Identifies an extended community list that can be used to filter routes based on their extended communities (including route-targets). This filter is applied before any other import policy, and any routes that don't match this list will be denied. This filter applies to routes of this <AFI, SAFI> learned from any peer. If set to a non-zero value, the list comprises the entries in the bgpExtCommListTable with bgpExtCommListIndex set to this value. Setting this field to zero means that no Extended Community List filter is applied, and so no routes will be denied.