Abstract: In one example, a method includes receiving, by a first network device, a route advertisement message including an attribute for upstream allocation specifying a plurality of next hops of a second network device for reaching a network destination, a plurality of forwarding semantics describing forwarding actions and respective attributes of the plurality of next hops, and a field indicating whether the attribute is provided for downstream allocation or upstream allocation. The method includes in response to determining, by the network device, that the field indicates the attribute is provided for upstream allocation: installing, by the network device and based on the forwarding semantics, next hops, forwarding actions, and the next hop attributes; and applying based on the forwarding information, the forwarding actions to network traffic received by the network device and destined for the network destination when forwarding the network traffic to one or more of the plurality of next hops.

Abstract: In some examples, a method includes selecting, by a first virtual routing node of a single-chassis network device having a plurality of forwarding components and a plurality of fabric links coupling respective pairs of the plurality of forwarding components at respective fabric interfaces of the plurality of forwarding components, a fabric interface of a forwarding component having an egress interface toward a network destination and that is associated with the first virtual routing node; advertising, to the second virtual routing node, the fabric interface as a next hop for the network destination; storing, by the second virtual routing node to a context data structure of the second virtual node, the fabric interface as a next hop for the network destination; selecting the fabric interface from among a plurality of fabric interfaces as a next hop for the network destination; and forwarding network traffic destined for the network destination to the selected fabric interface.

Abstract: In some examples, a method includes selecting, by a first virtual routing node of a single-chassis network device having a plurality of forwarding components and a plurality of fabric links coupling respective pairs of the plurality of forwarding components at respective fabric interfaces of the plurality of forwarding components, a fabric interface of a forwarding component of the plurality of forwarding components that has an egress interface toward a network destination and that is associated with the first virtual routing node; in response to receiving a message specifying the fabric interface, storing, by the second virtual routing node to a context forwarding table of the second virtual node, the fabric interface as a next hop for the network destination; selecting, by the second virtual routing node and based on the context forwarding table and a context next hop in a first forwarding table pointing to the context forwarding table, the fabric interface for forwarding network packets destined for the ne

Abstract: In one example, a management component executing on a single-chassis network device configures a virtual node with an abstract fabric interface having, as a destination address, identifiers of packet processors (e.g., PTFE-IDs) assigned to the virtual node on the other end of the abstract fabric interface. The management component of the single-chassis network device pre-creates an underlay network by using the fabric links at the packet processor. When the management component creates and connects an abstract fabric interface on the virtual nodes, the management component forms an overlay network and attaches the overlay network to the underlay network, e.g., by programming the forwarding plane packet processor, to connect the virtual nodes. However, users of the network device, external devices, and routing protocols will not view the abstract fabric interface as an overlay interface, but as a regular Ethernet interface (e.g.

Abstract: In some examples, a method includes selecting, by a first virtual routing node of a single-chassis network device having a plurality of forwarding components and a plurality of fabric links coupling respective pairs of the plurality of forwarding components at respective fabric interfaces of the plurality of forwarding components, a fabric interface of a forwarding component having an egress interface toward a network destination and that is associated with the first virtual routing node; advertising, to the second virtual routing node, the fabric interface as a next hop for the network destination; storing, by the second virtual routing node to a context data structure of the second virtual node, the fabric interface as a next hop for the network destination; selecting the fabric interface from among a plurality of fabric interfaces as a next hop for the network destination; and forwarding network traffic destined for the network destination to the selected fabric interface.

Abstract: In some examples, a method includes receiving, by a first network device, a private label route message from a second network device, the private label route message specifying a private label as a destination, a route distinguisher of an egress network device for the private label, a context protocol next hop address that identifies a private Multiprotocol Label Switching (MPLS) forwarding layer, and a next hop for the private label, determining, by the first network device and based on the private label route message, a label stack having a plurality of labels to use for forwarding traffic to the next hop for the private label, and storing, in a context forwarding table associated with the private MPLS forwarding layer, a private label destination with the label stack as a next hop for reaching the private label.

