Patent ID: 8571029

Claim:
A method of establishing inter-area point-to-multipoint (P2MP) segmented label switched paths (LSPs) across two or more routing areas within an autonomous system (AS) of a public network, the method comprising: advertising, with an egress network device in a first routing area, a first border gateway protocol (BGP) Leaf auto-discovery route identifying a leaf node for a first intra-area segment of a first inter-area P2MP segmented LSP in the first routing area; advertising, with the egress network device, a second BGP Leaf auto-discovery route identifying a leaf node for a second intra-area segment of a second inter-area P2MP segmented LSP in the first routing area, wherein the first and second BGP Leaf auto-discovery routes are used to establish an intra-area aggregate LSP within the first routing area that uses LSP hierarchy to carry the first intra-area segment of the first inter-area P2MP segmented LSP and the second intra-area segment of the second inter-area P2MP segmented LSP; establishing the first inter-area P2MP segmented LSP across two or more routing areas within the AS by stitching, with the egress network device, the first intra-area segment carried by the intra-area aggregate LSP in the first routing area to other intra-area segments of the first inter-area P2MP segmented LSP within a second routing area based on labels advertised in BGP; and establishing the second inter-area P2MP segmented LSP across two or more routing areas within the AS by stitching, with the egress network device, the second intra-area segment carried by the intra-area aggregate LSP in the first routing area to other intra-area segments of the second inter-area P2MP segmented LSP within the second routing area based on labels advertised in BGP.