Abstract: In general, the disclosure relates to techniques for initiating a targeted LDP session in a manner that includes information specifying one or more application for which a targeted LDP session is being initiated. In one example, a method includes receiving, by a network device, a LDP initialization message to initiate an Label Distribution Protocol (LDP) session with a peer network device, the LDP initialization message including a Targeted Applications Capability (TAC) field specifying one or more applications for which the LDP session is to be used for advertising forwarding equivalence class (FEC)-label bindings between the network device and the peer network device, and determining, by the network device, whether to allow the LDP session to be established based on the one or more applications specified in the TAC field.

Abstract: In general, the disclosure relates to techniques for initiating a targeted LDP session in a manner that includes information specifying one or more application for which a targeted LDP session is being initiated. In one example, a method includes receiving, by a network device, a LDP initialization message to initiate an Label Distribution Protocol (LDP) session with a peer network device, the LDP initialization message including a Targeted Applications Capability (TAC) field specifying one or more applications for which the LDP session is to be used for advertising forwarding equivalence class (FEC)-label bindings between the network device and the peer network device, and determining, by the network device, whether to allow the LDP session to be established based on the one or more applications specified in the TAC field.

Abstract: Techniques are described for providing fast reroute intra-area node protection for label switched paths (LSPs) using label distribution protocol (LDP). In one example, a network device may be configured to use network topology information, obtained by an Interior Gateway Protocol (IGP) executing on the network device, to identify a next next hop merge point to which to automatically establish a bypass LSP, and to which to establish a targeted LDP session for obtaining a label advertised by the next next hop merge point.

Abstract: Techniques are described for providing fast reroute inter-area node protection for label switched paths (LSPs) using label distribution protocol (LDP). In one example, a network device may be configured to determine that a protected node is an area border router, and use network topology information, obtained by an Interior Gateway Protocol (IGP) executing on the network device, to identify a second area border router in the same IGP area as the protected node, to which to automatically establish a bypass LSP and a targeted LDP session.

Abstract: Label Distribution Protocol (LDP) extensions are described that enable distribution of neighbor-label mappings for directly connected neighbor routers. A router capable of supporting the LDP extensions distributes neighbor-labels to be used by the router to label switch traffic destined for the directly connected neighbor router irrespective of a hop-by-hop Interior Gateway Protocol (IGP) path determined based on link metrics. In some examples, the neighbor-labels may increase backup coverage, e.g., link protection and/or node protection, in a network that, due to link metrics, does not have a viable loop-free alternate (LFA) path between an ingress router and an egress router of a label switched path (LSP). In other examples, the neighbor-labels may improve load balancing by enabling an ingress router in a first autonomous system (AS) to select a particular remote link on which to send traffic destined for remote routers in a second AS.

Abstract: The techniques of this disclosure provide local protection for network traffic in multipoint label switched paths (LSPs) due to link or node failure using loop-free alternate (LFA) next hops. The techniques include establishing a vanilla or point-to-point (P2P) LSP with LFA next hops between routers of a multipoint LSP for use in the event of link or node failure in the multipoint LSP. Upon a failure, the multicast traffic is tunneled between the routers using the P2P LSP with LFA to an alternate next hop with an associated label stack. The techniques of this disclosure define the label stack as including a P2P LSP label as well as a multipoint LSP label. In this way, the P2P LSP with LFA may be used for fast reroute (FRR) of traffic in the multipoint LSP until a convergence process completes for a new multipoint branch of the multipoint LSP.

Abstract: Label Distribution Protocol (LDP) extensions are described that enable distribution of neighbor-label mappings for directly connected neighbor routers. A router capable of supporting the LDP extensions distributes neighbor-labels to be used by the router to label switch traffic destined for the directly connected neighbor router irrespective of a hop-by-hop Interior Gateway Protocol (IGP) path determined based on link metrics. In some examples, the neighbor-labels may increase backup coverage, e.g., link protection and/or node protection, in a network that, due to link metrics, does not have a viable loop-free alternate (LFA) path between an ingress router and an egress router of a label switched path (LSP). In other examples, the neighbor-labels may improve load balancing by enabling an ingress router in a first autonomous system (AS) to select a particular remote link on which to send traffic destined for remote routers in a second AS.

Abstract: The techniques of this disclosure provide local protection for network traffic in multipoint label switched paths (LSPs) due to link or node failure using loop-free alternate (LFA) next hops. The techniques include establishing a vanilla or point-to-point (P2P) LSP with LFA next hops between routers of a multipoint LSP for use in the event of link or node failure in the multipoint LSP. Upon a failure, the multicast traffic is tunneled between the routers using the P2P LSP with LFA to an alternate next hop with an associated label stack. The techniques of this disclosure define the label stack as including a P2P LSP label as well as a multipoint LSP label. In this way, the P2P LSP with LFA may be used for fast reroute (FRR) of traffic in the multipoint LSP until a convergence process completes for a new multipoint branch of the multipoint LSP.