Abstract: A node apparatus includes a TTL memory configured to store a TTL value for a first node apparatus in the cluster; a receiving unit configured to receive a first Hello packet including a first sequence number and a second Hello packet including a second sequence number that is incremented when the node apparatus transmits a Hello packet; a sequence number judging unit configured to judge whether a first sequence number and a second sequence number match each other; a TTL decrementing unit configured to perform a process to decrement the TTL value stored in the TTL memory, when the first sequence number and the second sequence number are identical according to a judgment; and a cluster information updating unit configured to separate the first node apparatus from the cluster, when the TTL value for the first node apparatus becomes equal to or smaller than a prescribed value.

Abstract: When stored identifying information of a transmission target frame and identifying information of a received frame are equal, a node apparatus updates transmission feasibility information stored in association with the final destination of the received frame. The transmission feasibility information indicates feasibility of transmission to each of a plurality of adjacent node apparatuses being a transmission destination, and is updated so that feasibility of transmission to the transmission destination associated with the identifying information of the received frame indicates that “the transmission is infeasible”. The node apparatus transmits the received frame, when there is no adjacent apparatus to which transmission is feasible, and when the stored identifying information of the transmission target frame is equal to the identifying information of the received frame, to the adjacent node apparatus recognized as the origin in association with the identifying information of the received frame.

Abstract: A computer-readable recording medium has stored therein a program for causing a computer to execute a process including storing, as a variable set, a database of a variable that associates a key, a value and a synchronization destination corresponding to the key, executing a process of requesting that the variable in the variable set of the computer be referred to or updated in a state and evaluating a condition so as to make the state transition to a different state, and communicating the key specified by the request with the synchronization destination for the variable corresponding to the key specified by the request and synchronizing the value of the variable corresponding to the key in the computer and the value of the variable corresponding to the key in the variable set of the synchronization destination when the process of requesting is executed.

Abstract: A communication device includes a memory and a processor coupled to the memory and configured to, when a first vibration is detected in the communication device, set a certain state that protects information stored in the memory, and cancel the certain state based on receiving from another communication device a notification indicating that the other communication device detected a second vibration.

Abstract: A node device includes a processor, a wireless RF circuit, a memory, and a timer. The processor measures a clock time. The wireless RF circuit receives a clock time information frame containing clock time information used for correcting the clock time. The memory stores a transmission processing time period, as a fixed value, from when a transmission source node device of the clock time information frame obtains the clock time information until when the transmission source node device transmits the clock time information frame. The timer measures a reception processing time period, which is a period of time from when the clock time information frame is received until when the clock time information is obtained. The node device sets to the processor a value obtained by adding the fixed value and the reception processing time period to the clock time information.

Abstract: When stored identifying information of a transmission target frame and identifying information of a received frame are equal, a node apparatus updates transmission feasibility information stored in association with the final destination of the received frame. The transmission feasibility information indicates feasibility of transmission to each of a plurality of adjacent node apparatuses being a transmission destination, and is updated so that feasibility of transmission to the transmission destination associated with the identifying information of the received frame indicates that “the transmission is infeasible”. The node apparatus transmits the received frame, when there is no adjacent apparatus to which transmission is feasible, and when the stored identifying information of the transmission target frame is equal to the identifying information of the received frame, to the adjacent node apparatus recognized as the origin in association with the identifying information of the received frame.

Abstract: A node device includes a processor, a wireless RF circuit, a memory, and a timer. The processor measures a clock time. The wireless RF circuit receives a clock time information frame containing clock time information used for correcting the clock time. The memory stores a transmission processing time period, as a fixed value, from when a transmission source node device of the clock time information frame obtains the clock time information until when the transmission source node device transmits the clock time information frame. The timer measures a reception processing time period, which is a period of time from when the clock time information frame is received until when the clock time information is obtained. The node device sets to the processor a value obtained by adding the fixed value and the reception processing time period to the clock time information.

