draft-ietf-mext-nemo-pd-07.txt   rfc6276.txt 
Mobility Extensions for IPv6 R. Droms Internet Engineering Task Force (IETF) R. Droms
(MEXT) P. Thubert Request for Comments: 6276 P. Thubert
Internet-Draft Cisco Category: Standards Track Cisco
Intended status: Standards Track F. Dupont ISSN: 2070-1721 F. Dupont
Expires: June 23, 2011 ISC Internet Systems Consortium
W. Haddad W. Haddad
Ericsson Ericsson
CJ. Bernardos C. Bernardos
UC3M UC3M
December 20, 2010 July 2011
DHCPv6 Prefix Delegation for NEMO DHCPv6 Prefix Delegation for Network Mobility (NEMO)
draft-ietf-mext-nemo-pd-07
Abstract Abstract
One aspect of network mobility support is the assignment of a prefix One aspect of network mobility support is the assignment of a prefix
or prefixes to a mobile router for use on the links in the mobile or prefixes to a mobile router for use on the links in the mobile
network. This document specifies how DHCPv6 prefix delegation can be network. This document specifies how DHCPv6 prefix delegation can be
used for this configuration task. The mobile router plays the role used for this configuration task. The mobile router plays the role
of requesting router, while the home agent assumes the role of of requesting router, while the home agent assumes the role of
delegating router. When the mobile router is outside its home delegating router. When the mobile router is outside its home
network, the mobile router also assumes the role of DHCPv6 relay network, the mobile router also assumes the role of DHCPv6 relay
agent, co-located with the requesting router function. agent, co-located with the requesting router function.
Status of this Memo 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 This is an Internet Standards Track document.
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working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months This document is a product of the Internet Engineering Task Force
and may be updated, replaced, or obsoleted by other documents at any (IETF). It represents the consensus of the IETF community. It has
time. It is inappropriate to use Internet-Drafts as reference received public review and has been approved for publication by the
material or to cite them other than as "work in progress." Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 5741.
This Internet-Draft will expire on June 23, 2011. Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc6276.
Copyright Notice Copyright Notice
Copyright (c) 2010 IETF Trust and the persons identified as the Copyright (c) 2011 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
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described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. DHCPv6 Prefix Delegation of Mobile Network Prefixes . . . . . 4 3. DHCPv6 Prefix Delegation of Mobile Network Prefixes . . . . . 4
3.1. Exchanging DHCPv6 messages when the mobile router is 3.1. Exchanging DHCPv6 Messages When the Mobile Router Is
not at home . . . . . . . . . . . . . . . . . . . . . . . 5 Not at Home . . . . . . . . . . . . . . . . . . . . . . . 5
3.1.1. Relay agent configuration . . . . . . . . . . . . . . 7 3.1.1. Relay Agent Configuration . . . . . . . . . . . . . . 7
3.1.2. Transmission of DHCPv6 messages . . . . . . . . . . . 8 3.1.2. Transmission of DHCPv6 Messages . . . . . . . . . . . 8
3.1.3. Receipt of DHCPv6 messages . . . . . . . . . . . . . . 8 3.1.3. Receipt of DHCPv6 Messages . . . . . . . . . . . . . . 8
3.2. Exchanging DHCPv6 messages when the mobile router is 3.2. Exchanging DHCPv6 Messages When the Mobile Router Is
at home . . . . . . . . . . . . . . . . . . . . . . . . . 8 at Home . . . . . . . . . . . . . . . . . . . . . . . . . 8
3.3. Selecting a home agent that provides DHCPv6PD . . . . . . 9 3.3. Selecting a Home Agent That Provides DHCPv6PD . . . . . . 9
3.4. Minimizing DHCPv6PD messages . . . . . . . . . . . . . . . 10 3.4. Minimizing DHCPv6PD Messages . . . . . . . . . . . . . . . 10
3.5. Other DHCPv6 functions . . . . . . . . . . . . . . . . . . 10 3.5. Other DHCPv6 Functions . . . . . . . . . . . . . . . . . . 10
4. Security Considerations . . . . . . . . . . . . . . . . . . . 10 4. Security Considerations . . . . . . . . . . . . . . . . . . . 10
