摘要:
A method of constructing a backup path in an autonomous system (AS) for failure of a first inter-AS link serving a first set of prefixes is described. The method comprises identifying an alternate inter-AS link serving said plurality of prefixes and constructing a tunnel thereto.
摘要:
A method of constructing a backup path in an autonomous system (AS) for failure of an inter-AS link is described. The method comprises identifying an alternate inter-AS path and constructing a tunnel to an end point on the alternate path.
摘要:
A fast reroute (FRR) technique that may be deployed at the edge of a network having first and second edge devices coupled to a neighboring routing domain. If the first edge device detects a node or link failure that prevents it from communicating with the neighboring domain, the first edge device reroutes at least some data packets addressed to the neighboring domain to the second edge device. The second edge device receives the rerouted packets and then forwards the packets to the neighboring domain. Notably, the second edge device is not permitted to reroute the received packets a second time, e.g., upon identifying another inter-domain node or link failure. As such, loops are avoided at the edge of the network and packets are rerouted to the neighboring routing domain faster and more efficiently than in prior implementations.
摘要:
A packet data router comprises one or more first circuit boards comprising one or more first processors and first logic circuits programmed to perform packet data forwarding and packet data router control plane functions; and one or more second circuit boards comprising one or more second processors and second logic circuits programmed to perform only Border Gateway Protocol (BGP) route reflection server (RRS) functions. A distributed BGP route reflector system with the disclosed architecture distributes route reflection server software to a dedicated control board so that processing route reflection functions does not impact packet forwarding or protocol instances that converge forwarding tables.
摘要:
A method and system for protecting valuable resources within an autonomous system network. Address prefixes within the system are designated as valuable and a flag bit is associated with the address within routing tables of routers of the network. Interfaces to border routers are identified and when packets are received at those interfaces, the packets are flagged with a flag or tag bit. The destination address of the received packet is compared to the flag bit associated with the valuable resource prefix, and if the packet is directed to that resource the packet is dropped and/or logged, but the packet is not forwarded to that resource. In specific cases an interface from an external source may be configured to not create the flag or tag bit, wherein that packet will be delivered to the destination prefix of the packet.
摘要:
A method of implementing a backup path in an autonomous system (AS) for failure of an inter-AS link is described. The method comprises forwarding data elements destined for the failed link via a backup path and including a loop prevention attribute in the packet.
摘要:
A method and system for failure notification at a remote node in communication with a local node are disclosed. The local node is configured for faster failure detection than the remote node. In one embodiment, the method includes establishing a failure monitoring session between the local node and the remote node, receiving at the remote node, a failure notification from the local node, the failure notification sent using a protocol of the failure monitoring session, and rerouting traffic at the remote node in response to the failure notification.
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:
A local fast reroute (FRR) technique is implemented at the edge of a computer network. In accordance with the technique, if an edge device detects a node or link failure that prevents it from communicating with a neighboring routing domain, the edge device reroutes at least some data packets addressed to that domain to a backup edge device which, in turn, forwards the packets to the neighboring domain. The rerouted packets are designated as being “protected” (i.e., rerouted) data packets before they are forwarded to the backup edge device. The backup edge device identifies protected data packets as those which contain a predetermined “service” label in their MPLS label stacks. In other words, the service label is used as an identifier for packets that have been FRR rerouted. Upon receiving a data packet containing a service label, the backup edge device is not permitted to reroute the packet a second time, e.g., in response to another inter-domain node or link failure, thereby preventing loops from developing at the edge of the network.
摘要:
A technique enables an intermediate network node to efficiently process link-state packets using a single running context (i.e., process or thread). The intermediate network node floods received link-state packets (LSP) before performing shortest path first (SPF) calculations and routing information base (RIB) updates. In addition, the node limits the number of LSPs that are permitted to be flooded before the node performs its SPF calculations. More specifically, if the number of link-state packets that are flooded during a flooding cycle exceeds a first predetermined threshold value, the node performs the SPF calculations before additional packets may be flooded. The intermediate network node also limits how long its RIB update may be delayed in favor of flooding operations. When the number of LSPs flooded after the SPF calculations exceeds a second predetermined threshold value or there are no more packets to be flooded, the node updates the contents of its RIB based on the SPF calculations.