Patent ID: 7804848

Claim:
A method comprising the steps of: receiving, at a particular router, a neighbor discovery message through an interface to a border network segment between a first plurality of nodes for routing with Internet Protocol (IP) version 6 (IPv6) using a first routing protocol and a different second plurality of nodes for routing using a different second routing protocol, wherein the particular node is among the first plurality of nodes and the neighbor discovery message is received from an alien router among the second plurality of nodes, wherein the first routing protocol comprises an Enhanced Interior Gateway Router Protocol (EIGRP) configured to set a forwarding address (FA) field in advertisement messaging associated with external routes involving the particular router, and wherein the alien router and the particular router communicate level 3 summarized routing information using an External Border Gateway Protocol (EBGP); receiving, from the alien router through the interface, a border routing message that includes foreign routing data that indicates a route to a destination in the second plurality of nodes; determining whether an interface on the alien router to the border network segment has a global IP address, wherein the particular router includes a forward alien address process configured to forward an address for the alien router when the alien router does not have the global IP address; and if it is determined that the interface on the alien router does not have a global IP address, then performing the steps of: generating a fictive IPv6 address that includes data that indicates a global prefix of an IPv6 address for the particular router and an interface identifier (ID) associated with the alien router; inserting the fictive IPv6 address and the foreign routing data into a domain scope external advertisement message; sending the external advertisement message to the first plurality of nodes; receiving a neighbor solicitation message that indicates a request to resolve a MAC identifier for the fictive IPv6 address; and sending a neighbor advertisement message that includes data that indicates the MAC identifier for the interface on the alien router.