draft-ietf-dhc-dhcpv6-client-link-layer-addr-opt-00.txt   draft-ietf-dhc-dhcpv6-client-link-layer-addr-opt-01.txt 
Network Working Group G. Halwasia Network Working Group G. Halwasia
Internet-Draft S. Bhandari Internet-Draft S. Bhandari
Intended status: Standards Track W. Dec Intended status: Standards Track W. Dec
Expires: January 4, 2013 Cisco Systems Expires: February 15, 2013 Cisco Systems
July 3, 2012 August 14, 2012
Client Link-layer Address Option in DHCPv6 Client Link-layer Address Option in DHCPv6
draft-ietf-dhc-dhcpv6-client-link-layer-addr-opt-00 draft-ietf-dhc-dhcpv6-client-link-layer-addr-opt-01
Abstract Abstract
This document specifies the format and mechanism that is to be used This document specifies the format and mechanism that is to be used
for encoding client link-layer address in DHCPv6 messages by defining for encoding client link-layer address in DHCPv6 relay forward
a new DHCPv6 Client Link-layer Address option. messages by defining a new DHCPv6 Client Link-layer Address option.
Requirements Language Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119]. document are to be interpreted as described in RFC 2119 [RFC2119].
Status of this Memo Status of this Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
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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 January 4, 2013. This Internet-Draft will expire on February 15, 2013.
Copyright Notice Copyright Notice
Copyright (c) 2012 IETF Trust and the persons identified as the Copyright (c) 2012 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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to this document. Code Components extracted from this document must to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of include Simplified BSD License text as described in Section 4.e of
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. Problem Background and Scenario . . . . . . . . . . . . . . . . 3 2. Problem Background and Scenario . . . . . . . . . . . . . . . . 3
3. DHCPv6 Client Link-layer Address Option . . . . . . . . . . . . 4 3. DHCPv6 Client Link-layer Address Option . . . . . . . . . . . . 4
4. DHCPv6 Client Behavior . . . . . . . . . . . . . . . . . . . . 4 4. DHCPv6 Relay Agent Behavior . . . . . . . . . . . . . . . . . . 4
5. DHCPv6 Relay Agent Behavior . . . . . . . . . . . . . . . . . . 4 5. DHCPv6 Server Behavior . . . . . . . . . . . . . . . . . . . . 4
6. DHCPv6 Server Behavior . . . . . . . . . . . . . . . . . . . . 5 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 5
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 5 7. Security Considerations . . . . . . . . . . . . . . . . . . . . 5
8. Security Considerations . . . . . . . . . . . . . . . . . . . . 5 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 5
9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 5 9. Normative References . . . . . . . . . . . . . . . . . . . . . 5
10. Normative References . . . . . . . . . . . . . . . . . . . . . 5
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 6 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 6
1. Introduction 1. Introduction
This specification defines an optional mechanism and the related This specification defines an optional mechanism and the related
DHCPv6 option to allow DHCPv6 client or first hop DHCPv6 relay agent DHCPv6 option to allow first hop DHCPv6 relay agent directly
directly connected to the client to populate client link-layer connected to the client to populate client link-layer address in the
address in the DHCPv6 messages being sent towards the server. DHCPv6 messages being sent towards the server.
2. Problem Background and Scenario 2. Problem Background and Scenario
DHCPv4 protocol specification [RFC2131] provides a way to specify the DHCPv4 protocol specification [RFC2131] provides a way to specify the
client hardware address in the DHCPv4 message header. DHCPv4 message client hardware address in the DHCPv4 message header. DHCPv4 message
header has 'htype' and 'chaddr' fields to specify client hardware header has 'htype' and 'chaddr' fields to specify client hardware
address type and hardware address respectively. The client hardware address type and hardware address respectively. The client hardware
address thus learnt can be used by DHCPv4 server and relay in address thus learnt can be used by DHCPv4 server and relay in
different ways. In some of the deployments DHCPv4 servers use different ways. In some of the deployments DHCPv4 servers use
'chaddr' as a customer identifier and a key for lookup in the client 'chaddr' as a customer identifier and a key for lookup in the client
lease database. lease database.
