Patent ID: 7872971
Filing Date: 2011-01-18
Classification: H04L

Abstract:
1. A gateway unit having a function for mutual translation between an Ipv6 address and an Ipv4 address, said gateway unit comprising: a live list for storing entries, each of the entries, containing at least an identifier, an operational IP address, and a transmission Ipv4 address; an Ipv4 address pool for storing Ipv4 addresses; a translation rules storage section for storing translation rules for use in translation between the Ipv6 address and the Ipv4 address; an SM Device Annunciation processing section for making reference to an identifier if a message received is SM Device Annunciation, a multicast transmission in field bus communication between Ipv4-capable and Ipv6-capable field devices connected to a field bus executing HSE (High Speed Ethernet) communications, thereby retrieving the entry corresponding to the identifier, and acquiring an Ipv4 address from the Ipv4 address pool if the entry is not found while preparing translation rules from the Ipv4 address acquired so as to be stored in the translation rules storage section, and preparing an entry to be registered in the live list; a message processing section for making reference to the translation rules stored in the translation rules storage section, thereby executing mutual translation between the Ipv4 address and/or the Ipv6 address contained in the message received; an IP translating section for making reference to the translation rules stored in the translation rules storage section, thereby generating respective addresses of a transmission source and a transmission destination; and a packet transmitting section for generating a packet on the basis of the message processed by the message processing section, and the respective addresses of the transmission source, and the transmission destination, generated by the IP translating section, thereby transmitting the packet.