are represented by lines that extend between the radial lines.

Abstract: Upon executing data exchange between a pair of LAN's via a gate way, a root hub transmits the communication data, in an address describing area of which source/destination addresses are described, and a gate way decodes the source/destination addresses included in received communication data, decides whether or not the source and the destination belong to the same LAN based on decoded source/destination addresses and attribution identification information, selects an appropriate route as the destination of the communication data based on a result of this attribution decision, and then transmits the communication data to the destination via selected route.

Abstract: A network configuration protocol and algorithm are described which resolve deficiencies with existing protocols. A large network having many bridges may be built as a combination of smaller networks, many of which may each be arranged in a ring topology. Each ring may be monitored by a single master bridge regularly sending control packets, and each other bridge in the ring does not make decisions with respect to its status. A loop free topology is achieved by selectively blocking and unblocking data traffic in one of the ring ports of the single master bridge for the ring, while all other bridges in the ring keep their ports in non-blocked states. In multiple ring topologies, each ring has a single master bridge which chooses one of its ports to be blocking.

Abstract: Methods and systems provide for identical address tables in a software stack of switches. The software stack is maintained by organizing the switches into the software stack. Each switch in the software has a corresponding address table and one or more ports. Each address table maps one or more packet addresses to a port in the software stack. Synchronization of the address tables is initiated and enables significant performance improvements. Synchronization is initiated by populating a command buffer of a first switch in the stack with one or more address table commands. The buffer is distributed to remaining switches in the stack.

Abstract: A loop network hub including a hub port with a loop initialization insertion mechanism. The loop initialization insertion mechanism causes a hub port which detects a new node port connection to automatically begin generating loop initialization data. A hub port continues to generate loop initialization data until that hub port receives a loop initialization sequence. The loop initialization data propagates around the loop of the hub, halting ordinary processing. In this way, the entire loop is cleared. Upon receiving a loop initialization sequence, the hub port originating the loop initialization data inserts the new node port into the loop. At this point, loop initialization begins and each node port in the loop network obtains a unique loop network address.

Abstract: A technique efficiently transports token ring (TR) frames over trunks interconnecting switches of a distributed TR bridge. The TR bridge is characterized by a logical switch fabric that is distributed among the interconnected switches by the trunks, which are preferably interswitch link (ISL) trunks. Each switch includes a Bridge Relay Function (BRF) coupled to a plurality of Concentrator Relay Functions (CRFs) having a plurality of ports for receiving TR frames over TR segments. The BRF and CRF of the distributed TR bridge operate according to a 2-tier switching model wherein each CRF and BRF is assigned an individual virtual local area network identifier. The technique encapsulates the TR frames in a TR-ISL protocol format that accomodates differences in formats of various TR frames and that comports with the 2-tier switching model of the distributed TR bridge.

Abstract: A method of exchanging data streams between a local exchange and a number of access devices for serving a plurality of destination users, the method comprises the steps of: (a) providing a local exchange capable of generating at least one output data stream and of receiving at least one corresponding input data stream for carrying data blocks respectively relevant to one or more of the access devices; (b) providing two or more said access devices, each permitting passage there-through of at least one data stream carrying data blocks, being capable of extracting, from said at least one data stream, data blocks relevant to this particular device and of introducing there-into data blocks to be transmitted from this particular device to the local exchange; and (c) arranging one or more close loop data streams, each being intended for serving said two or more access devices using one of said output data streams and the corresponding input data stream of the local exchange, by causing the output data stream leaving

Abstract: A method described in this document enables building a (logical) SDH/SONET ring where the connections between the packet-switched Access Interfaces of the SDH/SONET ring are automatically and dynamically (at 1 ms time-scale) arranged based on the actual volumes of the packet traffic flows between the Access Interfaces of the SDH/SONET ring and fair sharing of network resources. Traffic prioritizing is possible within the Access Interface to Access Interface traffic flows. No packets are lost in the SDH/SONET ring, unless temporarily in case of line or equipment failure.

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: Network switching systems (10, 110, 210, 310, 410) for use in an Ethernet network are disclosed. Each of the switching systems includes switch devices (20) supporting multiple (e.g., eight) local ports, and one gigabit high-speed port; each of the high-speed ports are full-duplex ports. Each switching system also includes a gigabit switch device (30) having two full-duplex gigabit ports. According to one aspect of the invention, the switches (20, 30) are connected in a ring using their respective gigabit ports, with each of the switches (20, 30) having a Ring ID value. Upon receipt of a message packet at one of its local ports, the switches (20) attach a pretag with the Ring ID value upon the packet, and begin forwarding the packet around the ring until the destination address is registered with one of the switches (20, 30), or until the packet returns to the original switch (20) which, upon detecting its own Ring ID value, filters or discards the packet.

