Abstract: As apparatuses which construct a ring network, a structure including a monitoring apparatus and other relay apparatuses is employed. The monitoring apparatus monitors only a ring status of such a ring network to which the own monitoring apparatus belongs. The monitoring apparatus periodically transmits health check frames from ring ports thereof respectively so as to monitor whether or not the transmitted health check frame has been received by the ring port located opposite thereto. Also, in a structure of a multi-ring network having a shared link, auxiliary health check frames are periodically transmitted from two sets of shared apparatuses respectively with respect to a monitoring apparatus of a shared link non-monitored ring network. The monitoring apparatus also monitors the auxiliary health check frames in combination with the health check frames in order to avoid an occurrence of a loop which bridges a plurality of ring networks.

Abstract: A bandwidth calculation section calculates a usable bandwidth from a communication amount of each user or a session connection time stored in a statistic management memory and minimum bandwidth information and maximum bandwidth information recorded in a bandwidth setting memory. The bandwidth calculation section allocates a large usable bandwidth to a user with a small communication amount or a short session connection time. A transmission control section performs transmission scheduling of packet information stored in a packet buffer based on a transmission scheduled time calculated from the usable bandwidth stored in a transmission scheduled time memory.

Abstract: In a packet relay apparatus or bandwidth policing apparatus, when the bandwidth of a flow having a function to respond to a congestion notification surpasses a first threshold, a congestion notification is given to rewrite a value representing the congestion state of the network out of the packet headers of the packet received by the apparatus. The packet is dropped if the bandwidth of the flow surpasses a second threshold higher than the first threshold. One of the following, including packet drop, rewriting the value representing the priority level in the network out of the packet headers and altering the priority level in the apparatus is imposed on the packet when the bandwidth of the flows surpasses a second threshold higher than the first threshold.

Abstract: This invention provides a data transfer control device for carrying out data transfer using a plurality of transfer resources. The data transfer control device comprises a transfer resource management portion that set the plurality of transfer resources to either one of a transfer-enabled state whereby data transfer is enabled and a plurality of standby states on the basis of a load on the data transfer control device and that manages the plurality of transfer resources so as to assume the set operating status; and a load distribution portion that distributes the data to transfer resources that have been set to the transfer-enabled state. The plurality of standby states are states which data transfer is disabled and which mutually differ at a minimum in terms of at least one of power consumption level and transition time to the transfer-enabled state.

Abstract: A Provider Edge PE3 replicates a received packet and relays these to virtual circuits VC1, VC2 respectively, and Provider Edges PE2, PE2 respectively receive the packets from the virtual circuits VC1, VC2, whereupon the Provider Edges PE2, PE2, on the basis of an agreement between them, decide to handle the received packets such that one of the first edges relays the packet to a Customer Edge CE1 for forwarding to a Host A, while the other edge discards the packet without relaying it to the Customer Edge CE1.

Abstract: A packet relay apparatus of the type that can virtually use in the interlocking arrangement a plurality of apparatuses includes a link optimization adjustment part and a packet analyzing unit, automatically judges the mode of flow of communication and traffic and optimizes the line that is mainly operated, to manage the traffic flowing through a control port and make up for band insufficiency of the control port.

Abstract: Enables control of data transmission within a network. For this, for example, a network relay apparatus makes a determination as to permission to transmit data, based on a condition relating to at least one of the transmission origin of the data and transmission destination of the data. An administration unit contains administration information indicating permission to use shared devices by users of clients. The connection relay apparatus for a target client acquires user identifying information from the target client. The administration unit acquires the user identifying information from the connection relay apparatus for a target client, and referring to the administration information, detects a target shared device that is one of the shared device permission to use of which has been granted to a user of the target client.

Abstract: In the terminal affiliation switchover system of the invention, in the case of allocation of an IP address to one terminal in a VPN#1 in response to an IP address allocation request, a DHCP server module 121 changes registry information in a DHCP table 122 provided for the VPN#1 and simultaneously makes the change of the registry information reflected in registry of a DHCP table 222 provided for a VPN#2 via a DHCP server module 221. Similarly in the case of allocation of an IP address to one terminal in the VPN#2 in response to an IP address allocation request, the DHCP server module 221 changes the registry information in the DHCP table 222 for the VPN#2 and simultaneously makes the change of the registry information reflected in the registry of the DHCP table 122 for the VPN#1 via the DHCP server module 121.

Abstract: A first issue is to provide a packet transfer device for identifying a connection such as a TCP connection linked to a bandwidth control means, and provide a proxy acknowledgment for each identified connection such as TCP. A second issue is to provide a packet transfer device for providing a proxy acknowledgment for a connection such as TCP, and capable of improving throughput such as for TCP just by being installed at a network edge section connected to the communication terminal. As a means to resolve the first issue, a packet transfer device is provided that contains a means for identifying flows such as TCP flows for deciding if the proxy acknowledgment means requires proxy acknowledgment or not, based on the bandwidth conformance flow reported from the bandwidth control means.

Abstract: A network management apparatus is for managing a plurality of switching devices that relay data through a data communication network. The network management apparatus includes a configuration information storage, a connectivity relationship detector and a configuration information modifier. The configuration information storage stores first configuration information. The first configuration information is configured in the switching devices and includes information to be determined in accordance with connectivity relationships among the switching devices. The connectivity relationship detector detects changes of connectivity relationships among the switching devices. The configuration information modifier dynamically modifies the first configuration information in accordance with detected changes of connectivity relationships.

