Abstract: In one embodiment, one or more point-to-point (P2P) services are established between attachment circuits on provider edge (PE) devices in a computer network, and each of the one or more P2P services (e.g., Virtual Private Wire Service, VPWS) are associated with an Ethernet virtual private network (E-VPN) Ethernet Auto-Discovery (A-D) route, where links between the PE devices and customer edge (CE) devices are configured as Ethernet interfaces with Ethernet tagging. As such, the Ethernet A-D route may then be exchanged for each P2P service attachment circuit, and forwarding can be performed on the one or more P2P services without performing a media access control (MAC) address lookup and without performing MAC learning.

Abstract: In one embodiment, a particular PE device of a plurality of multi-homing PE devices between a core network and a local network determines a subset of traffic for which the particular PE device is responsible. The particular PE also establishes, with itself as root, a multicast tree within the local network for underlay multicast groups. Traffic received at the particular PE from the core network is admitted into the local network only if the core traffic corresponds to the subset of traffic for which the particular PE device is responsible (and mapped into one of the underlay multicast groups for which the particular PE device is the root). Also, multicast traffic received at the particular PE from the local network is forwarded into the core network only if the multicast traffic corresponds to the subset of traffic for which the particular PE device is responsible.

Abstract: In one embodiment, an edge device of a core network may receive a plurality of packets from a peripheral network having a plurality of active connections to the core network, where each packet has a destination address and a source address. The edge device may compute a hash on the destination address or the source address of each packet, and determine whether the computed hash corresponds to the edge device. In response to the computed hash not corresponding to the edge device, the edge device may drop the packet, and in response to the computed hash corresponding to the edge device, the edge device may process the packet to forward the packet, where the dropping and processing load balances the plurality of packets over the active connections and prevents formation of loops in the core network.

Abstract: In one embodiment, an access component of a local network edge device receives traffic, and generates a frame for the traffic that includes a remote context label that identifies an access component of the remote network edge device to which the traffic is to be forwarded upon arrival at the remote network edge device, and a virtual circuit label corresponding to a particular virtual service of the traffic. The local network edge device forwards the frame towards the remote network edge device. In another embodiment, the frame may be received at a core component of the remote network edge device, an in response to the remote context label identifying an access component of the remote network edge device, forwarded to the access component, which determines the particular virtual service, and forwards the traffic from the frame out the access component towards an endpoint for the traffic.

Abstract: In one embodiment, line cards of packet switching or other network devices are configured for terminating pseudowires. Typically, this includes multiple line cards being configured for terminating a same pseudowire, which allows the corresponding pseudowire traffic to be received by any one of these multiple line cards. Each of these pseudowire-terminating line cards is typically configured to apply one or more features to a pseudowire packet. Examples of these features include, but are not limited to: Access Control List, Quality of Service, Netflow, and Lawful Intercept. For a received packet to be sent out one of these pseudowires, a two-stage lookup operation can be used to first identify the pseudowire over which to forward the packet; and a second lookup operation based on the pseudowire to identify forwarding information corresponding to a path through a network over which a corresponding pseudowire is configured.

Abstract: In one embodiment, a connectivity verification protocol (CVP) session for a particular virtual interface (VI) may operate on a particular group of two or more line cards (LCs) on a network device. The group of LCs may then transmit CVP session packets, at a reduced rate that is sufficient to maintain the CVP session based on a negotiated CVP full rate, onto the particular VI through ingress path processing on the network device. Ingress path processing, in particular, takes transmitted CVP session packets and egresses them onto an appropriate LC of the network device currently responsible for the VI egress. Also, in response to receiving CVP session packets for the VI on an LC of the network device currently responsible for the VI ingress, the receiving LC may forward the received CVP session packets to the particular corresponding group of LCs, which may then process the received CVP session packets.

