OSPFv2 non-stop routing

OSPFv2 can continue operation without interruption during hitless failover when the OSPFv2 non-stop routing (NSR) feature is enabled.

During graceful restart (GR), the restarting neighbors must help build routing information during a failover. However, GR may not be supported by all devices in a network. NSR eliminates this dependency.

NSR does not require support from neighboring devices to perform hitless failover, and OSPF can continue operation without interruption.

Note: NSR does not support IPv6-over-IPv4 tunneling and virtual links, so traffic loss is expected while performing hitless failover.

If the active management module fails, the standby management module takes over and maintains the current OSPF routes, link-state advertisements (LSAs), and neighbor adjacencies, so that there is no loss of existing traffic to the OSPF destination.

Note: NSR and Graceful Restart (GR) are mutually exclusive.

In this section:

  1. Limitations of NSR
  2. Enabling OSPFv2 NSR
    OSPFv2 non-stop routing (NSR) can be re-enabled if it has been disabled. The following task re-enables NSR for OSPFv2.
Parent topic: OSPFv2