draft-ietf-dhc-dhcpv6-ero-01.txt   rfc4994.txt 
DHC S. Zeng Network Working Group S. Zeng
Internet-Draft B. Volz Request for Comments: 4994 B. Volz
Intended status: Standards Track K. Kinnear Category: Standards Track K. Kinnear
Expires: September 16, 2007 Cisco Systems, Inc. Cisco Systems, Inc.
J. Brzozowski J. Brzozowski
Comcast Cable Comcast Cable
March 15, 2007 September 2007
DHCPv6 Relay Agent Echo Request Option DHCPv6 Relay Agent Echo Request Option
draft-ietf-dhc-dhcpv6-ero-01
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Copyright Notice
Copyright (C) The IETF Trust (2007). This document specifies an Internet standards track protocol for the
Internet community, and requests discussion and suggestions for
improvements. Please refer to the current edition of the "Internet
Official Protocol Standards" (STD 1) for the standardization state
and status of this protocol. Distribution of this memo is unlimited.
Abstract Abstract
This memo defines a Relay Agent Echo Request option for the Dynamic This memo defines a Relay Agent Echo Request option for the Dynamic
Host Configuration Protocol for IPv6 (DHCPv6). The option allows a Host Configuration Protocol for IPv6 (DHCPv6). The option allows a
DHCPv6 relay agent to request a list of relay agent options that the DHCPv6 relay agent to request a list of relay agent options that the
server echoes back to the relay agent. server echoes back to the relay agent.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction ....................................................2
2. Requirements Terminology . . . . . . . . . . . . . . . . . . . 3 2. Requirements Terminology ........................................2
3. The Relay Agent Echo Request Option . . . . . . . . . . . . . . 3 3. The Relay Agent Echo Request Option .............................2
4. DHCPv6 Relay Agent Behavior . . . . . . . . . . . . . . . . . . 4 4. DHCPv6 Relay Agent Behavior .....................................3
5. DHCPv6 Server Behavior . . . . . . . . . . . . . . . . . . . . 4 5. DHCPv6 Server Behavior ..........................................3
6. Security Considerations . . . . . . . . . . . . . . . . . . . . 5 6. Security Considerations .........................................4
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 5 7. IANA Considerations .............................................4
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 5 8. Acknowledgements ................................................4
9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 5 9. References ......................................................4
9.1. Normative References . . . . . . . . . . . . . . . . . . . 5 9.1. Normative References .......................................4
9.2. Informative References . . . . . . . . . . . . . . . . . . 5 9.2. Informative References .....................................4
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 6
Intellectual Property and Copyright Statements . . . . . . . . . . 7
1. Introduction 1. Introduction
DHCPv6 [2] provides a framework for configuring IPv6 clients with DHCPv6 [2] provides a framework for configuring IPv6 clients with
addresses and other network parameters. It includes a relay agent addresses and other network parameters. It includes a relay agent
capability. A relay agent is an intermediary node that delivers DHCP capability. A relay agent is an intermediary node that delivers DHCP
messages between clients and servers. The relay agent and the server messages between clients and servers. The relay agent and the server
exchange information using options in relay agent messages. The exchange information using options in relay agent messages. The
relay agent may add relay agent options to the client DHCP message relay agent may add relay agent options to the client DHCP message
before forwarding it. before forwarding it.
The information that relay agents supply can be used in the server's The information that relay agents supply can be used in the server's
decision making about the addresses, delegated prefixes, and decision making about the addresses, delegated prefixes, and
configuration parameters that the client is to receive. Likewise, configuration parameters that the client is to receive. Likewise,
the relay may need some of the information to efficiently return the relay may need some of the information to efficiently return
replies to clients. replies to clients.
In DHCPv4, the server generally echoes the relay agent option back In DHCPv4, the server generally echoes the relay agent option back
verbatim to the relay agent in server-to-client replies [3]. verbatim to the relay agent in server-to-client replies [3].
However, DHCPv6 [2] does not require the server to do so. As a However, DHCPv6 [2] does not require the server to do so. This could
matter of fact, for certain relay agent options, the server is be problematic, as the relay agent may need to use some relay options
required to echo back the options only if it recognizes them (e.g., even if the server does not recognize them.
[4], [5]). This could be problematic, as the relay agent may need to
use some relay options even if the server does not recognize them.
This memo defines a relay agent echo request option that the relay This memo defines a relay agent echo request option that the relay
agent uses to explicitly request a list of options that the server agent uses to explicitly request a list of options that the server
echoes back to the relay agent. echoes back to the relay agent.
