DHCPv6 Relay Agent Echo Request Option
RFC 4994
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RFC - Proposed Standard
(September 2007; No errata)
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Last updated |
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2015-10-14
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Replaces |
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draft-szeng-dhc-dhcpv6-ero
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IETF
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plain text
html
pdf
htmlized
bibtex
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WG state
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(None)
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Document shepherd |
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No shepherd assigned
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IESG |
IESG state |
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RFC 4994 (Proposed Standard)
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Consensus Boilerplate |
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Unknown
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Telechat date |
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Responsible AD |
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Jari Arkko
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Send notices to |
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(None)
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Network Working Group S. Zeng
Request for Comments: 4994 B. Volz
Category: Standards Track K. Kinnear
Cisco Systems, Inc.
J. Brzozowski
Comcast Cable
September 2007
DHCPv6 Relay Agent Echo Request Option
Status of This Memo
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
This memo defines a Relay Agent Echo Request option for the Dynamic
Host Configuration Protocol for IPv6 (DHCPv6). The option allows a
DHCPv6 relay agent to request a list of relay agent options that the
server echoes back to the relay agent.
Table of Contents
1. Introduction ....................................................2
2. Requirements Terminology ........................................2
3. The Relay Agent Echo Request Option .............................2
4. DHCPv6 Relay Agent Behavior .....................................3
5. DHCPv6 Server Behavior ..........................................3
6. Security Considerations .........................................4
7. IANA Considerations .............................................4
8. Acknowledgements ................................................4
9. References ......................................................4
9.1. Normative References .......................................4
9.2. Informative References .....................................4
Zeng, et al. Standards Track [Page 1]
RFC 4994 Relay Agent ERO September 2007
1. Introduction
DHCPv6 [2] provides a framework for configuring IPv6 clients with
addresses and other network parameters. It includes a relay agent
capability. A relay agent is an intermediary node that delivers DHCP
messages between clients and servers. The relay agent and the server
exchange information using options in relay agent messages. The
relay agent may add relay agent options to the client DHCP message
before forwarding it.
The information that relay agents supply can be used in the server's
decision making about the addresses, delegated prefixes, and
configuration parameters that the client is to receive. Likewise,
the relay may need some of the information to efficiently return
replies to clients.
In DHCPv4, the server generally echoes the relay agent option back
verbatim to the relay agent in server-to-client replies [3].
However, DHCPv6 [2] does not require the server to do so. 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
agent uses to explicitly request a list of options that the server
echoes back to the relay agent.
2. Requirements Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [1].
3. The Relay Agent Echo Request Option
The relay agent adds options in the Relay Forward message that the
server uses to guide its decision making with regard to address
assignment, prefix delegation, and configuration parameters. The
relay agent also knows which of these options that it will need to
efficiently return replies to the client. It uses the relay agent
Echo Request option to inform the server of the list of relay agent
options that the server must echo back.
Zeng, et al. Standards Track [Page 2]
RFC 4994 Relay Agent ERO September 2007
The format of the DHCPv6 Relay Agent Echo Request option is shown
below:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| OPTION_ERO | option-len |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| requested-option-code-1 | requested-option-code-2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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