INTERNET DRAFT M. Ohta draft-ohta-address-allocation-00.txt Tokyo Institute of Technology Geoff Huston Telstra Corporation Masaki Hirabaru Merit Network, Inc. Jun Murai Keio University May 2000 Usage Based Address Allocation Considered Harmful Status of this Memo This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC2026. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet- Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. "Copyright (C) The Internet Society (May/1/2000). All Rights Reserved. Abstract The current usage based IPv4 address assignment policies might have prolonged the useful lifetime of IPv4 address space but this has to the detriment of the the end-to-end architecture of the Internet. This memo proposes the adoption of an address assignment strategy that releases large blocks of IPv4 address space into the Internet. The objective of this policy is to encourage healthy Internet deployment models with end-to-end transparency and association of permanent connectivity with a stable IP address. This is intended to encourage provider support for open transparent Internet service environments that can be sustained with the adoption of IPv6. M. Ohta Expires on November 1, 2000 [Page 1] INTERNET DRAFT UBAA Considered Harmful May 2000 Introduction Current address allocation policies [1] [2] [3] are primarily concerned with the conservation of the remaining unallocated IPv4 address space, and the suppression of rapid growth of the Internet routing tables. The criteria for address allocation is based on demonstrable need in terms of number of connected hosts and the nature of the intended deployment. Such allocation policies place a significant administrative overhead on parties wishing to obtain IPv4 address space. These overheads are compounded through the use of provider-based address allocation and associated CIDR blocks. Renumbering may be required if the client network grows so that it requires a larger address block to encompass all connected systems. Renumbering can be a painful and very expensive exercise, and the costs of such renumbering exercises often outweighs, from the administrative point of view of ISPs, any potential benefit for the ISPs to use globally unique addresses. Such considerations have lead to the widespread promotion of dynamic address translation tools, such as NAT. While NAT allows the client network to grow using private address space, and switch providers with considerable ease, the cost is one of a reduction in functionality and utility. NAT fundamentally affects the end-to-end transparency of the Internet architectural model [4], and impairs the concept of open global connectivity supported by the Internet. As a result, the Internet is dissolving into a loosely coupled collection of IP based networks with no end-to-end transparency [5]. Instead, we should keep the architectural principles of the Internet [4] and, before the IPv4 address space is completely exhausted, migrate to IPv6. The existing address allocation policies do not have a long term stable future. Either the conservation principle will require ever stricter implementation of usage policies to match the dwindling size of the remaining pool of unallocated IP addresses, or the previously allocated address space will need to be freed up into an open trading model, with consequent implications on the routability of the resultant system [6]. Both of these outcomes further encourage the fragmentation of the Internet through increasing use of NAT techniques as the premium for the use of routable IPv4 space escalates. It is now time to consider adoption of an alternative IPv4 allocation policy. The primary objective of such a policy should be the ordered migration of the Internet into a larger address space which can M. Ohta Expires on November 1, 2000 [Page 2] INTERNET DRAFT UBAA Considered Harmful May 2000 accommodate the known deployment requirements and also accommodate likely medium term future deployment scenarios. Such a policy fosters the continued growth of the Internet while at the same time does not place extraneous limitations on application models that have to operate in an end-to-end fashion across the network. Continued reliance on usage-based address allocation policies is harmful to the Internet. The ever decreasing size of the unallocated address pool, coupled with the increasing demand for addresses in the expanding network creates further pressures to push the network growth into private address space, and attempt to glue these networks into the Internet by using specific translation gateways that are not transparent to all application and security models. The harm is caused by the continued illusion of a single cohesive Internet, conflicting with the reality of a loosely coupled collection of completely autonomous network realms whose interconnection is poorly maintained and where applications cannot operate in an any-to-any connection mode. In short the concept of "one cohesive Internet" is