Patent ID: 8611359

Claim:
A method comprising: executing a first label distribution protocol at a border node positioned at a border between two of a plurality of interior gateway protocol (IGP) areas of a single autonomous system (AS); exchanging label distribution messages using the first label distribution protocol to establish a first intra-area label switched path (LSP) within a first one of the plurality of IGP areas; executing a labeled interior border gateway protocol (iBGP) at the border node; establishing, with the labeled iBGP, an iBGP peering session between the border node and a node associated with the first IGP area of the AS; and exchanging label distribution messages directly between the border node and the node associated with the first IGP area of the AS over the iBGP peering session using the labeled interior border gateway protocol to establish a hierarchical inter-area LSP that transports traffic over the previously established first intra-area LSP, wherein the hierarchical inter-area LSP extends across the plurality of IGP areas of the AS, wherein exchanging label distribution messages using the labeled interior gateway protocol comprises with the border node, receiving a first labeled interior border gateway protocol route advertisement over the iBGP peering session, wherein the route advertisement specifies a route to a destination within a first IGP area of the AS and a label to use for reaching the destination.