draft-ietf-idr-as-private-reservation-00.txt   draft-ietf-idr-as-private-reservation-01.txt 
Network Working Group J. Mitchell Network Working Group J. Mitchell
Internet-Draft Microsoft Corporation Internet-Draft Microsoft Corporation
Updates: 1930 (if approved) October 11, 2012 Updates: 1930 (if approved) December 20, 2012
Intended status: Informational Intended status: Informational
Expires: April 14, 2013 Expires: June 23, 2013
Autonomous System (AS) Reservation for Private Use Autonomous System (AS) Reservation for Private Use
draft-ietf-idr-as-private-reservation-00 draft-ietf-idr-as-private-reservation-01
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 should not be advertised to (ASNs) that are for Private Use only and should not be advertised to
the Internet, known as private use ASNs. This document enlarges the the Internet, known as Private Use ASNs. This document enlarges the
total space available for private use ASNs by documenting the total space available for Private Use ASNs by documenting the
reservation of a second, larger range and updates RFC 1930. reservation of a second, larger range and updates RFC 1930 by
replacing Section 10.
Status of this Memo Status of this Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on April 14, 2013. This Internet-Draft will expire on June 23, 2013.
Copyright Notice Copyright Notice
Copyright (c) 2012 IETF Trust and the persons identified as the Copyright (c) 2012 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
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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 IETF in Section 10 of [RFC1930]. Since the time when that range was
reserved, BGP has seen much wider deployment in service provider, reserved, BGP has seen much wider deployment in service provider,
enterprise and content provider networks. The places in these enterprise, and datacenter networks. The places in these networks
networks where private use ASNs are in use include networks that are where Private Use ASNs are in use include networks that are attached
attached to the Internet, utilizing implementation specific features to the Internet, utilizing implementation specific features to remove
to remove them upon advertisement to Internet peers, and networks them upon advertisement to Internet peers, and networks that are not
that are not attached to the Internet. The displacement of Frame attached to the Internet.
Relay and ATM based VPNs by BGP/MPLS IP VPNs [RFC4364] has also
increased the deployment of BGP to a larger number of sites,
especially in networks with requirements for multi-homing or provider
redundancy.
The limited size of the current range of private use ASNs has led to The limited size of the current range of Private Use ASNs has led to
the re-use of private use ASNs within a single organization, the re-use of the same ASN within a single organization, requiring
requiring the use of a number of implementation specific features the use of a number of implementation specific features that
that manipulate the AS_PATH or remove AS_PATH based loop prevention manipulate the AS_PATH or remove AS_PATH based loop prevention
described in Section 9 of [RFC4271]. These workarounds have described in Section 9 of [RFC4271]. These workarounds have
increased the operational complexity of the networks since the increased the operational complexity of the networks since the
implementations of these functions vary and are not defined in implementations of these functions vary and are not defined in
existing BGP standards. existing BGP standards.
Since the introduction of BGP Support for Four-octet AS Number Space Since the introduction of BGP Support for Four-octet AS Number Space
[I-D.ietf-idr-rfc4893bis], the total size of the ASN space has [RFC6793], the total size of the ASN space has increased
increased dramatically, and a larger subset of the space should be dramatically, and a larger subset of the space should be available to
available to network operators to deploy in private use cases. The network operators to deploy in Private Use cases. The existing range
existing range of private use ASNs is widely deployed and the ability of Private Use ASNs is widely deployed and the ability to renumber
to renumber this resource in existing networks cannot be coordinated this resource in existing networks cannot be coordinated given these
given these ASNs by definition are not registered. Therefore this ASNs by definition are not registered. Therefore this documents the
documents the existing private use ASN reservation, while also existing Private Use ASN reservation, while also introducing a
introducing a second, larger range that can also be utilized. second, larger range that can also be utilized.
2. Private Use ASNs 2. Private Use ASNs
To allow the continued growth of usage of the BGP protocol in To allow the continued growth of usage of the BGP protocol in
networks that utilize private ASNs, two ranges of ASNs are reserved networks that utilize Private Use ASNs, two ranges of ASNs are
by this document in Section 5. The first which was previously reserved by this document in Section 5. The first which was
defined in [RFC1930] out of the original 16-bit Autonomous System previously defined in [RFC1930] out of the original 16-bit Autonomous
range and a second, larger range out of the higher part of the Four- System range and a second, larger range out of the higher part of the
Octet AS Number Space [I-D.ietf-idr-rfc4893bis]. Four-Octet AS Number Space [RFC6793].
