Abstract: The present invention provides a technology for processing packets, such as VoIP packets, with priority. A priority-designating unit designates priority information based on header information. A pointer searching unit refers to a pointer table to obtain pointer information corresponding to a destination address. A sorting unit sorts the pointer information into a high-priority queue and a low-priority queue according to the priority information. A next queue holds pointer information obtained from a destination information table. A scheduler extracts and outputs the pointer information from each queue in the following order of priority: the next queue, a high-priority queue, and a low-priority queue.

Abstract: The present invention provides a VPN edge router with the ability of identifying VPNs by using the identifiers of logical channels multiplexed on a single input line.

Abstract: A high quality network is provided by not generating a sorting time when registering look-up conditions in a content addressable memory, and the physical banks activated during look-up of the look-up conditions are limited.

Abstract: A VPN edge router with the ability of identifying VPNs by using the identifiers of logical channels multiplexed on a single input line.

Abstract: A header processing unit includes a key information supply unit that manages MAC addresses and MAC key information having a short bit length that corresponds to the addresses, and decides key information corresponding to a source MAC address and a destination MAC address of an input frame. A destination decision unit performs destination decision processing based on corresponding key information instead of destination MAC addresses. A flow decision unit decides a flow based on key information corresponding to a destination MAC address and a source MAC address. Since the key information supply unit does not need to set plural identical MAC addresses, the header processing unit becomes inexpensive. Thus, this invention achieves an inexpensive switch that performs output decision processing and flow decision processing.

Abstract: The present invention provides a method for rapidly replacing an output destination port with a bypass port and replacing packet output header information with bypass header information when a port accommodated by a router within an IP or MPLS network becomes faulty. The present invention also provides a packet forwarding apparatus that accommodates two output ports. The packet forwarding apparatus comprises means for storing the output information about each of a plurality of pieces of input header information, means for storing the output information about an output port that is associated with input header information and used as a bypass in the event of a fault, and an output information address rewrite processor for writing, in the event of an output port failure, the output information address associated with an output port that should serve as a bypass.

Abstract: There is provided a packet forwarding device which always carries out high-speed search in a routing table by using a TCAM. The device includes a CAM (120) which includes a first CAM entry (120-1) to set high order bits of destination address conditions and a second CAM entry (120-2) to set low order bits of the destination address conditions, a first search unit which compares high order bits of a destination address of an input packet with the first CAM entry to search for a matching destination address condition, and a second search unit which compares low order bits of the destination address of the packet with the second CAM entry to search for a matching destination address condition when no destination address condition corresponding to the high order bits of the destination address of the packet is uniquely decided based on a result of the search.

Abstract: A communication statistic information collection apparatus comprises a unit for searching a flow table for a flow entry corresponding to a searching key, a unit for collecting statistics information for each of flows, a unit for generating a packet for notifying a collector apparatus of stored statistics information, a unit for updating the flow table in accordance with statistics control information shown by a statistics control entry found as a result of searching the flow table, and a unit for generating a sample packet to be transferred to the collect or apparatus at a specified sampling rate in accordance with the statistics control information shown by a specified entry found from the flow table.

Abstract: A router comprising a priority level distinguishing means for distinguishing the priority level of a packet by referring to the information contained in the header of the packet, a routing table where an output path comprising one or more output lines can be mapped to each level of priority, an output path determining unit that searches the routing table and determines an output path to be used for sending out packets, and a preferential delivery controller that executes delivery control in accordance with the priority level for each output line corresponding to the output path. In response to a fault state in a preferred output line, the router can reroute high priority packets over an alternative output line while maintaining priority. The router may also calculate a distribution ratio to determine the optimal load for each output line for a given packet priority.

