ISATAP tunneling system and method between IPv4 network and IPv6 network

A routing device of a tunneling system for tunneling data having address formats different from one another, the routing device comprising:

• an address comparator for receiving an encapsulated message of a second address format from a host encapsulating a message of a first address format in a message of the second address format, and for comparing a source address of the first address format with a source address of the second address format to generate a comparison result;
• a controller for determining whether to store the source addresses of the first address format and the second address format, respectively, depending on the generated comparison result;
• a routing address information database responsive to a determination, from the generated comparison result, that the source address of the first address format is not the same as the source address of the second address format for storing the source addresses of the first address format and the second address format, respectively, under the control of the controller;
• and
• a message generator for assigning the source address of the second address format stored in the routing address information database as a destination address, and for generating the message of the second address format having the assigned destination address included in prefix information.

A tunneling method for tunneling data having address formats different from one another, the method comprising the steps of:

• encapsulating and transmitting a message of a first address format in a message of a second address format;
• receiving the encapsulated message of the second address format, and translating a source address of a private address format into a global address format;
• assigning the source address translated into the global address format as a destination address;
• and
• generating the message of the second address format having the assigned destination address included in prefix information.