2. Requirements Terminology 2. Requirements Terminology
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 [1]. document are to be interpreted as described in [1].
3. The Relay Agent Echo Request Option 3. The Relay Agent Echo Request Option
The relay agent adds options in the Relay Forward message that the The relay agent adds options in the Relay Forward message that the
server uses to guide its decision making with regard to address server uses to guide its decision making with regard to address
assignment, prefix delegation, and configuration parameters. The assignment, prefix delegation, and configuration parameters. The
relay agent also knows which of these options that it will need to relay agent also knows which of these options that it will need to
efficiently return replies to the client. It uses the relay agent efficiently return replies to the client. It uses the relay agent
Echo Request option to inform the server the list of relay agent Echo Request option to inform the server of the list of relay agent
options that the server must echo back. options that the server must echo back.
The format of the DHCPv6 Relay Agent Echo Request option is shown The format of the DHCPv6 Relay Agent Echo Request option is shown
below: below:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| OPTION_ERO | option-len | | OPTION_ERO | option-len |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| requested-option-code-1 | requested-option-code-2 | | requested-option-code-1 | requested-option-code-2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... | | ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
option-code OPTION_ERO (TBD). option-code OPTION_ERO (43).
option-len 2 * number of requested options. option-len 2 * number of requested options.
requested-option-code-n The option code for an option requested by requested-option-code-n The option code for an option requested by
the relay agent. the relay agent.
4. DHCPv6 Relay Agent Behavior 4. DHCPv6 Relay Agent Behavior
A relay agent MAY include an Echo Request option in a Relay Forward A relay agent MAY include an Echo Request option in a Relay Forward
message to inform the server about options the relay agent wants the message to inform the server about options the relay agent wants the
server to echo back to the relay agent. If the relay agent takes server to echo back to the relay agent. If the relay agent takes
different actions based on whether an option is echoed back or not, different actions based on whether an option is echoed back or not,
then the relay agent SHOULD NOT include such an option in the Echo then the relay agent SHOULD NOT include such an option in the Echo
Request option. Note that the relay uses the OPTION_ORO [2] to Request option. Note that the relay uses the OPTION_ORO [2] to
request the server to return options (e.g., [6]) other than relay request the server to return options (e.g., [4]) other than relay
agent options in the Relay Forward message. agent options in the Relay Forward message.
5. DHCPv6 Server Behavior 5. DHCPv6 Server Behavior
When a server creates a Relay-Reply, it SHOULD perform ERO processing When a server creates a Relay-Reply, it SHOULD perform ERO processing
after processing the ORO and other options processing. For each after processing the ORO and other options processing. For each
option in the ERO: option in the ERO:
a. If the option is already in the Relay-Reply, the server MUST a. If the option is already in the Relay-Reply, the server MUST
ignore that option and continue to process any remaining options ignore that option and continue to process any remaining options
in the ERO. in the ERO.
b. If the option was not in the received Relay-Forward, the server b. If the option was not in the received Relay-Forward, the server
MUST ignore that option and continue to process any remaining MUST ignore that option and continue to process any remaining
options in the ERO. options in the ERO.
c. Otherwise, the server MUST copy the option, verbatim, from the c. Otherwise, the server MUST copy the option, verbatim, from the
received Relay-Forward to the Relay-Reply, even if the server received Relay-Forward to the Relay-Reply, even if the server
does not otherwise recognize that option. does not otherwise recognize that option.
6. Security Considerations 6. Security Considerations
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MUST ignore that option and continue to process any remaining MUST ignore that option and continue to process any remaining
options in the ERO. options in the ERO.
c. Otherwise, the server MUST copy the option, verbatim, from the c. Otherwise, the server MUST copy the option, verbatim, from the
received Relay-Forward to the Relay-Reply, even if the server received Relay-Forward to the Relay-Reply, even if the server
does not otherwise recognize that option. does not otherwise recognize that option.
6. Security Considerations 6. Security Considerations
As the Echo Request option is only exchanged between relay agents and As the Echo Request option is only exchanged between relay agents and
DHCPv6 servers, [2] section 21.1, provides details on securing DHCPv6 DHCPv6 servers, section 21.1 of [2] provides details on securing
messages sent between servers and relay agents. And, [2] section 23, DHCPv6 messages sent between servers and relay agents. And, section
provides general DHCPv6 security considerations. 23 of [2] provides general DHCPv6 security considerations.
