Upstream label assignment for the label distribution protocol
First Claim
1. A method comprising:
- establishing a point-to-multipoint (P2MP) tunnel across a network between an upstream router and two or more downstream routers using the Label Distribution Protocol (LDP) for carrying multicast traffic from the upstream router to the two or more downstream routers, where each of the two or more downstream routers are neighbors to the upstream router, and further wherein the upstream router is positioned between the two or more downstream routers and a source of multicast traffic;
receiving, with the upstream router, LDP Initialization messages that include upstream label assignment capability indications from one or more of the two or more downstream routers of the tunnel, wherein the upstream label assignment capability indications comprise a LDP Capability Type-Length-Value (TLV) with an Upstream Label Assignment Capability sub-TLV that indicates that the one or more downstream routers are capable of supporting labels for the tunnel that are assigned by the upstream router; and
allocating an upstream assigned label from the upstream router to the one or more downstream routers of the tunnel from which the upstream label assignment capability indications were received.
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Accused Products
Abstract
The invention is directed toward techniques for Multi-Protocol Label Switching (MPLS) upstream label assignment for the Label Distribution Protocol (LDP). The techniques include extensions to the LDP that enable distribution of upstream assigned labels from an upstream router to two or more downstream routers of a tunnel established over a network. The tunnel may comprise a LDP Point to Multi-Point (P2MP) Label Switched Path (LSP), an Internet Protocol (IP) multicast tunnel, or a Resource Reservation Protocol with Traffic Engineering extensions (RSVP-TE) P2MP LSP. The techniques also include extensions to the LDP that enable a router to advertise upstream label assignment capability to neighboring routers in the network. The MPLS upstream label assignment using LDP described herein enables a branch router to avoid traffic replication on a Local Area Network (LAN) for LDP P2MP LSPs.
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Citations
27 Claims
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1. A method comprising:
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establishing a point-to-multipoint (P2MP) tunnel across a network between an upstream router and two or more downstream routers using the Label Distribution Protocol (LDP) for carrying multicast traffic from the upstream router to the two or more downstream routers, where each of the two or more downstream routers are neighbors to the upstream router, and further wherein the upstream router is positioned between the two or more downstream routers and a source of multicast traffic; receiving, with the upstream router, LDP Initialization messages that include upstream label assignment capability indications from one or more of the two or more downstream routers of the tunnel, wherein the upstream label assignment capability indications comprise a LDP Capability Type-Length-Value (TLV) with an Upstream Label Assignment Capability sub-TLV that indicates that the one or more downstream routers are capable of supporting labels for the tunnel that are assigned by the upstream router; and allocating an upstream assigned label from the upstream router to the one or more downstream routers of the tunnel from which the upstream label assignment capability indications were received. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method comprising:
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establishing a point-to-multipoint (P2MP) tunnel across a network between an upstream router and two or more downstream routers using the Label Distribution Protocol (LDP) for carrying multicast traffic from the upstream router to the two or more downstream routers, where each of the two or more downstream routers are neighbors to the upstream router, and further wherein the upstream router is positioned between the two or more downstream routers and a source of multicast traffic; receiving, with the upstream router, LDP advertisements that include upstream label assignment capability indications from one or more of the two or more downstream routers of the tunnel, wherein the upstream label assignment capability indications indicate that the one or more downstream routers are capable of supporting labels for the tunnel that are assigned by the upstream router; and allocating an upstream assigned label from the upstream router to the one or more downstream routers of the tunnel from which the upstream label assignment capability indications were received, wherein allocating the upstream assigned label comprises sending a Label Mapping message to the one or more capable downstream routers of the tunnel, wherein the Label Mapping message includes an Upstream-Assigned Label Type-Length-Value (TLV) that signals the upstream assigned label.
