Abstract: In one example, a merge point network device (MP) receives a plurality of resource reservation request messages for establishing a plurality of label switched paths (LSPs), wherein each of the plurality of LSPs has a common point of local repair network device (PLR) and has the MP as a common MP, wherein each of the resource reservation request messages identifies a common bypass tunnel that extends between the PLR and the MP and avoids a protected resource. The MP stores an association between the bypass tunnel and each of the plurality of LSPs. The MP receives a single message to trigger creation at the merge point network device of backup LSP state information for all of the plurality of LSPs. In response to receiving the single message, the MP installs state information for all of the LSPs that correspond to the bypass tunnel according to the stored association.

Abstract: Techniques are described for reusing downstream-assigned labels when establishing a new instance of a label switched path (LSP) prior to tearing down an existing instance of the LSP using make-before-break (MBB) procedures for RSVP. The techniques enable a routing engine of any non-ingress router along a path of the new LSP instance to reuse a previously allocated label for the existing LSP instance as the downstream assigned label for the new LSP instance when the paths of the existing LSP instance and the new LSP instance overlap. In this way, the non-ingress router does not need to update a label route in its forwarding plane for the reused label. When the new LSP instance completely overlaps the existing LSP instance, an ingress router of the LSP may avoid updating an ingress route in its forwarding plane for applications that use the LSP.

Abstract: A device may identify a portion of a label-switched path (LSP) on which a simple hierarchical LSP (sH-LSP) is to be used for transferring traffic via a network. The device may determine attribute information associated with the sH-LSP. The attribute information may include information associated with one or more characteristics of the sH-LSP. The device may provide an indication associated with identifying an available sH-LSP or creating a sH-LSP. The indication may include, the attribute information associated with the sH-LSP, and may be being provided to cause the sH-LSP to be created on the portion of the LSP or an available sH-LSP, associated with the portion of the LSP, to be identified. The device may receive, based on providing the indication, an identifier associated with the sH-LSP. The device may cause the LSP to be set up based on the identifier associated with the sH-LSP.

Abstract: In general, techniques described are for bandwidth sharing between resource reservation protocol label switched paths (LSPs) and non-resource reservation protocol LSPs. For example, in networks where resource reservation protocol LSPs and non-resource reservation protocol LSPs co-exist within the same domain, resource reservation protocol LSPs and non-resource reservation protocol LSPs may share link bandwidth. However, when non-resource reservation protocol LSPs are provisioned, resource reservation protocol path computation elements computing resource reservation protocol paths may not account for non-resource reservation protocol LSP bandwidth utilization. The techniques described herein provide a mechanism for automatically updating traffic engineering database (TED) information about resource reservation protocol LSPs in a way that accounts for non-resource reservation protocol LSP traffic flow statistics, such as bandwidth utilization.

Abstract: Techniques are described for reusing downstream-assigned labels when establishing a new instance of a label switched path (LSP) prior to tearing down an existing instance of the LSP using make-before-break (MBB) procedures for RSVP. The techniques enable a routing engine of any non-ingress router along a path of the new LSP instance to reuse a previously allocated label for the existing LSP instance as the downstream assigned label for the new LSP instance when the paths of the existing LSP instance and the new LSP instance overlap. In this way, the non-ingress router does not need to update a label route in its forwarding plane for the reused label. When the new LSP instance completely overlaps the existing LSP instance, an ingress router of the LSP may avoid updating an ingress route in its forwarding plane for applications that use the LSP.

Abstract: Techniques are described for establishing a second label switched path (LSP) instance of an LSP having a first LSP instance. In one example, for each downstream router designated for the second LSP instance of the LSP, the router determines whether the router is part of the first instance of the LSP and, if so, whether the first and second LSP instances for that downstream router share a common link to a nexthop router. If the first and second LSP instances share a common link to a nexthop router, the downstream router transmits a first message to the nexthop router, wherein the first message includes a suggested label. The downstream router receives, from the nexthop router, a second message, wherein the second message includes the suggested label. In another example, a label reuse indicator flag in a message from the ingress router causes routers on the second LSP instance to reuse the label of the first LSP instance when the same link is used to the upstream router for both LSP instances.

Abstract: A device may identify a portion of a label-switched path (LSP) on which a simple hierarchical LSP (sH-LSP) is to be used for transferring traffic via a network. The device may determine attribute information associated with the sH-LSP. The attribute information may include information associated with one or more characteristics of the sH-LSP. The device may provide an indication associated with identifying an available sH-LSP or creating a sH-LSP. The indication may include the attribute information associated with the sH-LSP, and may be being provided to cause the sH-LSP to be created on the portion of the LSP or an available sH-LSP, associated with the portion of the LSP, to be identified. The device may receive, based on providing the indication, an identifier associated with the sH-LSP. The device may cause the LSP to be set up based on the identifier associated with the sH-LSP.

Abstract: In some examples, a network device of a network comprises a first component configured to store a plurality of next hop instructions corresponding to respective logical or physical network structures of the network. The network device also comprises a second component configured to send, to the first component, a message that identifies an association of the plurality of next hop instructions, wherein the first component is further configured to modify, in response to receiving the message, each of the plurality of next hop instructions.

