A first network element comprising a memory comprising instructions executable by a processor and a processor coupled to the memory and configured to execute the instructions. Executing the instructions causes the processor to receive, from a second network element during a border gateway protocol communication session, a communications capabilities message indicating capabilities of the second network element, receive, from the second network element, an advertisement message indicating connections and accesses of a second domain controlled by the second network element, receive a request to route data between a source located in a first domain and a destination, transmit a first request message to the second network element to cause the second network element to compute a path segment through the second domain, and transmit a second request message to create a segment of an end-to-end tunnel between the source and the destination crossing the first domain and the second domain.