Abstract: In a node device 1 in a communication network, an FID management table 5 stores an FID for unique identification of a frame and the information about a destination node of the frame, and a weighting table 7 stores weighting information about another node as a destination for relay of the frame for each final destination node of the frame. When a frame transmitted to a local node is received, and if the FID of the received frame is stored in the FID management table 5, the data about the destination node associated with the FID is updated. If the FID of the frame received from the frame reception device is not stored in the FID management table 5, the FID management table 5 corresponding to the destination node of the frame is referred to, and another node as a destination for relay of the frame is determined.

Abstract: A node device includes a transmitter, processor, and a receiver. The receiver receives a packet from an adjacent node device. The processor generates a cluster list and a first hello packet. The cluster list records device identification information of a node device included in a cluster. The cluster is a group of node devices for which route information is stored. The first hello packet reports the route information with cluster identification information of the cluster. The transmitter broadcasts the first hello packet. Upon receipt of, from a free-node device that does not belong to a cluster, a second hello packet that includes information that associates the cluster identification information with device identification information of the free-node device, the processor adds the device identification information of the free-node device to the cluster list until a number of node devices recorded in the cluster list reaches a threshold.

Abstract: Anode device includes a receiver, a processor, memory, and a transmitter. The receiver receives a path information packet for notification of path information about a network. The processor generates a participation request packet for requesting a first node device selected between an adjacent node device and a node device communicable through the adjacent node device to participate in a first local cluster. The memory stores a path to each affiliated node device affiliated with the first cluster. The transmitter transmits the participation request packet to the first node device. When a number of affiliated node devices which are affiliated with the first cluster exceeds a threshold, the processor generates a generation request packet for requesting a second node device which is not affiliated with the first cluster to generate a second cluster different from the first cluster. The transmitter transmits the generation request packet to the second node device.

Abstract: A node apparatus is provided that determines, according to the route stability indicator of the frame, whether to perform a process of judging whether the frame identification information to identify the frame is stored in a memory as the frame identification information, makes an update, only when a result of the judgment indicates a judgment is to be made on whether the frame identification information to identify the frame is stored in the memory as the frame identification information, the transmission possibility information stored in the memory such that the possibility of transmission to the node apparatus identified by the transmission-destination-node identification information indicates “not transmittable”, and selects, as a transmission-destination node apparatus, one adjacent node apparatus from the plurality of node apparatuses according to the transmission possibility information stored in the memory in association with the ultimate destination of the frame.

Abstract: A first node apparatus includes: ports; a storage device; and receiving, updating, and transmitting circuits. The storage device stores: information associating, with first identification information identifying a first frame, information distinguishing a first port having been used as a destination port when the first node apparatus has transmitted the first frame; and information associating, with each node apparatus, state information indicating whether frame transmission from each port is feasible. The receiving circuit receives, from a second node apparatus, a second frame including second identification information. When the second identification information is identical with the first, the updating circuit updates the state information associated with a node apparatus being a destination of the second frame to make the state information indicate frame transmission from the first port is not feasible.

Abstract: A gateway apparatus includes a sorting destination storing unit which stores information of a sorting destination that performs a process according to a destination, a sorting unit which outputs an input destination and transmission data to a sorting destination according to the destination searched from information stored in the sorting destination storing unit, a transmission destination storing unit which stores information of a transmission destination for each destination, an input/output unit which performs a transmission process and a reception process according to a corresponding protocol stack, and a protocol converting unit which assembles, when a destination and transmission data are input from the sorting unit, the destination and the transmission data as data that matches a format of a corresponding protocol stack, and instructs the input/output unit of a corresponding protocol stack to transmit the assembled data to a transmission destination according to the destination.

Abstract: A node transmits a route search demand, which is a demand to search for a route from the node to a predetermined device among adjacent communication devices, to an adjacent communication device that is not selected as a transmission destination of the route search demand. The node transmits the route search demand when the number of adjacent communication devices serving as confirmed routes is smaller than a predetermined number and when there is an adjacent communication device that has not been selected. The node stops transmission of the route search demand when the number of the adjacent communication devices serving as the confirmed routes reaches the predetermined number. The node transmits a warning to the predetermined device when the number of the adjacent communication devices serving as the confirmed routes is smaller than the predetermined number and when there is no adjacent communication device that has not been selected.