Abstract: A flow dubious of an abnormal flow is asked to be specified and flow statistic information of the flow is required to be collected. To comply with such a request, a discard information analyzer of apparatus administrator, for instance, analyzes the number of discard packets, the number of receiving packets or the number of transmitting packets counted by a bandwidth monitor of packet receiver or a bandwidth controller of packet transmitter and in accordance with the result of analysis, automatically sets, in an OUT side flow controller or In side flow controller, information for identifying a flow subject to flow control. Further, the OUT side flow controller or IN side flow controller picks flow statistic information from packets belonging to the object flow by using the set flow identification information.

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: A packet forwarding device equipped with a statistics collection device and statistics collection method for high speed ports at a low cost while maintaining the required statistical accuracy for each flow. In order to collect a statistic flow with the required accurate statistic information this device contains a high speed flow table, a flow table made up of many flow entries, a search decision table to decide whether to search the high speed flow table or large volume flow table; and the table to be searched is decided when a packet is received. The accuracy of the statistic information for the flow requiring accurate statistic information is guaranteed by the high speed flow table. Further by setting the large volume flow table and sampling rate as needed, statistic information for many flow entries can be collected with a sufficient flow of sampled statistic information, without lowering packet forwarding performance.

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 request routing system for offering high-quality, low-priced data delivery services to a large number of users is disclosed. Request router RR1 for redirecting data requests to delivery servers manages the data storage in each delivery server, the MPU load on each delivery server, the delay time involved between delivery servers and terminals, and the bandwidths of data delivery paths between delivery servers and terminals. If a bandwidth required for data delivery cannot be acquired, request router RR1 can perform a calculation to check whether an alternative path can be set between a delivery server and terminal. If the result of the calculation indicates that an alternative path can be set, request router RR1 can explicitly set such a path.

Abstract: A secure storage system for securely accessing a storage device on a network and improving volume management scalability, consisting of a client having a VPN capability; a storage device in an SAN; a management apparatus having a means for managing a storage capacity and a logical volume allocated to the storage device; a converter for converting a protocol used in the SAN to a protocol used in a LAN/MAN/WAN and vice versa; and a conversion apparatus having the VPN capability. A VPN is provided between the client and the conversion apparatus. The conversion apparatus is provided with a mapping between the VPN and an access range of the storage device. A VPN-ID is used for identifying the VPN. An address in the logical volume is used for the access range of the storage device.

Abstract: With respect to a router in a backup path in an MPLS network adopting a label stack method, it is an object of the present invention to achieve the same quality-guarantee control as the one performed in a current path. In a packet transfer device accommodating first and second output lines, when the first line has a fault, upon a first packet being received, communication quality information in a header of the first packet is copied. Further, a first header containing the copied priority information and a new label is added to the first packet, and a packet to which the first packet is added is outputted to a second output line. When a second packet is received, communication quality information in a header of the second packet is copied, a second header containing the copied priority information and the new label is added to the second packet, and a packet to which the second packet is added is outputted to the second output line.

Abstract: A packet routing apparatus has a routing information table comprised of a plurality of sub-tables. Each sub-table includes an entry of a first format indicative of routing information, and at least one of the sub-tables includes, in addition to the entry of the first format, an entry of a second format for designating another sub-table to be referred to. A routing processor of the packet routing apparatus refers to a sub-table designated by an input line interface. As a result, when the entry of the second format is retrieved, the routing processor executes routing of an input packet and header conversion by referring to another sub-table designated by the entry.

Abstract: A router comprising a priority level distinguishing means for distinguishing the priority level of a packet by referring to the information contained in the header of the packet, a routing table where an output path comprising one or more output lines can be mapped to each level of priority, an output path determining unit that searches the routing table and determines an output path to be used for sending out packets, and a preferential delivery controller that executes delivery control in accordance with the priority level for each output line corresponding to the output path. In response to a fault state in a preferred output line, the router can reroute high priority packets over an alternative output line while maintaining priority. The router may also calculate a distribution ratio to determine the optimal load for each output line for a given packet priority.

Abstract: The present invention provides a VPN edge router with the ability of identifying VPNs by using the identifiers of logical channels multiplexed on a single input line.