Technical Documentation

Configuring Node-Link Protection for OSPF

You can configure node-link protection on any interface for which OSPF is enabled. Node-link protection establishes an alternate path through a different router altogether for all destination routes that traverse a protected interface. Node-link protection assumes that the entire router, or node, has failed. The JUNOS Software therefore calculates a backup path that avoids the primary next-hop router.

Node-link protection is supported on the following:

  • OSPFv2 and OSPFv3 interfaces
  • OSPFv3 unicast realms
  • OSPFv2 unicast topologies
  • All routing instances supported by OSPFv2 and OSPFv3
  • Logical systems

To configure node-link protection for an OSPF interface:

  • Include the node-link-protection statement at the [edit protocols (ospf | ospf3) area area-id interface interface-name hierarchy level.

Best Practice: You must also configure a per-packet load-balancing routing policy to ensure that the routing protocol process installs all the next hops for a given route in the routing table.

In the following example, the OSPF interface so-0/0/0.0 in area 0.0.0.0 is configured for node-link protection. If a link for a destination route that traverses this interface becomes unavailable, the JUNOS Software creates a loop-free backup path through a different router altogether, thus avoiding the primary next-hop router.

[edit]protocols {ospf {area 0.0.0.0 {interface so-0/0/0.0 {node-link-protection;}}}}

Published: 2010-04-14