draft-ietf-v6ops-addcon-06.txt   draft-ietf-v6ops-addcon-07.txt 
IPv6 Operations G. Van de Velde IPv6 Operations G. Van de Velde
Internet-Draft C. Popoviciu Internet-Draft C. Popoviciu
Intended status: Informational Cisco Systems Intended status: Informational Cisco Systems
Expires: April 3, 2008 T. Chown Expires: May 8, 2008 T. Chown
University of Southampton University of Southampton
O. Bonness O. Bonness
C. Hahn C. Hahn
T-Systems Enterprise Services GmbH T-Systems Enterprise Services GmbH
October 1, 2007 November 5, 2007
IPv6 Unicast Address Assignment Considerations IPv6 Unicast Address Assignment Considerations
<draft-ietf-v6ops-addcon-06.txt> <draft-ietf-v6ops-addcon-07.txt>
Status of this Memo Status of this Memo
By submitting this Internet-Draft, each author represents that any By submitting this Internet-Draft, each author represents that any
applicable patent or other IPR claims of which he or she is aware applicable patent or other IPR claims of which he or she is aware
have been or will be disclosed, and any of which he or she becomes have been or will be disclosed, and any of which he or she becomes
aware will be disclosed, in accordance with Section 6 of BCP 79. aware will be disclosed, in accordance with Section 6 of BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that Task Force (IETF), its areas, and its working groups. Note that
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and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
The list of current Internet-Drafts can be accessed at The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt. http://www.ietf.org/ietf/1id-abstracts.txt.
The list of Internet-Draft Shadow Directories can be accessed at The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html. http://www.ietf.org/shadow.html.
This Internet-Draft will expire on April 3, 2008. This Internet-Draft will expire on May 8, 2008.
Copyright Notice Copyright Notice
Copyright (C) The IETF Trust (2007). Copyright (C) The IETF Trust (2007).
Abstract Abstract
One fundamental aspect of any IP communications infrastructure is its One fundamental aspect of any IP communications infrastructure is its
addressing plan. With its new address architecture and allocation addressing plan. With its new address architecture and allocation
policies, the introduction of IPv6 into a network means that network policies, the introduction of IPv6 into a network means that network
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Address space conservation is the main motivation for using a subnet Address space conservation is the main motivation for using a subnet
prefix length longer than 64 bits, however this kind of address prefix length longer than 64 bits, however this kind of address
conservation is of futile benefit compared with the additional conservation is of futile benefit compared with the additional
considerations one must make when creating and maintain an IPv6 considerations one must make when creating and maintain an IPv6
address plan. address plan.
The address assignment can be made either by manual configuration or The address assignment can be made either by manual configuration or
by a stateful Host Configuration Protocol [11]. by a stateful Host Configuration Protocol [11].
When assigning a subnet prefix of more then 80 bits, according to When assigning a subnet prefix of more then 70 bits, according to
RFC4291 [26] "u" and "g" bits (respectively the 81st and 82nd bit) RFC4291 [26] "u" and "g" bits (respectively the 71st and 72nd bit)
need to be taken into consideration and should be set correctly. In need to be taken into consideration and should be set correctly. In
currently implemented IPv6 protocol stacks, the relevance of the "u" currently implemented IPv6 protocol stacks, the relevance of the "u"
(universal/local) bit and "g" (the individual/group) bit are marginal (universal/local) bit and "g" (the individual/group) bit are marginal
and typically will not show an issue when configured wrongly, however and typically will not show an issue when configured wrongly, however
future implementations may turn out differently. future implementations may turn out differently.
When using subnet lengths longer then 64 bits, it is important to When using subnet lengths longer then 64 bits, it is important to
avoid selecting addresses that may have a predefined use and could avoid selecting addresses that may have a predefined use and could
confuse IPv6 protocol stacks. The alternate usage may not be a confuse IPv6 protocol stacks. The alternate usage may not be a
simple unicast address in all cases. The following points should be simple unicast address in all cases. The following points should be
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6. Security Considerations 6. Security Considerations
This IPv6 addressing document does not have any direct impact on This IPv6 addressing document does not have any direct impact on
Internet infrastructure security. Internet infrastructure security.
7. Acknowledgements 7. Acknowledgements
Constructive feedback and contributions have been received from Marla Constructive feedback and contributions have been received from Marla
Azinger, Stig Venaas, Pekka Savola, John Spence, Patrick Grossetete, Azinger, Stig Venaas, Pekka Savola, John Spence, Patrick Grossetete,
Carlos Garcia Braschi, Brian Carpenter, Mark Smith, Janos Mohacsi, Carlos Garcia Braschi, Brian Carpenter, Mark Smith, Janos Mohacsi,
Jim Bound, Fred Templin and Ginny Listman. Jim Bound, Fred Templin, Ginny Listman and Krishnan Thirukonda.
8. References 8. References
8.1. Normative References 8.1. Normative References
8.2. Informative References 8.2. Informative References
[1] Rekhter, Y., Moskowitz, R., Karrenberg, D., Groot, G., and E. [1] Rekhter, Y., Moskowitz, R., Karrenberg, D., Groot, G., and E.
Lear, "Address Allocation for Private Internets", BCP 5, Lear, "Address Allocation for Private Internets", BCP 5,
RFC 1918, February 1996. RFC 1918, February 1996.
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