Abstract: A rear-focusing type zoom lens includes in order from an object side: a positive first group that is fixed, a negative second group that is moved toward an image plane along an optical axis during zooming from a wide-angle end to a telephoto end, a negative third group that is fixed in an optical axis direction, and a positive fourth group that moves along the optical axis direction to correct image plane variation, which is caused by the zooming, and to perform focusing. The first group includes a first subgroup having a negative refractive power as a whole and a second subgroup having a positive refractive power as a whole. The first subgroup includes, in order from the object side, a negative meniscus lens having a convex surface directed toward the object side, a first negative lens, a positive lens, and a second negative lens.

Abstract: A rear-focusing type zoom lens includes, in order from an object side, a positive first group being fixed, a negative second group moving toward an image plane along an optical axis during zooming from a wide-angle end to a telephoto end; a negative third group being fixed in an optical axis direction, and a positive fourth group moving along the optical axis direction to correct image plane variation being caused by zooming. The first group includes a first subgroup having a negative power as a whole and a second subgroup having a positive power as a whole. The first subgroup includes a negative meniscus lens having a convex surface directed toward the object side and a negative lens. The second subgroup includes a positive lens group having at least one positive lens, a negative lens, a positive lens, and another positive lens group having at least one positive lens.

Abstract: A mobile communication apparatus includes a registration request part (47) requesting a correspondent node to make location registration, a BU list memory (45) keeping a list of the correspondent nodes which have made the location registration, a handover detection part (41) detecting the start of a handover, and a registration cancellation processing part (46) canceling the location registration of the correspondent nodes in the BU list, upon notification of start of handover by the handover detection part (41), thereby reducing loss of packets transmitted from the correspondent nodes during the handover, because the route optimization applied to the correspondent nodes registered in the BU list at the start of the handover is canceled by requesting the cancellation to the correspondent nodes.

Abstract: A router includes a multicast packet transmitting unit that multicasts the identifier of the router periodically, a relay determining unit that determines whether a received data packet should be relayed to a router in another segment, an order determining unit that determines, on the basis of information included in multicast packets from the other routers, the router to which the data packet shall be transferred, and a packet relaying unit that, when the data packet is not relayed, notifies the transmission source which transmitted the packet as to the router selected by the order determining unit to be the relay destination and then transfers the data packet to the selected router. A router suitable for relaying the packet is thus selected. Since switching of the relay router may be performed by following the router redirection message, it is unnecessary to add a new function to a terminal.

Abstract: Between network connection apparatuses connected to each other by use of a virtual redundant arrangement, a first network connection apparatus that is in a standby state receives an advertisement message from a second network connection apparatus that is active as a network connection apparatus, and uses a priority comparing section to compare its own priority with the priority in the received advertisement message. When its own priority is higher, the first network connection apparatus uses a master down timer comparing section to compare the remaining time of a master down timer with the time as weighted in accordance with its own priority and resets the timer for a shorter time.

Abstract: Provided are a service-type recording section for recording a characteristic of a service to be utilized by the mobile communication device and an interface recording section for recording an externally-connecting interface type of within a network and a characteristic thereof. The interface decision section selects at least one or more of interfaces satisfying a service request and notifies it to a mobile router possessing an externally-connecting interface. Due to this, in case there is a link status change in the external interface of the mobile router, the mobile communication device is allowed to swiftly switch the external interface and continue communication. Moreover, congestion can be avoided from occurring in communication between the mobile communication device and the mobile router during switchover.

Abstract: A router, if judging that a routing function is impossible to execute, sends out a connection instruction message including the address of a terminal on a local network terminating the relaying flow, to another router to solicit switching. The router having received the connection instruction message starts a process for connecting with an external network while executing a process for link connection with a terminal, and then sends out a connection completion notice message when the connection with both the external network and the terminal is established. This process enables the router to switch a path rapidly.

Abstract: The present invention provides a visible and infrared light image-taking optical system which can facilitate changing a wavelength of infrared light used to take an infrared video image with an infrared light camera and which can achieve an infrared video image not affected by infrared light of any wavelength other than a desired wavelength, by separating object light incident on an image-taking optical system into object light in a visible light region and object light in an infrared light region and taking an object image formed by each object light for each object light in each wavelength region decomposed by the color separation optical system.

Abstract: In a mobile communication system using a mobile IP, a mobile terminal determines a main home agent and a main home address. When the mobile terminal moved to a network different in service form, a home address for use on a moved-in domain network is registered as a primary care of address to the main home agent, thereby enabling communications by using the main home address even upon accessed from the other than the belonging domain network. This makes it possible to flexibly cope with an incoming call from the external by the use of a representative home address even on the Internet as a distributed network.

Abstract: When connected to an external network, a mobile router checks an address 0table if a home address is allocated. If it is not allocated, the mobile router derives the address of a position management server from a position-management-server address table and sends an allocation request message to the position management server. The position management server receives an address management table listing addresses to be allocated to each mobile network and the allocation request message sent from the mobile router, searches the address management table for an unused address, and sends an allocation permission message to the mobile router to automatically allocate a home address to the mobile router.