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12 5. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 12
6. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 12 6. References . . . . . . . . . . . . . . . . . . . . . . . . . . 12
7. Change Log . . . . . . . . . . . . . . . . . . . . . . . . . . 12 6.1. Normative References . . . . . . . . . . . . . . . . . . . 12
7.1. Revision -00 . . . . . . . . . . . . . . . . . . . . . . . 12 6.2. Informative References . . . . . . . . . . . . . . . . . . 13
7.2. Revision -01 . . . . . . . . . . . . . . . . . . . . . . . 12
7.3. Revision -02 . . . . . . . . . . . . . . . . . . . . . . . 13
7.4. Revision -04 . . . . . . . . . . . . . . . . . . . . . . . 13
7.5. Revision -05 . . . . . . . . . . . . . . . . . . . . . . . 13
7.6. Revision -06 . . . . . . . . . . . . . . . . . . . . . . . 14
7.7. Revision -07 . . . . . . . . . . . . . . . . . . . . . . . 14
8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 14
8.1. Normative References . . . . . . . . . . . . . . . . . . . 14
8.2. Informative References . . . . . . . . . . . . . . . . . . 15
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 15
1. Introduction 1. Introduction
One aspect of network mobility support is the assignment of a prefix One aspect of network mobility support is the assignment of a prefix
or prefixes to a Mobile Router for use on the links in the NEMO. or prefixes to a mobile router for use on the links in Network
DHCPv6 prefix delegation (DHCPv6PD) [RFC3633] can be used for this Mobility (NEMO). DHCPv6 prefix delegation (DHCPv6PD) [RFC3633] can
configuration task. be used for this configuration task.
The model of operation of DHCPv6PD for prefix delegation is as The model of operation of DHCPv6PD for prefix delegation is as
follows [RFC3633]. A delegating router is provided IPv6 prefixes to follows [RFC3633]. A delegating router is provided IPv6 prefixes to
be delegated to requesting routers. A requesting router requests be delegated to requesting routers. A requesting router requests
prefix(es) from the delegating router. The delegating router chooses prefix(es) from the delegating router. The delegating router chooses
prefix(es) for delegation, and responds with prefix(es) to the prefix(es) for delegation, and responds with prefix(es) to the
requesting router. The requesting router is then responsible for the requesting router. The requesting router is then responsible for the
delegated prefix(es). Note that DHCPv6 options for prefix delegation delegated prefix(es). Note that DHCPv6 options for prefix delegation
defined in [RFC3633] have been defined for general use across defined in [RFC3633] have been defined for general use across
routers, and not only for mobile routers running the NEMO Basic routers, and not only for mobile routers running the NEMO Basic
Support protocol [RFC3963]. Support protocol [RFC3963].
To use DHCPv6PD as prefix assignment mechanism in mobile networks, To use DHCPv6PD as a prefix assignment mechanism in mobile networks,
when the mobile router is located at home the home agent assumes the when the mobile router is located at home, the home agent assumes the
role of the delegating router and the mobile router assumes the role role of the delegating router and the mobile router assumes the role
of the requesting router. However, when the mobile router is away of the requesting router. However, when the mobile router is away
from home, in addition to the roles when the mobile router is located from home, in addition to the roles when the mobile router is located
at home, the mobile router also assumes the role of a DHCPv6 relay at home, the mobile router also assumes the role of a DHCPv6 relay
agent co-located with the requesting router function. agent co-located with the requesting router function.
The DHCPv6PD server running at the home agent is provisioned with The DHCPv6PD server running at the home agent is provisioned with
prefixes to be assigned using any of the prefix assignment mechanisms prefixes to be assigned using any of the prefix assignment mechanisms
described in the DHCPv6PD specification [RFC3633]. described in the DHCPv6PD specification [RFC3633].