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10. A computer-readable storage medium comprising instructions that cause a programmable processor to:
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establish a tunnel across a network between an upstream router and two or more downstream routers using the Label Distribution Protocol (LDP) for carrying multicast traffic from the upstream router to the two or more downstream routers, where each of the two or more downstream routers are neighbors to the upstream router, and further wherein the upstream router is positioned between the two or more downstream routers and a source of multicast traffic; receive, with the upstream router, LDP Initialization messages that include upstream label assignment capability indications from one or more of the two or more downstream routers of the tunnel, wherein the upstream label assignment capability indications comprise a LDP Capability Type-Length-Value (TLV) with an Upstream Label Assignment Capability sub-TLV that indicates that the two or more downstream routers are capable of supporting labels for the tunnel that are assigned by the upstream router; and allocate an upstream assigned label from the upstream router to the one or more downstream routers of the tunnel from which the upstream label assignment capability indications were received. - View Dependent Claims (11, 12, 13, 14, 15, 16)
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17. A computer-readable storage medium comprising instructions that cause a programmable processor to:
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establish a tunnel across a network between an upstream router and two or more downstream routers using the Label Distribution Protocol (LDP) for carrying multicast traffic from the upstream router to the two or more downstream routers, where each of the two or more downstream routers are neighbors to the upstream router, and further wherein the upstream router is positioned between the two or more downstream routers and a source of multicast traffic; receive, with the upstream router, LDP advertisements that include upstream label assignment capability indications from one or more of the two or more downstream routers of the tunnel, wherein the upstream label assignment capability indications indicate that the one or more downstream routers are capable of supporting labels for the tunnel that are assigned by the upstream router; allocate an upstream assigned label from the upstream router to the one or more downstream routers of the tunnel from which the upstream label assignment capability indications were received by sending a Label Mapping message to the one or more capable downstream routers of the tunnel, wherein the Label Mapping message includes an Upstream-Assigned Label Type-Length-Value (TLV) to signal the upstream assigned label to the one or more capable downstream routers.
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18. An upstream router comprising:
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a microprocessor; a signaling protocol executing on the microprocessor that establishes a tunnel across a network between the upstream router and two or more downstream routers for carrying multicast traffic from the upstream router to the two or more downstream routers, wherein the signaling protocol comprises the Label Distribution Protocol (LDP), where each of the two or more downstream routers are neighbors to the upstream router, and further wherein the upstream router is positioned between the two or more downstream routers and a source of multicast traffic; an upstream capability module of the signaling protocol that receives LDP Initialization messages including upstream label assignment capability indications from one or more of the two or more downstream routers of the tunnel, wherein the upstream label assignment capability indications comprise a LDP Capability Type-Length-Value (TLV) with an Upstream Label Assignment Capability sub-TLV that indicates that the one or more downstream routers are capable of supporting labels for the tunnel that are assigned by the upstream router; and an upstream label module of the signaling protocol that allocates an upstream assigned label to the one or more downstream routers of the tunnel from which the upstream label assignment capability indications were received. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25)
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26. An upstream router comprising:
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a microprocessor a signaling protocol, executing on the microprocessor, that establishes a tunnel across a network between the upstream router and two or more downstream routers for carrying multicast traffic from the upstream router to the two or more downstream routers, wherein the signaling protocol comprises the Label Distribution Protocol (LDP), where each of the two or more downstream routers are neighbors to the upstream router, and further wherein the upstream router is positioned between the downstream routers and a source of multicast traffic; an upstream capability module of the signaling protocol that receives LDP advertisements including upstream label assignment capability indications from one or more of the two or more downstream routers of the tunnel, wherein the upstream label assignment capability indications indicate that the one or more downstream routers are capable of supporting labels for the tunnel that are assigned by the upstream router; and an upstream label module of the signaling protocol that allocates an upstream assigned label to the one or more downstream routers of the tunnel from which the upstream label assignment capability indications were received, wherein the upstream label module sends a Label Mapping message that includes an Upstream-Assigned Label Type-Length-Value (TLV) to the one or more capable downstream routers of the tunnel.
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27. A system comprising:
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an upstream router that establishes a point-to-multipoint (P2MP) tunnel across a network using the Label Distribution Protocol (LDP); and two or more downstream routers of the tunnel that output LDP Initialization messages having an LDP Capability Type-Length-Value (TLV) and an Upstream Label Assignment Capability sub-TLV that advertise upstream label assignment capability indications to the upstream router, wherein the upstream router is positioned between the two or more downstream routers and a source of multicast traffic, wherein the upstream label assignment capability indications indicate that the two or more downstream routers are capable of supporting labels for the tunnel that are assigned by the upstream router, wherein the upstream router allocates an upstream assigned label to the two or more downstream routers of the tunnel upon receiving the LDP Initialization messages from the two or more downstream routers.
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Specification