Internet DRAFT - draft-xia-mext-hioptv4
draft-xia-mext-hioptv4
Network Working Group F. Xia
Internet-Draft B. Sarikaya
Expires: July 14, 2012 Huawei USA
January 11, 2012
DHCPv4 Options for Home Information Discovery in Dual Stack MIPv6
draft-xia-mext-hioptv4-04.txt
Abstract
This document defines DHCPv4 options for dynamic discovery of home
network information in Dual Stack Mobile IPv6. New DHCPv4 options
are defined which allow a mobile node to request the home agent
IPv4/v6 address, FQDN, or home network prefix and obtain it via the
DHCPv4 response.
Status of this Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on July 14, 2012.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Home Network Information Discovery Using DHCPv6 . . . . . . . 4
4. DHCPv4 options for HA Dynamic Discovery . . . . . . . . . . . 4
4.1. Home Network Information Option . . . . . . . . . . . . . 4
4.2. DSMIP6 DHCPv4 Relay Agent Option . . . . . . . . . . . . . 5
4.3. Common Sub-options . . . . . . . . . . . . . . . . . . . . 6
5. Appearance of the options . . . . . . . . . . . . . . . . . . 8
6. Security Considerations . . . . . . . . . . . . . . . . . . . 8
7. IANA considerations . . . . . . . . . . . . . . . . . . . . . 8
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 9
9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 9
9.1. Normative References . . . . . . . . . . . . . . . . . . . 9
9.2. Informative References . . . . . . . . . . . . . . . . . . 9
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 10
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1. Introduction
Before a mobile node can exchange Mobile IPv6 signaling with a home
agent (HA), it should either know the IP address of the home agent
via pre-configuration, or dynamically discover it. For dynamic
discovery, new Dynamic Host Configuration Protocol for IPv6 (DHCPv6)
options are defined in [I-D.ietf-mip6-hiopt] which allow a mobile
node to request the home agent IPv4/ IPv6 address, Fully Qualified
Domain Name (FQDN), or home network prefix, collectively called home
network information and obtain it via the DHCPv6 response.
Mobile IPv6 Support for Dual Stack Hosts and Routers (DSMIPv6)
extends Mobile IPv6 specification [RFC3775] to allow the registration
of IPv4 addresses and the transport of packets over IPv4 tunnels
between mobile nodes and home agents ([RFC5555]). DSMIPv6 home
agents are dual-stacked and can support IPv4 only mobile nodes.
DSMIPv6 HA can support dual-stacked mobile nodes connected to the
networks that are IPv4 only. Mobile nodes can register their IPv4
home and care-of addresses with HA and can tunnel IPv4 packets to the
HA.
With home network information discovery in DSMIPv6, there are
actually four different cases:
o Discovering HA's IPv6 address with DHCPv6 for IPv6 only mobile
nodes
o Discovering HA's IPv4 address with DHCPv6 for dual-stacked mobile
nodes in IPv6 network
o Discovering HA's IPv4 address with DHCPv4 for IPv4 only mobile
nodes
o Discovering HA's IPv6 address with DHCPv4 for dual-stacked mobile
nodes in IPv4 network
The first two cases are dealt with in [I-D.ietf-mip6-hiopt], while
the last two cases are specified in this document. DHCPv4 options
are defined based on DHCPv4 protocol specified in [RFC2131].
2. 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 [RFC2119].
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3. Home Network Information Discovery Using DHCPv6
The following DHCPv6 options and their sub-options are used for
dynamic discovery of the home agent's IPv4/IPv6 address, IPv6 home
network prefix, or FQDN information in DSMIPv6:
Home Network Information Option
This option allows the exchange of home network information
between the mobile node (DHCPv6 client) and the DHCPv6 server. It
is used to indicate the target home network requested by the
mobile node to the DHCPv6 server. It also conveys the home
network information assigned by the DHCPv6 server to the mobile
node as a response.
MIP6 Relay Agent Option
This option carries the home network information for the mobile
node from the DHCPv6 relay agent to the DHCPv6 server. This is
needed in case when the NAS is collocated with the DHCPv6 relay
agent and the NAS gets the home network information from external
AAA servers. MIP6 Relay Agent option is added to DHCPv6 message
when the NAS/DHCP relay agent relays DHCPv6 request message from
the mobile node to the DHCPv6 server. Being populated with this
information, the DHCPv6 server uses Home Network Information
Option to reply to the mobile node.
Common Sub-options
This sub-option is a container for a home network parameter in the
Home Network Information option.
In this document, Home Network Information Option and DSMIP6 DHCPv4
Relay Agent Option for DHCPv4 are defined in Section 4.1 and
Section 4.2, respectively. These options carry the information such
as IPv4 address of the dual-stacked home agent, IPv6 home network
prefix, IPv6 home agent address, FQDN of HA and Home network
identifier. Common Sub-options are defined in Section 4.3.
4. DHCPv4 options for HA Dynamic Discovery
4.1. Home Network Information Option
The option allows the exchange of home network information between
the mobile node (DHCPv4 client) and the DHCPv4 server. It is used to
indicate the target home network requested by the mobile node to the
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DHCPv4 server. It also conveys the home network information assigned
by the DHCPv4 server to the mobile node as a response.
