draft-ietf-dhc-duid-uuid-00.txt   draft-ietf-dhc-duid-uuid-01.txt 
Internet Engineering Task Force T. Narten Internet Engineering Task Force T. Narten
Internet-Draft J. Johnson Internet-Draft J. Johnson
Intended status: Standards Track IBM Intended status: Standards Track IBM
Expires: April 4, 2011 October 1, 2010 Expires: June 18, 2011 December 15, 2010
Definition of the UUID-based DHCPv6 Unique Identifier (DUID-UUID) Definition of the UUID-based DHCPv6 Unique Identifier (DUID-UUID)
draft-ietf-dhc-duid-uuid-00 draft-ietf-dhc-duid-uuid-01
Abstract Abstract
This document defines a new DHCPv6 Unique Identifier (DUID) type, This document defines a new DHCPv6 Unique Identifier (DUID) type,
called DUID-UUID. DUID-UUIDs are derived from the already called DUID-UUID. DUID-UUIDs are derived from the already
standardized UUID format. DUID-UUID makes it possible for devices to standardized UUID format. DUID-UUID makes it possible for devices to
use UUIDs to identify themselves to DHC servers and vice versa. use UUIDs to identify themselves to DHC servers and vice versa.
UUIDs are globally unique and readily available on many systems, UUIDs are globally unique and readily available on many systems,
making them convenient identifiers to leverage within DHCP. making them convenient identifiers to leverage within DHCP.
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Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/. Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
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."
This Internet-Draft will expire on April 4, 2011. This Internet-Draft will expire on June 18, 2011.
Copyright Notice Copyright Notice
Copyright (c) 2010 IETF Trust and the persons identified as the Copyright (c) 2010 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
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6.1. Normative References . . . . . . . . . . . . . . . . . . . 5 6.1. Normative References . . . . . . . . . . . . . . . . . . . 5
6.2. Informative References . . . . . . . . . . . . . . . . . . 6 6.2. Informative References . . . . . . . . . . . . . . . . . . 6
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 6 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 6
1. Introduction 1. Introduction
In DHCPv6, clients identify themselves to servers via DHCP Unique In DHCPv6, clients identify themselves to servers via DHCP Unique
Identifiers (DUIDs) [RFC3315]. DUIDs are identifiers that DHCP Identifiers (DUIDs) [RFC3315]. DUIDs are identifiers that DHCP
servers treat as opaque objects with no internal structure. DUIDs servers treat as opaque objects with no internal structure. DUIDs
are intended to be globally unique, with no two devices using the are intended to be globally unique, with no two devices using the
same DUID. Three DUIDs types have been defined so far: same DUID. Three DUIDs types have been defined previously:
DUID-LLT - the Link-Layer address of one of the device's network DUID-LLT - the Link-Layer address of one of the device's network
interfaces, concatenated with a timestamp interfaces, concatenated with a timestamp
DUID-EN - an Enterprise Number plus additional information specific DUID-EN - an Enterprise Number plus additional information specific
to the enterprise to the enterprise
DUID-LL - the Link-Layer address of one of the device's network DUID-LL - the Link-Layer address of one of the device's network
interfaces interfaces
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address identifier generally remains constant across machine address identifier generally remains constant across machine
restarts, installation of new operating system releases, changes in restarts, installation of new operating system releases, changes in
hardware configuration such as addition or removal of storage hardware configuration such as addition or removal of storage
devices, etc. While the MAC address will change if the network devices, etc. While the MAC address will change if the network
interface is replaced, this is a relatively uncommon event. interface is replaced, this is a relatively uncommon event.
