The import command is used to apply one or more policies (up to 15) to a neighbor, group or to the entire BGP context. The import command that is most-specific to a peer is the one that is applied. An import policy command applied at the neighbor level takes precedence over the same command applied at the group or global level. An import policy command applied at the group level takes precedence over the same command specified on the global level. The import policies applied at different levels are not cumulative. The policies listed in an import command are evaluated in the order in which they are specified.
When an IP route is rejected by an import policy it is still maintained in the RIB-IN so that a policy change can be made later on without requiring the peer to re-send all its RIB-OUT routes. This is sometimes called soft reconfiguration inbound and requires no special configuration in SR OS.
When a VPN route is rejected by an import policy or not imported by any services it is deleted from the RIB-IN. For VPN-IPv4 and VPN-IPv6 routes this behavior can be changed by configuring the mp-bgp-keep command; this option maintains rejected VPN-IP routes in the RIB-IN so that a Route Refresh message does not have to be issued when there is an import policy change.