Abstract: A switch that can report unavailability in a label-switched network is provided. During operation, the switch can determine that a label-switched path is unavailable for forwarding a packet. The switch can then generate a notification message for collecting unavailability information at a respective upstream hop of the label-switched path. The notification message includes a depth indicator indicating the depth of collected unavailability information and an ingress label of the packet at the switch. If the switch is an intermediate switch on the label-switched path, the switch can forward the notification message to an upstream switch on the label-switched path, thereby allowing the upstream switch to collect further unavailability information in the notification message.

Abstract: A system related to black hole filtering is provided. The system can allow a dynamic routing protocol on a network device to determine whether a route learned by the dynamic routing protocol is a black hole route. The route may be learned through another source. In response to a determination that the route is the black hole route, the dynamic routing protocol may generate a routing update that indicates the route as the black hole route. The dynamic routing protocol may then advertise the routing update to each neighbor network device.

Abstract: Examples include determining a first hop for a preferred route from a networking device to a destination device, calculating a cumulative cost for the preferred route based on a cost of the first hop and an original cost of the preferred route, determining whether a secondary route is available, and, in response to a determination that the secondary route is available, determining a first hop in the secondary route. Examples also include determining a cost of the first hop in the secondary route, determining a new route from the networking device to the destination computing device based on the cumulative cost of the preferred route and the cost of the first hop in the secondary route, and entering the new route into a forwarding data structure of the networking device.

Abstract: A switch that can report unavailability in a label-switched network is provided. During operation, the switch can determine that a label-switched path is unavailable for forwarding a packet. The switch can then generate a notification message for collecting unavailability information at a respective upstream hop of the label-switched path. The notification message includes a depth indicator indicating the depth of collected unavailability information and an ingress label of the packet at the switch. If the switch is an intermediate switch on the label-switched path, the switch can forward the notification message to an upstream switch on the label-switched path, thereby allowing the upstream switch to collect further unavailability information in the notification message.

Abstract: Examples disclosed herein relate to a method comprising receiving, at a first label manager of a first network device, a first request to allocate a first label for a first route prefix for a first protocol, wherein the first network device and a second network device are part of a virtualized network device. The method includes receiving, at a second label manager of the second network device, a second request to determine the first label for the first route prefix for the first protocol, wherein the second request originates from the first label manager and determining, at the second label manager, the first label for the first route prefix for the first protocol. The method includes transmitting, the first label to the first label manager and transmitting, by the first label manager, the first label to a label management protocol corresponding to the first protocol, in response to the first request.

Abstract: A system and a method for eliminating data loss in a virtually aggregated network are described. A first network device may identify inactivity of a central network device present in a communication network. The central network device is responsible for distributing routing information between a plurality of network devices including the first network device. The first network device delays network route calculations until a second network device is elected from the plurality of network devices to perform functions of the central network device. The second network device generates link state information related to the plurality of network devices, and shares the link state information with the plurality of network devices. Upon receiving the link state information, the plurality of network device may resume the route calculations.

Abstract: A method for use in a network, including: receiving network traffic at a redundant gateway device established according to a redundant gateway protocol; forwarding known unicast traffic received at the redundant gateway device from the redundant gateway device to a tunnel endpoint through a tunnel established according to a tunneling protocol; forwarding broadcast, unknown unicast, and multicast traffic to the tunnel endpoint through the tunnel if the redundant gateway device is a master gateway under the redundant gateway protocol; and dropping the broadcast, unknown unicast, and multicast traffic if the redundant gateway device is a backup gateway under the redundant gateway protocol.

Abstract: Examples disclosed herein relate to a method comprising receiving, at a first switch, a bidirectional forwarding detection packet, wherein the first switch and a second switch are part of a virtualized switch and each switch in the virtualized switch has a same Media Access Control (MAC) address, determining, at the first switch, that a destination MAC address included in the bidirectional forwarding detection packet is not owned by the first switch, determining, at the first switch, that the destination MAC address is owned by the second switch and bridging, from the first switch, the bidirectional forwarding detection packet to the second switch that owns the MAC address.

Abstract: Examples disclosed herein relate to a method comprising receiving, at a first label manager of a first network device, a first request to allocate a first label for a first route prefix for a first protocol, wherein the first network device and a second network device are part of a virtualized network device. The method includes receiving, at a second label manager of the second network device, a second request to determine the first label for the first route prefix for the first protocol, wherein the second request originates from the first label manager and determining, at the second label manager, the first label for the first route prefix for the first protocol. The method includes transmitting, the first label to the first label manager and transmitting, by the first label manager, the first label to a label management protocol corresponding to the first protocol, in response to the first request.

Abstract: In some examples, a first router establishes a fault detection session between the first router connected to a routing area and an outside router assigned a forwarding address, the outside router located outside the routing area, and the forwarding address used by a second router of the routing area to send a data packet to the outside router. The first router detects, in the fault detection session, a fault associated with the outside router, and in response to detecting the fault associated with the outside router in the fault detection session, provides an indication to the routing area that the forwarding address is no longer accessible.

