Abstract: A transport LAN segment service is provided over a transport network. Responsibilities for configuring, provisioning and forwarding over a transport LAN segment are divided between layer 2 and 3 service provider edge devices, where the layer 3 edge device handles discovery and tunneling responsibilities, the layer 2 edge device handles learning and flooding responsibilities, and information can be exchanged between the layer 2 and 3 edge devices. Configuration is simplified by advertising TLS-label information, layer 2 address learning, and flooding when the needed configuration information has not yet been learned or discovered.

Abstract: A router maintains routing information including (i) route data representing destinations within a computer network, (ii) next hop data representing interfaces to neighboring network devices, and (iii) indirect next hop data that maps a subset of the routes represented by the route data to a common one of the next hop data elements. In this manner, routing information is structured such that routes having the same next hop use indirect next hop data structures to reference common next hop data. In particular, in response to a change in network topology, the router need not change all of the affected routes, but only the common next hop data referenced by the intermediate data structures. This provides for increased efficiency in updating routing information after a change in network topology, such as link failure.

Abstract: A method performed by a network device may include assembling a multiprotocol label switching (MPLS) echo request, the echo request including an instruction for a transit node to forward the echo request via a bypass path associated with the transit node, and an instruction for an egress node to send an echo reply indicating that the echo request was received on the bypass path. The method may also include sending the MPLS echo request over a functioning label switched path (LSP).

Abstract: A network device receives a packet with a multicast nexthop identifier, and creates a mask that includes addresses of egress packet forwarding engines, of the network device, to which to provide the packet. The network device divides the mask into two portions, generates two copies of the packet, provides a first portion of the mask in a first copy of the packet, and provides a second portion of the mask in a second copy of the packet. The network device also forwards the first copy of the packet to an address of a first egress packet forwarding engine provided in the first portion of the mask, and forwards the second copy of the packet to an address of a second egress packet forwarding engine provided in the second portion of the mask.

Abstract: In general, techniques are described for packet queuing within ring networks. In accordance with the techniques, a network device of a ring network comprises a memory having a different queue for each order-dependent pair of the network devices. Each pair represents a different order-dependent combination of the network devices that includes an ingress network device that provides an ingress to the ring network and an egress network device that provides an egress from the ring network. The network device further comprises an interface for receiving a packet from a neighboring one of the plurality of network devices and a control unit that, in response to receiving the packet, stores the packet to one of the queues based on which network devices is the ingress and which network device is the egress for the packet. The control unit forwards the stored packet via the ring network according to a scheduling algorithm.

Abstract: A method performed by a network device may include assembling a multiprotocol label switching (MPLS) echo request, the echo request including an instruction for a transit node to forward the echo request via a bypass path associated with the transit node, and an instruction for an egress node to send an echo reply indicating that the echo request was received on the bypass path. The method may also include sending the MPLS echo request over a functioning label switched path (LSP).

Abstract: Techniques are described for verifying a status of a set of paths through a computer network for two or more connectivity protocols. For example, a node uses a first connectivity protocol to concurrently learn information that will cause packets conforming to the first connectivity protocol and packet conforming to a second connectivity protocol to traverse a set of paths through a computer network. After learning this information, the node may verify a status of each of the paths using the first connectivity protocol. In addition, the node may verify a status of each of the paths using the second connectivity protocol. By verifying the status of the paths using both the first and the second connectivity protocols, the node may be able to quickly and accurately determine whether a path has failed.

Abstract: Routers balance network traffic among multiple paths through a network according to an amount of bandwidth that can be sent on an outgoing interface computed for each of the paths. For example, a router receives a link bandwidth for network links that are positioned between the first router and a second router of the network, and selects a plurality of forwarding paths from the first router to the second router. Upon determining that one of the network links is shared by multiple of the plurality of forwarding paths, the router computes a path bandwidth for each of the plurality of outgoing interfaces so as to account for splitting of link bandwidth of the shared network link across the multiple forwarding paths that share the network link. The router assigns packet flows to the forwarding paths based at least on the computed amount of bandwidth for each of the outgoing interfaces.

Abstract: A method and apparatus for switching a data packet between a source and destination in a network. The data packet includes a header portion and a data portion. The header portion includes routing information for the data packet. The method includes defining a data path in the router comprising a path through the router along which the data portion of the data packet travels and defining a control path comprising a path through the router along which routing information from the header portion travels. The method includes separating the data path and control path in the router such that the routing information can be separated from the data portion allowing for the separate processing of each in the router. The data portion can be stored in a global memory while routing decisions are made on the routing information in the control path.

Abstract: A transport LAN segment service is provided over a transport network. Responsibilities for configuring, provisioning and forwarding over a transport LAN segment are divided between layer 2 and 3 service provider edge devices, where the layer 3 edge device handles discovery and tunneling responsibilities, the layer 2 edge device handles learning and flooding responsibilities, and information can be exchanged between the layer 2 and 3 edge devices. Configuration is simplified by advertising TLS-label information, layer 2 address learning, and flooding when the needed configuration information has not yet been learned or discovered.

