Abstract: Techniques are described which provide mechanisms for dual-homing an access ring for virtual private wire service (VPWS) Ethernet line (E-Line) services. The mechanism may provide resiliency against access ring failures and offer a restoration time of 50 msec upon failure. A method to provide such resiliency may generally include determining, at a first ring port of an access node, a ring failure in an Ethernet ring. Upon determining the first ring port of the access node is not situated on a same side of the Ethernet ring as a node designated as a ring protection link (RPL) owner, a message is transmitted on a second ring port of the access node towards a provider edge (PE) node. The message is used to activate pseudowires (PWs) at the PE node for virtual local area networks (VLANs) of the access node.

Abstract: The invention provides multicast communication using distributed topologies in a network. The control nodes in the network build a distributed topology of processor nodes for providing multicast packet distribution. Multiple processor nodes in the network participate in the decisions regarding the forwarding of multicast packets as opposed to multicast communications being centralized in the control nodes.

Abstract: A data transmission method with multiple token mechanism in wireless token ring protocol is provided. First, (a) a logical ring with M nodes is provided; (b) a k-th node is selected from the logical ring, and a token in the k-th node is generated; (c) a first message is sent to a (k+1)-th node from the k-th node with the token, and whether the (k+1)-th node responds a second message is judged, if yes, the data to be transmitted is transmitted from the k-th node, otherwise, the token of the k-th node is eliminated; (d) the token is sent to the (k+1)-th node from the k-th node after completing the transmission of the transmitted data of the k-th node, a generation token sequence is generated in a i-th node, and sent to a (i?1)-th node; and (e) the token is generated for the (i?1)-th node with the generation token sequence.

Abstract: The present invention discloses a method for ensuring service classes of packet services, which includes limiting the rate of services with different service classes uploaded to a ringlet from an RPR station in accordance with the RPR physical packet lengths; monitoring, in real time, the rate of non-class A0 services uploaded to the ringlet from the RPR station and forwarded by the RPR station in accordance with the RPR physical packet lengths, and when the rate of the non-class A0 services exceeds the un-reserved rate of the RPR network, reporting a congestion message and adjusting the rate of the non-class A0 services uploaded to the ringlet from the RPR stations in the congestion domain. A method of rate limitation is also disclosed, by which rate limitation is conducted based on a Token Bucket according to the total length of the sent packet after encapsulation.

Abstract: A method and apparatus for token distribution include providing one or more nodes of a plurality of network nodes with a token machine that includes counters associated with each of other network nodes having a token machine. Each time a token possessing network node implicitly or explicitly passes the token to another network node having a token machine, counter values of each of the counters associated with each node having a token machine are adjusted. When a token is passed, the counter value of the receiving node is adjusted based, at least in part, on an initial token interval value, and counter values associated with other nodes are adjusted toward a threshold value. The decision as to where the token is passed may be based, at least in part, on the value of a counter and/or an assigned counter priority level.

Abstract: A control command, which has a command header sequence and a sequence of n parameters, is generated in a data source of a local network. The control command has a variable length defined by the data source. The control command is passed to the ring data line of the local network and is forwarded to a data sink. This data sink contains a control unit, a picture output unit, an interface and a memory, in which video data are stored. The video data can be read out and displayed on the picture output unit. The control command has n parameters of which the first m parameters are interpreted by the control unit. The number m is determined by the properties of the data sink and is independent of the properties of the data source. Using the m interpreted parameters, specific video data are read from the memory and are reproduced.

Abstract: The present invention describes a method for configuring a station connected to a field bus, wherein a logical address is allocated to said station. The method comprises the steps of: transmitting said logical address from an address-allocation unit to said station; transmitting a physical address from said address-allocation unit to said station, said physical address corresponding to an assumed physical position of said station relative to said field bus; verifying said physical address being transmitted to said station based on an actual physical position of said station relative to said field bus; and storing said transmitted logical address in a memory of said station depending on the verification of said physical address.

Abstract: A network system comprises a main loop in which one master node which issues a token packet for data communication, and at least one slave node are connected in a loop; a first sub loop in which the master node, one sub-master node, and at least one slave node are connected in a loop; and at least one second sub loop in which the master node, at least two sub-master nodes including the sub-master node of the first sub loop, and at least one slave node are connected in a loop. In this network system, each node has an analysis execution unit which performs analysis of the token packet, control of data transmission and data reception, and a switch for changing the connection. When each node receives and analyzes the token packet, it controls the switch so as to output, transmit, or discard the token packet and a data packet. Therefore, addition of nodes and loops is facilitated while maintaining the transmission efficiency, without increasing the packet transmission time.

Abstract: A local area network with a plurality of nodes for transmitting cells in the asynchronous transfer mode over a ring system having two opposite direction rings. In the event of a defect in a transmitting line from a node, or a defect in a neighboring node, a loop is formed in this node to reroute messages from one ring to the other. First, a node detecting a defect transmits a message of a first type to all other involved nodes, identifying the location of the detected defect. This information is entered in a respective status table in each node. After evaluating the information in its status table, a node which should form a loop does so, and sends a message of a second type identifying the loop to any nodes which do not already have this information.

Abstract: A ring topology based architecture for a local area network. The transmission medium is unshielded twisted-pair wire. A set of two such twisted-pairs are used to connect the nodes of the network together, with the transmit twisted-pair wires from one node being connected to the receive twisted-pair wires of the next node. When a node of the network is powered up, a relay is opened which disconnects the incoming receive lines from the outgoing transmit lines. This brings the node on line. The relay is controlled via software command and a timer which is used to take a preceding node off-line for a predetermined period in the event jabber from that node is detected. A 16 byte FIFO bypass built into the medium access control hardware of the system is used to reduce the ring latency which normally results from the need to store entire data packets at each node, prior to the packet being forwarded.

Abstract: The dynamic synchronous transfer mode dual ring topology has two rings with opposite fiber directions. The dual rings may have a plurality of common nodes. A first channel may be established in a first segment extending between a first and second nodes. Tokens associated with the first channel may be provided. In this way, time slots may be transmitted in the first channel from the first node to the second node. If a fiber failure occurs in the first segment, the second node is likely to first detect the fiber failure and transmit a fiber failure message. It is then determined if the first channel extends across the fiber failure. If the first channel is affected by the fiber failure then a channel failure message is transmitted and the first channel is terminated and all the tokens associated with the first segment are removed. If the first channel is not affected then time slots are continued to be transmitted on the first channel.

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

Abstract: In a communications network, first information items are transmitted synchronously and second information items asynchronously. The second information items are overlaid on the synchronously transmitted first information items. A bandwidth accessible on transmission can be variably distributed between the first and second information items and, with the desired variable distribution, transmitting and receiving units become synchronized by synchronization information which is transmitted via a channel established for asynchronous transmission between the transmitting and receiving units.

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.