draft-ietf-dhc-duid-uuid-02.txt   draft-ietf-dhc-duid-uuid-03.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: June 19, 2011 December 16, 2010 Expires: August 8, 2011 February 4, 2011
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-02 draft-ietf-dhc-duid-uuid-03
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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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 June 19, 2011. This Internet-Draft will expire on August 8, 2011.
Copyright Notice Copyright Notice
Copyright (c) 2010 IETF Trust and the persons identified as the Copyright (c) 2011 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
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the Trust Legal Provisions and are provided without warranty as the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Background . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Background . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. UUID Considerations . . . . . . . . . . . . . . . . . . . . . . 4 3. UUID Considerations . . . . . . . . . . . . . . . . . . . . . . 4
4. DUID-UUID Format . . . . . . . . . . . . . . . . . . . . . . . 5 4. DUID-UUID Format . . . . . . . . . . . . . . . . . . . . . . . 5
5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 5 5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 5
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 5 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 5
7. Security Considerations . . . . . . . . . . . . . . . . . . . . 5 7. Security Considerations . . . . . . . . . . . . . . . . . . . . 6
8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 6 8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 6
8.1. Normative References . . . . . . . . . . . . . . . . . . . 6 8.1. Normative References . . . . . . . . . . . . . . . . . . . 6
8.2. Informative References . . . . . . . . . . . . . . . . . . 6 8.2. Informative References . . . . . . . . . . . . . . . . . . 6
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 6 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 6
1. Introduction 1. Introduction
DHCP Unique Identifiers (DUIDs) are used in DHCPv6 to identify DHCP Unique Identifiers (DUIDs) are used in DHCPv6 to identify
clients and servers. This document defines a new DHCP Unique clients and servers. This document defines a new DHCP Unique
Identifier (DUID) type that embeds a Universally Unique IDentifier Identifier (DUID) type that embeds a Universally Unique IDentifier
(UUID) [RFC4122]. UUIDs are already in wide spread use and serve as (UUID) [RFC4122]. UUIDs are already in wide spread use and serve as
an existing identifier that could be leveraged by DHCPv6. For an existing identifier that could be leveraged by DHCPv6. For
example, x86 based systems ship with an embedded UUID in firmware example, x86 based systems ship with an embedded UUID in firmware
that is readily available to the software running on the device. that is readily available to the software running on the device.
Although DUIDs are new to DHCPv6, identifying clients in DHCP via a Although DUIDs are new to DHCPv6, identifying clients in DHCP via a
UUID is not. DHCPv4 [RFC2132] defines a Client Machine Identifier UUID is not. DHCPv4 [RFC2132] defines a Client Machine Identifier
Option (option 97) that embeds a UUID (aka GUID) [RFC4578]. This Option (option 97) that embeds a UUID (aka GUID) [RFC4578]. This
document extends that capability to DHCPv6. document extends that capability to DHCPv6.
Terminology specific to IPv6 and DHCPv6 are used in the same way as
is defined in the "Terminology" sections of [RFC3315].
2. Background 2. Background
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 previously: 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
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can return the proper configuration information (including the can return the proper configuration information (including the
pointer to the correct image to load). pointer to the correct image to load).
Unfortunately, none of the previously defined DUIDs are ideal for Unfortunately, none of the previously defined DUIDs are ideal for
multi-step network booting. The DUID-LLT and DUID-LL identifiers multi-step network booting. The DUID-LLT and DUID-LL identifiers
that a given device may use are not guaranteed to remain constant that a given device may use are not guaranteed to remain constant
across each booting step. Even if the different stages used DUID-LL across each booting step. Even if the different stages used DUID-LL
or DUID-LLT, on devices with multiple interfaces, there is no way to or DUID-LLT, on devices with multiple interfaces, there is no way to
guarantee that the same interface (and hence DUID) will be selected. guarantee that the same interface (and hence DUID) will be selected.
Finally, in the case of DUID-LLT, even if the same interface were Finally, in the case of DUID-LLT, even if the same interface were
chosen, it can be difficult to ensure that each stage would use the chosen, it can be difficult to ensure that each stage uses the same
same timestamp value. While a DUID-EN could be defined and used, timestamp value. While a DUID-EN could be defined and used, such
such usage would be proprietary by definition. usage is 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 used 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. In some environments, a UUID-based DUID would be preferable by DHCP. In some environments, a UUID-based DUID is preferable to
to the other existing DUID types. the other existing DUID types.