Abstract: A layer 2 transport network, and components thereof, supporting virtual network functionality among customer edge devices. Virtual private network configuration can be accomplished with merely local intervention by preprovisioning extra channel (or circuit) identifiers at each customer edge device and by advertising label base and range information corresponding to a list of channel (or circuit) identifiers.

Abstract: A method and a network device for enabling communication between unnumbered interfaces are provided. A device level address may be assigned to a network device. The network device may announce the assigned device level address to a neighboring network device over a link. A corresponding device level address associated with the neighboring network device may be received over the link. A route may be stored including the received device level address associated with the neighboring network device and the link. In some implementations, the announcement of the assigned device level address is performed during protocol configuration.

Abstract: An access network is described in which a centralized controller provides seamless end-to-end service from a core-facing edge of a service provider network through aggregation and access infrastructure out to access nodes located proximate to the subscriber devices. The controller operates to provide a central configuration point for configuring aggregation nodes (AGs) of a network of the service provider so as to provide transport services to transport traffic between access nodes (AXs) and edge routers on opposite borders of the network.

Abstract: When a node has to restart its control component, or a (e.g., label-switched path signaling) part of its control component, if that node can preserve its forwarding information across the restart, the effects of such restarts on label switched path(s) include the restarting node are minimized. A node's ability to preserve forwarding information across a control component (part) restart is advertised. In the event of a restart, stale forwarding information can be used for a limited time before. The restarting node can use its forwarding information, as well as received label-path advertisements, to determine which of its labels should be associated with the path, for advertisement to its peers.

Abstract: A transport LAN segment service is provided over a transport network. Responsibilities for configuring, provisioning and forwarding over a transport LAN segment are divided between layer 2 and 3 service provider edge devices, where the layer 3 edge device handles discovery and tunneling responsibilities, the layer 2 edge device handles learning and flooding responsibilities, and information can be exchanged between the layer 2 and 3 edge devices. Configuration is simplified by advertising TLS-label information, layer 2 address learning, and flooding when the needed configuration information has not yet been learned or discovered.

Abstract: A network device includes a hybrid switch fabric configured for switching packets and circuits that includes a packet switching portion that distributes packets across a plurality of packet ports of fabric chips within the hybrid switch fabric and operates in accordance with packet switching behavior requirements, and a circuit switching portion for switching circuits, wherein the circuit switching portion of the hybrid switch fabric directly connects a single input of the hybrid switch fabric to a single output of the hybrid switch fabric via a pre-determined path through the fabric chips and operates in accordance with circuit switching behavior requirements. The packet switching portion and the circuit switching portion include one or more fabric chips, wherein the fabric chips each include a plurality of ports each dynamically configurable as one of a packet port for receiving and outputting packet-switched data and a circuit port for receiving and outputting circuit-switched data.

Abstract: A method and apparatus for switching a data packet between a source and destination in a network. The data packet includes a header portion and a data portion. The header portion includes routing information for the data packet. The method includes defining a data path in the router comprising a path through the router along which the data portion of the data packet travels and defining a control path comprising a path through the router along which routing information from the header portion travels. The method includes separating the data path and control path in the router such that the routing information can be separated from the data portion allowing for the separate processing of each in the router. The data portion can be stored in a global memory while routing decisions are made on the routing information in the control path.

Abstract: A router maintains routing information including (i) route data representing destinations within a computer network, (ii) next hop data representing interfaces to neighboring network devices, and (iii) indirect next hop data that maps a subset of the routes represented by the route data to a common one of the next hop data elements. In this manner, routing information is structured such that routes having the same next hop use indirect next hop data structures to reference common next hop data. In particular, in response to a change in network topology, the router need not change all of the affected routes, but only the common next hop data referenced by the intermediate data structures. This provides for increased efficiency in updating routing information after a change in network topology, such as link failure.

Abstract: Techniques are described for scaling Multiprotocol Label Switching (MPLS) across areas of an autonomous system using a labeled interior Border Gateway Protocol (iBGP). A method includes executing a first label distribution protocol at a border node at a border between two of a plurality of interior gateway protocol (IGP) areas of a single autonomous system (AS), and exchanging label distribution messages using the first label distribution protocol to establish a first intra-area label switched path (LSP) within a first one of IGP areas. The method also includes executing a labeled interior border gateway protocol at the border node, and exchanging label distribution messages using the labeled interior border gateway protocol to establish a hierarchical inter-area LSP that runs over the previously established first intra-area LSP, wherein the hierarchical inter-area LSP extends across the plurality of IGP areas of the AS.

Abstract: A route for a data unit through a network may be defined based on a number of next hops. Exemplary embodiments described herein may implement a router forwarding table as a chained list of references to next hops. In one implementation, a device includes a forwarding table that includes: a first table configured to store, for each of a plurality of routes for data units in a network, a chain of links to next hops for the routes; and a second table configured to store the next hops. The device also includes a forwarding engine configured to assemble the next hops for the data units based on using the chain of links in the first table to retrieve the next hops in the second table and to forward the data units in the network based on the assembled next hops.