Abstract: A base station serves as a relay node between a mobile terminal and an application server on a backbone network. The base receives a radio packet from the mobile terminal through a wireless I/F section, and transfers the radio packet to a IP processing section, a TCP input section and a protocol relay section successively in this order. At this point, with respect to the packet, the IP header is processed and then removed in the IP processing section, the TCP header is processed and then removed in a TCP processing section, and the data is transferred to a protocol relay section along with the TCP segment information described in both headers. The protocol relay section has a conversion table, and performs proxy processing based on the table.

Abstract: A mobile communication apparatus includes a registration request part (47) requesting a correspondent node to make location registration, a BU list memory (45) keeping a list of the correspondent nodes which have made the location registration, a handover detection part (41) detecting the start of a handover, and a registration cancellation processing part (46) canceling the location registration of the correspondent nodes in the BU list, upon notification of start of handover by the handover detection part (41), thereby reducing loss of packets transmitted from the correspondent nodes during the handover, because the route optimization applied to the correspondent nodes registered in the BU list at the start of the handover is canceled by requesting the cancellation to the correspondent nodes.

Abstract: The invention provides an address information setting method such that when home agent information such as an address of a home agent, which is basic information for activating mobile IP protocol processing, is acquired, it is made possible to perform communication that satisfies requirements desired by a user or an application by starting mobile IP protocol processing using home agent information acquired according to an instruction of a user. In addition, it is possible to reduce the work burden on a user for making settings and provide a mobile terminal with high convenience by automatically acquiring home agent information on a link at a time specified by the user.

Abstract: A router device includes a lower-layer information acquisition section for acquiring connection information of whether or not connected with a base station in an external network from a lower layer, and a route judgment section for transferring the received packet to the base station in the case of being connected with the base station and judging a transfer destination by looking up a routing table in the case of not being connected with the base station, when receiving a packet destined for a terminal in an external network from a radio terminal device in a same local network. Because the received packet is transferred to the base station during connection with the base station, the packet can be transferred to the external via the router intended by the terminal. Furthermore, the load in the local network can be reduced.

Abstract: A mobile communication apparatus includes a mobile IP/Fast Mobile IP processing part, an access router searching part for acquiring information on access router apparatuses, a Fast Mobile IP compliance determining part for determining whether the access router apparatuses comply with Fast Mobile IP, and a Fast Mobile IP control part for controlling the contents of a message produced by the mobile IP/Fast Mobile IP processing part. In this way, even if one of the access router apparatuses does not comply with Fast Mobile IP, the procedure of Fast Mobile IP can be implemented, thereby reducing packet loss.

Abstract: A router includes a multicast packet transmitting unit that multicasts the identifier of the router periodically, a relay determining unit that determines whether a received data packet should be relayed to a router in another segment, an order determining unit that determines, on the basis of information included in multicast packets from the other routers, the router to which the data packet shall be transferred, and a packet relaying unit that, when the data packet is not relayed, notifies the transmission source which transmitted the packet as to the router selected by the order determining unit to be the relay destination and then transfers the data packet to the selected router. A router suitable for relaying the packet is thus selected. Since switching of the relay router may be performed by following the router redirection message, it is unnecessary to add a new function to a terminal.

Abstract: A home gateway device having a home agent function selects communication interfaces other than the communication interface which has acquired network information for setting a home network to be home links, and appropriately sets the home link and a home agent by using the acquired network information, thereby reliably achieving the automatization of the device setting. Moreover, the home gateway device selects a link connected to a mobile terminal based on a mobile IP as home link, acquires existing home agent information from the mobile terminal and makes settings with this information, thereby setting the home link without compelling the mobile terminal to change its setting.

Abstract: A router device includes a VRRP (Virtual Redundancy Router Protocol) realizing a virtual router device for operating a plurality of router devices virtually as one router device. The router device further includes a virtual router processing section for executing virtual router processing and a virtual router information processing section for extracting virtual router information upon reception of a virtual router information message and performing setting necessary for operation as a virtual router. When performing a new connection to a local area network, the virtual router information can be automatically set. Thus, it is possible to significantly reduce the load required for building a virtual router system by manual setting conventionally performed by a management operator.

Abstract: When connected to an external network, a mobile router checks an address 0table if a home address is allocated. If it is not allocated, the mobile router derives the address of a position management server from a position-management-server address table and sends an allocation request message to the position management server. The position management server receives an address management table listing addresses to be allocated to each mobile network and the allocation request message sent from the mobile router, searches the address management table for an unused address, and sends an allocation permission message to the mobile router to automatically allocate a home address to the mobile router.

Abstract: Physical router devices report router status information to a router priority calculation device via a local network. According to the router status information reported, the router priority calculation device calculates priority of each physical router device and reports the priority to the physical router devices via the local network. According to the priority reported, the physical router devices decide one master router and a backup router other than this from a plurality of physical router devices. Thus, by utilizing the priority obtained from the router status information on the physical router devices, it is possible to automatically and flexibly constitute a virtual router device.