Abstract: A Distributed Ring Protocol (DRiP) arrangement includes a database and protocol for maintaining and distributing information within a distributed token ring (TR) bridge having a logical switch fabric that is distributed over a TR switching network of switches interconnected by trunk links, such as Inters witch Link (ISL) trunks. The DRiP information is used by switches within the ISL switched fabric to determine the status (configured and/or activated) and association (within a switch) of ports of the distributed bridge.

Abstract: System for minimizing the cost of an optical network. A method is provided for designing an optical network to have minimized costs. The optical network has a plurality of nodes connected by interconnecting optical fibers. The method comprises inputting channel parameters associated with the optical network, inputting cost parameters associated with the optical network, calculating band parameters associated with the optical network, restricting at least one parameter associated with the optical network to having only integer values, and using an integer linear program to solve a minimization objective function that allows the cost of the optical network to be minimized, wherein the minimization objective function includes selected channel, cost and band parameters.

Abstract: A communication network system comprises ring systems (A, B, C, D) and a common node device 20 that is connected in common to ring circuits (5A, 5B, 5C, 5D) of each of the ring systems (A, B, C, D) and that gathers data from each of the ring circuits (5A, 5B, 5C, 5D) relaying it to a relay circuit 30. The common node device 20 accommodates virtual channel paths within all the ring circuits (5A, 5B, 5C, 5D) by means of a virtual path switching path. The relay transmission is realized by means of virtual path switching control that uses this common node device 20 and virtual channel switching control that uses each of the ring nodes within the ring circuits (5A, 5B, 5C, 5D).

Abstract: The present invention is based on a ring architecture wherein each chip in the multiplicity of chips is connected in a chain so that it can receive packets from the next previous chip in the chain and forward packets to the next following chip in the chain, whereby to form a ring. Before a packet is placed on the ring by a device it is provided with a ‘masking’ field which identifies each of the other devices and the ports within any such device to which the packet must be sent in order to achieve a multicast. When a device in its turn receives such a packet it will examine the masking field to determine whether the field identifies that device. If so, the packet, which may be held in temporary storage, may be processed for forwarding from a port of that device. The device will strip from the masking field the identification of the respective device and transmit the packet with a thus modified masking field to the next device in turn.

Abstract: Each node (130) of a SONET bidirectional line switch ring (BLSR)(120) generates a squelch table. Squelch table generation does not require a separate computer connected to the node. Each node also generates a payload table indicating a type of a synchronous transport signals (STS) on each link (140) in the ring. The payload table allows each node to quickly determine the STS type on the protection channels when a ring switch occurs.

Abstract: In a ring network system in which a plurality of devices each having a first communication IC are connected in a ring-like manner by a transmission line to mutually effect transmission and reception of data among the devices, an rack unit is disposed between two adjacent ones of the plurality of devices, the rack unit and the plurality of devices are connected in the ring-like manner by the transmission line, wherein the rack unit has a plurality of device inserting slots in which a plurality of additional devices are installed and which are provided in correspondence with the plurality of additional devices, and a second communication IC for controlling data communication among the plurality of additional devices installed in the plurality of device inserting slots and for controlling data communication between the additional device and the network device.

Abstract: A communications system and method is provided in which data is transmitted between a plurality of nodes (A, B, C, D) in a network comprising a closed loop configuration of one or more pairs of unidirectional transmission rings (1, 2) arranged to transmit data in opposite directions around the rings. Each node includes a respective message processor (5, 6) for each of the transmission rings (1, 2) and a host processor (60) linked to the message processors (5, 6). The traffic of data in each ring is dynamically monitored to obtain traffic information which is utilized by the message processors in accordance with a traffic control process to select one of the rings to transmit data from an originating node to a destination node. In the event of a fault in one of the rings, the other ring is utilized to transmit data at a reduced performance level while repairs are made to the faulty ring.

Abstract: A method of identifying the current route of paths on communications MS-SPRINGs is described. The method comprises the steps of providing the network manager with information relating to the Nominal Route of the at least one path; and providing the management system with information of current status of the at least one network element, and being characterized by comprising the steps of processing the information provided through steps a) and b) so as to calculate the current route of the at least one path. The invention further concerns a network manager able to carry out the various steps of the method.