With the incremental deployment of IPv6 to existing IPv4 networks, With the incremental deployment of IPv6 to existing IPv4 networks,
effectievly an enablement of dual-stack, there will be devices that effectively an enablement of dual-stack, there will be devices that
act as both DHCPv4 and DHCPv6 clients. In service provider act as both DHCPv4 and DHCPv6 clients. In service provider
deployments, a typical DHCPv4 implemention will use the client deployments, a typical DHCPv4 implementation will use the client
hardware address as one of the keys to build DHCP client lease hardware address as one of the keys to build DHCP client lease
database. In dual stack scenarios it is desirable for the operator database. In dual stack scenarios it is desirable for the operator
to associate DHCPv4 and DHCPv6 messages as belonging to the same to associate DHCPv4 and DHCPv6 messages as belonging to the same
client interface based on an identifier that is already used by that client interface based on an identifier that is already used by that
operator such as the client hardware address. operator such as the client hardware address.
Currently, the DHCPv6 protocol specification [RFC3315] does not Currently, the DHCPv6 protocol specification [RFC3315] does not
define a way for DHCP clients to specify client link-layer address in define a way for DHCP clients to specify client link-layer address in
the DHCPv6 message sent towards DHCPv6 Server. Similarly DHCPv6 the DHCPv6 message sent towards DHCPv6 Server. Similarly DHCPv6
Relay or Server cannot glean client link-layer address from the Relay or Server cannot glean client link-layer address from the
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mandates all clients to prepare and send DUID as the client mandates all clients to prepare and send DUID as the client
identifier option in all the DHCPv6 message exchange. However none identifier option in all the DHCPv6 message exchange. However none
of these methods provide a simple way to extract client's link-layer of these methods provide a simple way to extract client's link-layer
address.This presents a problem to an operator who is using an address.This presents a problem to an operator who is using an
existing DHCPv4 system with the client hardware address as the existing DHCPv4 system with the client hardware address as the
customer identifier, and desires to correlate DHCPv6 assignments customer identifier, and desires to correlate DHCPv6 assignments
using the same identifier. Modifying the system to use DUID based using the same identifier. Modifying the system to use DUID based
correlation across DHCPv4 and DHCPv6 is possible, but it requires a correlation across DHCPv4 and DHCPv6 is possible, but it requires a
modification of the DHCPv4 system and associated back-ends. modification of the DHCPv4 system and associated back-ends.
Providing an option in DHCPv6 messages to carry client link-layer Providing an option in DHCPv6 relay forward messages to carry client
address explicitly will help above mentioned scenarios. For e.g. it link-layer address explicitly will help above mentioned scenarios.
can be used along with other identifiers to associate DHCPv4 and For e.g. it can be used along with other identifiers to associate
DHCPv6 messages from a dual stack client. Further, having client DHCPv4 and DHCPv6 messages from a dual stack client. Further, having
link-layer address in DHCPv6 will help in proving additional client link-layer address in DHCPv6 will help in proving additional
information in event debugging and logging related to the client at information in event debugging and logging related to the client at
relay and server. The proposed option may be used in wide range of relay and server. The proposed option may be used in wide range of
networks, two notable deployment models are service provider and networks, two notable deployment models are service provider and
enterprise network environments. enterprise network environments.
3. DHCPv6 Client Link-layer Address Option 3. DHCPv6 Client Link-layer Address Option
The format of the DHCPv6 Client Link-layer Address option is shown The format of the DHCPv6 Client Link-layer Address option is shown
below. below.
0 1 2 3 0 1 2 3
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| | | |
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
option-code: OPTION_CLIENT_LINKLAYER_ADDR (TBD) option-code: OPTION_CLIENT_LINKLAYER_ADDR (TBD)
option-length: 2 + length of link-layer address option-length: 2 + length of link-layer address
hardware type: Client Link-layer address type. The hardware type MUST be a hardware type: Client Link-layer address type. The hardware type MUST be a
valid hardware type assigned by the IANA, as described in [RFC0826] valid hardware type assigned by the IANA, as described in [RFC0826]
link-layer address: Client Link-layer address. link-layer address: Client Link-layer address.