Abstract: Examples include determining a first hop for a preferred route from a networking device to a destination device, calculating a cumulative cost for the preferred route based on a cost of the first hop and an original cost of the preferred route, determining whether a secondary route is available, and, in response to a determination that the secondary route is available, determining a first hop in the secondary route. Examples also include determining a cost of the first hop in the secondary route, determining a new route from the networking device to the destination computing device based on the cumulative cost of the preferred route and the cost of the first hop in the secondary route, and entering the new route into a forwarding data structure of the networking device.

Abstract: A method for use in a network, including: receiving network traffic at a redundant gateway device established according to a redundant gateway protocol; forwarding known unicast traffic received at the redundant gateway device from the redundant gateway device to a tunnel endpoint through a tunnel established according to a tunneling protocol; forwarding broadcast, unknown unicast, and multicast traffic to the tunnel endpoint through the tunnel if the redundant gateway device is a master gateway under the redundant gateway protocol; and dropping the broadcast, unknown unicast, and multicast traffic if the redundant gateway device is a backup gateway under the redundant gateway protocol.

Abstract: Examples disclosed herein relate to a method comprising receiving, at a first switch, a bidirectional forwarding detection packet, wherein the first switch and a second switch are part of a virtualized switch and each switch in the virtualized switch has a same Media Access Control (MAC) address, determining, at the first switch, that a destination MAC address included in the bidirectional forwarding detection packet is not owned by the first switch, determining, at the first switch, that the destination MAC address is owned by the second switch and bridging, from the first switch, the bidirectional forwarding detection packet to the second switch that owns the MAC address.

Abstract: In some examples, a first router establishes a fault detection session between the first router connected to a routing area and an outside router assigned a forwarding address, the outside router located outside the routing area, and the forwarding address used by a second router of the routing area to send a data packet to the outside router. The first router detects, in the fault detection session, a fault associated with the outside router, and in response to detecting the fault associated with the outside router in the fault detection session, provides an indication to the routing area that the forwarding address is no longer accessible.

Abstract: Examples disclosed herein relate to black hole filtering. In an example, a dynamic routing protocol on a network device may determine whether a route learned by the dynamic routing protocol is a black hole route. In an example, the route may be learned through another source. In response to a determination that the route learned by the dynamic routing protocol is the black hole route, the dynamic routing protocol may generate a routing update that indicates the route as the black hole route. The dynamic routing protocol may then advertise the routing update to each neighbor network device.

Abstract: Examples disclosed herein relate to a grace link state advertisement (LSA) from a virtual stack device. In an example, a first member network device of a virtual stack device may an input from a Multi-Active Detection (MAD) device. The virtual stack device may be a logical network device comprising the first member network device and a second member network device. Based on the input from the MAD device, the first member network device may determine whether a grace link state advertisement (LSA) is to be sent to a neighbor Open Shortest Path First (OSPF) enabled router by the first member network device, wherein the neighbor OSPF enabled router is an OSPF neighbor to the virtual stack device.

Abstract: In some examples, a first router includes a communication interface to communicate over a network, and a processor to participate in an election process to determine, based on respective priorities assigned to a plurality of routers including the first router, which of the plurality of routers is an elected router responsible for distributing routing information to another router, and in response to the first router being selected as the elected router in the election process, adjust a priority of the first router for a subsequent election process.

Abstract: Examples disclosed herein relate to reducing flooding of route updates of a dynamic routing protocol. In an example, number of route updates received by a router from each neighbor router may be determined, wherein the router may be present in a network using a dynamic routing protocol. Each neighbor router may be classified into one of a plurality of groups of neighbor routers in such a manner that number of route updates originating from each group of neighbor routers is approximately same. A first route update interval may be determined for each group of neighbor routers for sending a respective first set of future route updates therefrom to the router. The respective first route update interval for sending the respective first set of future route updates may be notified to the respective member routers of each group of neighbor routers.

Abstract: Examples disclosed herein relate to a grace link state advertisement (LSA) from a virtual stack device. In an example, a first member network device of a virtual stack device may an input from a Multi-Active Detection (MAD) device. The virtual stack device may be a logical network device comprising the first member network device and a second member network device. Based on the input from the MAD device, the first member network device may determine whether a grace link state advertisement (LSA) is to be sent to a neighbor Open Shortest Path First (OSPF) enabled router by the first member network device, wherein the neighbor OSPF enabled router is an OSPF neighbor to the virtual stack device.

Abstract: Examples disclosed herein relate to reducing flooding of route updates of a dynamic routing protocol. In an example, number of route updates received by a router from each neighbor router may be determined, wherein the router may be present in a network using a dynamic routing protocol. Each neighbor router may be classified into one of a plurality of groups of neighbor routers in such a manner that number of route updates originating from each group of neighbor routers is approximately same. A first route update interval may be determined for each group of neighbor routers for sending a respective first set of future route updates therefrom to the router. The respective first route update interval for sending the respective first set of future route updates may be notified to the respective member routers of each group of neighbor routers.