摘要:
A network system that comprises a plurality of communication apparatuses, each of the communication apparatuses being capable of performing a VLAN setting by using a VLAN number set for a connection port, that sets a VLAN number for each of the communication apparatuses, and that performs communication among cars of a train, wherein in a case where a specific type of packet that disables a VLAN setting is a packet of a multicast address, when a distribution target apparatus is connected to a communication apparatus that has received the specific type of packet, the communication apparatus transfers the specific type of packet to the distribution target apparatus and, irrespective of a VLAN number set for another communication apparatus, regards a VLAN different from a VLAN of the communication apparatus as a same network and transfers the specific type of packet to the another communication apparatus.
摘要:
An IP-address distribution system according to the present invention includes a network formed by a plurality of switching devices, and a plurality of IP-address distribution devices connected to the network, wherein the switching devices are grouped into two or more groups, and the switching devices interrupt an IP-address request signal transmitted from a terminal that requests allocation of an IP address at a physical port to which a switching device in another group is connected.
摘要:
A train communication system includes a communication relay device that is installed in each vehicle and a communication terminal device that is connected to the communication relay device. The communication relay device acquires vehicle information indicating an in-formation position of a vehicle in which the communication relay device is installed. The communication terminal device refers to a correspondence table that defines a correspondence relationship between vehicle information and communication identification information, and determines communication identification information to be provided to the communication terminal device, based on vehicle information obtained from the communication relay device.
摘要:
When data is transmitted from a first communication terminal to a second communication terminal, a communication relay device converts car identification information of a communication source of communication-source identification information included in a communication packet into a car number of a vehicle, and transmits the data to an inter-vehicle communication path. When data is transmitted from the second communication terminal to the first communication terminal, the communication relay device converts car identification information of a communication destination of communication-destination identification information included in a communication packet into a “0”-th car indicating own car, and transmits the data to an in-vehicle communication path.
摘要:
A path-information obtaining unit obtains a piece of path information of a communication network by inquiring a port number of an Ethernet switch that transmits a MAC address of a request source of an IP address. An IP-address specifying unit specifies an IP address that corresponds to the piece of path information of the communication network by referring to an IP-address correspondence table, and distributes the specified IP address to the request source of an IP address.
摘要:
A rotary magnetic head device has a plurality of bobbins to which coils are respectively fixedly attached, and a plate spring fixedly attached to the bobbins. The plate spring has a plurality of front ends to which magnetic heads are respectively fixed. The magnetic heads are held in such a manner that, when a current is selectively supplied to one or more of the coils, the respective one or more of the magnetic heads independently move in the axial direction. A rotary magnetic head device has a head supporting base plate, and a head supporting table which is tilted by an angle with respect to the head supporting base plate. The tilt angle is adjusted by moving the head supporting table. In a rotary magnetic lead device, the position in the axial direction of a magnetic head is detected, and the level of a current to be supplied to a coil is adjusted on the basis of the detection result.
摘要:
To provide a network system including a network constructed by combining a plurality of switching devices. The network includes a first partial network including switching devices and a second partial network that is formed outside the first partial network and includes switching devices. The switching device in the first partial network connected to the second partial network blocks passage of a broadcast signal that is transmitted from a terminal device and that has a specific logical port number as transmission information at a physical port.
摘要:
A communication apparatus for performing communication among cars of a train includes two or more connection ports, and two or more VLANs set through VLAN numbers in each connection port. When receiving a specific kind of packet for disabling the VLAN settings, the communication apparatus regards the set two or more VLANs as the same network with respect to the specific kind of packet and transfers the packet to a desired destination apparatus set in any one of the VLANs irrespective of the VLAN settings.
摘要:
A network system according to the present invention includes a backbone network that is constituted by combining a plurality of switch devices, and a subnetwork that is constituted by a plurality of switch devices connected linearly, where the switch devices positioned at both ends of the linear connection are connected to the backbone network, wherein among physical ports included in the switch devices that constitute the backbone network, a first physical port that is one of two physical ports to which the subnetwork is connected blocks a packet with a specific logical port number having arrived from a specific direction, and passes other packets, and a second physical port that is the other of the two physical ports passes a packet with the specific logical port number having arrived from the specific direction, and blocks other packets.
摘要:
An IP address delivery system includes an IP address delivery apparatus and a path-information granting unit. The IP address delivery apparatus includes: a path-information reading unit configured to read, from an IP address request signal transmitted from a request source of an IP address, path information of the request source; an IP address correspondence table in which a correspondence relation between the path information and the IP address is registered; and an IP-address determining unit configured to determine, based on the path information and the IP address correspondence table, an IP address delivered to the request source. The path-information granting unit is provided on a communication path between the IP address delivery apparatus and the request source and configured to grant the path information to the IP address request signal transmitted from the request source.