1. In an internetwork comprising a plurality of coupled autonomous systems, wherein the plurality of coupled autonomous systems communicate routing information via a Border Gateway Protocol (BGP), and the internetwork includes a routing overlay network to communicate routing parameters between the plurality of coupled autonomous systems, a BGP update message comprising: a Network Layer Reachability Information (NLRI) field, the NLRI field including: a first network prefix; and a first network mask; an origin attribute, the origin attribute including an identifier for the routing overlay network; and a first community attribute, the first community attribute including: an identifier for a private autonomous system from the plurality of autonomous systems.