Abstract: In some examples, a method includes selecting, by a first virtual routing node of a single-chassis network device having a plurality of forwarding components and a plurality of fabric links coupling respective pairs of the plurality of forwarding components at respective fabric interfaces of the plurality of forwarding components, a fabric interface of a forwarding component of the plurality of forwarding components that has an egress interface toward a network destination and that is associated with the first virtual routing node; in response to receiving a message specifying the fabric interface, storing, by the second virtual routing node to a context forwarding table of the second virtual node, the fabric interface as a next hop for the network destination; selecting, by the second virtual routing node and based on the context forwarding table and a context next hop in a first forwarding table pointing to the context forwarding table, the fabric interface for forwarding network packets destined for the ne

Abstract: In one example, a method includes receiving, by a first network device, a route advertisement message including an attribute for upstream allocation specifying a plurality of next hops of a second network device for reaching a network destination, a plurality of forwarding semantics describing forwarding actions and respective attributes of the plurality of next hops, and a field indicating whether the attribute is provided for downstream allocation or upstream allocation. The method includes in response to determining, by the network device, that the field indicates the attribute is provided for upstream allocation: installing, by the network device and based on the forwarding semantics, next hops, forwarding actions, and the next hop attributes; and applying based on the forwarding information, the forwarding actions to network traffic received by the network device and destined for the network destination when forwarding the network traffic to one or more of the plurality of next hops.

Abstract: In some examples, a method includes selecting, by a first virtual routing node of a single-chassis network device having a plurality of forwarding components and a plurality of fabric links coupling respective pairs of the plurality of forwarding components at respective fabric interfaces of the plurality of forwarding components, a fabric interface of a forwarding component of the plurality of forwarding components that has an egress interface toward a network destination and that is associated with the first virtual routing node; advertising, to the second virtual routing node, the fabric interface as a next hop for the network destination and a label for use in establishing a transport label switched path (LSP); and computing, by the second virtual routing node, a path for the transport LSP to include the fabric interface, and establishing the transport LSP along the computed path.

Abstract: The disclosed method may include (1) identifying a customer edge router that is multi-homed to a provider edge router and another provider edge router, (2) determining, by the provider edge router, that the other provider edge router has identified an Internet Protocol address of the customer edge router by way of an Address Resolution Protocol, (3) learning, by the provider edge router, the Internet Protocol address of the customer edge router from the other provider edge router, and then (4) advertising, by the provider edge router to at least one gateway of at least one other customer edge router, a route that facilitates communication with the customer edge router via the provider edge router based at least in part on the Internet Protocol address of the customer edge router. Various other methods, systems, and apparatuses are also disclosed.

Abstract: A device may receive a set of border gateway protocol labels via a set of corresponding border gateway protocol messages. A border gateway protocol label, of the set of border gateway protocol labels, may be associated with a label descriptor attribute. The label descriptor attribute being associated with providing information regarding a forwarding semantic associated with the border gateway protocol label. The device may select the border gateway protocol label for routing network traffic toward a network device associated with the border gateway protocol label based on the label descriptor attribute. The device may route the network traffic toward the network device based on the border gateway protocol label and after selecting the border gateway protocol label.

Abstract: A device may receive a set of border gateway protocol labels via a set of corresponding border gateway protocol messages. A border gateway protocol label, of the set of border gateway protocol labels, may be associated with a label descriptor attribute. The label descriptor attribute being associated with providing information regarding a forwarding semantic associated with the border gateway protocol label. The device may select the border gateway protocol label for routing network traffic toward a network device associated with the border gateway protocol label based on the label descriptor attribute. The device may route the network traffic toward the network device based on the border gateway protocol label and after selecting the border gateway protocol label.

Abstract: In one example, an autonomous system boundary router (ASBR) forms part of a first autonomous system (AS). The ASBR is between a first provider edge (PE) router of the first AS and a second PE router of a second, different AS. The first PE router and the second PE router form a Multiprotocol Label Switching (MPLS) path. The ASBR includes an interface communicatively coupled to a routing device external to the first AS, a memory configured to store a forwarding table associated with the interface, and one or more processing units configured to receive a packet via the interface, determine that the packet is encapsulated by an MPLS label, select a forwarding table based on the interface by which the packet was received, and forward the packet according to forwarding information of the forwarding table when the forwarding table includes the MPLS label.

