Fujitsu Corporation

Naoki Oguchi

Tetsumei Tsuruoka

Makoto Kubota

Ryoichi Mutoh

Paparao Palacharla

Yuji Nomura

Mukul Ranjan Prasad

Toshiyuki Sudo

Yuji Saito

Jun Ogawa

Takeshi Kodama

Alexander Horn

Satoshi Nojima

Takuma Utsunomiya

Chunghan Lee

Yosuke Takano

A network management apparatus configured to obtain multiple rules that each control communication in accordance with an address range of a packet, divide a full set of the address range of the multiple rules into multiple subsets that are mutually disjoint in accordance with inclusion relations of the address range among the multiple rules, extract, with respect to each rule of the multiple rules, one or more subsets that are included in the address range from the multiple subsets, and determine, with respect to each rule of the multiple rules, an inclusion relation of the one or more subsets between a particular rule and another rule of the multiple rules that is assigned higher priority than that of the particular rule and determine disposition for each of the multiple rules in accordance with a determination result of the inclusion relation of the one or more subsets.

Network management apparatus, network management method, and non-transitory computer-readable storage medium

A non-transitory computer-readable recording medium stores therein a program that causes a computer to execute a process, the process comprising: acquiring update information of forwarding tables and event logs for respective relay devices at predetermined intervals; performing consistency determination of determining consistency of the forwarding tables when update completion of the forwarding tables have been confirmed for all of the relay devices; when a first relay device is determined to have a problem in consistency, associating the problem with an event log, among the event logs of the first relay device, corresponding to a time when update information of a first forwarding table of the first relay device is acquired; and outputting information including the first relay device and the event log associated with the problem.

Abnormality detection method and abnormality detection device

A method may include obtaining packet handling rules from at least one firewall in a network and at least one routing table in the network, and translating the packet handling rules to canonical data structures based on priority of rules at a given routing table or a given firewall. Each canonical data structure may represent a subset of packets affected by one or more corresponding packet handling rules such that each packet handling rule is covered by at least one canonical data structure. The method may also include generating a graph representation of the firewalls and the nodes corresponding to the routing tables in the network. The method may additionally include labeling vertices and edges in the graph representation based on the packet handling rules. The method may also include, using the graph representation, verifying one or more network properties to identify any network issues.

Network property verification

An available bandwidth measuring apparatus classifies, into one group, a plurality of virtual machines communicating with a physical node. Then, the available bandwidth measuring apparatus obtains available bandwidth measurements with respect to the virtual machines belonging to the same group by transmitting, to the physical node, measuring packets emulating each of the virtual machines. The available bandwidth measurements represent available bandwidth available when each of the virtual machines performs data transmission in a different time slot. Based on the available bandwidth measurements, the available bandwidth measuring apparatus determines actual available bandwidth of each of the virtual machines, to be used when the virtual machines perform data transmission to the physical node in the same time slot, and notifies each of the virtual machines of the actual available bandwidth determined for the virtual machine.

Method and apparatus for available bandwidth measurement

A communication control device including: a memory, and a processor coupled to the memory and the processor configured to: transmit packets from the communication control device to a network device at each of a plurality of transmission rates, acquire a plurality of index values respectively indicating amounts of packet loss at the plurality of transmission rates, specify, among the plurality of transmission rates, a first transmission rate on which a corresponding index value among the plurality of index values has a dependence, and specify an upper limit of a vacant band between the communication control device and the network device based on the first transmission rate.

Communication control device, communication control method, and computer readable storage medium for specifying an upper limit of a network connection

A wireless communication apparatus attachable to an information processing apparatus. The wireless communication apparatus includes a wireless communication interface configured to perform wireless communication. The wireless communication apparatus also includes a processor configured to input, on detecting an error in the wireless communication interface, a signal for recognizing a temporary interruption to the information processing apparatus, and to initialize the wireless communication interface.

Wireless communication apparatus, wireless base station, and abnormality restoration method

A relay device is arranged on a path of a Transmission Control Protocol (TCP) packet transmitted and received between a transmission-side end device and a reception-side end device. The relay device stores packet information obtained by snooping on a first TCP packet that is addressed to the reception-side end device and received from the transmission-side end device and on a second TCP packet that is addressed to the transmission-side end device and received from another relay device that is arranged between the relay device and the reception-side end device on the path. The relay device performs, based on the packet information, first communication control between the relay device and the another relay device, where the first communication control is independent of second communication control that is performed between the transmission-side end device and the reception-side end device.