2. Terminology 2. 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 RFC2119 [RFC2119]. document are to be interpreted as described in RFC 2119 [RFC2119].
The following terms used in this document are defined in the IPv6 The following terms used in this document are defined in the IPv6
Addressing Architecture document [RFC4291]: Addressing Architecture document [RFC4291]:
Link-Local Unicast address Link-Local Unicast address
Link-Local Scope Multicast address Link-Local Scope Multicast address
The following terms used in this document are defined in the Mobile The following terms used in this document are defined in the Mobile
IPv6 specification [I-D.ietf-mext-rfc3775bis]: IPv6 specification [RFC6275]:
Home Agent (HA) Home Agent (HA)
Home Link Home Link
Home Address (HoA) Home Address (HoA)
Care-of Address (CoA) Care-of Address (CoA)
Binding Update (BU) Binding Update (BU)
skipping to change at page 4, line 42 skipping to change at page 4, line 21
DHCPv6 Relay Agent (DRA) DHCPv6 Relay Agent (DRA)
The following acronym is used in this document: The following acronym is used in this document:
DHCPv6PD: DHCPv6 Prefix Delegation DHCPv6PD: DHCPv6 Prefix Delegation
3. DHCPv6 Prefix Delegation of Mobile Network Prefixes 3. DHCPv6 Prefix Delegation of Mobile Network Prefixes
The NEMO Basic Support protocol [RFC3963] extends the Mobile IPv6 The NEMO Basic Support protocol [RFC3963] extends the Mobile IPv6
protocol [I-D.ietf-mext-rfc3775bis] to enable network mobility. With protocol [RFC6275] to enable network mobility. With the NEMO Basic
the NEMO Basic Support protocol a mobile router uses Mobile IPv6 to Support protocol, a mobile router uses Mobile IPv6 to establish and
establish and maintain a session with its home agent, and uses maintain a session with its home agent and uses bidirectional
bidirectional tunneling between the mobile router and the home agent tunneling between the mobile router and the home agent to provide a
to provide a path through which nodes attached to links in the mobile path through which nodes attached to links in the mobile network can
network can maintain connectivity with nodes not in the NEMO. maintain connectivity with nodes not in the NEMO.
The requirements for Network Mobility [RFC4885] include the ability The requirements for Network Mobility [RFC4885] include the ability
of the mobile router to receive delegated prefixes that can then be of the mobile router to receive delegated prefixes that can then be
assigned to links in the mobile network. DHCPv6PD can be used to assigned to links in the mobile network. DHCPv6PD can be used to
meet this requirement for prefix delegation. meet this requirement for prefix delegation.
To use DHCPv6PD for mobile networks, when the mobile router is To use DHCPv6PD for mobile networks, when the mobile router is
located at home the home agent assumes the role of the delegating located at home, the home agent assumes the role of the delegating
router and the mobile router assumes the role of the requesting router and the mobile router assumes the role of the requesting
router. However, when the mobile router is away from home, in router. However, when the mobile router is away from home, in
addition to the roles when the mobile router is located at home, the addition to the roles when the mobile router is located at home, the
mobile router also assumes the role of a DHCPv6 relay agent co- mobile router also assumes the role of a DHCPv6 relay agent
located with the requesting router function. co-located with the requesting router function.
When the mobile router is not at home, the home agent and the mobile When the mobile router is not at home, the home agent and the mobile
router exchange DHCPv6PD protocol messages as specified in router exchange DHCPv6PD protocol messages as specified in [RFC6275].
[I-D.ietf-mext-rfc3775bis]. This means that the messages sent by the This means that the messages sent by the mobile router MUST include
mobile router MUST include the Home Address destination option and the Home Address destination option and messages sent by the home
messages sent by the home agent MUST make use of a Routing Header agent MUST make use of a Routing Header type 2. See Figure 1 for the
type 2. See Figure 1 for the deployment topologies when the MR is at deployment topologies when the MR is at home and when it is visiting
home and when it is visiting a foreign network. a foreign network.