Abstract: A high-performance, scalable data center switch fabric and infrastructure is described that provides a clean separation between of routing and forwarding information between a transport layer of the data center and a service layer of data center that includes the endpoint devices, such as virtual or physical machines deployed within the data center. For example, techniques are described that enable the automatic creation of a transport hierarchy of label switched paths (LSPs) across the transport layer of the data center. For example, the techniques may be applied with the Border Gateway Protocol (BGP) labeled unicast (LU) in a manner that constructs a hierarchy of LPSs in the transport layer of the data center.

Abstract: In one example, an autonomous system boundary router (ASBR) forms part of a first autonomous system (AS). The ASBR is between a first provider edge (PE) router of the first AS and a second PE router of a second, different AS. The first PE router and the second PE router form a Multiprotocol Label Switching (MPLS) path. The ASBR includes an interface communicatively coupled to a routing device external to the first AS, a memory configured to store a forwarding table associated with the interface, and one or more processing units configured to receive a packet via the interface, determine that the packet is encapsulated by an MPLS label, select a forwarding table based on the interface by which the packet was received, and forward the packet according to forwarding information of the forwarding table when the forwarding table includes the MPLS label.

Abstract: A device may receive a set of border gateway protocol labels via a set of corresponding border gateway protocol messages. A border gateway protocol label, of the set of border gateway protocol labels, may be associated with a label descriptor attribute. The label descriptor attribute being associated with providing information regarding a forwarding semantic associated with the border gateway protocol label. The device may select the border gateway protocol label for routing network traffic toward a network device associated with the border gateway protocol label based on the label descriptor attribute. The device may route the network traffic toward the network device based on the border gateway protocol label and after selecting the border gateway protocol label.

Abstract: This disclosure describes techniques to reduce traffic loss for a Border Gateway Protocol (BGP) session by delaying re-advertisement of routes received from a newly re-established multi-homed router by a primary router until all the routes are installed in a forwarding plane of the primary router. The techniques of this disclosure make use of a BGP marker received from the multi-homed router that indicates the end of a route download for an address family. Upon receiving the BGP marker, a control plane of the primary router requests a route acknowledgement message (Route-ACK) from the forwarding plane for only the last route of the address family received before the BGP marker. When the control plane receives the Route-ACK indicating that the last route has been installed in the forwarding plane, the primary router initiates re-advertisement of the routes to other BGP peer routers.

Abstract: In general, techniques are described that provide a modular software architecture for a route server within an Internet Exchange. The route server comprises an interface and a control unit. The interface receives a route advertisement advertising a route from one of the SP networks and defining attributes for the route. The control unit includes inbound, route and outbound processing modules to process the route advertisement. The inbound processing module updates the route advertisement to add an optional field that stores a copy of the attributes. The route processing module produces an outbound route advertisement that includes attributes of the Internet Exchange and, within the optional field, the original path attributes. The outbound processing module processes the outbound route advertisement to replace the attributes of the Internet Exchange with the original path attributes and outputs the outbound route advertisement to advertise the route to the SP networks.

Abstract: This disclosure describes techniques to reduce traffic loss for a Border Gateway Protocol (BGP) session by delaying re-advertisement of routes received from a newly re-established multi-homed router by a primary router until all the routes are installed in a forwarding plane of the primary router. The techniques of this disclosure make use of a BGP marker received from the multi-homed router that indicates the end of a route download for an address family. Upon receiving the BGP marker, a control plane of the primary router requests a route acknowledgement message (Route-ACK) from the forwarding plane for only the last route of the address family received before the BGP marker. When the control plane receives the Route-ACK indicating that the last route has been installed in the forwarding plane, the primary router initiates re-advertisement of the routes to other BGP peer routers.