Internet Routing Overlay Network (IRON) http://www.ietf.org/mail-archive/web/rrg/current/msg06621.html

"IRON introduces a new class of routers called IRON Routers (IRs). These routers can be simple commodity hardware platforms that are introduced incrementally, and without affecting existing infrastructure. The purpose of these new IRs is to provide waypoints (or "cairns") for navigating the IRON so that packets with Endpoint Interface iDentifier (EID) destination addresses can be delivered to the correct End User Networks (EUNs) through the use of encapsulation with minimum path stretch for initial packets and optimized routes for most packets."