Internet DRAFT - draft-ietf-dhc-dhcpv6-tunnel
draft-ietf-dhc-dhcpv6-tunnel
Network Working Group O. Troan
Internet-Draft Cisco
Intended status: Informational M. Blanchet
Expires: October 28, 2012 Viagenie
X. Xu
D. Guo
Huawei Technologies
W. Townsley
Cisco
April 28, 2012
DHCPv6 through Tunnels
draft-ietf-dhc-dhcpv6-tunnel-01.txt
Abstract
The host configuration protocol DHCPv6 [RFC3315] relies on link-local
addresses as source addresses and multicast addresses for destination
addresses. However, some tunnel links (e.g., 6rd [RFC5969] ) do not
have IPv6 link-local addresses and do not support IPv6 multicast
addresses. Taking 6rd as an example, this document specifies how
DHCPv6 is 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 October 28, 2012.
Copyright Notice
Copyright (c) 2012 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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(http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
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described in the Simplified BSD License.
1. Introduction
Various tunnel techniques are used to deploy IPv6 over IPv4, such as
6rd. The source tunnel end-point typically generates its IPv6 global
address and for some tunnel techniques such as 6rd, generates a
prefix for the downstream network. By some means, the source tunnel
end-point always knows the IPv6 address of the other tunnel end-
point.
The source tunnel end-point often need more configuration data for
itself and its downstream network, such as DNS, SIP, NTP IPv6 server
addresses or else. Therefore, the source tunnel end-point needs to
send DHCPv6 requests over its IPv6 upstream link, the tunnel link.
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 some tunnel links such as 6rd [RFC5969] .
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].
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3. Using DHCPv6 over Tunnel 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.
This document describes a possible solution to the above two problems
which doesn't require any change to the DHCPv6 protocol [RFC3315] .
The basic idea of this solution 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.
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6. Acknowledgements
The authors would like to thank Ted Lemon, Fred Templin, Brian E
Carpenter 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.,
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]
Bumgardner, G., "Automatic Multicast Tunneling",
draft-ietf-mboned-auto-multicast-13 (work in progress),
April 2012.
[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
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Marc Blanchet
Viagenie
2875 boul. Laurier, suite D2-630
Quebec,
Canada
Phone:
Fax:
Email: Marc.Blanchet@viagenie.ca
URI:
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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