Abstract: The present invention improves a network forwarding device, such as a router, in a computer network system. When an address to which a received packet is to be forwarded is searched for based on path information, a path search data structure is changed to the one in which, in a 2-branch tree search in which a destination address of the received packet is checked, one bit at a time beginning at a highest-order bit, p (p is an integer equal to or larger than 2) levels are combined into one 2P-branch tree to perform a search of the p levels of the 2-branch tree as a one-level search. This data structure speeds up path search processing.

Abstract: Cells are discarded in conformity with the order of priority when congestion occurs by discarding cells of a traffic class without any special contract for a transfer rate at the time of setting up a connection. A node stores priority information concerning cell discard corresponding to a connection identifier and controls the cell discard in accordance with the discard condition determined by the accumulated number of cells for each connection in the node and cell priority.

Abstract: In a bandwidth policing apparatus which accommodates a large number of user groups, bandwidth policing for each user group is performed at high speed. When there is any extra bandwidth in bandwidth for a user group, the contracted committed information rate for each user is guaranteed invariably while using this effectively. The bandwidth policing apparatus accumulates packets of a plurality of user groups under bandwidth policing in the same packet accumulate FIFO. Also, for a packet which does not exceed the contracted bandwidth for each user, the contracted bandwidth for each user is guaranteed by deciding that the packet does not exceed the contracted bandwidth for each user group.

Abstract: An input interface segments a variable length packet into plurality of fixed length cells and generates an internal switching information based on the header information of the variable length packet. The input interface transmits the information to a switch and, after that, transmits the cells as the following cells of the information to the switch. The switch performs switching processing to the succeeding cells based on the information. Therefore, the information is not added to the cells. When an input interface starts to transmit cells generated from a packet to its destination output interface through the switch, the switch is reserved until all the cells arrive at the output interfaces.

Abstract: A bandwidth monitoring device for use in a network for transferring priority packets in preference to non priority packets as far as the amount of the priority packets is within a contract bandwidth established between a network user and a network operator, comprising a bandwidth check result decision unit for detecting whether the bandwidth of the priority packets is less than the contract bandwidth, and a DSCP decision unit for determining that a non priority packet may be transferred as a priority packet when the bandwidth of the priority packets is less than the contract bandwidth thereby to sufficiently use the contract bandwidth.

Abstract: A traffic shaping apparatus calculates a minimum transmission interval, an allowed transmission frame rate of a user frame, and a reference transmission interval for each user according to a minimum transmission frame rate and a peak transmission frame rate specified for each user. The traffic shaping apparatus also calculates a first estimated transmission time according to the reference transmission interval, and a second estimated transmission time according to the minimum transmission interval for each user. The traffic shaping apparatus determines the user having the earliest first estimated transmission time, and determines according to the second estimated transmission time of the user whether a user frame is to be transmitted.

Abstract: A packet forwarding apparatus provided with a plurality of line interface units, comprises a routing processing unit for referring to a routing table, based on header information of received packet to specify one of output lines to output the received packet, a flow detection unit for referring to an entry table, in which a plurality of entries with flow conditions and control information are registered, to retrieve control information defined by the entry with a flow condition which coincides with that of the header information of the received packet, and a packet forwarding unit for transferring the received packet to one of the line interface units connected to the output line specified by the routing processing unit.

Abstract: In one embodiment, a bandwidth monitoring device comprises a packet receiving circuit configured to receive packets; a counter configured to count a total packet length by adding up inputted packet lengths including a packet length of a next input packet and subtracting outputted packet lengths to produce a counted value; a timer configured to time a packet receiving time; a memory configured to store a number of packet receiving times and a number of counted values counted by the counter which correspond to the packet receiving times, respectively; a counter rate-of-change calculating portion configured to calculate a change rate by a first counted value corresponding to an oldest packet receiving time stored in the memory representing an oldest time at which a packet was received and a second counted value corresponding to a latest packet receiving time stored in the memory representing a latest time at which a packet was received; and a determining portion configured to decide whether the next input packet

Abstract: In a high speed multicast route searching method of searching information of a transmission port to which a received multicast packet is next transferred: a route address is formed by coupling a receiver address and a sender address in this order; one p-th power-of-2-branch tree node is configured by a collection of one two-branch tree node and two-branch tree nodes of p−1 stages totalling ((p-th power of 2)−1) nodes just under the one two-branch tree node to form a p-th power-of-2-branch tree which is stored in a memory; not one bit but consecutive p bits of the route address coupling the receiver address and sender address in a received multicast packet in this order are checked at the same time; and in accordance with the values of the consecutive bits, a search tree stored in the memory is searched. In this manner, a search process can be completed by tracing nodes (the number of bits of a search key divided by p) times at a maximum, independently from the number of entries.

Abstract: A packet forwarding apparatus provided with a plurality of line interface units, comprises a routing processing unit for referring to a routing table, based on header information of received packet to specify one of output lines to output the received packet, a flow detection unit for referring to an entry table, in which a plurality of entries with flow conditions and control information are registered, to retrieve control information defined by the entry with a flow condition which coincides with that of the header information of the received packet, and a packet forwarding unit for transferring the received packet to one of the line interface units connected to the output line specified by the routing processing unit.

