schema:     AUT-NUM-SCHEMA
ref:        dn42.aut-num
key:        aut-num    required  single   primary schema
key:        as-name    required  single
key:        descr      optional  single
key:        mnt-by     required  multiple lookup=dn42.mntner
key:        member-of  optional  multiple lookup=dn42.as-set
key:        admin-c    optional  multiple lookup=dn42.person,dn42.role
key:        tech-c     optional  multiple lookup=dn42.person,dn42.role
key:        org        optional  single   lookup=dn42.organisation
key:        import     optional  deprecate multiple
key:        export     optional  deprecate multiple
key:        default    optional  deprecate multiple
key:        mp-peer    depricate multiple
key:        mp-group   depricate multiple
key:        mp-import  optional  multiple
key:        mp-export  optional  multiple
key:        mp-default optional  multiple
key:        geo-loc    optional  multiple > [lat-c] [long-c] [name]
key:        remarks    optional  multiple
mnt-by:     XUU-MNT
mnt-by:     HEXA-MNT