Abstract: A node receives, from a neighboring node that is a node in the neighborhood, neighboring node information indicating a node that neighbors the neighboring node and determines whether a common neighboring node is present, the common neighboring node being common amongst a neighboring node and a node indicated by the received neighboring node information. When it is determined that the common neighboring node is present, the node registers, in a storage unit, information that a link on a simplex path is to be formed with the common neighboring node or the neighboring node that is the source of the neighboring node information. Alternatively, when it is determined that the common neighboring node is not present, the node registers, in the storage unit, information that a link on a duplex path is to be formed with the neighboring node that is the source of the neighboring node information.

Abstract: A communication apparatus includes an encryption key generation unit that generates encryption key information at constant encryption key generation intervals, a common key generation unit that generates common key information uniquely with respect to a generation time at common key generation intervals set longer than the encryption key generation intervals, a common key application unit that performs encryption or decryption of the encryption key information by using the common key information, and an encryption key distribution unit that makes a request to a data transmitting/receiving unit to distribute the encryption key information to a plurality of communication apparatuses to be communicated simultaneously at encryption key distribution intervals set shorter than the encryption key generation intervals to perform communication with higher security.

Abstract: A node apparatus changes a first access key unique to itself; changes a shared key same for node apparatuses; encrypts, using the shared key, the first access key and transmits it; receives an access key notification frame; decrypts it using the shared key, thereby obtaining a second access key; attaches, to a first plaintext frame, first signature data obtained by encrypting, using the shared key, data including a first value calculated from the first plaintext frame; encrypts the first plaintext frame using the second access key and transmits thus encrypted frame; receives a second encrypted frame; decrypts it by the first access key to obtain a second plaintext frame; obtains a second value by decrypting, using the shared key, a second signature data attached to the second plaintext frame; calculates a third value from the second plaintext frame; and confirms whether the second and third values are consistent.

Abstract: A communication device includes a data storage unit, a decryption unit, an encryption unit, and a judgment unit. The data storage unit stores a piece of encrypted data or a piece of decrypted data. The decryption unit decrypts each provided piece of encrypted data. The encryption unit encrypts each provided piece of decrypted data. The judgment unit issues an instruction to the encryption unit to read from the data storage unit first decrypted data obtained by the decryption unit decrypting first encrypted data with a cryptographic key, and to write back to the data storage unit second encrypted data obtained by the encryption unit encrypting the first decrypted data with the cryptographic key.

Abstract: When stored identifying information of a transmission target frame and identifying information of a received frame are equal, a node apparatus updates transmission feasibility information stored in association with the final destination of the received frame. The transmission feasibility information indicates feasibility of transmission to each of a plurality of adjacent node apparatuses being a transmission destination, and is updated so that feasibility of transmission to the transmission destination associated with the identifying information of the received frame indicates that “the transmission is infeasible”. The node apparatus transmits the received frame, when there is no adjacent apparatus to which transmission is feasible, and when the stored identifying information of the transmission target frame is equal to the identifying information of the received frame, to the adjacent node apparatus recognized as the origin in association with the identifying information of the received frame.

Abstract: A first node apparatus includes: ports; a storage device; and receiving, updating, and transmitting circuits. The storage device stores: information associating, with first identification information identifying a first frame, information distinguishing a first port having been used as a destination port when the first node apparatus has transmitted the first frame; and information associating, with each node apparatus, state information indicating whether frame transmission from each port is feasible. The receiving circuit receives, from a second node apparatus, a second frame including second identification information. When the second identification information is identical with the first, the updating circuit updates the state information associated with a node apparatus being a destination of the second frame to make the state information indicate frame transmission from the first port is not feasible.