Nec Corporation

Tutomu Murase

Hideyuki Shimonishi

Yohei Hasegawa

Satoshi Kamiya

Masayoshi Kobayashi

Toru Takamichi

Takashi Iwasaki

Yasuhiro Yamasaki

Yasuhiro Yamazaki

Kurenai Murakami

Yumi Hirano

Goh Shibata

Atsushi Kawabata

Yuko Asano

Ethan Spiegel

A network environment capable of performing a smooth and comfortable TCP session operation is provided to a user. The session relay equipment includes a bridge portion which relays a session by which a sequence of packets are transmitted and received between terminals connected with each other via a network; a socket information table which has socket information containing (1) address information of the terminal and (2) protocol information used in the session, the socket information being associated with information on whether or not the session is to be terminated; and a service information table which has information on a communication service to be provided for each service provision unit, the communication service being identified based on predetermined information within a header of the packet. The bridge portion terminates the session and executes a communication service based on the information contained in the header of the packet and the socket information.

Session relay equipment and session relay method

A great delay in communication and deterioration in quality are avoided from occurring. A pseudo acknowledgement frame communication system includes: at least one communication device that transmits a frame; a second communication device that receives the frame; and a pseudo acknowledgement frame transmission device that monitors link-by-link communication between the first and second communication devices, in which the first communication device has a frame transmission means for transmitting a transmission frame to the second communication device, and an acknowledgement frame reception means for receiving an acknowledgement frame transmitted by the second communication device, the second communication device has an acknowledgement frame transmission means for transmitting the acknowledgement frame upon receiving the transmission frame from the first communication device, and the pseudo acknowledgement frame transmission device has a monitor means for monitoring the transmission frame transmitted by the first communication device, and a pseudo acknowledgement frame transmission means for generating a pseudo acknowledgement frame from a monitor result of the monitor means, based on a pseudo acknowledgement frame transmission condition, and transmitting the pseudo acknowledgement frame to the first communication device.

Pseudo-response frame communication system, pseudo-response frame communication method, and pseudo-response frame transmitting device

In a communication device () which realizes communication with data distributed to a plurality of connections, a data division restoration processing unit (-), when transmitting data, receives data from an application processing unit (-), divides the data into an arbitrary number of blocks, stores information for restoring the block to original data within a TCP header and sends the data to a network processing unit (-) by using an arbitrary number of TCP connections, and when receiving data, refers to restoration information stored within the TCP header with respect to data of the plurality of TCP connections received from the network processing unit (-), identifies a divisional block, combines the blocks to restore data as of before division and sends the data to the application processing unit (-).

Communication device, and communication method and program thereof

A session identification unit () determines a session to which an incoming packet belongs, while a session relay unit (---N) relays between a session with a transmission terminal and a session with a reception terminal. A packet scheduler () instructs and controls the delivery of packets from each session relay unit (---N), and a delivery control unit () delivers packets from each session relay unit (---N) based on the instruction. In the session relay unit (-), a transmission session processing unit (-) processes a session for transmitting data to the reception terminal, and a transmission buffer (-) stores received data until the end of a transmission. A reception session processing unit (-) processes a session for receiving data from the transmission terminal.

Session relay apparatus for relaying data, and a data relaying method

A cache table management device for raising the cache hit probability for entries inserted in groups between a forwarding tableand cache. A forwarding tablestores the priority level of entries inserted and extracted in a cache. A packet processing circuitextracts the destination address from the received packet, searches the packet using the destination address, and searches the forwarding table if no hits occur. The hit databasestores the contents of the forwarding table for all forwarding table entries, as well as rating values for the cache usage status. An entry selection devicerefers to the hit database when an entry must be added or deleted between the forwarding table and the cache, and selects the corresponding entry group. That determination is made utilizing typical values for attributes of the priority level such as the average bit rate of each entry group.

Cache table management device for router and program recording medium thereof

A router allowing the entry hit probability of the cache to be increased is disclosed. The cache is searched using a different mask for each cache entry. A maximum or optimum cache prefix length is determined as a length of upper bits of the destination address of the received packet which are not masked by a corresponding mask. Alternatively, the cache is searched using longest prefix match (LFM). A cache entry allowing a plurality of destination addresses to be hit can be registered in the cache, resulting in increased cache hit probability.

Router with a cache having a high hit probability

A router having a high-speed and flexible longest match retrieval device is disclosed. A plurality of entries are divided into a plurality of primary retrieving circuits each retrieving a primary match mask and a primary match entry depending on a given address. The primary match masks and entries obtained by the primary retrieving circuits are used to determine the longest match routing information.

High-speed flexible longest match retrieval

To provide a list management system of the same effectiveness with the LRU method with smaller overhead of the CPU, a list management system comprises: a trigger generating means ( ) for generating a trigger signal every time when a time interval is passed; counters ( ) each corresponding to each of a plurality of processes ( ) and counting a reference frequency of each of the processes ( ); a list ( ) of elements each corresponding to each of the processes ( ) and connected with each other by way of pointer data; and a list maintenance means ( ) for rearranging order of the elements according to count values of the counters in descending order of the count values, when the trigger signal is generated.

