Abstract: In one embodiment, a replacement network communications path is determined using dedicated resources of an existing path. One or more network elements in a network determines a new communications path between a first network node and a second network node in the network while an existing communications path is currently configured in the network to carry traffic between the first and second network nodes. The existing communications path includes one or more exclusive physical resources dedicated to the existing communications path. The new communications path includes at least one of said exclusive physical resources dedicated to the existing communications path. One embodiment includes: subsequent to said determining the new communications path, removing the existing communications path from service, and then instantiating the new communications path, with the new communications path including said at least one of said exclusive physical resources.

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, 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: In one embodiment, forwarding information bases (FIBs) are selectively populated in a packet switch. A packet switching device determines, based on one or more protocol signaling messages, a subset, which is less than all, on which FIBs a lookup operation may be performed for identifying forwarding information for a received particular packet. The packet switching device populates each of these FIBs, but not all of the FIBs of the packet switching device, with forwarding information corresponding to the particular forwarding value. Thus, FIB resources are consumed for only those FIBs which could actually be used, and not all of the FIBs, for forwarding packets in the data plane of the packet switching device, whether these packets are received on a primary or backup path.

Abstract: In one embodiment, a replacement network communications path is determined using dedicated resources of an existing path. One or more network elements in a network determines a new communications path between a first network node and a second network node in the network while an existing communications path is currently configured in the network to carry traffic between the first and second network nodes. The existing communications path includes one or more exclusive physical resources dedicated to the existing communications path. The new communications path includes at least one of said exclusive physical resources dedicated to the existing communications path. One embodiment includes: subsequent to said determining the new communications path, removing the existing communications path from service, and then instantiating the new communications path, with the new communications path including said at least one of said exclusive physical resources.

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: In one embodiment, information is exchanged between independent control planes of different layers in a multilayer network, such as, but not limited to, between a packet switching client-layer network and an optical server-layer network. This exchanged information includes signaling regarding a server-layer communications service, having server-layer characteristics, within the server-layer network for use in communicatively coupling at least two devices of the client-layer network. In one embodiment, the client-layer network specifies at least one of these server-layer characteristics that the server-layer communications service provided by the server-layer network must have. In one embodiment, the server-layer network signal to the client-layer network at least one of these server-layer characteristics of the existing server-layer communications service.

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, forwarding information bases (FIBs) are selectively populated in a packet switch. A packet switching device determines, based on one or more protocol signaling messages, a subset, which is less than all, on which FIBs a lookup operation may be performed for identifying forwarding information for a received particular packet. The packet switching device populates each of these FIBs, but not all of the FIBs of the packet switching device, with forwarding information corresponding to the particular forwarding value. Thus, FIB resources are consumed for only those FIBs which could actually be used, and not all of the FIBs, for forwarding packets in the data plane of the packet switching device, whether these packets are received on a primary or backup path.

Abstract: A pseudowire verification framework gathers and maintains status of individual pseudowires by aggregating the state of the individual node hops defining the pseudowire. The framework provides complete assessment of a network by gathering status feedback from network nodes (forwarding entities) that are inaccessible directly from a requesting node by employing an intermediate forwarding entity as a proxy for inquiring on behalf of the requesting node. Therefore, status regarding inaccessible pseudowires is obtainable indirectly from nodes able to “see” the particular pseudowire. Configurations further assess multihop pseudowires including a plurality of network segments; in which each segment defines a pseudowire hop including forwarding entities along the pseudowire path. In this manner, pseudowire health and status is gathered and interrogated for nodes (forwarding) entities unable to directly query the subject pseudowire via intermediate forwarding entities.

Abstract: To reveal link bundles' component links in an MPLS network, transmit a sequence of request and reply packets. For a router receiving a request packet, the packet identifies that link bundles should be revealed, detect the link bundle links connected to the router, and for each, its component links are added to a downstream mapping field (DMF). A link bundle mapping field (LBMF) is also added to the request packet. Each LBMF specifies the component links of that link bundle by pointing to the component links added to the DMF. For a router responding to a request packet with a reply packet, determine if any links in the DMF are component links, and for each, identify a LBMF containing information regarding that link. Each component link in the DMF is processed. The component links in each LBMF are iterated through to ensure each matches the determined links in the DMF.