It should be noted that use of a DUID-UUID will not by itself solve It should be noted that use of a DUID-UUID will not by itself solve
all the network boot problems described in this document. Given the all the network boot problems described in this document. Given the
availablility of a suitable DUID-UUID, implementations will still availablility of a suitable DUID-UUID, implementations will still
need to take steps to ensure that all boot stages use the same DUID- need to take steps to ensure that all boot stages use the same DUID-
UUID as appropriate. Given that DHCP has already defined multiple UUID as appropriate. Given that DHCP has already defined multiple
DUID types, the question of which of several DUIDs to select from DUID types, the question of which of several DUIDs to select from
already exists -- and defining a new DUID type doesn't by itself already exists -- and defining a new DUID type doesn't by itself
help. It is believed, however, that network boot services can be help. It is believed, however, that network boot services can be
configured to use a DUID-UUID and that other software can do so as configured to use a DUID-UUID and that other software can do so as
well. Ensuring this happens in general is beyond the scope of this well. Ensuring this happens in general is beyond the scope of this
document. document.
3. UUID Considerations 3. UUID Considerations
Although many UUIDs are in use today, not all UUIDs meet the Although many UUIDs are in use today, not all UUIDs meet DHCP's
requirements of the DHCP protocol (see Section 9 of [RFC3315]). DHCP requirements (see Section 9 of [RFC3315]). DHCP UUIDs should be
UUIDs should be persistant across system restarts, across system persistant across system restarts, across system reconfiguration
reconfiguration events, system software and operating system upgrades events, system software and operating system upgrades or
or reinstallation, and be easily available to any part of the boot reinstallation, and be easily available to any part of the boot
process that requires access to the DHCP UUID. For example, UUIDs process that requires access to the DHCP UUID. For example, UUIDs
used in Microsoft's Component Object Module (COM), and for labeling used in Microsoft's Component Object Module (COM), and for labeling
partitions in filesystems, are likely not appropriate as they may not partitions in filesystems, are likely not appropriate as they may not
be accessible to firmware boot loaders, and can change over time. be accessible to firmware boot loaders, and can change over time.
Implementations of this specification using DUID-UUID must select a Implementations of this specification using DUID-UUID must select a
UUID that is persistent across system restart and reconfiguration UUID that is persistent across system restart and reconfiguration
events, and that is available to all DHCP protocol agents that may events, and that is available to all DHCP protocol agents that may
need to identify themselves. For instance, a UUID that is part of need to identify themselves. For instance, a UUID that is part of
the system firmware, or managed by the system firmware, would satisfy the system firmware, or managed by the system firmware, satisfies
this requirement. this requirement.
4. DUID-UUID Format 4. 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 (4) | UUID (128 bits) | | DUID-Type (4) | UUID (128 bits) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| | | |
| | | |
| -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
DUID-UUID format. . DUID-UUID format.
Figure 1 Figure 1
DUID-Type - DUID-UUID (4) - (16 bits) DUID-Type - DUID-UUID (4) - (16 bits)
UUID - An RFC4122 UUID (128 bits) UUID - An RFC4122 UUID (128 bits)
5. Acknowledgements 5. 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.
We would like to thank the following individuals in particular for We would like to thank the following individuals in particular for
their specific comments and suggestions on this draft: Andre Kostur, their specific comments and suggestions on this draft: Thomas Huth,
Suresh Krishnan, Ted Lemon, Bernie Volz & Vincent Zimmer. Andre Kostur, Suresh Krishnan, Ted Lemon, Bernie Volz & Vincent
Zimmer.
6. IANA Considerations 6. IANA Considerations
IANA has assigned the value 4 for use by the DHCPv6 DUID-UUID type. IANA has assigned the value 4 for use by the DHCPv6 DUID-UUID type.
[TO BE REMOVED UPON PUBLICATION: IANA should update the registry [TO BE REMOVED UPON PUBLICATION: IANA should update the registry
entry for the DUID-UUID DUID-Type and mark the assignment permanent.] entry for the DUID-UUID DUID-Type and mark the assignment permanent.]
7. Security Considerations 7. Security Considerations
DHCP traffic between a client and server is sent in the clear. An DHCP traffic between a client and server is sent in the clear. An
eavesdroppper residing on the path between the client and server eavesdroppper residing on the path between the client and server
could see DHCP traffic and obtain the UUID for a particular machine. could see DHCP traffic and obtain the UUID for a particular machine.
This may raise some privacy issues. This may raise some privacy issues, but is not a new issue brought on
by the use of DUID type defined in this document.
8. References 8. References
8.1. Normative References 8.1. Normative References
[RFC2132] Alexander, S. and R. Droms, "DHCP Options and BOOTP Vendor [RFC2132] Alexander, S. and R. Droms, "DHCP Options and BOOTP Vendor
Extensions", RFC 2132, March 1997. Extensions", RFC 2132, March 1997.
[RFC3315] Droms, R., Bound, J., Volz, B., Lemon, T., Perkins, C., [RFC3315] Droms, R., Bound, J., Volz, B., Lemon, T., Perkins, C.,
and M. Carney, "Dynamic Host Configuration Protocol for and M. Carney, "Dynamic Host Configuration Protocol for
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