Hitachi, Ltd.

Masaya Hayashi

Yukiko Takeda

Hidenori Inouchi

Keisuke Takeuchi

Takamitsu Senou

Masashi Yano

Tetsuhiko Hirata

Hiroaki Nakazawa

A translator includes a unit for communication with a DNS-ALG. The DNS-ALG detects a DNS query to a destination terminal, and performs once translation to IPv6. The DNS-ALG translates a destination temporary IPv6 address, in which a real address of IPv4 acquired from a DNS server of the destination terminal is added with a virtual IPv6 prefix, to a destination temporary IPv4. The IPv6-based DNS-ALG cooperates with the translator to permit alleviation of processing load on the DNS-ALG and reduction in capacity of a translation table of large capacity. A technique is disclosed which, with the above construction, can permit mutual connection among a plurality of VPN's without exchanging the existing VPN's.

Address translation method

A mobile data communication system capable of shortening the interruption time of communication includes an HA device, advertising routers, base stations, routers, and mobile terminal devices. Each base station advertises an address having '1' set in a different bit of an interface ID of a routing address. When a mobile terminal has received radio waves from a plurality of base stations in the vicinity of a boundary between cells, the mobile terminal combines a plurality of received routing addresses by logical summation and registers a resultant routing address with the HA device. As for a packet delivered from the HA device to the routing address and having '1' in a plurality of bits of the host section, a router resolves the address of the host section into destination addresses each having &#x201c;1&#x201d; in one bit, generates packets each having one of resultant addresses, and transmits the generated packets.

Mobile communication system

Growing community of inventors

Kawasaki, Japan

Masaya Hayashi