Apparatus and method for controlling transmission between relay devices

A communication device includes a memory configured to store a program, and a processor, based on the program, configured to control a number of communication segments that are allowed to be continuously transmitted after a first communication segment to be transmitted in accordance with a number of acknowledgments that have been received, and set a communication segment length of the first communication segment based on a length of time before completion of reception of an acknowledgment for a transmitted second communication segment.

Communication device, communication method, and recording medium

A TCP node stores a congestion window size before congestion is detected, the congestion window size limiting the amount of data to be transmitted. If congestion is detected, the TCP node reduces a current congestion window size to a predetermined size. If path switching subsequently occurs after congestion is detected, the TCP node uses a round-trip time or bandwidth information of a path after switching to correct the congestion window size before congestion detection. The TCP node then changes the reduced congestion window size to the corrected size.

Information processing apparatus, congestion control method, and computer-readable recording medium

A communication device including: a processor configured to perform a wireless communication protocol including an upper layer and a lower layer, wherein the processor is configured to estimate, based on a round trip time measured at the upper layer in case of carrying out a retransmission control at the lower layer and a time taking for retransmissions at the lower layer, a first estimated round trip time, to estimate, based on the number of times of packet loss at the upper layer in case of carrying out the retransmission control at the lower layer, and the number of times of successful transmission at the upper layer being recovered by the retransmission control, a first estimated packet loss rate, and to obtain, based on the first estimated round trip time and the first estimated packet loss rate, a first estimated throughput in case of not carrying out the retransmission control.

Communication device and communication method

A communication control device measures a size of burst data transmitted from a first device through the use of a predetermined protocol in a transport layer. The communication control device selects a protocol ruled by an algorithm with the smallest latency, which is estimated from the measured size of burst data and characteristics of a network, from among plural protocols used in the transport layer. The communication control device terminates the communication of the burst data transmitted through the predetermined protocol from the first device and transmits the burst data to a destination through the use of the selected protocol.

Communication control device, communication control method, and computer-readable recording medium

A transmission control method includes performing communication between a transmission source communication device and a transmission destination communication device by using a transmission control protocol which includes a plurality of congestion control functions corresponding to a plurality of congestion control methods, respectively, and causing, when the transmission source communication device and the transmission destination communication device switch from a first congestion control function to a second congestion control function, at least one of a plurality of parameters for controlling operating states in the first congestion control function to be inherited by a parameter for controlling an operating state in the second congestion control function.

Transmission control method, transmission control system, communication device and recording medium of transmission control program

A relay apparatus for performing relay possessing is disclosed. The relay apparatus includes a first logical relay unit; a second logical relay unit; a sending unit configured to add a packet header including a first protocol identifier or a second protocol identifier registered in a protocol assignment unit to a packet to be sent by the first logical relay unit or the second logical relay unit, and to send the packet to a network; a receiving unit configured to pass a received packet to the first logical relay unit or the second logical relay unit by referring to the protocol assignment unit based on a protocol identifier in a packet header of the received packet; and a switching process unit configured to change correspondence relationship for the first and the second protocol identifiers to switch between the first logical relay unit and the second logical relay unit.

Network configuring method, network system and relay apparatus

In a wireless communication system, time point information is transmitted from a second wireless base station. The time point information indicates a time point at which service information is transmitted from the second wireless base station. Moreover, at the time point indicated by the time point information, the service information is transmitted from the second wireless base station. On the wireless terminal side, firstly, the time point information is obtained in a first non-communication period in which communication with the first wireless base station is temporarily stopped. Then, the service information is obtained in a second non-communication period which is ensured in accordance with the time point indicated by the time point information.

Wireless terminal, wireless base station and communication method in wireless communication system

A wireless connecting method includes a connection monitoring step, a connection parameter retaining step, and a connection restoring step. The connection monitoring step monitors the wireless connection between the communication terminal device and the base station. The connection parameter retaining step sets a communication session retention time period that is longer than a connection parameter retention time period, and retains a connection parameter. A connection parameter when the wireless connection is disconnected is retained in at least one of the communication terminal device and the base station for the communication session retention time period exceeding the connection parameter retention time period. The connection restoring step executes, after the connection parameter retention time period has elapsed, when the communication session retention time period has not elapsed, an initial connecting process and restores the connection using the connection parameter stored when the wireless connection is disconnected.

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Kawasaki, Japan

Naoki Oguchi