Network Working Group O. Troan
Internet-Draft Cisco
Intended status: Informational M. Blanchet
Expires: April 12, 2012 Viagenie
X. Xu
D. Guo
Huawei Technologies
W. Townsley
Cisco
October 10, 2011
DHCPv6 through Tunnels
draft-ietf-dhc-dhcpv6-tunnel-00.txt
Abstract
The host configuration protocol DHCPv6 [RFC3315] relies on link-local
addressing and multicast to function. However, most of the existing
6over4 tunnel link types (e.g., 6rd [RFC5969] ) don't support IPv6
link-local addresses and even IPv6 multicast addresses. Taking 6rd
as an example, this document specifies how DHCPv6 can be used across
such tunnel links .
Status of this Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
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material or to cite them other than as "work in progress."
This Internet-Draft will expire on April 12, 2012.
Copyright Notice
Copyright (c) 2011 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
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Internet-Draft DHCPv6 through Tunnels October 2011
(http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
1. Introduction
As specified in the DHCPv6 specification [RFC3315], "...The client
MUST use a link-local address assigned to the interface for which it
is requesting configuration information as the source address in the
header of the IP datagram." and "...Unless otherwise specified in
this document, or in a document that describes how IPv6 is carried
over a specific type of link (for link types that do not support
multicast), a client sends DHCP messages to the
All_DHCP_Relay_Agents_and_Servers".
However, link-local addresses and even multicast addresses are not
supported over most of the existing 6over4 tunnel link types. 6rd as
described in [RFC5969] is a real example.
Taking 6rd as an example, this document describes how DHCPv6 service
can be provided across such tunnel links .
2. Conventions
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 RFC 2119 [RFC2119].
3. DHCPv6 over 6rd links
There are two problems to be solved with regards to providing DHCPv6
service over a 6rd link:
o A DHCPv6 client uses an IPv6 link-local address as the source
address when requesting configuration information [RFC3315].
Link-local addressing is not supported on an 6rd link.
o A DHCPv6 client sends a request to the
All_DHCP_Relay_Agent_and_Servers multicast address. 6rd as
specified in [RFC5969] does not support IPv6 multicast.
The first problem can be solved by changing the DHCPv6 protocol to
allow for a global address to be used as the source address in
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requests. Another solution that does not require protocol changes,
is to send DHCPv6 requests via a local DHCPv6 relay on the 6rd CE.
The 6rd CE MUST support a local DHCPv6 client and relay. The DHCPv6
client running on the 6rd CE's virtual tunnel interface MUST send
DHCPv6 messages through a local DHCPv6 relay that encapsulates the
client message and forwards it to a DHCPv6 server or relay using one
of the 6rd CE's global unicast addresses as the source address.
The 6rd CE DHCPv6 relay agent SHOULD use the 6rd BR IPv6 anycast
address as the destination address, section 20 of [RFC3315]. If the
6rd link supports multicast [I-D.ietf-mboned-auto-multicast] the 6rd
CE DHCPv6 relay MAY use the All_DHCP_Servers [RFC3315] as the
destination address of Relay-forward messages.
The 6rd BRs in the 6rd domain must be configured as DHCPv6 relays or
servers on their 6rd virtual interfaces.
The 6rd CE SHOULD behave according to
[I-D.ietf-v6ops-ipv6-cpe-router]. In particular it operates a DHCPv6
client on the WAN side (6rd virtual) interface and as a DHCPv6 server
on the LAN-side interface(s).
4. IANA Considerations
This specification does not require any IANA actions.
5. Security Considerations
There are no new security considerations pertaining to this document.
6. Acknowledgements
The authors would like to thank Ted Lemon, Fred Templin and other
people for their valuable comments.
7. References
7.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC3315] Droms, R., Bound, J., Volz, B., Lemon, T., Perkins, C.,
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Internet-Draft DHCPv6 through Tunnels October 2011
and M. Carney, "Dynamic Host Configuration Protocol for
IPv6 (DHCPv6)", RFC 3315, July 2003.
[RFC5969] Townsley, W. and O. Troan, "IPv6 Rapid Deployment on IPv4
Infrastructures (6rd) -- Protocol Specification",
RFC 5969, August 2010.
7.2. Informative References
[I-D.ietf-mboned-auto-multicast]
Thaler, D., Talwar, M., Aggarwal, A., Vicisano, L.,
Pusateri, T., and T. Morin, "Automatic IP Multicast
Tunneling", draft-ietf-mboned-auto-multicast-11 (work in
progress), July 2011.
[I-D.ietf-v6ops-ipv6-cpe-router]
Singh, H., Beebee, W., Donley, C., Stark, B., and O.
Troan, "Basic Requirements for IPv6 Customer Edge
Routers", draft-ietf-v6ops-ipv6-cpe-router-09 (work in
progress), December 2010.
Authors' Addresses
Ole Troan
Cisco
Oslo,
Norway
Email: ot@cisco.com
Marc Blanchet
Viagenie
2875 boul. Laurier, suite D2-630
Quebec,
Canada
Phone:
Fax:
Email: Marc.Blanchet@viagenie.ca
URI:
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Xiaohu Xu
Huawei Technologies
No.3 Xinxi Rd., Shang-Di Information Industry Base
Beijing, 100085
P.R. China
Phone: +86 10 82882573
Email: xuxh@huawei.com
Dayong Guo
Huawei Technologies
No.3 Xinxi Rd., Shang-Di Information Industry Base
Beijing, Hai-Dian District 100085
P.R. China
Phone: +86-10-82882578
Email: guoseu@huawei.com
Mark Townsley
Cisco
Paris,
France
Email: mark@townsley.net
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