US 8,571,029 B1 · Label switched path hierarchy for intra-area segments of inter-area point-to-multipoint label switched paths

Abstract

In general, techniques are described for providing multicast communication in a seamless MPLS architecture, in which thousands of PE routers within different routing areas of the same AS require P2MP connectivity to receive multicast communication. In particular, the techniques enable building inter-area P2MP segmented LSPs within an AS by stitching together intra-area segments of the inter-area P2MP segmented LSPs. The techniques provide LSP hierarchy with segmentation to enable aggregation of congruent intra-area segments within a routing area into an intra-area aggregate LSP. The AS may use the BGP as the inter-area label distribution protocol, and each routing area within the AS may independently select one of the multicast MPLS protocols as its intra-area label distribution protocol. The seamless MPLS architecture may be used by private network instances, such as multicast VPLS instances, MVPN instances, and IP multicast instances.

Claims27

Dependent claims

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.

2 more elements

A network system of an autonomous system (AS) of a public network for establishing inter-area point-to-multipoint (P2MP) segmented label switched paths (LSPs) across two or more routing areas within the AS, the network system comprising:

an egress network device within a first routing area that advertises 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, and advertises 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;
and
an ingress network device within the first routing area that establishes an intra-area aggregate LSP within the first routing area based on the first and second BGP Leaf auto-discovery routes, wherein the intra-area aggregate LSP 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, and advertises binding of the intra-area aggregate LSP to the first and second inter-area P2MP segmented LSPs using BGP Provider Multicast Service Interface (PMSI) auto-discovery routes that include an identity of the intra-area aggregate LSP and Multi-Protocol Label Switching (MPLS) labels of the first and second intra-area segments,
wherein the egress network device establishes the first inter-area P2MP segmented LSP across two or more routing areas of the AS by stitching the first intra-area segment 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 the BGP PMSI auto-discovery routes, and
wherein the egress network device establishes the second inter-area P2MP segmented LSP across two or more routing areas of the AS by stitching the second intra-area segment 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 the BGP PMSI auto-discovery routes.

2 more elements

An ingress network device within a first routing area of an autonomous system (AS) of a public network for establishing inter-area point-to-multipoint (P2MP) segmented label switched paths (LSPs) across two or more routing areas within the AS, the network device comprising:

a control unit configured to:
establish an intra-area aggregate LSP within the first routing area that uses LSP hierarchy to carry a first intra-area segment of a first inter-area P2MP segmented LSP and a second intra-area segment of a second inter-area P2MP segmented LSP;
advertise a binding of the intra-area aggregate LSP to the first inter-area P2MP segmented LSP using a first BGP Provider Multicast Service Interface (PMSI) auto-discovery route that includes an identity of the intra-area aggregate LSP and a first Multi-Protocol Label Switching (MPLS) label of the first intra-area segment, wherein the first inter-area P2MP segmented LSP is established by stitching the first intra-area segment in the first routing area to other intra-area segments of the first inter-area P2MP segmented LSP in a second routing area based on the advertised first BGP PMSI auto-discovery route;
and
advertise a binding of the intra-area aggregate LSP to the second inter-area P2MP segmented LSP using a second BGP PMSI auto-discovery route that includes the identity of the intra-area aggregate LSP and a second MPLS label of the second intra-area segment, wherein the second inter-area P2MP segmented LSP is established by stitching the second intra-area segment in the first routing area to other intra-area segments for the second inter-area P2MP segmented LSP in the second routing area based on the advertised second BGP PMSI auto-discovery route.

2 more elements

A non-transitory computer-readable storage medium encoded with instructions for 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 instructions causing one or more programmable processors to:

advertise 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 a first routing area;
advertise 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;
establish the first inter-area P2MP segmented LSP across two or more routing areas within the AS by stitching the first intra-area segment 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;
establish the second inter-area P2MP segmented LSP across two or more routing areas within the AS by stitching the first intra-area segment 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.

1 more element

establishing, with an ingress network device in a first routing area, an intra-area aggregate LSP within the first routing area that uses LSP hierarchy to carry a first intra-area segment of a first inter-area P2MP segmented LSP and a second intra-area segment of a second inter-area P2MP segmented LSP;
advertising, with the ingress network device, a binding of the intra-area aggregate LSP to the first inter-area P2MP segmented LSP using a first Border Gateway Protocol (BGP) Provider Multicast Service Interface (PMSI) auto-discovery route that includes an identity of the intra-area aggregate LSP and a first Multi-Protocol Label Switching (MPLS) label of the first intra-area segment, wherein the first inter-area P2MP segmented LSP is established by stitching the first intra-area segment in the first routing area to other intra-area segments of the first inter-area P2MP segmented LSP in a second routing area based on the advertised first BGP PMSI auto-discovery route;
and
advertising, with the ingress network device, a binding of the intra-area aggregate LSP to the second inter-area P2MP segmented LSP using a second BGP PMSI auto-discovery route that includes the identity of the intra-area aggregate LSP and a second MPLS label of the second intra-area segment, wherein the second inter-area P2MP segmented LSP is established by stitching the second intra-area segment in the first routing area to other intra-area segments for the second inter-area P2MP segmented LSP in the second routing area based on the advertised second BGP PMSI auto-discovery route.

1 more element

Dependencies are inferred from the claim text.

Label switched path hierarchy for intra-area segments of inter-area point-to-multipoint label switched paths

Life of this patent

Label switched path hierarchy for intra-area segments of inter-area point-to-multipoint label switched paths

Life of this patent

Abstract

Claims27