In contrast, the DUID-LLT and DUID-LL identifiers that a given device In contrast, the DUID-LLT and DUID-LL identifiers that a given device
may use are less likely to remain constant on some types of devices may use are less likely to remain constant on some types of devices
and deployments. Specifically, when a machine goes through a multi- and deployments. Specifically, when a machine goes through a multi-
step boot process, it may first load a simple boot loader, followed step boot process, it may first load a simple boot loader, followed
by a one or more secondary loaders before the eventual actual target by a one or more secondary loaders before the eventual desired target
system is loaded. In IPv4, all steps of a multi-step boot processes system is loaded. In IPv4, all steps of a multi-step boot processes
that invoke DHCP are guaranteed to use the same MAC identifier during that invoke DHCP are guaranteed to use the same MAC identifier during
each stage. In contrast, with DHCPv6, it is more difficult to ensure each stage. In contrast, with DHCPv6, it is more difficult to ensure
or arrange that each boot stage uses the same identifier. First, or arrange that each boot stage uses the same identifier. First,
there are multiple DUID types, and different systems might choose to there are multiple DUID types, and different stages might choose to
use different formats. Second, even if the different stages used use different formats. Second, even if the different stages used
DUID-LL or DUID-LLT, on devices with multiple interfaces, there is no DUID-LL or DUID-LLT, on devices with multiple interfaces, there is no
way to guarantee that the same interface (and hence DUID) will be way to guarantee that the same interface (and hence DUID) will be
selected. Finally, in the case of DUID-LLT, even if the same selected. Finally, in the case of DUID-LLT, even if the same
interface were chosen, there is no guarantee that each stage would interface were chosen, there is no guarantee that each stage would
use the same timestamp value. While a DUID-EN could be defined and use the same timestamp value. While a DUID-EN could be defined and
used, such usage would be proprietary by definition. used, such usage would be proprietary by definition.
This document defines a new DUID type, based on the Universally This document defines a new DUID type, based on the Universally
Unique IDentifier (UUID) [RFC4122]. UUIDs are already use in Unique IDentifier (UUID) [RFC4122]. UUIDs are already used in
practice and serve as an existing identifier that could be leveraged practice and serve as an existing identifier that could be leveraged
by DHCP. For example, x86 based systems ship with an embedded UUID by DHCP. For example, x86 based systems ship with an embedded UUID
in firmware that could be accessed for this purpose. in firmware that could be accessed for this purpose.
Although DUIDs are new to DHCPv6, the idea of identifying clients via Although DUIDs are new to DHCPv6, the idea of identifying clients via
a UUID is not. DHCPv4 defines a Client Machine Identifier Option a UUID is not. DHCPv4 defines a Client Machine Identifier Option
(option 97) that can contain a UUID [RFC4578]. (option 97) that can contain a UUID [RFC4578].
Although many UUIDs are in use today, not all UUIDs meet the Although many UUIDs are in use today, not all UUIDs meet the
requirements of the DHCP protocol (see Section 9 of [RFC3315]). DHCP requirements of the DHCP protocol (see Section 9 of [RFC3315]). DHCP
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exists and is not a new problem. exists and is not a new problem.
2. DUID-UUID Format 2. DUID-UUID Format
The DUID-UUID is carried within Client Identifier or Server The DUID-UUID is carried within Client Identifier or Server
Identifier options. It has the following format: Identifier options. It has the following format:
0 1 2 3 0 1 2 3
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 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| DUID-Type (TBD) | UUID (128 bits) | | DUID-Type (4) | UUID (128 bits) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| | | |
| | | |
| -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
DUID-UUID format. . DUID-UUID format. .
Figure 1 Figure 1
DUID-Type - TBD (16 bits) DUID-Type - DUID-UUID (4) - (16 bits)
UUID - An RFC4122 UUID (128 bits) UUID - An RFC4122 UUID (128 bits)
3. Acknowledgements 3. Acknowledgements
This document was inspired by a discussion on the DHC mailing list in This document was inspired by a discussion on the DHC mailing list in
November, 2009 on the topic of netboot for IPv6. Specifically, some November, 2009 on the topic of netboot for IPv6. Specifically, some
scenarios were described where it was difficult to do something in scenarios were described where it was difficult to do something in
DHCPv6 that had worked well in DHCPv4. DHCPv6 that had worked well in DHCPv4.
4. IANA Considerations 4. IANA Considerations
IANA has assigned the value TBD for use by DHCPv6 DUID-UUID type IANA has assigned the value 4 for use by the DHCPv6 DUID-UUID type.
described in this document. [TO BE REMOVED UPON PUBLICATION: IANA should update the registry
entry for the DUID-UUID DUID-Type and mark the assignment permanent.]
5. Security Considerations 5. Security Considerations
DHCP traffic is sent in the clear. An eavesdroppper could see DHCP DHCP traffic is sent in the clear. An eavesdroppper could see DHCP
traffic and obtain the UUID for a particular machine. This may raise traffic and obtain the UUID for a particular machine. This may raise
some privacy issues. some privacy issues.
6. References 6. References
6.1. Normative References 6.1. Normative References
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