------ ------ ------ ------
| MR |----------------| HA | | MR |----------------| HA |
|(RR)| (home network) |(DR)| |(RR)| (home network) |(DR)|
------ ------ ------ ------
------- /-----------\ ------ ------- /-----------\ ------
| MR |----| Internet |-----| HA | | MR |----| Internet |-----| HA |
|(RR) | \-----------/ |(DR)| |(RR) | \-----------/ |(DR)|
|(DRA)| ------ |(DRA)| ------
skipping to change at page 5, line 46 skipping to change at page 5, line 29
The DHCPv6PD server is provisioned with prefixes to be assigned using The DHCPv6PD server is provisioned with prefixes to be assigned using
any of the prefix assignment mechanisms described in the DHCPv6PD any of the prefix assignment mechanisms described in the DHCPv6PD
specifications. Other updates to the home agent data structures specifications. Other updates to the home agent data structures
required as a side effect of prefix delegation are specified by the required as a side effect of prefix delegation are specified by the
particular network mobility protocol. For example, in the case of particular network mobility protocol. For example, in the case of
NEMO Basic Network Mobility Support [RFC3963], the HA would add an NEMO Basic Network Mobility Support [RFC3963], the HA would add an
entry in its binding cache registering the delegated prefix to the entry in its binding cache registering the delegated prefix to the
mobile router to which the prefix was delegated. mobile router to which the prefix was delegated.
3.1. Exchanging DHCPv6 messages when the mobile router is not at home 3.1. Exchanging DHCPv6 Messages When the Mobile Router Is Not at Home
The case when the mobile router is away from home is described in The case when the mobile router is away from home is described in
this section. Section 3.2 describes the protocol operation for the this section. Section 3.2 describes the protocol operation for the
case when the mobile router is attached to its home link. case when the mobile router is attached to its home link.
The mobile router MUST register at the home agent (i.e., by sending a The mobile router MUST register at the home agent (i.e., by sending a
Binding Update to the home agent) before initiating a DHCPv6 message Binding Update to the home agent) before initiating a DHCPv6 message
exchange for prefix delegation. The mobile router MUST use implicit exchange for prefix delegation. The mobile router MUST use implicit
BU signaling, since the mobile router may not have yet requested any BU signaling, since the mobile router may not have yet requested any
prefixes. prefixes.
If the mobile router does not have any active delegated prefixes If the mobile router does not have any active delegated prefixes
(with unexpired leases), the mobile router MUST initiate a DHCPv6 (with unexpired leases), the mobile router MUST initiate a DHCPv6
message exchange with a DHCPv6 Solicit message as described in message exchange with a DHCPv6 Solicit message as described in
section 17 of [RFC3315] and section 11.1 of [RFC3633]. The Section 17 of [RFC3315] and Section 11.1 of [RFC3633]. The
delegating router at the home agent responds with an Advertise delegating router at the home agent responds with an Advertise
message. Then, the mobile router MUST request a set of prefixes by message. Then, the mobile router MUST request a set of prefixes by
sending a Request message. The delegating router includes the sending a Request message. The delegating router includes the
delegated prefixes in a Reply message. Note that in this case, the delegated prefixes in a Reply message. Note that in this case, the
mobile router has previously sent a Binding Update to the home agent mobile router has previously sent a Binding Update to the home agent
without knowing yet the set of prefixes that it can use as mobile without knowing yet the set of prefixes that it can use as mobile
network prefixes. The home agent, upon reception of the implicit network prefixes. The home agent, upon reception of the implicit
Binding Update from the mobile router, MUST select (in case this was Binding Update from the mobile router, MUST select (in case this was
not pre-configured already) the prefixes that would then be delegated not pre-configured already) the prefixes that would then be delegated
to the mobile router via DHCPv6PD. The home agent, once the DHCPv6 to the mobile router via DHCPv6PD. The home agent, once the DHCPv6
signaling has been completed, MUST add an entry in its binding cache signaling has been completed, MUST add an entry in its binding cache
including the delegated prefixes. including the delegated prefixes.