7. IANA Considerations 7. IANA Considerations
IANA is requested to assign a DHCPv6 option code for the OPTION_ERO IANA has assigned a DHCPv6 option code for the OPTION_ERO (Relay
(Relay Agent Echo Request) Option. Agent Echo Request) Option (43).
8. Acknowledgements 8. Acknowledgements
Thanks to Ralph Droms, Josh Littlefield, Richard Johnson, and Hemant Thanks to Ralph Droms, Josh Littlefield, Richard Johnson, and Hemant
Singh for their consistent input, ideas and review during the Singh for their consistent input, ideas, and review during the
production of this document. production of this document.
9. References 9. References
9.1. Normative References 9.1. Normative References
[1] Bradner, S., "Key words for use in RFCs to Indicate Requirement [1] Bradner, S., "Key words for use in RFCs to Indicate Requirement
Levels", BCP 14, RFC 2119, March 1997. Levels", BCP 14, RFC 2119, March 1997.
[2] Droms, R., Bound, J., Volz, B., Lemon, T., Perkins, C., and M. [2] Droms, R., Bound, J., Volz, B., Lemon, T., Perkins, C., and M.
Carney, "Dynamic Host Configuration Protocol for IPv6 (DHCPv6)", Carney, "Dynamic Host Configuration Protocol for IPv6 (DHCPv6)",
RFC 3315, July 2003. RFC 3315, July 2003.
[3] Patrick, M., "DHCP Relay Agent Information Option", RFC 3046, [3] Patrick, M., "DHCP Relay Agent Information Option", RFC 3046,
January 2001. January 2001.
9.2. Informative References 9.2. Informative References
[4] Volz, B., "Dynamic Host Configuration Protocol for IPv6 (DHCPv6) [4] Droms, R., Volz, B., and O. Troan, "DHCPv6 Relay Agent
Relay Agent Subscriber-ID Option", RFC 4580, June 2006. Assignment Notification (RAAN) Option", Work in Progress,
November 2006.
[5] Volz, B., "Dynamic Host Configuration Protocol for IPv6 (DHCPv6)
Relay Agent Remote-ID Option", RFC 4649, August 2006.
[6] Droms, R., "DHCPv6 Relay Agent Assignment Notification (RAAN)
Option", draft-ietf-dhc-dhcpv6-agentopt-delegate-02 (work in
progress), November 2006.
Authors' Addresses Authors' Addresses
Shengyou Zeng Shengyou Zeng
Cisco Systems, Inc. Cisco Systems, Inc.
1414 Massachusetts Ave. 1414 Massachusetts Ave.
Boxborough, MA 01719 Boxborough, MA 01719
USA USA
Phone: +1 978 936 0000 Phone: +1 978 936 0000
Email: szeng@cisco.com EMail: szeng@cisco.com
Bernard Volz Bernard Volz
Cisco Systems, Inc. Cisco Systems, Inc.
1414 Massachusetts Ave. 1414 Massachusetts Ave.
Boxborough, MA 01719 Boxborough, MA 01719
USA USA
Phone: +1 978 936 0000 Phone: +1 978 936 0000
Email: volz@cisco.com EMail: volz@cisco.com
Kim Kinnear Kim Kinnear
Cisco Systems, Inc. Cisco Systems, Inc.
1414 Massachusetts Ave. 1414 Massachusetts Ave.
Boxborough, MA 01719 Boxborough, MA 01719
USA USA
Phone: +1 978 936 0000 Phone: +1 978 936 0000
Email: kkinnear@cisco.com EMail: kkinnear@cisco.com
John Jason Brzozowski John Jason Brzozowski
Comcast Cable Comcast Cable
1800 Bishops Gate Boulevard 1800 Bishops Gate Boulevard
Mt. Laurel, NJ 08054 Mt. Laurel, NJ 08054
USA USA
Phone: +1 856 324 2671 Phone: +1 856 324 2671
Email: john_brzozowski@cable.comcast.com EMail: john_brzozowski@cable.comcast.com
Full Copyright Statement Full Copyright Statement
Copyright (C) The IETF Trust (2007). Copyright (C) The IETF Trust (2007).
This document is subject to the rights, licenses and restrictions This document is subject to the rights, licenses and restrictions
contained in BCP 78, and except as set forth therein, the authors contained in BCP 78, and except as set forth therein, the authors
retain all their rights. retain all their rights.
This document and the information contained herein are provided on an This document and the information contained herein are provided on an
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Acknowledgment
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