Abstract: To analyze traffic at an application level, a stream according to TCP or SCTP is required to be reconstructed and to be analyzed. When a packet is transferred to analyzing equipment using a port mirroring function with which a router and a switch are provided, transferred traffic volume increases and exceeds the throughput of the analyzing equipment. As only a part of packets configuring a stream is transferred to the analyzing equipment in transfer to the analyzing equipment using a packet sampling function, analysis at the application level is impossible. To solve the problem, when a packet communication unit recognizes a stream start packet, samples a stream initiated by the packet on a condition and at a rate respectively determined beforehand and generates a condition for copying the packet based upon information of both ends of the stream included in the packet, packets sampled in units of stream can be transferred to the analyzing equipment.

Abstract: A router stands by in a power saving state when there is no multicast joining message received. The router increases transfer performance with granularity such as the bandwidth of each multicast channel or the maximum bandwidth of each receiving line when a multicast joining message is received. On the other hand, the router decreases transfer performance with granularity such as the bandwidth of each multicast channel or the maximum bandwidth of each receiving line when a multicast disjoining message is received. The aforementioned processing permits achievement of power saving in the router connected to a multicast network.

Abstract: In a packet relay apparatus equipped with a hierarchical bandwidth control function, a queuing unit of a bandwidth controller for controlling a bandwidth of a packet to be transmitted recognizes user information for identifying a user from VLAN ID of a received Tag-VLAN packet, acquires queue information representative of a queue position by referring to a priority mapping table by using a user priority order in the packet, and queues the packet to the queue identified by the user information and queue information. Bandwidth control can therefore be performed without searching a QoS information management table.

Abstract: A multi-plane cell switch fabric system prevents a decrease of the effective switching capacity when switching the variable-length packets. Distribution units classify input variable-length packets for each address, arranges the packets by a first division length unit, divides the packets into fixed-length cell payloads by a second division length unit that is an integer multiple being twice or more as large as the first division length unit, and forms a fixed-length cell by providing destination information, a source ID, a sequential number, and packet head tail information to each of the cell payloads. The cells are distributed to all the switching units one by one whenever the cells are collected to be the same number as the plural switching units. The reordering units classify the cells, reorder the sequential number in an original order, and reassemble the packets by the packet head tail information of the cell.

Abstract: A network switch with a plurality of crossbar switches that is available to suppress increase in the circuit scale is provided. The network switch has: the plurality of crossbar switches that transfer unit data in a specified format; a receiving side transfer unit that transfers data received from a network to the plurality of crossbar switches in the unit data basis; and a plurality of transmitting side transfer units that transmit data transferred from the plurality of crossbar switches to the network. The receiving side transfer sets a consecutive serial number to the unit data in transfer sequence, and distributes the unit data to the plurality of crossbar switches. Each of the plurality of transmitting side transfer units has a plurality of queues for the respective crossbar switches that stores the transferred unit data, and extracts the unit data with smallest serial number of the unit data stored in the queues when all of the queues store the unit data.

Abstract: When a network apparatus of this invention receives an IEEE 802.3ad link application control packet from a subscriber line with a VPWS function, it processes the packet in a control unit without relaying the packet by VPWS. More specifically, the network apparatus receives an IEEE802.3ad link aggregation control packet along with receiving an IEEE802.3x flow control packet. The network apparatus transmits a link aggregation control packet. The network apparatus also relays other layer 2 control protocol packets without receiving them, and does not transmit the other layer 2 control protocol packets.

Abstract: In order to allow priority transfer (fluctuation) over VLL packets while keeping each contracted bandwidth constantly, a leaky bucket model is expanded to have a threshold 1509 for permitting transmission of a packet (e.g. a WFQ packet) other than an LLQ packet and a threshold 1501 (larger than the threshold 1509) for permitting transmission of the LLQ packet (two-threshold leaky bucket model). In this manner, even when a WFQ cannot be transmitted, an LLQ can be transmitted with priority. In addition, while the total bandwidth of the WFQ and LLQ, i.e. the bandwidth of the VLL contains fluctuation, the contracted bandwidth can be complied with. The circuit of the model is provided in LLQ and WFQ transmission appointed time calculating circuits so as to calculate respective transmission appointed times so that an LLQ/WFQ is selected and a packet is selected based on the times considering priority.

Abstract: In a virtual network apparatus, even when a fault occurs on a private line connecting plural physical network apparatuses to communicate a control signal, the redundancy is maintained, and the lower forwarding capability is prevented. In this network system, a control signal for virtualization to be transmitted and received between plural physical network apparatuses is relayed via a unit spanning LA connecting each physical network apparatus and an adjacent network apparatus in the adjacent network apparatus. Thereby, even when a fault occurs in the private line, it is possible to continue to communicate the control signal between the physical network apparatuses and continuously operate the virtual network apparatus.

Abstract: The communication device has a frame transfer unit that executes frame transfer via the first communication link and the second communication link, a link confirmation frame sending unit, and a return link confirmation frame monitoring unit. The link confirmation frame sending unit causes the frame transfer processing unit to send a link confirmation frame for use in confirming a normal link status via the first communication link from the communication device to the counterpart communication device. The return link confirmation frame monitoring unit performs fault detection of the first and second communication links by monitoring a return link confirmation frame which is to be returned from the counterpart communication device to the communication device via the second communication link when the counterpart communication device receives the link confirmation frame via the first communication link.

Abstract: A power-saving packet forwarding device realizing electric power that accords to the number of lines in which communication is performed and a traffic volume inputted from the lines. A header processing unit with which the packet forwarding device is equipped has a plurality of packet processing circuits for performing a packet processing. A line number decision circuit monitors the number of lines in which communication is performed and a traffic volume inputted from the line, and decides presence or absence of an operation of a packet processing circuit. Based on this decision result, a power supply and a clock of the packet processing circuit that does not need to operate are interrupted, and accordingly power saving of the packet forwarding device is realized.