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backup-spf-options (Protocols IS-IS)


Hierarchy Level


Configure options for running the shortest-path-first (SPF) algorithm for backup next hops for protected interfaces. Use these options to override the default behavior of having Junos OS calculate backup paths for all the topologies in an instance when at least one interface is configured with link protection or node-link protection.

This configuration option is used in conjunction with the node-link-protection statement to compute per-prefix loop-free alternate routes (LFAs).



Degrade an interface from node-link to link protection in case no node protection LFA route is found for a given destination node.


Calculate backup next hops for non-best prefix originators.


Determine the remote LFA backup paths from the point of local repair (PLR) in an IS-IS network. For every protected link on the PLR, Junos OS creates a dynamic LDP label-switched path to reach the remote LFA node. When the primary link fails, the PLR uses these remote LFA backup paths to reach all the destinations reachable through the primary-link.


Enable use of source packet routing node segment labels for computing backup paths for normal IPv4 or IPv6 IS-IS prefixes and primary IS-IS source packet routing node segments.

Required Privilege Level

routing—To view this statement in the configuration.

routing-control-level—To add this statement to the configuration.

Release Information

Statement introduced in Junos OS Release 11.4R3.

node-link-degradation option added in Junos OS Release 14.2.

use-source-packet-routing option introduced in Junos OS Release 16.2R1 for MX Series and PTX Series routers.Support for this option introduced in Junos OS Release 17.2R1 for QFX5100 and QFX10000 switches.

Support for remote-backup-calculation option introduced in Junos OS Release 18.2R1 for QFX5100, QFX5110, and QFX5200 switches.