draft-ietf-idr-as-private-reservation-05.txt   rfc6996.txt 
Network Working Group J. Mitchell Internet Engineering Task Force (IETF) J. Mitchell
Internet-Draft Microsoft Corporation Request for Comments: 6996 Microsoft Corporation
Updates: 1930 (if approved) May 29, 2013 BCP: 6 July 2013
Intended status: Best Current Practice Updates: 1930
Expires: November 30, 2013 Category: Best Current Practice
ISSN: 2070-1721
Autonomous System (AS) Reservation for Private Use Autonomous System (AS) Reservation for Private Use
draft-ietf-idr-as-private-reservation-05
Abstract Abstract
This document describes the reservation of Autonomous System numbers This document describes the reservation of Autonomous System Numbers
(ASNs) that are for Private Use only and MUST NOT be advertised to (ASNs) that are for Private Use only, known as Private Use ASNs, and
the Internet, known as Private Use ASNs. This document enlarges the provides operational guidance on their use. This document enlarges
total space available for Private Use ASNs by documenting the the total space available for Private Use ASNs by documenting the
reservation of a second, larger range and updates RFC 1930 by reservation of a second, larger range and updates RFC 1930 by
replacing Section 10. replacing Section 10 of that document.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This memo documents an Internet Best Current Practice.
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months This document is a product of the Internet Engineering Task Force
and may be updated, replaced, or obsoleted by other documents at any (IETF). It represents the consensus of the IETF community. It has
time. It is inappropriate to use Internet-Drafts as reference received public review and has been approved for publication by the
material or to cite them other than as "work in progress." Internet Engineering Steering Group (IESG). Further information on
BCPs is available in Section 2 of RFC 5741.
This Internet-Draft will expire on November 30, 2013. Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc6996.
Copyright Notice Copyright Notice
Copyright (c) 2013 IETF Trust and the persons identified as the Copyright (c) 2013 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
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publication of this document. Please review these documents publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License. described in the Simplified BSD License.
1. Introduction 1. Introduction
The original IANA reservation of Autonomous System Numbers (ASNs) for The original IANA reservation of Autonomous System Numbers (ASNs) for
Private Use was a block of 1023 ASNs. This was also documented by Private Use was a block of 1023 ASNs. This was also documented by
IETF in Section 10 of [RFC1930]. Since the time when that range was the IETF in Section 10 of [RFC1930]. Since the time that the range
reserved, Border Gateway Protocol (BGP), documented in [RFC4271], has was reserved, the Border Gateway Protocol (BGP) [RFC4271] has seen
seen deployment in new application domains, such as datacenter deployment in new application domains, such as data center networks,
networks, which require a larger Private Use AS Space. which require a larger Private Use AS space.
Since the introduction of BGP Support for Four-octet AS Number Space Since the introduction of "BGP Support for Four-Octet Autonomous
[RFC6793], the total size of the ASN space has increased System (AS) Number Space" [RFC6793], the total size of ASN space has
dramatically, and a larger subset of the space should be available to increased dramatically. A larger subset of the space is available to
network operators to deploy in these Private Use cases. The existing network operators to deploy in these Private Use cases. The existing
range of Private Use ASNs is widely deployed and the ability to range of Private Use ASNs is widely deployed, and the ability to
renumber this resource in existing networks cannot be coordinated renumber this resource in existing networks cannot be coordinated
given these ASNs by definition are not registered. Therefore this given that these ASNs, by definition, are not registered. Therefore,
documents the existing Private Use ASN reservation, while also this RFC documents the existing Private Use ASN reservation while
introducing a second, larger range that can also be utilized. also introducing a second, larger range that can also be utilized.
2. Requirements Language 2. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119]. document are to be interpreted as described in RFC 2119 [RFC2119].
3. Private Use ASNs 3. Private Use ASNs
To allow the continued growth of usage of the BGP protocol in new To allow the continued growth of BGP protocol usage in new network
network applications that utilize Private Use ASNs, two ranges of applications that utilize Private Use ASNs, two ranges of ASNs are
ASNs are reserved by this document in Section 6. The first, which reserved by Section 5 of this document. The first is part of the
was previously defined in [RFC1930] out of the original 16-bit original 16-bit Autonomous System range previously defined in
Autonomous System range, and a second, larger range out of the higher [RFC1930], and the second is a larger range out of the Four-Octet AS
part of the Four-Octet AS Number Space [RFC6793]. Number Space [RFC6793].
4. Operational Considerations 4. Operational Considerations
If Private Use ASNs are used and prefixes are originated from these If Private Use ASNs are used and prefixes originate from these ASNs,
ASNs, Private Use ASNs MUST be removed from AS path attributes Private Use ASNs MUST be removed from AS path attributes (including
(including AS4_PATH if utilizing four-octet AS number space) before AS4_PATH if utilizing a four-octet AS number space) before being
being advertised to the global Internet. Operators SHOULD ensure all advertised to the global Internet. Operators SHOULD ensure that all
EBGP speakers support [RFC6793] and ensure any implementation External Border Gateway Protocol (EBGP) speakers support the
specific features that recognize Private Use ASNs have been updated extensions described in [RFC6793] and that implementation-specific
to recognize both ranges prior to making use of the newer, features that recognize Private Use ASNs have been updated to
numerically higher range of Private Use ASNs in the four-octet AS recognize both ranges prior to making use of the newer, numerically
number space. Some existing implementations that remove Private Use higher range of Private Use ASNs in the four-octet AS number space.
