Configuring RSVP Label-Switched Paths as Backup Paths for OSPF
When configuring an OSPF interface for link protection or node-link protection, relying on the shortest-path-first (SPF) calculation of backup paths for one-hop neighbors might result in less than 100 percent backup coverage for a specific network topology. You can enhance coverage of OSPF and LDP label-switched-paths (LSPs) by configuring RSVP LSPs as backup paths.
When configuring an LSP, you must specify the IP address of the egress router.
 | Note: RSVP LSPs can be used as backup paths only for the default topology for OSPFv2 and not for a configured topology. Additionally, RSVP LSP cannot be used a backup paths for non-default instances for OSPFv2 or OSPFv3. |
To configure a specific RSVP LSP as a backup path:
- Include the backup statement at the [edit protocols mpls labeled-switched-path lsp-name] hierarchy level.
- Specify the address of the egress router by including the to ip-address statement at the [edit protocols mpls label-switched-path hierarchy level.
In the following example, the RSVP LSP f-to-g is configured a backup LSP for protected OSPF interfaces. The egress router is configured with the IP address 192.168.1.4.
