Branch node-initiated point to multi-point label switched path signaling with centralized path computation
First Claim
1. A method comprising:
- receiving, with a controller, a request for a point-to-multipoint (P2MP) label switched path (LSP) from a source node through one or more branch nodes to a plurality of leaf nodes within a network;
determining, with the controller, a hierarchy of point-to-point (P2P) sub-LSPs, wherein a first level of the hierarchy includes at least one P2P source-to-leaf (S2L) sub-LSP from the source node as an ingress for the P2P S2L sub-LSP through one or more of the branch nodes to a first one of the leaf nodes as an egress for the P2P S2L LSP, and wherein each remaining level of the hierarchy includes at least one P2P branch-to-leaf (B2L) sub-LSP from one of the branch nodes as in ingress to the P2P B2L sub-LSP to a different one of the leaf nodes as an egress for the P2P B2L sub-LSP; and
outputting messages, with the controller, to direct the source node, the one or more branch nodes and the plurality of leaf nodes to signal the hierarchy of P2P sub-LSPs to form the P2MP LSP.
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Abstract
Techniques are described for establishing a point-to-multipoint (P2MP) label switched path (LSP) using a branch node-initiated signaling model in which branch node to leaf (B2L) sub-LSPs are signaled and utilized to form a P2MP LSP. The techniques described herein provides a scalable solution in which the number of sub-LSPs for which the source node or any given branch node need maintain state is equal to the number of physical data flows output from that node to downstream nodes, i.e., the number of output interfaces used for the P2MP LSP by that node to output data flows to downstream nodes. As such, unlike the conventional source node-initiated model in which each node maintains state for sub-LSPs that service each of the leaf nodes downstream from the device, the size and scalability of a P2MP LSP is no longer bound to the number of leaves that are downstream from that node.
206 Citations
20 Claims
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1. A method comprising:
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receiving, with a controller, a request for a point-to-multipoint (P2MP) label switched path (LSP) from a source node through one or more branch nodes to a plurality of leaf nodes within a network; determining, with the controller, a hierarchy of point-to-point (P2P) sub-LSPs, wherein a first level of the hierarchy includes at least one P2P source-to-leaf (S2L) sub-LSP from the source node as an ingress for the P2P S2L sub-LSP through one or more of the branch nodes to a first one of the leaf nodes as an egress for the P2P S2L LSP, and wherein each remaining level of the hierarchy includes at least one P2P branch-to-leaf (B2L) sub-LSP from one of the branch nodes as in ingress to the P2P B2L sub-LSP to a different one of the leaf nodes as an egress for the P2P B2L sub-LSP; and outputting messages, with the controller, to direct the source node, the one or more branch nodes and the plurality of leaf nodes to signal the hierarchy of P2P sub-LSPs to form the P2MP LSP. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A device comprising:
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a network interface to receive a request for a point-to-multipoint (P2MP) label switched path (LSP) from a source node through one or more branch nodes to a plurality of leaf nodes within a network; a path computation module executing on one or more processors, wherein the path computation module determines a hierarchy of point-to-point (P2P) sub-LSPs, wherein a first level of the hierarchy includes at least one P2P source-to-leaf (S2L) sub-LSP from the source node as an ingress for the P2P S2L sub-LSP through one or more of the branch nodes to a first one of the leaf nodes as an egress for the P2P S2L LSP, and wherein each remaining level of the hierarchy includes at least one P2P branch-to-leaf (B2L) sub-LSP from one of the branch nodes as in ingress to the P2P B2L sub-LSP to a different one of the leaf nodes as an egress for the P2P B2L sub-LSP; and a path provisioning module to output messages to direct the source node, the one or more branch nodes and the plurality of leaf nodes to signal the hierarchy of P2P sub-LSPs to form the P2MP LSP. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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17. A computer-readable storage medium comprising instructions that cause a network device to:
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receive a request for a point-to-multipoint (P2MP) label switched path (LSP) from a source node through one or more branch nodes to a plurality of leaf nodes within a network; determine a hierarchy of point-to-point (P2P) sub-LSPs, wherein a first level of the hierarchy includes at least one P2P source-to-leaf (S2L) sub-LSP from the source node as an ingress for the P2P S2L sub-LSP through one or more of the branch nodes to a first one of the leaf nodes as an egress for the P2P S2L LSP, and wherein each remaining level of the hierarchy includes at least one P2P branch-to-leaf (B2L) sub-LSP from one of the branch nodes as in ingress to the P2P B2L sub-LSP to a different one of the leaf nodes as an egress for the P2P B2L sub-LSP; and output messages, with the controller, to direct the source node, the one or more branch nodes and the plurality of leaf nodes to signal the hierarchy of P2P sub-LSPs to form the P2MP LSP. - View Dependent Claims (18, 19, 20)
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Specification