Network Working Group S. Miyakawa
Internet-Draft NTT Communications Corporation
Expires: December 28, 2003 R. Droms
Cisco
June 29, 2003
Requirements for IPv6 prefix delegation
draft-ietf-ipv6-prefix-delegation-requirement-02.txt
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Copyright Notice
Copyright (C) The Internet Society (2003). All Rights Reserved.
Abstract
This document describes requirements for how IPv6 address prefixes
should be delegated to an IPv6 subscriber's network (or "site").
1. Introduction
With the deployment of IPv6 [1], several Internet Service Providers
are ready to offer IPv6 access to the public. In conjunction with
widely deployed "always on" media such as ADSL and the expectation
that cusomters will be assigned a /48 IPv6 unicast address prefix
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(see RFC3513 [2] and section 3 of RFC3177 [3]), an efficient
mechanism for delegating address prefixes to the customers sites is
needed. The delegation mechanism will be intended to automate the
process of informing the customer's networking equipment of the
prefixes to be used at the customer's site.
This document clarifies the requirements for IPv6 address prefix
delegation from the ISP to the site.
2. Scenario and terminology
The following figure illustrates a likely example for the
organization of a network providing subscription IPv6 service:
/------\
/ \
+ |
/ \ /
+---------------+ +--------+/ \------/
|ISP Edge Router|Point-to-point|Customer+
| +--------------+ Router | Customer networks
| (PE) | link | (CPE) +
+---------------+ +--------+\ /------\
\ / \
+ |
\ /
\------/
Figure 1: Illustration of ISP-customer network architecture
Terminology:
PE: Provider edge device; the device connected to the service
provider's network infrastructure at which the link to the
customer site is terminated
CPE: Customer premises equipment; the device at the customer site at
which the link to the ISP is terminated
3. Requirements for Prefix Delegation
The purpose of the prefix delegation mechanism is to delegate and
manage prefixes to the CPE automatically.
3.1 Number and Length of Delegated Prefixes
The prefix delegation mechanism should allow for delegation of
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prefixes of lengths between /48 and /64, inclusively. Other lengths
may be supported. The mechanism should allow for delegation of more
than one prefix to the customer.
3.2 Use of Delegated Prefixes in Customer Network
The prefix delegation mechanism must not prohibit or inhibit the
assignment of longer prefixes, created from the delegated prefixes,
to links within the customer network. It is not a requirement that
the prefix delegation mechanism provide for the reporting of prefix
delegation within the customer network back to the ISP.
3.3 Static and Dynamic Assignment
The prefix delegation mechanism should allow for long-lived static
pre-assignment of prefixes and for automated, possibly short-lived
on-demand dynamic assignment of prefixes to a customer.
3.4 Policy-based Assignment
The prefix delegation mechanism should allow for the use of policy in
assigning prefixes to a customer. For example, the customer's
identity and type of subscribed service may be used to determine the
address block from which the customer's prefix is selected, and the
length of the prefix assigned to the customer.
3.5 Security and Authentication
The prefix delegation mechanism must provide for reliable
authentication of the identity of the customer to which the prefixes
are to be assigned, and must provide for reliable, secure
transmission of the delegated prefixes to the customer.
3.6 Accounting
The prefix delegation mechanism must allow for the ISP to provide
accounting information about delegated prefixes.
3.7 Hardware technology Considerations
The prefix delegation mechanism should work on any hardware
technology and should be hardware technology independent. The
mechanism must work on shared links. The mechanism should work with
all hardware technologies either with authentication mechanism or
without, but ISPs would like to take advantage of hardware
technology's authentication mechanism if it exits.
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4. IANA Considerations
There are no IANA considerations in this document.
5. Security considerations
Section 3.5 specifies security requirements for the prefix delegation
mechanism. For point to point links, where one trusts that there is
no man in the middle, or one trusts layer two authentication,
authentication may not be necessary.
A rogue delegating router can issue bogus prefixes to a requesting
router. This may cause denial of service due to unreachability.
An intruder requesting router may be able to mount a denial of
service attack by repeated requests for delegated prefixes that
exhaust the delegating router's available prefixes.
Informative References
[1] Deering, S. and R. Hinden, "Internet Protocol, Version 6 (IPv6)
Specification", RFC 2460, December 1998.
[2] Hinden, R. and S. Deering, "Internet Protocol Version 6 (IPv6)
Addressing Architecture", RFC 2460, December 1998.
[3] IESG, IAB,., "IAB/IESG Recommendations on IPv6 Address", RFC
3177, September 2001.
Authors' Addresses
Shin Miyakawa
Innovative IP Architecture Center, NTT Communications Corporation
Tokyo
Japan
Phone: +81-3-6800-3262
EMail: miyakawa@nttv6.jp
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Ralph Droms
Cisco
1414 Massachusetts Avenue
Boxborough, MA 01719
USA
Phone: +1 978.936.1674
EMail: rdroms@cisco.com
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