wdiff rfc6996.original rfc6996.txt

Network Working Group
Internet Engineering Task Force (IETF) J. Mitchell
Internet-Draft
Request for Comments: 6996 Microsoft Corporation
BCP: 6 July 2013
Updates: 1930 (if approved) May 29, 2013
Intended status:
Category: Best Current Practice
Expires: November 30, 2013
ISSN: 2070-1721

Autonomous System (AS) Reservation for Private Use
draft-ietf-idr-as-private-reservation-05

Abstract

This document describes the reservation of Autonomous System numbers Numbers
(ASNs) that are for Private Use only and MUST NOT be advertised to
the Internet, only, known as Private Use ASNs. ASNs, and
provides operational guidance on their use. This document enlarges
the total space available for Private Use ASNs by documenting the
reservation of a second, larger range and updates RFC 1930 by
replacing Section 10. 10 of that document.

Status of This Memo

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This Internet-Draft will expire on November 30, 2013.
http://www.rfc-editor.org/info/rfc6996.

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1. Introduction

The original IANA reservation of Autonomous System Numbers (ASNs) for
Private Use was a block of 1023 ASNs. This was also documented by
the IETF in Section 10 of [RFC1930]. Since the time when that the range
was reserved, the Border Gateway Protocol (BGP), documented in [RFC4271], (BGP) [RFC4271] has seen
deployment in new application domains, such as datacenter data center networks,
which require a larger Private Use AS Space. space.

Since the introduction of BGP "BGP Support for Four-octet AS Four-Octet Autonomous
System (AS) Number Space Space" [RFC6793], the total size of the ASN space has
increased
dramatically, and a dramatically. A larger subset of the space should be is available to
network operators to deploy in these Private Use cases. The existing
range of Private Use ASNs is widely deployed deployed, and the ability to
renumber this resource in existing networks cannot be coordinated
given that these ASNs ASNs, by definition definition, are not registered. Therefore Therefore,
this RFC documents the existing Private Use ASN reservation, reservation while
also introducing a second, larger range that can also be utilized.

2. Requirements Language

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].

3. Private Use ASNs

To allow the continued growth of usage of the BGP protocol usage in new network
applications that utilize Private Use ASNs, two ranges of ASNs are
reserved by this document in Section 6. 5 of this document. The first, which
was previously defined in [RFC1930] out first is part of the
original 16-bit Autonomous System range, range previously defined in
[RFC1930], and the second is a second, larger range out of the higher
part of the Four-Octet AS
Number Space [RFC6793].

4. Operational Considerations

If Private Use ASNs are used and prefixes are originated originate from these ASNs,
Private Use ASNs MUST be removed from AS path attributes (including
AS4_PATH if utilizing a four-octet AS number space) before being
advertised to the global Internet. Operators SHOULD ensure that all
EBGP
External Border Gateway Protocol (EBGP) speakers support the
extensions described in [RFC6793] and ensure any implementation
specific that implementation-specific
features that recognize Private Use ASNs have been updated to
recognize both ranges prior to making use of the newer, numerically
higher range of Private Use ASNs in the four-octet AS number space.
Some existing implementations that remove Private Use ASNs from the
AS_PATH are known to not remove Private Use ASNs if the AS_PATH
contains a mixture of Private Use and Non-Private Use ASNs. If such
implementations have not been updated to recognize the new range of
ASNs in this document and a mix of old and new range Private Use ASNs
exist in the AS4_PATH, these implementations will likely cease to
remove any Private Use ASNs from either of the AS path attributes.
Normal AS path filtering MAY also be used to prevent prefixes
originating from Private Use ASNs from being advertised to the global
Internet.

5. Acknowledgements

The author would like to acknowledge Christopher Morrow, Jason
Schiller, and John Scudder for their advice on how to pursue this
change. The author would also like to thank Brian Dickson, David
Farmer, Jeffrey Haas, Nick Hilliard, Joel Jaeggli, Warren Kumari, and
Jeff Wheeler for their comments and suggestions.

6. IANA Considerations

[Note to IANA, this paragraph to be removed upon publication: The
IANA should update the "16-bit Autonomous System Numbers" registry to
reference this RFC for the existing Private Use reservation. The end
of the "32-bit Autonomous System Numbers" range will be reserved for
Private Use, and a size of 94,967,295 (value to replace TBD1 below)
corresponding to the range of 4200000000 (value to replace TBD2
below) to 4294967294 (value to replace TBD3 below). Text after this
sentence should be published in the document.]

IANA has reserved, for Private Use, a contiguous block of 1023
Autonomous System numbers from the "16-bit Autonomous System Numbers"
registry, namely 64512 - 65534 inclusive.

IANA has also reserved, for Private Use, a contiguous block of TBD1
94,967,295 Autonomous System numbers from the "32-bit Autonomous
System Numbers" registry, namely TBD2 4200000000 - TBD3 4294967294 inclusive.

These reservations have been documented in the IANA Autonomous "Autonomous
System
Numbers Registry (AS) Numbers" registry [IANA.AS].

6. Security Considerations

Private Use ASNs do not raise any unique security concerns. Loss of
connectivity might result from their inappropriate use of them, use, specifically
outside of a single organization, since they are not globally unique.
This loss of connectivity is limited to the organization using
Private Use ASNs inappropriately or without reference to Section 4.
General BGP security considerations are discussed in [RFC4271] and
[RFC4272]. Identification of the originator of a route with a
Private Use ASN in the AS path would have to be done by tracking the
route back to the neighboring globally unique AS in the path or by
inspecting other attributes.

7. References

8.1.

7.1. Normative References

[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.

[RFC4271] Rekhter, Y., Li, T., and S. Hares, "A Border Gateway
Protocol 4 (BGP-4)", RFC 4271, January 2006.

[RFC6793] Vohra, Q. and E. Chen, "BGP Support for Four-Octet
Autonomous System (AS) Number Space", RFC 6793,
December 2012.

8.2.

7.2. Informative References

[IANA.AS] IANA, "Autonomous System (AS) Numbers", May 2013,
<http://www.iana.org/assignments/as-numbers/>.

[RFC1930] Hawkinson, J. and T. Bates, "Guidelines for creation,
selection, and registration of an Autonomous System (AS)",
BCP 6, RFC 1930, March 1996.

[RFC4272] Murphy, S., "BGP Security Vulnerabilities Analysis",
RFC 4272, January 2006.

8. Acknowledgements

Author's Address

Jon Mitchell
Microsoft Corporation
One Microsoft Way
Redmond, WA 98052
USA

Email:

EMail: Jon.Mitchell@microsoft.com