Abstract: A method for creating a single virtual LAN including a source (S) attached to a first Token ring LAN (N1), a target (T) within a subnet attached to a different Token ring LAN (N2), and an interconnecting router (R). The source (S) encapsulates the first packet with a Token ring header including the router MAC address (RMAC), SMAC as source MAC address as layer 2 information, and IP address of T (TIP) as layer 3 data and sends this packet over N1 toward the router. When receiving the first packet, R reads its IP table for best match with TIP address to identify the subnet including T. The net handler runs an ARP protocol to identify TMAC address, substitutes the MAC header with said TMAC address into said first packet destination MAC address field and forwards said first packet over N2. R then sends a conventional ICMP message over N1 limited broadcast and reconfigures itself in proxy ARP for the defined subnet.

Abstract: The present invention provides a method and system in which the lower address bits of an IP address are used as a mobile station's short identifier. According to exemplary embodiments of the present invention, the operator of a MSC/PMSC node is normally assigned, from an ISP, several class C-networks to provide to its packet mobile subscribers. When these networks are chosen with the same high order bits, as is most often the case, it is possible to directly map the lower bits of the IP-address to a unique key value that could be used within the node. For a PPDC-node, this key value can be used as a short mobile station identifier in the LAPDm protocol. For other data-link protocols on other platforms, it is also possible to use the new key value as a short identifier for the mobile station. Therefore, the translation process turns simply into a matter of adding or removing the high order bits in order to convert the IP address into the mobile station identifier.

Abstract: A switch, switched architecture and process for transferring data through an FCAL switch is disclosed. The switch uses multiple switch control circuits each coupled to one FCAL network and all connected to a crossbar switch. The switch control circuits are coupled together by a protocol bus for coordination purposes. Local conversations can occur on each FCAL loop and crossing conversations through the switch can occur concurrently. The OPN primitive is used to establish the connection before any data is transferred thereby eliminating the need for buffer memory in the switch control circuits. The destination address of each OPN is used to address a lookup table in each switch control circuit to determine if the destination node is local. If not, the destination is looked up and a connection request made on the protocol bus. If the remote port is not busy, it sends a reply which. causes both ports to establish a data path through the backplane crossbar switch.

Abstract: A switch, switched architecture and process for transferring data through an FCAL switch is disclosed. The switch uses multiple switch control circuits each coupled to one FCAL network and all connected to a crossbar switch. The switch control circuits are coupled together by a protocol bus for coordination purposes. Local conversations can occur on each FCAL loop and crossing conversations through the switch can occur concurrently. The OPN primitive is used to establish the connection before any data is transferred thereby eliminating the need for buffer memory in the switch control circuits. The destination address of each OPN is used to address a lookup table in each switch control circuit to determine if the destination node is local. If not, the destination is looked up and a connection request made on the protocol bus. If the remote port is not busy, it sends a reply which. causes both ports to establish a data path through the backplane crossbar switch.

Abstract: A switch, switched architecture and process for transferring data through an FCAL switch is disclosed. The switch uses multiple switch control circuits each coupled to one FCAL network and all connected to a crossbar switch. The switch control circuits are coupled together by a protocol bus for coordination purposes. Local conversations can occur on each FCAL loop and crossing conversations through the switch can occur concurrently. The OPN primitive is used to establish the connection before any data is transferred thereby eliminating the need for buffer memory in the switch control circuits. The destination address of each OPN is used to address a lookup table in each switch control circuit to determine if the destination node is local. If not, the destination is looked up and a connection request made on the protocol bus. If the remote port is not busy, it sends a reply which. causes both ports to establish a data path through the backplane crossbar switch.

Abstract: A switch, switched architecture and process for transferring data through an FCAL switch is disclosed. The switch uses multiple switch control circuits each coupled to one FCAL network and all connected to a crossbar switch. The switch control circuits are coupled together by a protocol bus for coordination purposes. Local conversations can occur on each FCAL loop and crossing conversations through the switch can occur concurrently. The OPN primitive is used to establish the connection before any data is transferred thereby eliminating the need for buffer memory in the switch control circuits. The destination address of each OPN is used to address a lookup table in each switch control circuit to determine if the destination node is local. If not, the destination is looked up and a connection request made on the protocol bus. If the remote port is not busy, it sends a reply which. causes both ports to establish a data path through the backplane crossbar switch.

