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Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) ** Obsolete normative reference: RFC 3315 (Obsoleted by RFC 8415) Summary: 1 error (**), 0 flaws (~~), 1 warning (==), 1 comment (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Internet Engineering Task Force T. Narten 3 Internet-Draft J. Johnson 4 Intended status: Standards Track IBM 5 Expires: November 29, 2010 May 28, 2010 7 Definition of the UUID-based DHCPv6 Unique Identifier (DUID-UUID) 8 draft-narten-dhc-duid-uuid-00 10 Abstract 12 This document defines a new DHCPv6 Unique Identifier (DUID) type, 13 called DUID-UUID. DUID-UUIDs are derived from the already 14 standardized UUID format. DUID-UUID makes it possible for devices to 15 use UUIDs to identify themselves to DHC servers and vice versa. 16 UUIDs are globally unique and readily available on many systems, 17 making them convenient identifiers to leverage within DHCP. 19 Status of this Memo 21 This Internet-Draft is submitted in full conformance with the 22 provisions of BCP 78 and BCP 79. 24 Internet-Drafts are working documents of the Internet Engineering 25 Task Force (IETF). Note that other groups may also distribute 26 working documents as Internet-Drafts. The list of current Internet- 27 Drafts is at http://datatracker.ietf.org/drafts/current/. 29 Internet-Drafts are draft documents valid for a maximum of six months 30 and may be updated, replaced, or obsoleted by other documents at any 31 time. It is inappropriate to use Internet-Drafts as reference 32 material or to cite them other than as "work in progress." 34 This Internet-Draft will expire on November 29, 2010. 36 Copyright Notice 38 Copyright (c) 2010 IETF Trust and the persons identified as the 39 document authors. All rights reserved. 41 This document is subject to BCP 78 and the IETF Trust's Legal 42 Provisions Relating to IETF Documents 43 (http://trustee.ietf.org/license-info) in effect on the date of 44 publication of this document. Please review these documents 45 carefully, as they describe your rights and restrictions with respect 46 to this document. Code Components extracted from this document must 47 include Simplified BSD License text as described in Section 4.e of 48 the Trust Legal Provisions and are provided without warranty as 49 described in the Simplified BSD License. 51 Table of Contents 53 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 54 2. DUID-UUID Format . . . . . . . . . . . . . . . . . . . . . . . 4 55 3. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 4 56 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 5 57 5. Security Considerations . . . . . . . . . . . . . . . . . . . . 5 58 6. Normative References . . . . . . . . . . . . . . . . . . . . . 5 59 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 5 61 1. Introduction 63 In DHCPv6, clients identify themselves to servers via DHCP Unique 64 Identifiers (DUIDs) [RFC3315]. DUIDs are identifiers that DHCP 65 servers treat as opaque objects with no internal structure DUIDs are 66 intended to be globally unique, with no two devices using the same 67 DUID. Three DUIDs types have been defined so far: 69 DUID-LLT - contains the Link-Layer address of one of the device's 70 network interfaces, concatenated with a timestamp 72 DUID-EN - contains an Enterprise Number plus additional information 73 specific to the enterprise 75 DUID-LL - contains the Link-Layer address of one of the device's 76 network interfaces 78 The intention of DUIDs is that they remain constant over time, so 79 that they can be used as permanent identifiers for a device. In the 80 case of DUID-LLTs, they are intended to be generated once, and then 81 stored in stable storage and reused from that point forward. 83 In DHCPv4, all clients identify themselves to servers via the MAC 84 address of the interface on which the DHCP packet is sent. The MAC 85 address identifier generally remains constant across machine 86 restarts, installation of new operating system releases, changes in 87 hardware configuration such as addition or removal of storage 88 devices, etc. While the MAC address will change if the network 89 interface is replaced, this is a relatively uncommon event. 91 In contrast, the DUID-LLT and DUID-LL identifiers that a given device 92 may use are less likely to remain constant on some types of devices 93 and deployments. Specifically, when a machine goes through a multi- 94 step boot process, it may first load a simple boot loader, followed 95 by a one or more secondary loaders before the eventual actual target 96 system is loaded. In IPv4, all steps of a multi-step boot processes 97 that invoke DHCP are guaranteed to use the same MAC identifier during 98 each stage. In contrast, with DHCPv6, it is more difficult to ensure 99 or arrange that each boot stage uses the same identifier. First, 100 there are multiple DUID types, and different systems might choose to 101 use different formats. Second, even if the different stages used 102 DUID-LL or DUID-LLT, on devices with multiple interfaces, there is no 103 way to guarantee that the same interface (and hence DUID) will be 104 selected. Finally, in the case of DUID-LLT, even if the same 105 interface were chosen, there is no guarantee that each stage would 106 use the same timestamp value. While a DUID-EN could be defined and 107 used, such usage would be proprietary by definition. 109 This document defines a new DUID type, based on the Universally 110 Unique IDentifier (UUID) [RFC4122]. UUIDs are already use in 111 practice and serve as an existing identifier that could be leveraged 112 by DHCP. For example, x86 based systems ship with an embedded UUID 113 in firmware that could be accessed for this purpose. 115 Many UUIDs are in use today. For example, they are used in 116 Microsoft's Component Object Module (COM), and for labeling 117 partitions in filesystems. In order to identify a system 118 consistently within DHCP, however, it is important to choose a UUID 119 that will remain constant across system reconfigurations and other 120 system changes, and to choose a UUID that different system images and 121 boot stages will have easy access to. This document recommends 122 selecting a UUID that is part of the system firmware. 124 2. DUID-UUID Format 126 The DUID-UUID is carried within Client Identifier or Server 127 Identifier options. It has the following format: 129 0 1 2 3 130 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 131 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 132 | DUID-Type (TBD) | UUID (128 bits) | 133 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 134 | | 135 | | 136 | -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 137 | | 138 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- 140 DUID-UUID format. . 142 Figure 1 144 DUID-Type - TBD (16 bits) 146 UUID - An RFC4122 UUID (128 bits) 148 3. Acknowledgements 150 This document was inspired by a discussion on the DHC mailing list in 151 November, 2009 on the topic of netboot for IPv6. Specifically, some 152 scenarios were described where it was difficult to do something in 153 DHCPv6 that had worked well in DHCPv4. 155 4. IANA Considerations 157 IANA has assigned the value TBD for use by DHCPv6 DUID-UUID type 158 described in this document. 160 5. Security Considerations 162 This document does not create any new security considerations. 164 6. Normative References 166 [RFC3315] Droms, R., Bound, J., Volz, B., Lemon, T., Perkins, C., 167 and M. Carney, "Dynamic Host Configuration Protocol for 168 IPv6 (DHCPv6)", RFC 3315, July 2003. 170 [RFC4122] Leach, P., Mealling, M., and R. Salz, "A Universally 171 Unique IDentifier (UUID) URN Namespace", RFC 4122, 172 July 2005. 174 Authors' Addresses 176 Thomas Narten 177 IBM 179 Email: narten@us.ibm.com 181 Jarrod B. Johnson 182 IBM 184 Email: jarrod.b.johnson@gmail.com