LIST MANAGEMENT SYSTEM, A LIST MANAGEMENT METHOD, A RECORDING MEDIUM WHEREIN A COMPUTER PROGRAM FOR REALIZING THE LIST MANAGEMENT SYSTEM IS RECORDED AND A PACKET EXCHANGE WHEREIN THE LIST MANAGEMENT SYSTEM IS APPLIED

A packet switching network includes a transmitting station, an ATM switching system and a receiving station. The transmitting station has a traffic rate controller for controlling the traffic rate based on the congestion in the ATM switching system as well as the data cells stored in the transmission data storage section for receiving data for transmission. The traffic rate controller controls the number of transmitted cells between adjacent forward resource management (FRM cells, thereby avoiding a reduction in the traffic rate during data transmission which is caused by lack of available data for transmission supplied to the transmission station.

Traffic rate controller in a packet switching network

A packet switching apparatus is disclosed which is adapted to determine and control an allowed transmission rate of a transmitting terminal in a packet switching network. The packet switching apparatus comprises a rate discriminator to monitor an interval of packet reception for each of connections, judge, based on the interval of packet reception, whether the transmitting terminal having sent the packet is in pause of transmission and determine a first allowed transmission rate for the transmitting terminal correspondingly to a result of the judgment, an ER calculator to calculate, based on a predetermined algorithm, a second allowed transmission rate for the transmitting terminal, and an ER setter to select one of the first allowed transmission rate determined by the rate discriminator and second allowed transmission rate calculated by the ER calculator, whichever is smaller, and write it into a packet returned to the transmitting terminal.

Packet switching apparatus adapted to control allowed transmission rate in packet switching network, and method of controlling allowed transmission rate

When one or more storage data are coincident with single search data (,), an associative memory with a shortest mask producing function carries out logical multiplication for all of mask information corresponding to the coincident storage data with a mask valid state as true. The result of logical multiplication is used as shortest mask information. In a primary searching operation, the associative memory with a shortest mask producing function is supplied with the search data (,) to provide the shortest mask information on shortest mask lines. Then, as a secondary searching operation, the shortest mask information thus extracted is used as the search data and supplied to the associative memory with a shortest mask producing function. Among the coincident storage data, only a mask match line connected to a particular word having mask information coincident with the shortest mask information is selected as the secondary search result. The associative memory is used in a network router, to calculate an optimum memory address signal (,) by encoding the selected mask match line. In response to the memory address signal (,), a memory data signal (,) enabling shortest network connection is produced as a transfer network address (,). The transfer network address (,) is combined with a data area (,) and a destination network address (,) contained in input transfer data (,) to produce output transfer data (,).

Associative memory having a mask function for use in a network router

The prior art suffered from problems such as communication quality degradation including reductions in network throughput, delays, and cell loss. An additional problem was the consumption of large amounts of the VCI and VPI required at links between nodes of each connection due to the use of a plurality of connections. In response to these problems, according to the routing system of the present invention, the plurality of connections are not changed for sections in which the routes to be taken are different but are consolidated into one connection for sections in which the routes to be taken are the same; and a connecting device provided at the node, which are set up for a plurality of connections to either or to both the input and output sides, discretionary makes either a first connection, which is either the plurality of connections or one consolidated connection, to the input side, or a second connection, which is either the plurality of connections or one consolidated connection, to the output side.

Routing system

An associative memory with a shortest mask output function has data cells, mask cells, comparators for the data cells, comparators for the mask cells, a first bit lines for inputting compared bits to the data cell comparators, and a second bit lines for inputting compared bits to the mask cell comparator, a search data are input to the first bit line and bit data corresponding to the shortest mask lines are input to the second bit line.

Associative memory with a shortest mask output function and search method

A UPC unit 1 includes a congestion detecting circuit 4 for detecting a congesting status of a network 3 from a flow of cells in the backward direction and calculating or determining a parameter required for UPC based on the congestion status, a rewritable parameter memory 5 for storing the parameter, and a DGCRA circuit 6 for checking a conformance of cells in the forward direction on the basis of the information of the parameter memory 5 and the specified information.

UPC unit and UPC controlling method

The invention provides a dynamic traffic shaping apparatus which allows dynamic shaping processing wherein the shaping cell rate is varied dynamically in response to a rate variation of a terminal acquired from a network. The dynamic traffic shaping apparatus includes a rate information processing section for predicting a sending rate of a transmission terminal in response to rate control information detected from a cell directed from a reception terminal side toward a transmission terminal side and successively storing the sending rate in an updating manner as sending rate information of an arrival cell for each virtual path and each virtual channel. The cell stored in a cell buffer for temporarily storing an arrival cell arriving from the transmission terminal side for each virtual path and each virtual channel is read out at an interval based on the sending rate information stored in the rate information processing section corresponding to the virtual path and the virtual channel and is sent out to the reception terminal side by a read control section.

Growing community of inventors

Tokyo, Japan

Tutomu Murase