4. DHCPv6 Client Behavior 4. DHCPv6 Relay Agent Behavior
All hosts or clients MAY include DHCPv6 Client link-layer address
option in all the upstream DHCPv6 messages.
5. DHCPv6 Relay Agent Behavior
DHCPv6 Relay agents which are directly connected to clients/hosts MAY DHCPv6 Relay agents which are directly connected to clients/hosts MAY
look for Client Link-layer Address option in the incoming DHCPv6
client message. Irrespective of the presence of client link-layer
option in incomming DHCPv6 client messages, DHCPv6 Relay agents MAY
include client link-layer address option in relayed DHCPv6 (RELAY- include client link-layer address option in relayed DHCPv6 (RELAY-
FORW) message. The DHCPv6 Relay agent behaviour can depend on FORW) message. The DHCPv6 Relay agent behaviour can depend on
configuration that decides whether Client Link-layer Address option configuration that decides whether Client Link-layer Address option
needs to be processed and included. needs to be processed and included.
In Relay chaining scenarios, any other relay agent other than first In Relay chaining scenarios, any other relay agent other than first
hop DHCPv6 Relay agent or DHCPv6 LDRA [RFC6221] MUST not add this hop DHCPv6 Relay agent or DHCPv6 LDRA [RFC6221] MUST not add this
option. option.
6. DHCPv6 Server Behavior 5. DHCPv6 Server Behavior
If DHCPv6 Server is configured to store or use client link-layer If DHCPv6 Server is configured to store or use client link-layer
address, it SHOULD first look for the client link-layer address address, it SHOULD look for the client link-layer address option in
option in the RELAY-FORW DHCP message of the DHCPv6 Relay agent the RELAY-FORW DHCP message of the DHCPv6 Relay agent closest to the
closest to the client. In case it is not found, Server SHOULD look client.
for client link-layer address option in the client DHCP message.
Further, this behavior w.r.t the precedence of DHCPv6 server to look
for Client link-layer address option can be overridden based upon the
local policies.
There is no requirement that a server return this option and its data There is no requirement that a server return this option and its data
in a downstream DHCP message. in a downstream DHCP message.
7. IANA Considerations 6. IANA Considerations
IANA is requested to assign an option code to IANA is requested to assign an option code to
OPTION_CLIENT_LINKLAYER_ADDR from the "DHCPv6 and DHCPv6 options" OPTION_CLIENT_LINKLAYER_ADDR from the "DHCPv6 and DHCPv6 options"
registry (http://www.iana.org/assignments/dhcpv6-parameters/dhcpv6- registry (http://www.iana.org/assignments/dhcpv6-parameters/dhcpv6-
parameters.xml). parameters.xml).
8. Security Considerations 7. Security Considerations
Security issues related DHCPv6 are described in section 23 of Security issues related DHCPv6 are described in section 23 of
[RFC3315]. [RFC3315].
9. Acknowledgements 8. Acknowledgements
Many thanks to Bernie Volz, Hemant Singh, Simon Hobson, Tina TSOU, Many thanks to Bernie Volz, Hemant Singh, Simon Hobson, Tina TSOU,
Andre Kostur, Chuck Anderson, Steinar Haug, Niall O'Reilly, Jarrod Andre Kostur, Chuck Anderson, Steinar Haug, Niall O'Reilly, Jarrod
Johnson, Tomek Mrugalski and Vincent Zimmer for their input and Johnson, Tomek Mrugalski and Vincent Zimmer for their input and
review. review.
10. Normative References 9. Normative References
[RFC0826] Plummer, D., "Ethernet Address Resolution Protocol: Or [RFC0826] Plummer, D., "Ethernet Address Resolution Protocol: Or
converting network protocol addresses to 48.bit Ethernet converting network protocol addresses to 48.bit Ethernet
address for transmission on Ethernet hardware", STD 37, address for transmission on Ethernet hardware", STD 37,
RFC 826, November 1982. RFC 826, November 1982.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997. Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2131] Droms, R., "Dynamic Host Configuration Protocol", [RFC2131] Droms, R., "Dynamic Host Configuration Protocol",
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