4.2.1 Description of the AUT-NUM Object

Below is the object template for the aut-num object. It lists all possible attributes that are allowed in this object type. Required attributes are shown as ‘optional*'.

Attribute Name   Presence   Repeat     Indexed 
aut-num: mandatory single primary/lookup
as-name: mandatory single
descr: mandatory multiple
member-of: optional multiple inverse
import-via: optional multiple
import: optional multiple
mp-import: optional multiple
export-via: optional multiple
export: optional multiple
mp-export: optional multiple
default: optional multiple
mp-default: optional multiple
remarks: optional multiple
org: optional* single inverse
sponsoring-org: optional single
admin-c: mandatory multiple inverse
tech-c: mandatory multiple inverse
abuse-c: optional single inverse
status: generated single
notify: optional multiple inverse
mnt-lower: optional multiple inverse
mnt-routes: optional multiple inverse
mnt-by: mandatory multiple inverse
changed: optional multiple
created: generated single
last-modified: generated single
source: mandatory single

The aut-num object serves a dual purpose in the database. As part of the RIPE Internet Number Registry, it contains the registration details of an Autonomous System Number (ASN) resource assigned by the RIPE NCC. As part of an Internet Routing Registry, it allows routing policies to be published. It refers to a group of IP networks that have a single and clearly defined external routing policy, operated by one or more network operators – an Autonomous System (AS). This is the only primary object that crosses over between these two registries in the RIPE Database.

Because of this crossover between the two registries contained within the RIPE Database, authorisation for creation of route(6) objects can and must be provided by both the address space holder and the holder of the AS number. For more details, see the section 'Authorisation'.

The number part of an ASN is a 32-bit number. Historically, these were 16-bit numbers. But when the pool of available numbers was running low, they were extended to 32 bits. In theory, there is no difference between a 16-bit ASN and a 32-bit ASN, except perhaps the size of the number. One is just a subset of the other. For technical reasons, some users still prefer a 16-bit ASN.

The primary key value will be in this format:

‘ASn' where ‘n' is a 32-bit unsigned, number in the range 0: 4,294,967,295.

Leading zeroes (AS065536) are not allowed and will be removed (AS65536) by the database software.

4.2.1 Description of Attributes Specific to the AUT-NUM Object

  • "aut-num:" – the registered AS Number of the Autonomous System (AS) that this object describes. It must start with the two letters ‘AS'.
  • “as-name:” – a symbolic name of the AS. Must be a single word of letters, numbers and the characters ‘-‘ and ‘_'.
  • “descr:” - A short description related to the object.
  • "member-of:" - references a set object that this AS wants to be a member of. This membership claim must be acknowledged by a respective "mbrs-by-ref:" attribute in the referenced set object.
  • "import:", "export:" and "default:" - specify the IPv4 routing policies of the AS.
  • "import-via:" and "export-via:" - specify routing policies regarding non-adjacent networks. These attributes help participants of Multi-Lateral Peering services to inform the intermediate autonomous system what routing policy should be applied towards other participants.
  • "mp-import:", "mp-export:" and "mp-default:" - specify IPv4, IPv6 and multicast routing policies.
  • "org:" – single-valued to make sure that only one organisation is responsible for this resource. This is a required attribute in the aut-num object. If the “status:” value is ‘ASSIGNED' then the object must have an “org:” attribute.
  • “sponsoring-org:” – references an organisation object representing the sponsoring organisation that is administratively responsible for the resource. This value is generated by the software and synchronised with the registry information. If a resource is no longer subject to a contract with the sponsoring organisation, or a contract is signed with a new sponsoring organisation, this will be updated in the registry information for this resource. The aut-num object in the RIPE Database will then be synchronised with the changes. A user cannot set, remove or change this value. An aut-num object cannot be created without this attribute. But the RIPE NCC can remove the attribute during a period in-between the ending of a contract with one sponsoring organisation and the signing of a contract with a new sponsoring organisation.
  • “status:” – There are three different categories of aut-num objects in the RIPE Database. This generated “status:” attribute clearly shows which category an aut-num object belongs to. The categories are:
    • ‘ASSIGNED', - all AS Number resources assigned by the RIPE NCC
    • ‘LEGACY' - all legacy AS Numbers used within the RIPE region but not assigned by the RIPE NCC
    • ‘OTHER' – any aut-num that is not one of the above, typically a non-authoritative copy of an aut-num from another RIR region used for routing authentication in the RIPE Database
    A user cannot set, remove or change this value. It is determined from the status noted for this resource in the registry information and set by the software when the object is updated. An update to an aut-num object will never fail because of a missing “status:” attribute or incorrect value. The software will add or correct it. The status of an aut-num is only administrative. It does not affect the usage of an aut-num for any routing purpose or impact certification in any way.
  • “abuse-c:” – This attribute references an abuse contact object. If present, this overrides any existing reference on a referenced organisation object. This can only be a role object that contains an "abuse-mailbox:" attribute. Making this reference will remove any query limits for that role object, which must only include business data (no personal information).
  • “mnt-lower:” – This attribute has no meaning in the aut-num object. In the RIPE NCC service region, we do not allocate blocks of AS numbers for users to assign from. All AS numbers are assigned by the RIPE NCC therefore there is no hierarchy to ‘maintain' or authorise against. This attribute should be deprecated.
  • “mnt-routes:” – This attribute is used to specify one or more mntner objects that can authorise the creation of route(6) objects originated by this AS number. Without this attribute, this function defaults to the mntner objects referenced in the “mnt-by:” attributes. For more details see the section on Authorisation.
  • “mnt-by:” – This attribute may have extra powers in addition to its default behaviour. In the absence of any “mnt-routes:” attributes, the mntner objects listed in the “mnt-by:” attributes can authorise the creation of route(6) objects originated by this AS number. For more details, see the section 'Authorisation'.