Policy Manual (v2.1 - 25/03/2014)

3. Allocation of Autonomous System Numbers (ASN)

An Autonomous System (AS) is a group of IP address networks managed by one or more network operators having a clear and unique routing policy. Each Autonomous System (AS) has an associated number that is used as the Autonomous System's identifier when exchanging external routing information. Exterior routing protocols, such as BGP, are used for exchanging routing information among Autonomous Systems.

The term "Autonomous System" is frequently misinterpreted as merely a convenient way to refer to a group networks that are under the same management. However, if there is more than one routing policy in the group, then more than one AS is necessary. On the other hand, if the group of networks has the same policy as the other groups, they fall within the same AS regardless of their management structure. Thus, by definition, all networks that make up an Autonomous System share the same routing policy.

In order to simplify global routing tables, a new Autonomous System Number (ASN) should only be assigned when a new routing policy is necessary.
Sharing the same ASN among a group of networks that are not under the same management will require additional coordination among network administrators and, in some cases, will require redesigning the network to a certain degree. However, this is probably the only way to implement the desired routing policy

LACNIC shall allocate Autonomous System Numbers to those organizations that meet the following requirements:

  1. The organization must be multi-homed and each provider must have two or more independent Autonomous Systems at the time of the application, or planning to become multi-homed within a period of no more than two weeks as of the moment of the application.
  2. The organization must submit detailed documentation describing the applicant's routing policy, which must be unique and different to that applied by the ASN to which it is connected. This documentation must include the exterior routing protocol to be used, IP addresses that will conform the AS, and a detailed explanation of the reasons why its routing policy differs from that of its providers.

It is the obligation of the organization receiving an Autonomous System Number from LACNIC to maintain updated records of postal addresses and points of contact.

LACNIC's WHOIS system allows representing up to three different points of contact, namely:

owner-c, which represents the administrative contact of the organization to which the ASN was assigned;

routing-c, contact who, by means of the IP and ASN administration system, may register the routing policies adopted by the Autonomous System;

abuse-c, security contact (Abuse Contact).

3.1. Terminology

16-bit AS numbers were defined in RFC 1930 and integers ranging from 0 to 65535 will be used for their identification. Likewise, 32-bit AS numbers were defined by RFC 4893 and integers ranging from 0 to 4294967295 will be used for their identification. In both cases the "asplain" decimal value representation defined in RFC 5396 will be used.

Consequently, the following terminology will be adopted to refer to 16-bit and 32-bit ASNs:

  • "16-bit only AS Numbers" refers to AS numbers in the range 0 - 65535
  • "32-bit only AS Numbers" refers to AS Numbers in the range 65536 - 4294967295
  • "32-bit AS Numbers" refers to AS Numbers in the range 0 - 4294967295

3.2. AS Allocation Phases

There shall be three phases for ASN allocation on the part of LACNIC:

  1. On 1 January, 2007, the registry will process applications that specifically request 32-bit only AS Numbers and allocate such AS Numbers as requested by the applicant. In the absence of any specific request for a 32-bit only AS Number, a 16-bit only AS Number will be allocated by the registry.
  2. On 1 January, 2009, the registry will process applications that specifically request 16-bit only AS Numbers and allocate such AS Numbers as requested by the applicant. In the absence of any specific request for a 16-bit only AS Number, a 32-bit only AS Number will be allocated by the registry .
  3. As of January 1st, 2010, LACNIC shall allocate 32-bit AS numbers by default. 16-bit AS numbers shall be allocated, if available, in response to applications specifically requesting said resource and that duly justify the technical reasons why a 32-bit AS number would not be appropriate for its needs.