Configuring CSPF interface constraint
Under the default condition, hops configured as interface addresses in an LSP path are resolved to the router ID.
An LSP can be configured that does or does not traverse a specified interface. The protocols mpls-rsvp tunnels tunnel <name> primary path-selection affinities constraints exclude-any command forces the CSPF calculation to exclude any interface that was assigned to the excluded administrative group when creating an LSP.
To configure the device to always include a specified interface when forming an LSP, complete the following step.
vyatta@R1# set protocols mpls-rsvp tunnels tunnel pe1-pe2 primary path-selection affinities constraints include-any