摘要:
A technique calculates a shortest path for a traffic engineering (TE) label switched path (LSP) from a head-end node in a local domain to a tail-end node of a remote domain in a computer network. The novel path calculation technique determines a set of different remote domains through which the TE-LSP may traverse to reach the tail-end node (e.g., along “domain routes”). Once the set of possible routes is determined, the head-end node sends a path computation request to one or more path computation elements (PCEs) of its local domain requesting a computed path for each domain route. Upon receiving path responses for each possible domain route, the head-end node selects the optimal (shortest) path, and establishes the TE-LSP accordingly.
摘要:
In one embodiment, a trigger to add a leaf node to a multicast group of a computer network is detected, and the leaf node may determine a root node of the multicast group to request a path between a tunnel tree and the leaf node of the multicast group. In response to the multicast group having an existing tree, a reply is received from the root node with a computed path to add the leaf node to the tree at a selected node of the tree. The leaf node may then be added to the multicast group tunnel tree over the computed path at the selected node.
摘要:
In one embodiment, one or more path computation requests from path computation clients (PCCs) in a first network domain are received at a first border router (BR) arranged at the border of the first network domain and a second network domain. The first BR learns of a path communication element (PCE) in the second network domain. The PCE in the second network domain is informed of path computation information for the first network domain. One or more tunnels are established between the first BR and the PCE in the second network domain. One or more path computation requests from PCCs in the first network domain are passed from the first BR, through the one or more tunnels, to the PCE in the second network domain, to be serviced by the PCE in the second network domain using the path computation information for the first network domain.
摘要:
In one embodiment, a first path computation element (PCE) operates between first and second network domains, and is adapted to service requests from path computation clients (PCCs) in at least the first domain. In response to a backup event (e.g., failure of a second PCE), a backup PCE in the second domain may be informed of path computation information for the first domain used by the first PCE, and tunnels may be bi-directionally established between the first PCE and the backup PCE. Once the tunnels are established, the backup PCE may be advertised into the first domain, and the backup PCE may operate to load balance service requests for the first domain through the bi-directionally established tunnels.
摘要:
A technique protects against the failure of a border router between two domains in a computer network using Fast Reroute and backup tunnels. According to the technique, the protected border router advertises a list of all its adjacent next-hop routers (i.e., its “neighbors”). A neighbor in the first domain that is immediately upstream to the protected border router and that is configured to protect the border router (i.e., the “protecting router”) selects a neighbor in a second domain (i.e., a “next-next-hop,” NNHOP) to act as a “merge point” of all the NNHOPs of that domain. The protecting router calculates a backup tunnel to the merge point that excludes the protected border router and associates the backup tunnel with all “protected prefixes.” The merge point then “stitches” additional backup tunnels onto the backup tunnel to provide a stitched tunnel to each remaining NNHOP. When the protected border router fails, Fast Reroute is triggered, and all protected prefix traffic is rerouted onto the backup tunnel to the merge point, which either forwards the traffic to its reachable prefixes or to a corresponding stitched tunnel.
摘要:
In one embodiment, a node receives traffic sent from one or more sources toward one or more destinations (e.g., Multipoint-to-Point, MP2P traffic). The node may detect a burst of received traffic based on one or more characteristics of the burst traffic, and, in response, may dynamically apply traffic shaping to the burst traffic. The traffic shaping is adapted to forward burst traffic received below a configurable threshold at a configurable pace and to drop burst traffic received above the configurable threshold. In addition, the node may also store the burst traffic dropped by traffic shaping, and forwards the stored burst traffic toward its destination after a configurable delay.
摘要:
A technique dynamically retrieves reachability information from a target node, including a tail-end or any intermediate node, along a traffic engineering (TE) label switched path (LSP) that spans multiple domains in a computer network. The interdomain information retrieval technique is illustratively based on a request/response signaling exchange whereby at least a portion of the reachability, i.e., routing, information maintained by the target node is propagated to a head-end node of the TE-LSP. The routing information may comprise a list of address prefixes reachable by the target node, but may optionally include next-hop and metric attributes associated with those prefixes. The head-end node uses the retrieved routing information to calculate routes reachable from the target node for insertion into its routing table.
摘要:
A technique dynamically resizes Traffic Engineering (TE) Label Switched Paths (LSPs) at a head-end node of the TE-LSPs in preparation to receive redirected traffic in response to an event in a computer network. The novel dynamic TE-LSP resizing technique is based on the detection of an event in the network that could cause traffic destined for one or more other (“remote”) head-end nodes of one or more TE-LSPs to be redirected to an event-detecting (“local”) head-end node of one or more TE-LSPs. An example of such a traffic redirection event is failure of a remote head-end node or failure of any of its TE-LSPs. Specifically, the local head-end node maintains TE-LSP steady state sampling and resizing frequencies to adapt the bandwidth of its TE-LSP(s) to gradual changes in the network over time. Upon detection of an event identifying possible traffic redirection, the local head-end node enters a Fast Resize (FR) state, in which the sampling and resizing frequencies are increased to quickly adapt the TE-LSP bandwidth(s) to any received redirected traffic.
摘要:
In one embodiment, an inter-domain routing protocol stores an inter-domain routing protocol route having an associated next-hop address. A routing table is searched for an for an intra-domain routing protocol route that may be used to reach the next-hop address of the inter-domain routing protocol route. Such route is marked as an important route for convergence. Later, in response to a change in the network requiring a routing table update, the intra-domain routing protocol route marked as an important route for convergence is processed by an intra domain routing protocol before any other intra-domain routing protocol routes are processed that are not marked as important routes for convergence.
摘要:
In one embodiment, a node receives traffic sent from one or more sources toward one or more destinations (e.g., Multipoint-to-Point, MP2P traffic). The node may detect a burst of received traffic based on one or more characteristics of the burst traffic, and, in response, may dynamically apply traffic shaping to the burst traffic. The traffic shaping is adapted to forward burst traffic received below a configurable threshold at a configurable pace and to drop burst traffic received above the configurable threshold. In addition, the node may also store the burst traffic dropped by traffic shaping, and forwards the stored burst traffic toward its destination after a configurable delay.