3. Operational Considerations 3. Operational Considerations
If private use ASNs are used and prefixes are originated from these If Private Use ASNs are used and prefixes are originated from these
private use ASNs which are destined to the Internet, private use ASNs ASNs which are destined to the Internet, Private Use ASNs must be
must be removed from the AS_PATH before being advertised to the removed from the AS_PATH before being advertised to the global
global Internet. Operators are cautioned to ensure any filters or Internet. Operators are cautioned to ensure any implementation
implementation specific features that recognize private use ASNs have specific features that recognize Private Use ASNs have been updated
been updated to recognize both ranges prior to making use of the to recognize both ranges prior to making use of the newer,
newer, numerically higher range of private use ASNs. numerically higher range of Private Use ASNs. Some implementations
of such features will fail to remove any Private Use ASNs from the
AS_PATH if the AS_PATH contains a mix of Private Use and non-Private
Use ASNs and if these implementations are not updated, the newer
range may be classified as the later. Normal AS_PATH filtering may
also be used to limit prefixes originating from Private Use ASNs from
being advertised to the global Internet and can help in transition
scenarios until the implementation specific features that manipulate
AS_PATH are updated.
4. Acknowledgements 4. Acknowledgements
The author would like to acknowledge Christopher Morrow and Jason The author would like to acknowledge Christopher Morrow, Jason
Schiller for their advice on how to pursue this change. The author Schiller, and John Scudder for their advice on how to pursue this
also thanks Brian Dickson, David Farmer, and Jeffrey Haas for their change. The author would also like to thank Brian Dickson, David
comments and suggestions. Farmer, Jeffrey Haas, Nick Hilliard, Warren Kumari, and Jeff Wheeler
for their comments and suggestions.
5. IANA Considerations 5. IANA Considerations
[Note to IANA, NOT for publication: The IANA should update the "16- [Note to IANA, NOT for publication: The IANA should update the "16-
bit Autonomous System Numbers" registry to reference this RFC (when bit Autonomous System Numbers" registry to reference this RFC (when
published) for the existing private use reservation. Further, to published) for the existing Private Use reservation. Further, to
maintain consistency from an operator standpoint, it is suggested maintain consistency from an operator standpoint, it is suggested
that the end of the "32-bit Autonomous System Numbers" range be that the end of the "32-bit Autonomous System Numbers" range be
reserved for Private Use, and a size of 16777215 (value to replace reserved for Private Use, and a size of 94,967,295 (value to replace
TBD1 below) is suggested corresponding to the range of 4278190080 TBD1 below) is suggested corresponding to the range of 4200000000
(value to replace TBD2 below) to 4294967294 (value to replace TBD3 (value to replace TBD2 below) to 4294967294 (value to replace TBD3
below).] below).]
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 TBD1
Autonomous System numbers from the "32-bit Autonomous System Numbers" Autonomous System numbers from the "32-bit Autonomous System Numbers"
registry, namely TBD2 - TBD3 inclusive. registry, namely TBD2 - TBD3 inclusive.
These reservations have been documented in the IANA Autonomous System These reservations have been documented in the IANA Autonomous System
Numbers Registry [IANA.AS]. Numbers Registry [IANA.AS].
6. Security Considerations 6. Security Considerations
This document does not introduce any additional security concerns in This document does not introduce any additional security concerns in
regards to private use ASNs. regards to Private Use ASNs.
7. References 7. References
7.1. Normative References 7.1. Normative References
[I-D.ietf-idr-rfc4893bis]
Vohra, Q. and E. Chen, "BGP Support for Four-octet AS
Number Space", draft-ietf-idr-rfc4893bis-07 (work in
progress), June 2012.
[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
Autonomous System (AS) Number Space", RFC 6793,
December 2012.
7.2. Informative References 7.2. Informative References
[IANA.AS] IANA, "Autonomous System (AS) Numbers", October 2012, [IANA.AS] IANA, "Autonomous System (AS) Numbers", December 2012,
<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.
[RFC4364] Rosen, E. and Y. Rekhter, "BGP/MPLS IP Virtual Private
Networks (VPNs)", RFC 4364, February 2006.
Author's Address Author's Address
Jon Mitchell Jon Mitchell
Microsoft Corporation Microsoft Corporation
12012 Sunset Hills Road 12012 Sunset Hills Road
Reston, VA 20190 Reston, VA 20190
USA USA
Email: Jon.Mitchell@microsoft.com Email: Jon.Mitchell@microsoft.com
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