This parameter indicates how ASE tags will be generated for those
ASEs whose tags are not altered by an export route filter or
announce route policy. default(1) indicates that a zero value is
used. automatic(2) indicates that an automatic tag will be generated
as specified in RFC 1403. proprietary(3) indicates that the wellfleet
proprietary scheme will be used. In this case, the next hop
is used for IGP routes and the neighbor AS is used for EGP routes.