Routes that traverse a protected interface. Path through a different routing device altogether for all destination Node-link protection establishes an alternative You can configure node-link protection on any interface for Neighboring node would still be available through another interface. Use link protection when youĪssume that only a single link might become unavailable but that the When you enable link protection, Junos OS createsĪn alternate path to the primary next hop for all destination routes You can configure link protection for any interface for Next hop for all destination routes that traverse a protected interface. OSPF interface, Junos OS creates an alternate path to the primary When you enable link protection or node-link protection on an Local repair coverage for the OSPF protocol. In such cases, per prefix LFA can be used to increase the In lieu of the LFA to the best prefix originator to provide local Per-prefix LFA isĪ mechanism by which LFA to a non-best prefix originator can be used Is no viable LFA to the best prefix originator, while a non-best prefix That multiple destinations are originating the same prefix and there In certain topologies and usage scenarios, it may be possible Set of interior gateway protocol (IGP) prefixes. Respect to a primary next hop towards a destination, originating a Is that the selected backup neighbor provides a loop-free path with Local repair path for the traffic to flow temporarily in case of failures Per-prefix loop-free alternates (LFAs)-It is a technologyīy which a neighbor can be used as a backup next hop to provide a As a result, Junos OS calculates a backup path that avoids When you assume that access to a node is lost when a link is no longerĪvailable. Through a different routing device altogether. Node-link protection-Establishes an alternate path Would still be available through another interface. Use link protection when you assume that only a single link mightīecome unavailable but that the neighboring node on the primary path Link protection-Offers per-link traffic protection. Junos OS provides three mechanisms for route redundancyįor OSPF through alternate loop-free routes: On the actual network topology and is typically less than 100 percentįor all destinations on any given routing device. The level of backup coverage available through OSPF routes depends If you enable support for alternate loop-free routes onĪn interface configured for both LDP and OSPF, you can use the traceroute command to trace the active path to the primary OSPF is already enabled, this feature also provides support for LDP YouĬan enable support for alternate loop-free routes on any OSPF interface.īecause it is common practice to enable LDP on an interface for which Shortest-path-first (SPF) calculations on each one-hop neighbor. Toĭetermine loop-free alternate paths for OSPF routes, Junos OS runs Whose shortest path first to the destination traverses the routingĭevice that is not used as a backup route to that destination. The routing device to reach a given destination. Using a backup path until global repair is able to calculate a newĪ loop-free path is one that does not forward traffic back through Local repair enables traffic to continue to be routed In contrast, global repair can take up to 800 milliseconds to computeĪ new route. Local repair reduces theĪmount of time needed to reroute traffic to less than 50 milliseconds. Precomputed paths from the Routing Engine. Packet Forwarding Engine can correct a path failure before it receives Implements the backup path when the link for a primary next hop forĪ particular route is no longer available. In the Packet Forwarding Engine, which performs a local repair and Junos OS precomputes loop-freeīackup routes for all OSPF routes. Support for OSPF loop-free alternate routes essentiallyĪdds IP fast-reroute capability for OSPF. The following topology explains the deployment case where per Originating a set of interior gateway protocol (IGP) prefixes.
The basic requirement is that the selected backup neighbor providesĪ loop free path with respect to primary next hop towards a destination, In case of failures in the primary next hop (node or link). Next hop to provide a local repair path for the traffic to flow temporarily (LFA) is a technology by which a neighbor can be used as a backup Per-Prefix Loop Free Alternates (LFA)-Loop Free Alternates This canīe used to increase the local repair coverage for the OSPF protocol LFA to the best prefix originator to provide local repair. The LFA to a non-best prefix originator can be used in lieu of the To the best prefix originator, whilst a non-best prefix originator In certain topologies and usage scenarios, when multipleĭestinations originate the same prefix and there is no viable LFA