RFC 1884: “IP Edition 6 Addressing Architecture” employs that phrase for a few bits at the end of an IPv6 tackle. (The volume of bits looked as if it would fluctuate in certain different illustrations, but this identifier was typically according to the MAC-forty eight handle of the network card.) https://felixzktah.bcbloggers.com/25964121/the-smart-trick-of-whatsmyip-that-no-one-is-discussing