ASNs from the AS_PATH are known to not remove Private Use ASNs if the Some existing implementations that remove Private Use ASNs from the
AS_PATH contains a mixture of Private Use and Non-Private Use ASNs. AS_PATH are known to not remove Private Use ASNs if the AS_PATH
If such implementations have not been updated to recognize the new contains a mixture of Private Use and Non-Private Use ASNs. If such
range of ASNs in this document and a mix of old and new range Private implementations have not been updated to recognize the new range of
Use ASNs exist in the AS4_PATH, these implementations will likely ASNs in this document and a mix of old and new range Private Use ASNs
cease to remove any Private Use ASNs from either of the AS path exist in the AS4_PATH, these implementations will likely cease to
attributes. Normal AS path filtering MAY also be used to prevent remove any Private Use ASNs from either of the AS path attributes.
prefixes originating from Private Use ASNs from being advertised to Normal AS path filtering MAY also be used to prevent prefixes
the global Internet. 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 5. IANA Considerations
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 IANA has reserved, for Private Use, a contiguous block of 1023
Autonomous System numbers from the "16-bit Autonomous System Numbers" Autonomous System numbers from the "16-bit Autonomous System Numbers"
registry, namely 64512 - 65534 inclusive. registry, namely 64512 - 65534 inclusive.
IANA has also reserved, for Private Use, a contiguous block of TBD1 IANA has also reserved, for Private Use, a contiguous block of
Autonomous System numbers from the "32-bit Autonomous System Numbers" 94,967,295 Autonomous System numbers from the "32-bit Autonomous
registry, namely TBD2 - TBD3 inclusive. System Numbers" registry, namely 4200000000 - 4294967294 inclusive.
These reservations have been documented in the IANA Autonomous System These reservations have been documented in the IANA "Autonomous
Numbers Registry [IANA.AS]. System (AS) Numbers" registry [IANA.AS].
7. Security Considerations 6. Security Considerations
Private Use ASNs do not raise any unique security concerns. Loss of Private Use ASNs do not raise any unique security concerns. Loss of
connectivity might result from inappropriate use of them, connectivity might result from their inappropriate use, specifically
specifically outside of a single organization, since they are not outside of a single organization, since they are not globally unique.
globally unique. This loss of connectivity is limited to the This loss of connectivity is limited to the organization using
organization using Private Use ASNs inappropriately or without Private Use ASNs inappropriately or without reference to Section 4.
reference to Section 4. General BGP security considerations are General BGP security considerations are discussed in [RFC4271] and
discussed in [RFC4271] and [RFC4272]. Identification of the [RFC4272]. Identification of the originator of a route with a
originator of a route with a Private Use ASN in the AS path would Private Use ASN in the AS path would have to be done by tracking the
have to be done by tracking the route back to the neighboring route back to the neighboring globally unique AS in the path or by
globally unique AS in the path or by inspecting other attributes. inspecting other attributes.
8. References 7. References
8.1. Normative References 7.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997. Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC4271] Rekhter, Y., Li, T., and S. Hares, "A Border Gateway [RFC4271] Rekhter, Y., Li, T., and S. Hares, "A Border Gateway
Protocol 4 (BGP-4)", RFC 4271, January 2006. Protocol 4 (BGP-4)", RFC 4271, January 2006.
[RFC6793] Vohra, Q. and E. Chen, "BGP Support for Four-Octet [RFC6793] Vohra, Q. and E. Chen, "BGP Support for Four-Octet
Autonomous System (AS) Number Space", RFC 6793, December Autonomous System (AS) Number Space", RFC 6793,
2012. December 2012.
8.2. Informative References 7.2. Informative References
[IANA.AS] IANA, "Autonomous System (AS) Numbers", May 2013, [IANA.AS] IANA, "Autonomous System (AS) Numbers",
<http://www.iana.org/assignments/as-numbers/>. <http://www.iana.org/assignments/as-numbers/>.
[RFC1930] Hawkinson, J. and T. Bates, "Guidelines for creation, [RFC1930] Hawkinson, J. and T. Bates, "Guidelines for creation,
selection, and registration of an Autonomous System (AS)", selection, and registration of an Autonomous System (AS)",
BCP 6, RFC 1930, March 1996. BCP 6, RFC 1930, March 1996.
[RFC4272] Murphy, S., "BGP Security Vulnerabilities Analysis", RFC [RFC4272] Murphy, S., "BGP Security Vulnerabilities Analysis",
4272, January 2006. RFC 4272, January 2006.
8. 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.
Author's Address Author's Address
Jon Mitchell Jon Mitchell
Microsoft Corporation Microsoft Corporation
One Microsoft Way One Microsoft Way
Redmond, WA 98052 Redmond, WA 98052
USA USA
Email: Jon.Mitchell@microsoft.com EMail: Jon.Mitchell@microsoft.com
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