Event-based VPN import introduces three path selection policies:
All—Import all available paths from the exporting net that match any route target (RT) associated with the importing VRF
Best path—Import the best available path that matches the RT of the VRF instance. If the best path in the exporting net does
not match the RT of the VRF instance, a best available path that matches the RT of the VRF instance is imported.
Multipath—Import the best path and all paths marked as multipaths that match the RT of the VRF instance. If there are no
best path or multipath matches, then the best available path is selected.
Multipath and best path options can be restricted using an optional keyword to ensure that the selection is made only on
the configured option. If the
strict keyword is configured in the
selection command, the software disables the fall back safety option of choosing the best available path. If no paths appropriate to
the configured option (best path or multipath) in the exporting net match the RT of the VRF instance, then no paths are imported.
This behavior matches the behavior of the software before the BGP Event-Based VPN Import feature was introduced.
When the restriction is not set, paths that are imported as the best available path are tagged. In
show command output these paths are identified with the wording, “imported safety path.”
The paths existing in an exporting net that are considered for import into a VRF instance may have been received from another
peer router and were not subject to the VPN importing rules. These paths may contain the same route-distinguisher (RD) information
because the RD information is local to a router, but some of these paths do not match the RT of the importing VRF instance
and are marked as “not-in-vrf” in the
show command output. Any path that is marked as “not-in-vrf” is not considered as a best path because paths not in the VRF appear
less attractive than paths in the VRF.