Abstract: A network relaying apparatus and method for routing and transferring packets at high speed. A transfer engine stores the packets received through a network interface in a packet buffer, and stores the header information in a header RAM. A search engine searches the transfer control information including the transfer destination information and the action information in accordance with the header information, and writes it in the header RAM. The transfer engine produces an output packet based on the information stored in the packet buffer and the header RAM and outputs it to the transfer destination. A switch switches the output packet to the routing process of the destination. The transfer engine executes the receiving process and the transmission process, and the search engine executes the input search process and the output search process. Each of these processes is executed by pipelining control using a required table independently.

Abstract: A network relaying apparatus and a network relaying method for securing a high communication quality (QoS), a high reliability and security. A transfer engine stores the packets received through at least a network interface in a packet buffer, and the header information in a header RAM. A search engine searches for the transfer control information such as the destination information and the action information based on the header information, and writes them in the header RAM. The transfer engine prepares an output packet based on the information stored in the packet buffer and the header RAM, and outputs the output packet to the destination. A switch switches the output packet to the routing processor of the destination. Each header RAM is asynchronously accessible independently of the packet buffer and suppresses the competition for access between the transfer engine and the search engine.

Abstract: A network relaying apparatus and method for high quality transfer of packets under stable quality-of-service (QoS) control. A transfer engine stores the packets received through a network interface, in a packet buffer, and the header information in a RAM. A search engine searches the transfer control information including the transfer destination information and the action information according to the header information and writes the resulting information in the header RAM. The transfer engine produces an output packet based on the information stored in the packet buffer and the header RAM and outputs it to the transfer destination. A switch operates to switch the output packet to the routing processor of the destination. The QoS control is performed at each of a plurality of points including the input-side routing processor, the output-side routing processor 10 and the switch.

Abstract: A network relaying apparatus and method for detecting a flow at high speed and performing a variety of control operations including quality-of-service (QoS) control and filtering at high speed. A transfer engine stores the packet received through a network interface, in a packet buffer, and stores the header information in a header RAM. A search engine searches the transfer control information including the transfer destination information and the action information according to the header information, and writes it in the header RAM. The transfer engine produces an output packet based on the information stored in the packet buffer and the header RAM and outputs it to the transfer destination. A switch operates to switch the output packet to the routing processor of the final destination.

Abstract: A terminal with a shaper comprising an ABR bandwidth calculator for calculating a shaping bandwidth from congestion notification information in each received RM cell and a bandwidth allocator for calculating bandwidths allocated between respective connections with the bandwidths given priorities, wherein cells are transmitted with one small in value, of the result of calculation by the ABR bandwidth calculator and the result of calculation by the bandwidth allocator as a shaping bandwidth. With respect to connections subjected to a limitation of each shaping bandwidth by the congestion notification information, the priority for bandwidth allocation is lowered so that the bandwidths unavailable to the connections are deallocated to other connections.

Abstract: A network relaying apparatus and method for routing and transferring packets at high speed. A transfer engine stores the packets received through a network interface in a packet buffer, and stores the header information in a header RAM. A search engine searches the transfer control information including the transfer destination information and the action information in accordance with the header information, and writes it in the header RAM. The transfer engine produces an output packet based on the information stored in the packet buffer and the header RAM and outputs it to the transfer destination. A switch switches the output packet to the routing process of the destination. The transfer engine executes the receiving process and the transmission process, and the search engine executes the input search process and the output search process. Each of these processes is executed by pipelining control using a required table independently.

Abstract: A packet switch for switching variable length packets, wherein each of output port interfaces includes a buffer memory for storing transmission packets, a transmission priority controller for classifying, based on a predetermined algorithm, transmission packets passed from a packet switching unit into a plurality of queue groups to which individual bandwidths are assigned respectively, and queuing said transmission packets in said buffer memory so as to form a plurality of queues according to transmission priority in each of said queue groups, and a packet read-out controller for reading out said transmission packets from each of said queue groups in the buffer memory according to the order of transmission priority of the packets while guaranteeing the bandwidth assigned to the queue group.

Abstract: A traffic shaper which includes a cell buffer for temporarily storing an ATM cell arrived thereat, a first calculator for calculating an estimated cell sending time according to a VC contracted bandwidth, a second calculator for calculating an estimated cell sending time according to a VP contracted bandwidth, a binary tree VP sorting circuit for determining VP to be sent in top priority, a binary tree VC sorting circuit for determining VC to be sent in top priority, and a sending circuit for sending a cell in which the determined VP and VC are both brought to a transmittable state. The VP estimated sending time is revised according to the VC estimated sending time.

Abstract: A traffic shaper comprises a cell buffer for temporarily storing an ATM cell arrived thereat, a first calculator for calculating an estimated cell sending time according to a VC contracted bandwidth, a second calculator for calculating an estimated cell sending time according to a VP contracted bandwidth, a binary tree VP sorting circuit for determining VP to be sent in top priority, a binary tree VC sorting circuit for determining VC to be sent in top priority, and a sending circuit for sending a cell in which the determined VP and VC are both brought to a transmittable state. The VP estimated sending time is revised according to the VC estimated sending time.

Abstract: A packet switch for switching variable length packets, wherein each of output port interfaces includes a buffer memory for storing transmission packets, a transmission priority controller for classifying, based on a predetermined algorithm, transmission packets passed from a packet switching unit into a plurality of queue groups to which individual bandwidths are assigned respectively, and queuing said transmission packets in said buffer memory so as to form a plurality of queues according to transmission priority in each of said queue groups, and a packet readout controller for reading out said transmission packets from each of said queue groups in the buffer memory according to the order of transmission priority of the packets while guaranteeing the bandwidth assigned to the queue group.