Cisco Technology, Inc.

Danny Prairie

George Swallow

Thomas David Nadeau

Jean-Philippe Vasseur

Daniel C Tappan

Richard W Bradford

Vanson Lim

Yufei Shi

David Delano Ward

Reshad Rahman

Optimal automated exploration of hierarchical Multiprotocol Label Switching Label Switch Paths (MPLS LSPs) is disclosed. A path verification message (PVM) is transmitted from an initial router. Each label in the PVM's label stack corresponds to a hierarchy layer and is associated with a time-to-live (TTL) field. The TTL field for the label of a current layer is set so the PVM travels one hop from the initial router. In response, a reply message indicating that the PVM reached its destination is received.

Optimal automated exploration of hierarchical multiprotocol label switching label switch paths

In one embodiment, a trigger is signaled to protect a tunnel from a head-end node to one or more tail-end nodes in a computer network via one or more intermediate nodes along the tunnel. One or more receiving nodes along the tunnel receive the trigger, and in response, establish a tunnel connectivity verification session from the receiving node to a corresponding downstream next-next-hop (NNHOP) node along the tunnel. Illustratively, the head-end node may thus recompute a new tunnel path excluding a path segment corresponding to a particular failed tunnel connectivity verification session.

Locating tunnel failure based on next-next hop connectivity in a computer network

Improved detection of specific BFD LSP path failures is herein disclosed. The improved detection described herein allow for faster fault isolation of a failure along a LSP path, which in turn may allow for faster repair of the failure. When opening a BFD session with a LSP egress node, the LSP ingress node provides the LSP egress node a path descriptor along with the BFD Discriminator. If a BFD failure is detected at the LSP egress node, the LSP egress node can signal an alarm that includes a full description of the path.

Detection of specific BFD path failures

Optimal automated exploration of hierarchical MPLS LSPs is disclosed. A path verification message (PVM) is transmitted from an initial router. Each label in the PVM's label stack corresponds to a hierarchy layer and is associated with a time-to-live (TTL) field. The TTL field for the label of a current layer is set so the PVM travels one hop from the initial router. In response, a reply message indicating that the PVM reached its destination is received. These steps are then repeated. For each successive PVM transmitted, the TTL field associated with a label corresponding to the current hierarchy layer is incremented. For any reply message including information describing a non-current layer, modify the next PVM's label stack and increment the TTL field of the label for the described different layer; any other TTL fields are unchanged. If any received reply message indicates a destination router was reached, the process terminates.

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.

Extensions to the path verification protocol to support link bundling constructs

Systems and methods for link discovery and verification technique that minimize the need for line termination resources that generate and interpret packets. Of two nodes verifying a link to one another, only one node need have any line termination capability. The node lacking line termination capability simply loops back packets generated by the other node thus verifying the link. Thus, an optical cross-connect can verify links to a wide variety of node types by employing a single line termination unit capable of terminating any suitable packet type. Alternatively, a router can verify connectivity to an optical cross-connect even when the optical cross-connect lacks any line termination capability at all. This saves greatly on implementation costs for optical networks.

Growing community of inventors

Kanata, Canada

Danny Prairie