Patent ID: 7302496
Filing Date: 2007-11-27
Classification: H04L

Abstract:
1. A method in an endpoint device having a first Internet Protocol (IP) network address for use in a first IP address realm of a local IP network, the local IP network including a network address translator configured for converting the first IP network address to a second IP address for a second IP address realm, the method including: sending a query by the endpoint device to a destination endpoint device, the query having an IP source address field specifying the first IP network address and an IP destination address field specifying an available IP address for the destination endpoint device having a value outside the first IP address realm, the sending including specifying, within the query, a first unique identifier identifiable solely by the endpoint device for validating any received reply to the query; receiving by the endpoint device a response from the destination endpoint device that specifies the first unique identifier, a second unique identifier used for responding to the destination endpoint device, and alias IP addresses for reaching the destination endpoint device via the respective IP address realms, the alias IP addresses including at least the available IP address for the destination endpoint device and an alternate IP address; using by the endpoint device one of the alias IP addresses for communicating with the destination endpoint device via the corresponding IP address realm, including inserting the one alias IP address in the corresponding IP destination address field of each IP datagram destined for the destination endpoint device; and sending a second query for each of the alias IP addresses, each second query including the second unique identifier, the using of the one alias IP address including selecting the one alias IP address based on receiving a reply specifying, by the destination endpoint device, preferred use of the one alias IP address relative to the alias IP addresses specified in the respective second queries received by the destination endpoint device.