being lost, partly because of the usage based address allocation. Usage based address allocation is considered harmful. The Assignment Plan A large block of IPv4 address space should be allocated to an ISP, if the ISP Provides full time Internet connectivity. On-demand connectivity to a host through PPP or DHCP is not useful to deliver packets to the host which has not demanded the connectivity merely because the host has no packets to send and, in this memo, is not considered to be the full time connectivity. Allocate all the end users a globally unique block of IPv4 addresses /29 or more. Allocate the end users who request more space a globally unique block of IPv4 addresses /27 or more without additional charge. Provide all the end users experimental service of IPv6 Internet connectivity. Allocate all the end users a block of 64K IPv6 subnets or more. Delegate the end users who request their own management of DNS reverse lookup the DNS domains of allocated addresses without additional charge. M. Ohta Expires on November 1, 2000 [Page 3] INTERNET DRAFT UBAA Considered Harmful May 2000 When the ISP needs more addresses, multiple address blocks should be allocated with no renumbering requested. The More Restricted Assignment Plan Such an address allocation policy has the potential to increase the consumption of the unallocated IPv4 address pool, and there will be a consequent need to formulate an refined IPv4 address allocation policy that would, in all probability, be used to allocate the final remaining IPv4 address blocks. At this stage the primary objective of the address allocation policy is to provide a very strong incentive for migration of the network base to IPv6. One way to achieve this is with the adoption of an additional restriction on the above address allocation policy, namely: No IPv4 address space should be allocated to an ISP, unless the ISP support fully operational fully transparent IPv6 service with at least 64K IPv6 subnets to all the end users. Security Considerations Many security models use the end systems' allocated IP addresses as part of the means of authentication of the identity of the remote entity. Without globally unique addresses, it is difficult, if not impossible, to use the IP addresses for such authentication. Acknowledgements The Authors are grateful to useful comments from Randy Bush. References [1] K. Hubbard, M. Kosters, D. Conrad, D. Karrenberg, J. Postel, "Internet Registry IP Allocation Guidelines", RFC 2050, November 1996. [2] "Policies for Address Space Management in the Asia Pacific Region", APNIC, http://www.apnic.net/docs/add-manage-policy.html, January 2000. [3] "ISP Guidelines for Requesting Initial IP Address Space", ARIN, http://www.arin.net/regserv/initial-isp.html. [4] B. Carpenter, "Architectural Principles of the Internet", RFC 1958, June 1996. M. Ohta Expires on November 1, 2000 [Page 4] INTERNET DRAFT UBAA Considered Harmful May 2000 [5] B. Carpenter, "Internet Transparency", RFC 2775, February 2000. [6] G. Huston, "Observations on the Management of the Internet Address Space", RFC 1744, December 1994. Authors' Addresses Masataka Ohta Tokyo Institute of Technology 2-12-1, O-okayama, Meguro-ku, Tokyo 152, JAPAN Phone: +81-3-5734-3299 Fax: +81-3-5734-3415 EMail: mohta@necom830.hpcl.titech.ac.jp Geoff Huston Telstra Corporation 5/490 Northbourne Ave, Dickson, ACT 2602 AUSTRARIA EMail: gih@telstra.net Masaki Hirabaru Merit Network, Inc. 4251 Plymouth Road, Suite 2000 Ann Arbor, MI 48105-2785, USA Phone: +1-734-764-9430 Fax: +1-734-647-3185 EMail: masaki@merit.edu Jun Murai Keio University 5322 Endo, Fujisawa Kanagawa 252, JAPAN Fax: +81-466-49-1101 EMail: jun@wide.ad.jp A mailing list is set up for the discussion at: Restoring The Transparency To subscribe, send a mail containing a single line of subscribe your name M. Ohta Expires on November 1, 2000 [Page 5] INTERNET DRAFT UBAA Considered Harmful May 2000 to rtt-ctl@real-internet.org M. Ohta Expires on November 1, 2000 [Page 6] INTERNET DRAFT UBAA Considered Harmful May 2000 Full Copyright Statement "Copyright (C) The Internet Society (May/1/2000). All Rights Reserved. This document and translations of it may be copied and furnished to others, and derivative works that comment on or otherwise explain it or assist in its implementation may be prepared, copied, published and distributed, in whole or in part, without restriction of any kind, provided that the above copyright notice and this paragraph are included on all such copies and derivative works. However, this document itself may not be modified in any way, such as by removing the copyright notice or references to the Internet Society or other Internet organizations, except as needed for the purpose of developing Internet standards in which case the procedures for copyrights defined in the Internet Standards process must be followed, or as required to translate it into languages other than English. 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