Abstract: A ring network provides transparent local area network (LAN) service by allocating respective proportions of data transmission capacity of the ring to different closed user groups (CUGs), each including a plurality of LAN clients. At each node of the ring, the use of a connected segment of the ring is monitored for both pass-through and locally-generated traffic by the LAN clients on a per-CUG basis. When it is detected that use of the connected segment for a CUG is approaching the allocated proportion, an active LAN client of the CUG is selected and sent a throttle message indicating that the LAN client is to reduce its data transmission rate. Rate monitoring for is accomplished using a “leaky bucket” mechanism. A “rate cache” identifying the active senders and their transmission rates can also be used in selecting a LAN client for receiving the throttle message.

Abstract: A switch, switched architecture and process for transferring data through an FCAL switch is disclosed. The switch uses multiple switch control circuits each coupled to one FCAL [net]work and all connected to a crossbar switch. The switch control circuits are coupled together by a protocol bus for coordination purposes. Local conversations can occur on each FCAL loop and crossing conversations through the switch can occur concurrently. The OPN primitive is used to establish the connection before any data is transferred thereby eliminating the need for buffer memory in the switch control circuits. The destination address of each OPN is used to address a lookup table in each switch control circuit to determine if the destination node is local. If not, the destination is looked up and a connection request made on the protocol bus. If the remote port is not busy, it sends a reply which causes both ports to establish a data path through the backplane crossbar switch.

Abstract: A portable electronic device is disclosed. The portable electronic device includes a wireless transceiver, a processor coupled to the wireless transceiver, a memory coupled to the processor and a program stored in the memory and running on the processor. The program provides automatic transitioning between a wireless infrastructure communication mode to an ad-hoc communication mode. The infrastructure mode is used when a request from a mobile device is received to access a communications network. The ad-hoc mode is used when a request from the mobile device is received to access resources on the portable electronic device.

Abstract: A switch, switched architecture and process for transferring data through an FCAL switch is disclosed. The switch uses multiple switch control circuits each coupled to one FCAL network and all connected to a crossbar switch. The switch control circuits are coupled together by a protocol bus for coordination purposes. Local conversations can occur on each FCAL loop and crossing conversations through the switch can occur concurrently. The OPN primitive is used to establish the connection before any data is transferred thereby eliminating the need for buffer memory in the switch control circuits. The destination address of each OPN is used to address a lookup table in each switch control circuit to determine if the destination node is local. If not, the destination is looked up and a connection request made on the protocol bus. If the remote port is not busy, it sends a reply which causes both ports to establish a data path through the backplane crossbar switch.

Abstract: A Time Slotted Logical Ring protocol manages the flow of traffic in a duplex media including a cable distribution network with a head end, a local node, and a group of subscribers. The subscriber includes a cable modem which produces an HDLC serial interface which then goes to the subscriber or gets converted to ethernet by a router and then to the subscriber. The Time Slot portion of TSLR protocol manages upstream and downstream access and uses time tick identification frames in the downstream direction to control upstream traffic. A multiple logical ring protocol in TSLR is used to allocate cable bandwidth between the multiple subscribers.

Abstract: A switch, switched architecture and process for transferring data through an FCAL switch is disclosed. The switch uses multiple switch control circuits each coupled to one FCAL network and all connected to a crossbar switch. The switch control circuits are coupled together by a protocol bus for coordination purposes. Local conversations can occur on each FCAL loop and crossing conversations through the switch can occur concurrently. The OPN primitive is used to establish the connection before any data is transferred thereby eliminating the need for buffer memory in the switch control circuits. The destination address of each OPN is used to address a lookup table in each switch control circuit to determine if the destination node is local. If not, the destination is looked up and a connection request made on the protocol bus. If the remote port is not busy, it sends a reply which causes both ports to establish a data path through the backplane crossbar switch.

Abstract: A communications network comprising at least two nodes is disclosed. The network has two communication paths that carry traffic in opposite directions and work as a bi-directional bus. The network has a first inactive segment that carries no traffic and is arranged to allow the first inactive segment to be made active and another segment to be made inactive, especially in the case of fault in the other segment. The activation and inactivation logically “move” the first inactive segment. Additional protection paths are provided between the nodes.

Abstract: A telecommunications network is provided. The network uses a ring of ring switches to provide a transport mechanism for data packets that is transparent to the data and protocols contained in the data packets. This transport mechanism is simple and low cost to implement. Such networks can carry, for example, control data between a primary site and secondary sites of a cable network to set up and deliver pay per view, video on demand or near video on demand programming. The network can also be used, in other embodiments, to provide remote access to utility meters, to centralize network management of the cable network, and other appropriate monitoring and control functions.