Abstract: Techniques are described for providing fast re-route (FRR) node and/or link protection along a primary label switched path (LSP) using generic routing encapsulation (GRE) over multi-protocol label switching (MPLS). An ingress edge router of a primary LSP is configured to encapsulate incoming packets into GRE with a destination address of an egress edge router of the primary LSP, and push a primary label onto the encapsulated packet for forwarding along the primary LSP. Upon a failover to a bypass LSP, a point of local repair (PLR) router swaps the primary label on the encapsulated packet with a bypass label. A merge point (MP) router then receives the encapsulated packet via the bypass LSP, and performs a lookup using the destination address of the egress edge router included on the encapsulated packet in order to determine a primary label for forwarding the encapsulated packet along the primary LSP.

Abstract: A device may identify a portion of a label-switched path (LSP) on which a simple hierarchical LSP (sH-LSP) is to be used for transferring traffic via a network. The device may determine attribute information associated with the sH-LSP. The attribute information may include information associated with one or more characteristics of the sH-LSP. The device may provide an indication associated with identifying an available sH-LSP or creating a sH-LSP. The indication may include the attribute information associated with the sH-LSP, and may be being provided to cause the sH-LSP to be created on the portion of the LSP or an available sH-LSP, associated with the portion of the LSP, to be identified. The device may receive, based on providing the indication, an identifier associated with the sH-LSP. The device may cause the LSP to be set up based on the identifier associated with the sH-LSP.

Abstract: In general, techniques are described for configuration of label switched paths in multi-protocol label switched networks. A router comprising a control unit and an interface may be configured to perform the techniques. The control unit may determine a label to bind to the LSP. The interface may transmit a message specifying the label that has been bound to the LSP prior to confirming that the LSP has been successfully configured within the support router to use the bound label.

Abstract: Techniques include providing ingress protection for multipoint label switched paths (LSPs). According to the techniques, a primary ingress node and a backup ingress node of a network are both configured to advertise a virtual node identifier of a virtual node as a next hop for a multicast source. Two or more egress nodes of the network then use the virtual node as a root node reachable through the primary ingress node to establish a multipoint LSP. After the multipoint LSP is established, the primary ingress node forwards traffic of the multicast source on the multipoint LSP. When failure occurs at the primary ingress node, the backup ingress node forwards the traffic of the multicast source along a backup path and onto the same multipoint LSP with the virtual node as the root node reachable through the backup ingress node. The techniques enable ingress protection without tearing down the multipoint LSP.

Abstract: In general, techniques are described for a path computation delay timer for multi-protocol label switched networks. As an example, an ingress network device configured to act as an ingress for a label switched path (LSP) may perform the techniques. The ingress network device comprises an interface and a processor. The interface may receive a message indicating an error along the LSP. The processor may delay an operation performed to configure a replacement LSP to be used in place of the LSP in order to provide time during which a cause of the error along the LSP is able to be determined. When the cause of the error is determined to be a failure of a network device supporting operation of the LSP, the processor may further perform the operation to configure the replacement LSP with the ingress network device such that the replacement LSP avoids the failed network device.

Abstract: Techniques are described for generating a No-Acknowledgement (NACK) message if the installation of a route for a label-switched path at a router has failed or is likely to fail. In some examples, a network device includes at least one processor and at least one module operable by the at least one processor to: receive a request to forward network packets for an LSP; responsive to receiving the request, initiate configuration of at least one forwarding unit of the network device to forward network packets for the LSP; generate a NACK message that indicates the at least one forwarding unit is not configured to forward the network packets for the LSP; and terminate based at least in part on the NACK message, the configuration of the at least one forwarding unit for the LSP.

Abstract: An apparatus may include a processor and a control plane that directs the processor to (1) detect that at least a portion of an initial branch path of a point-to-multipoint label-switched path has failed over to a failover route that rejoins the initial branch path at a network node and (2) establish an alternate branch path that merges with the initial branch path at the network node. The apparatus may also include a network interface and a data plane that uses the network interface to transmit data via the alternate branch path, where after the data plane begins transmitting data via the alternate branch path, the control plane instructs the network node to forward data from the alternate branch path rather than from the failover route. Various other apparatuses, systems, and methods are also disclosed.

Abstract: Techniques are described for specifying and constructing multi-protocol label switching (MPLS) rings. Routers may signal membership within MPLS rings and automatically establish ring-based label switch paths (LSPs) as components of the MPLS rings for packet transport within ring networks. In one example, a router includes a processor configured to output Label Distribution Protocol (LDP) messages, as described herein, to establish an MPLS ring having a plurality of ring LSPs. Each of the ring LSPs is configured to transport MPLS packets around the ring network to a different one of the routers operating as an egress router for the respective ring LSP. Moreover, each of the ring LSPs comprises two counter-rotating multipoint-to-point (MP2P) LSPs for which any of the routers can operate as an ingress to source packet traffic into the ring LSP for transport to the respective egress router for the ring LSP.

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: Network traffic is sent via alternate paths in cases of network link or node failure. An alternate node responds to U-Turn traffic from a primary neighbor to select a further alternate. An algorithm for determining the alternate paths is provided to select loop-free neighbors.