Mpls traffic engineering for point-to-multipoint label switched paths

A method in a core router in a Multiprotocol Label Switching (MPLS) network, comprising the steps of:

• receiving a set of one or more first PATH messages from an upstream node, wherein the set of first PATH messages identify at least a portion of a first point-to-point label switched path (LSP) between a source edge router and a first receiver edge router and identify at least a portion of a second point-to-point LSP between the source edge router and a second receiver edge router, wherein the set of first PATH messages each includes a same identifier of a point-to-multipoint (P2MP) LSP that includes a session object that contains a tunnel identifier and a P2MP identifier;
• sending a second PATH message to a first downstream node on the first point-to-point LSP, the second PATH message including the identifier of the P2MP LSP;
• sending a third PATH message to a second downstream node on the second point-to-point LSP, the third PATH message including the identifier of the P2MP LSP;
• receiving, from the first downstream node, a first RESV message responsive to the second PATH message, the first RESV message including the identifier of the P2MP LSP and a first label allocated by the first downstream node;
• receiving, from the second downstream node, a second RESV message responsive to the third PATH message, the second RESV message including the identifier of the P2MP LSP and a second label allocated by the second downstream node;
• allocating a third label to be used by the upstream node when transmitting packets for the P2MP LSP to the core router;
• mapping the third label with the first label and the second label to enable the core router to replicate packets that are received from the upstream node that are labeled with the third label, send each replicated packet to the first downstream node being labeled with the first label, and send each replicated packet to the second downstream node being labeled with the second label;
• and
• sending a set of one or more third RESV messages to the upstream node responsive to receiving the first RESV message and the second RESV message, wherein the set of third RESV messages each includes the identifier of the P2MP LSP and the third label.

An apparatus, comprising:

• a set of one or more processors;
• a non-transitory machine-readable medium that stores instructions that, when executed by the set of processors, cause said processors to perform operations comprising:
• identifying a plurality of receivers that are requesting to receive data from the source in a session;
• sending a set of one or more PATH messages to one or more nodes downstream of the source edge router to signal a plurality of separate point-to-point label switched paths (LSPs) between the source edge router and a plurality of receiver edge routers associated with the plurality of receivers, wherein each one of the set of PATH messages includes a same identifier of a point-to-multipoint (P2MP) LSP that includes a session object that contains a tunnel identifier and a P2MP identifier;
• and
• receiving, from each of the one or more nodes downstream of the source edge router, a set of one or more RESV messages, wherein each one of the received RESV messages includes the identifier of the P2MP LSP and a label allocated by that downstream node that is to be used by the source edge router when sending traffic of the P2MP LSP to that downstream node.

An apparatus, comprising:

• a set of one or more processors;
• a non-transitory machine-readable medium that stores instructions that, when executed by the set of processors, cause said processors to perform operations comprising:
• receiving a set of one or more first PATH messages from an upstream node, wherein the set of first PATH messages identify at least a portion of a first point-to-point label switched path (LSP) between a source edge router and a first receiver edge router and identify at least a portion of a second point-to-point LSP between the source edge router and a second receiver edge router, wherein the set of first PATH messages each includes a same identifier of a point-to-multipoint (P2MP) LSP that includes a session object that contains a tunnel identifier and a P2MP identifier;
• sending a second PATH message to a first downstream node on the first point-to-point LSP, the second PATH message including the identifier of the P2MP LSP;
• sending a third PATH message to a second downstream node on the second point-to-point LSP, the third PATH message including the identifier of the P2MP LSP;
• receiving, from the first downstream node, a first RESV message responsive to the second PATH message, the first RESV message including the identifier of the P2MP LSP and a first label allocated by the first downstream node;
• receiving, from the second downstream node, a second RESV message responsive to the third PATH message, the second RESV message including the identifier of the P2MP LSP and a second label allocated by the second downstream node;
• allocating a third label to be used by the upstream node when transmitting packets for the P2MP LSP to the core router;
• mapping the third label with the first label and the second label to enable the core router to replicate packets that are received from the upstream node that are labeled with the third label, send each replicated packet to the first downstream node being labeled with the first label, and send each replicated packet to the second downstream node being labeled with the second label;
• and
• sending a set of one or more third RESV messages to the upstream node responsive to receiving the first RESV message and the second RESV message, wherein the set of third RESV messages each includes the identifier of the P2MP LSP and the third label.