Abstract: In one embodiment, a method includes obtaining a first indication from a first source included in an Ethernet ring and obtaining a second indication from a second source associated with a provider edge (PE) node The method also includes determining when the first indication and the second indication are indicative of a direct failure of the PE node and determining when the first indication and the second indication are indicative of a ring partition failure associated with the Ethernet ring. The direct failure of the PE node is identified when it is determined that the first indication and the second indication are indicative of the direct failure of the PE node, and the ring partition failure associated with the Ethernet ring is identified when it is determined that the first indication and the second indication are indicative of the ring partition failure associated with the Ethernet ring.

Abstract: A system and method for advertising out-of-resources (OOR) conditions for entities, such as nodes, line cards and data links, in a manner that does not involve using a maximum cost to indicate the entity is “out-of-resources.” According to the technique, an OOR condition for an entity is advertised in one or more type-length-value (TLV) objects contained in an advertisement message. The advertisement message is flooded to nodes on a data network to inform them of the entity's OOR condition. Head-end nodes that process the advertisement message may use information contained in the TLV object to determine a path for a new label switched path (LSP) that does not include the entity associated with the OOR condition.

Abstract: In one embodiment, a method includes determining when a predetermined period of time has elapsed, and determining whether at least a first message has been obtained on a first port of a node during the predetermined period of time when it is determined that the predetermined period of time has elapsed. The method also includes identifying the first port as being connected to a single-homed site when it is determined that the at least first message has not been obtained on the first port during the predetermined period of time. The first port is identified as being connected to a multi-homed network, a multi-homed device, or a hierarchical Ethernet segment when it is determined that the at least first message has been obtained on the first port during the predetermined period of time.

Abstract: In one embodiment, single-homing and active-active multi-homing is provided in a Virtual Private LAN Service (VPLS). A customer edge node actively communicates frames of a same Virtual Private Network (VPN) instance with two or more VPLS nodes of a VPLS network. The VPLS nodes are configured to appropriately forward frames throughout the VPLS network: without looping of a frame sent by the same external node back to the same external node, without flooding multiple copies of a frame to the same external node, and while performing learning of addresses in forwarding tables of said VPLS nodes such that said forwarding tables of said VPLS nodes converge despite frames of the same LAN service being received by said at least two of said VPLS nodes from the same external node.

Abstract: An example method includes detecting a failure at a first network element, the failure is associated with a link between the first network element and a second network element. The method also includes generating a list of network elements to be notified based on the failure, the second network element is included on the list. The method further includes generating an alarm indication signal (AIS) message, the AIS message identifies a plurality of tunnels affected by the failure. The AIS message is communicated to the second network element. In more detailed embodiments, each link between the first network element and the second network element includes a globally unique link identifier, which includes an associated autonomous system number. The globally unique link identifier can represent a string to be associated with the plurality of tunnels, the globally unique link identifier includes a source address and a destination address.

Abstract: A system and method for advertising out-of-resources (OOR) conditions for entities, such as nodes, line cards and data links, in a manner that does not involve using a maximum cost to indicate the entity is “out-of-resources.” According to the technique, an OOR condition for an entity is advertised in one or more type-length-value (TLV) objects contained in an advertisement message. The advertisement message is flooded to nodes on a data network to inform them of the entity's OOR condition. Head-end nodes that process the advertisement message may use information contained in the TLV object to determine a path for a new label switched path (LSP) that does not include the entity associated with the OOR condition.

Abstract: In one embodiment, a primary bidirectional LSP is established between an originating LSP packet switching device and a destination LSP packet switching device through an intermediate packet switching device. A corresponding backup LSP is also established. The originating LSP packet switching device sends a particular label switched packet to the destination LSP packet switching device over the primary bidirectional LSP. An intermediate packet switching device sends the particular label switched packet back to the originating LSP packet switching device over the primary bidirectional LSP in response to an error condition identified as affecting the primary bidirectional LSP towards the destination LSP packet switching device. The originating LSP packet switching device receives the particular label switched packet and sends it to the destination packet switching device over the backup LSP.

