--- 1/draft-ietf-6man-reserved-iids-02.txt 2008-12-04 00:12:03.000000000 +0100 +++ 2/draft-ietf-6man-reserved-iids-03.txt 2008-12-04 00:12:03.000000000 +0100 @@ -1,18 +1,18 @@ Network Working Group S. Krishnan Internet-Draft Ericsson -Intended status: Standards Track December 2, 2008 -Expires: June 5, 2009 +Intended status: Standards Track December 3, 2008 +Expires: June 6, 2009 Reserved IPv6 Interface Identifiers - draft-ietf-6man-reserved-iids-02 + draft-ietf-6man-reserved-iids-03 Status of this Memo By submitting this Internet-Draft, each author represents that any 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 aware will be disclosed, in accordance with Section 6 of BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that @@ -23,37 +23,38 @@ 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. - This Internet-Draft will expire on June 5, 2009. + This Internet-Draft will expire on June 6, 2009. Abstract Interface Identifiers in IPv6 unicast addresses are used to identify interfaces on a link. They are required to be unique within a subnet. Several RFCs have specified interface identifiers or identifier ranges that have a special meaning attached to them. An IPv6 node autoconfiguring an interface identifier in these ranges will encounter unexpected consequences. Since there is no centralized repository for such reserved identifiers, this document aims to create one. Table of Contents 1. Requirements notation . . . . . . . . . . . . . . . . . . . . 3 2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 + 2.1. Applicability . . . . . . . . . . . . . . . . . . . . . . 4 3. Issues with reusing reserved Interface Identifiers . . . . . . 5 3.1. Possible solutions . . . . . . . . . . . . . . . . . . . . 5 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6 5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 7 6. Security Considerations . . . . . . . . . . . . . . . . . . . 8 7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 9 7.1. Normative References . . . . . . . . . . . . . . . . . . . 9 7.2. Informative References . . . . . . . . . . . . . . . . . . 9 Appendix A. List of potentially affected RFCs . . . . . . . . . . 10 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 11 @@ -75,29 +76,32 @@ | n bits | 128-n bits | +-------------------------------+---------------------------------+ | subnet prefix | interface ID | +-------------------------------+---------------------------------+ Figure 1: IPv6 Unicast Address Format For all unicast addresses, except those that start with the binary value 000, Interface IDs are required to be 64 bits long and to be - constructed in Modified EUI-64 format. If the interface identifiers - are generated from an unique token like an ethernet MAC address, they - need to set bit 6 of the first octet to one. If they are not - generated from an unique token they need to set bit 6 to zero. - Examples of mechanisms that generate interface identifiers without an - unique token include Cryptographically Generated Addresses [RFC3972], - Privacy Addresses [RFC4941], Hash Based Addresses [HBA] etc. Non- - unique interface identifiers can also be allocated using managed - address assignment mechanisms like DHCPv6 [RFC3315]. + constructed in Modified EUI-64 format. Examples of mechanisms that + generate interface identifiers without an unique token include + Cryptographically Generated Addresses [RFC3972], Privacy Addresses + [RFC4941], Hash Based Addresses [HBA] etc. Non-unique interface + identifiers can also be allocated using managed address assignment + mechanisms like DHCPv6 [RFC3315]. + +2.1. Applicability + + This document applies only to interface identifiers that are formed + in the modified EUI-64 format as defined in Appendix A of [RFC4291]. + All other types of interface identifiers are out of scope. 3. Issues with reusing reserved Interface Identifiers Let us assume a node comes up with an interface identifier that has been reserved for use in some other capacity. e.g. An IPv6 node that uses temporary IPv6 addresses [RFC4941] comes up with an IID of fdff: ffff:ffff:fff . This node will receive requests from all nodes that are requesting a service from a MobileIPv6 home agent since the above mentioned interface identifier has been reserved in [RFC2526] to serve as a MIPv6 home agents anycast address. At best this is an @@ -123,48 +127,44 @@ 4. IANA Considerations This document requests the creation of an IANA registry for reserved IPv6 Interface Identifiers. Initial values for the reserved IPv6 Interface Identifiers are given below. +-----------------------------------------+-------------------------+ | Interface Identifier Range | Description | +-----------------------------------------+-------------------------+ - | 0000:0000:0000:0000-0000:0000:0000:0000 | Subnet-Router Anycast | + | 0000:0000:0000:0000 | Subnet-Router Anycast | | | [RFC4291] | | | | | FDFF:FFFF:FFFF:FF80-FDFF:FFFF:FFFF:FFFF | Reserved Subnet Anycast | | | Addresses[RFC2526] | +-----------------------------------------+-------------------------+ Table 1: Current Assignments It is possible that implementations might predate a specific assignment from this registry and hence not be cognizant of the - reserved nature of the interface identifier. Hence. future - assignments from this registry are discouraged but in exceptional - circumstances are to be made through Standards Action [RFC5226]. + reserved nature of the interface identifier. Hence, future + assignments from this registry are discouraged. Future assignments, + if any, are to be made through Standards Action [RFC5226]. Assignments consist of a single interface identifier or a range of interface identifiers. NOTE: Please note that the address :: (all zeros in the interface - identifier field) is used as the unspecified address. In addition, - many IETF protocols and data formats prescribe that the unused bits - in prefixes be set to 0. Hence, prefixes with prefix lengths up to - 64 are usually stored and transmitted with an interface identifier - part of all zeros. This includes ::/0, used as a default route - indicator, as specified in [RFC5156]. These uses do not conflict - with the reserved interface identifiers defined here, since the - reserved identifiers defined in this document are used for avoiding - conflicts with stateless address autoconfiguration that utilizes a 64 - bit prefix length. + identifier field) is used as the unspecified address and ::/0 is used + as a default route indicator, as specified in [RFC5156]. These uses + do not conflict with the reserved interface identifiers defined here, + since the reserved identifiers defined in this document are used for + avoiding conflicts with stateless address autoconfiguration that + utilizes a 64 bit prefix length. 5. Acknowledgements The author would like to thank Alain Durand, Alex Petrescu, Bernie Volz, Bob Hinden, Christian Huitema, Fred Templin, Jordi Palet Martinez, Pekka Savola, Remi Denis-Courmount, Tim Enos, Alex Petrescu, Ed Jankiewicz, Brian Carpenter, Alfred Hoenes, Jari Arkko, Pasi Eronen, Tim Polk, Lars Eggert, Derek Atkins and Robert Sparks for reviewing this document and suggesting changes.