0 1
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| option-code | option-length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Id-type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sub-options |
| ... ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Option-code
OPTION_DSMIP6_HNINF (TDB)
Option-len
Length of the 'options' field in octets;
MUST be a multiple of four (4).
Id-type
The type of Home Network Information.
0 Visited domain (local ASP)
1 Target MSP
2 No preference by the mobile node
Sub-options
A series of sub-options as defined in Section 4.3.
4.2. DSMIP6 DHCPv4 Relay Agent Option
This option carries the home network information for the mobile node
from the DHCPv4 relay agent to the DHCPv4 server.
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0 1
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| option-code | option-length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sub-options |
| ... ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Option-code
OPTION_DSMIP6_RELAY (TBD)
Option-len
Length of the 'options' field in octets;
MUST be a multiple of four (4).
Sub-options
A series of sub-options as defined in Section 4.3.
4.3. Common Sub-options
This sub-option is a container for a home network parameter in the
Home Network Information option or in the DSMIP6 DHCPv4 Relay Agent
option.
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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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sub-opt-code | Sub-opt-len |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. .
. Home Network Parameter .
. .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Sub-opt-code
A 16-bit unsigned integer for the type of the following
Home Network Parameter field. Possible values are:
0 Reserved
1 Home network identifier
2 IPv6 home network prefix
3 IPv6 home agent address
4 IPv4 address of the dual-stacked home agent
5 Home agent FQDN
6 .. (2^16-1) Reserved
Sub-opt-len
The length of the Home Network Parameter field in units
of octets.
Home Network Parameter
The provided home network information according to the
Sub-opt-code. This is encoded as specified below.
Mobile node MUST set the Sub-opt-code to 1 in the requesting Home
Network Information option. Mobile node MUST NOT set the Sub-opt-
code to any other value. DHCPv4 Relay Agent or DHCP server MAY set
the Sub-opt-code to 1, 2, 3, 4, and 5 as needed.
When the Sub-opt-code is set to 1 in the request, the Home Network
Parameter field MUST contain an identifier to specify the home
network requested by the mobile node. This field MUST be set in the
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form of a FQDN [RFC1035], encoded as specified in Section 8 of
[RFC3315]. This sub-option in the request SHOULD be copied into the
Home Network Information option returned in the reply.
When the Sub-opt-code is set to 2, the Home Network Parameter field
MUST include the 8-bit Prefix-Len followed by the 128-bit IPv6 Home
Network Prefix. The Prefix-Len information indicates the number of
leading bits in the IPv6 Home Network Prefix that are valid. The
IPv6 Home Network Prefix information may be used to allow the mobile
node to determine whether the home agent information received via
DHCPv6 corresponds to a home agent on-link or not.
When the Sub-opt-code is set to 3, the Home Network Parameter field
MUST contain the 128-bit IPv6 address of the home agent.
When the Sub-opt-code is set to 4, the Home Network Parameter field
MUST contain the 32-bit IPv4 address of the dual-stacked home agent.
When the Sub-opt-code is set to 5, it MUST contain the FQDN of the
home agent as described in Section 8 of [RFC3315].
5. Appearance of the options
The Home Network Information Option MUST NOT appear in any message
other than the following messages: DHCPDISCOVER, DHCPOFFER,
DHCPREQUEST, DHCPACK,DHCPINFORM.
The DSMIP6 DHCPv4 Relay Agent Option MUST NOT appear in any message
other than the following messages: DHCPDISCOVER, DHCPREQUEST,
DHCPINFORM.
6. Security Considerations
The security considerations in [RFC2131] and [RFC2132]apply. Special
considerations in [I-D.ietf-mip6-hiopt] are also applicable.
7. IANA considerations
IANA is requested to assign the OPTION_DSMIP6_HNINF and
OPTION_DSMIP6_RELAY Option Codes for DHCPv4 in the registry
maintained.
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8. Acknowledgements
The authors are grateful to Tomek Mrugalski and Ted Lemon for their
constructive comments that helped us improve the draft.
9. References
9.1. Normative References
[RFC1981] McCann, J., Deering, S., and J. Mogul, "Path MTU Discovery
for IP version 6", RFC 1981, August 1996.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2131] Droms, R., "Dynamic Host Configuration Protocol",
RFC 2131, March 1997.
[RFC2132] Alexander, S. and R. Droms, "DHCP Options and BOOTP Vendor
Extensions", RFC 2132, 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.
[RFC1035] Mockapetris, P., "Domain names - implementation and
specification", STD 13, RFC 1035, November 1987.
[RFC3775] Johnson, D., Perkins, C., and J. Arkko, "Mobility Support
in IPv6", RFC 3775, June 2004.
[RFC5555] Soliman, H., "Mobile IPv6 Support for Dual Stack Hosts and
Routers", RFC 5555, June 2009.
9.2. Informative References
[I-D.ietf-mip6-hiopt]
Jang, H., Yegin, A., Chowdhury, K., and J. Choi, "DHCP
Options for Home Information Discovery in MIPv6",
draft-ietf-mip6-hiopt-17 (work in progress), May 2008.
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Authors' Addresses
Frank Xia
Huawei USA
1700 Alma Dr. Suite 500
Plano, TX 75075
Phone: +1 972-509-5599
Email: xiayangsong@huawei.com
Behcet Sarikaya
Huawei USA
5340 Legacy Dr. Suite 175
Plano, TX 75074
Phone:
Email: sarikaya@ieee.org
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