Abstract: An example method is provided that includes determining whether an address resolution protocol reply from a local machine has been received at an edge node; updating a local cache based on the reply from the local machine; and sending the reply to a plurality of edge nodes through a data plane of a data center interconnect. In more specific implementations, the method can include determining whether an address resolution protocol request has been received from the local machine. The method could also include updating a local machine cache based on the request. In certain implementations, the method can include determining whether the request is targeting the local machine; and dropping the request if the request is targeting the local machine. The method could also include sending the request through the data center interconnect if the request is not targeting the local machine.

Abstract: In one embodiment, a method includes determining when a predetermined period of time has elapsed, and determining whether at least a first message has been obtained on a first port of a node during the predetermined period of time when it is determined that the predetermined period of time has elapsed. The method also includes identifying the first port as being connected to a single-homed site when it is determined that the at least first message has not been obtained on the first port during the predetermined period of time. The first port is identified as being connected to a multi-homed network, a multi-homed device, or a hierarchical Ethernet segment when it is determined that the at least first message has been obtained on the first port during the predetermined period of time.

Abstract: Techniques for stitching multicast trees in a multiple data center environment. According to one embodiment, a technique for stitching multicast trees is provided, which includes determining, at an edge device of a data center, one or more Virtual Local Area Networks (VLANs) assigned to the edge device as a result of a designated forwarder election. An assigned forwarder message is sent by the edge device to one or more devices on the data center, the assigned forwarder message advertising the edge device as a designated forwarder for the VLANs assigned to the edge device. For each of the VLANs assigned to the edge device, the assigned forwarder message causes the edge device to be included in a multicast tree for the VLAN when the assigned forwarder message is received by specific ones of the devices in the data center that are associated with the VLAN.

Abstract: Disclosed are, inter alia, methods, apparatus, computer-storage media, mechanisms, and means associated with the coordinated updating of forwarding information bases (FIBs) in a multistage packet switching device, which performs at least lookup operations on multiple different FIBs in determining how to forward a packet. One embodiment uses lookup operations on two different FIBs, with these being an ingress FIB on an ingress line card and an egress FIB on an egress line card. In response to a change in the forwarding information for a stream of packets, the egress FIBs are first updated to include both the old and new forwarding information. After all egress FIBs have been updated, the ingress FIBs are updated to use the new forwarding information. This update procedure is designed to eliminate loss or duplication of packets induced during the updating of these FIBs to use the new forwarding information.

Abstract: In one embodiment, a network device in a set of network devices obtains a pseudowire label for a Provider Edge (PE) device, where the pseudowire label corresponds to a Virtual Local Area Network (VLAN) on the PE device. In addition, the network device obtains a set of one or more MAC addresses reachable via the PE device, wherein the set of network devices support Ethernet Virtual Private Network (E-VPN) and are in the same redundancy group such that the set of network devices are coupled to the same customer edge device. The network device stores the pseudowire label in association with the set of one or more MAC addresses. The network device uses the pseudowire label to encapsulate traffic associated with the VLAN that is received from the customer edge device and destined to the set of MAC addresses reachable via the PE device.

Abstract: In one embodiment, a Bidirectional Forwarding Detection (BFD) asynchronous mode session is established between two packet switching devices interconnected by one or more physical links. Prior to L2 or L3 services being established, each of these packet switching devices does not know the Media Access Control (MAC) nor Internet Protocol (IP) addresses of each interface of the other packet switching device that is connected to one of these link(s). A request to establish a BFD session is sent from one packet switching device to the other, with a MAC frame including the request being addressed to a group, broadcast, or other address that the receiving packet switching device will recognize and thus process the received request. Based on information contained in this received MAC frame, the receiving packet switching device has the information it needs, and sends a BFD control frame to the other packet switching device.

Abstract: In one embodiment, an initiating maintenance end point (MEP) may transmit a lock message to lock a circuit traversing one or more maintenance intermediate points (MIPs) between the initiating MEP and an end MEP. The initiating MEP may then transmit an in-band packet containing a loopback request to a particular MIP along the circuit using a particular time-to-live (TTL) value in the packet to reach the particular MIP. Upon receiving the packet at the particular MIP, and in response to determining that the TTL has expired, the particular MIP inspects the packet to discover the loopback request, and correspondingly operates in a loopback mode.