In case the mobile router has one or more active delegated prefixes In case the mobile router has one or more active delegated prefixes
-- as for example if the mobile router reboots or the mobile network -- for example, as if the mobile router reboots or the mobile network
prefix(es) currently used by the mobile router is about to expire -- prefix(es) currently used by the mobile router is about to expire --
the mobile router MUST initiate a DHCPv6 message exchange with a the mobile router MUST initiate a DHCPv6 message exchange with a
DHCPv6 Rebind message as described in section 18.1.2 of [RFC3315] and DHCPv6 Rebind message as described in Section 18.1.2 of [RFC3315] and
section 12.1 of [RFC3633]. Section 12.1 of [RFC3633].
A DHPCv6 relay agent function [RFC3315] MUST be used at the mobile A DHPCv6 relay agent function [RFC3315] MUST be used at the mobile
router. This relay agent function is co-located in the mobile router router. This relay agent function is co-located in the mobile router
with the DHCPv6 client function (see Figure 2). The DHCPv6 signaling with the DHCPv6 client function (see Figure 2). The DHCPv6 signaling
between the mobile router and the home agent is exchanged between the between the mobile router and the home agent is exchanged between the
DHCPv6 relay agent in the mobile router and the DHCPv6 server on the DHCPv6 relay agent in the mobile router and the DHCPv6 server on the
home agent. DHCPv6 messages from the mobile router to the home agent home agent. DHCPv6 messages from the mobile router to the home agent
are unicast packets sent from the unicast home address of the mobile are unicast packets sent from the unicast home address of the mobile
router to the global unicast address of the home agent, and therefore router to the global unicast address of the home agent, and therefore
the Home Address destination option MUST be used. DHCPv6 replies the Home Address destination option MUST be used. DHCPv6 replies
from the home agent to the mobile router MUST be sent using the from the home agent to the mobile router MUST be sent using the
Routing Header type 2, as specified in [I-D.ietf-mext-rfc3775bis]. Routing Header type 2, as specified in [RFC6275]. The DHCPv6 client
The DHCPv6 client in the mobile router MUST hand any outbound DHCPv6 in the mobile router MUST hand any outbound DHCPv6 messages to the
messages to the co-located relay agent. Responses from the DHCPv6 co-located relay agent. Responses from the DHCPv6 server are
server are delivered to the relay agent function in the mobile delivered to the relay agent function in the mobile router, which
router, which MUST extract the encapsulated message and deliver it to MUST extract the encapsulated message and deliver it to the DHCPv6
the DHCPv6 client in the mobile router. client in the mobile router.
----------------------------- -------- ----------------------------- --------
| MR | | HA | | MR | | HA |
| (RR) (DRA) | | (DR) | | (RR) (DRA) | | (DR) |
---------------------------- -------- ---------------------------- --------
| | Binding Update | | | Binding Update |
| |------------------------>| | |------------------------>|
| | (HoA, CoA) | | | (HoA, CoA) |
| | | | | |
| | Binding Ack | | | Binding Ack |
skipping to change at page 7, line 39 skipping to change at page 7, line 39
Figure 2: Signaling sequence when the mobile router is not at home Figure 2: Signaling sequence when the mobile router is not at home
Note that a mobile router using DHCPv6PD to obtain the set of Note that a mobile router using DHCPv6PD to obtain the set of
prefixes to be used as mobile network prefixes cannot derive its home prefixes to be used as mobile network prefixes cannot derive its home
address from one of its mobile network prefix(es) (as the mobile address from one of its mobile network prefix(es) (as the mobile
router does not know them before registering to the home agent). router does not know them before registering to the home agent).
Therefore, the mobile router MUST assign its home address from the Therefore, the mobile router MUST assign its home address from the
prefix on its Home Link. prefix on its Home Link.
3.1.1. Relay agent configuration 3.1.1. Relay Agent Configuration
The use of the relay agent function in the mobile router allows the The use of the relay agent function in the mobile router allows the
mobile router to unicast DHCPv6 messages to the DHCPv6 server. The mobile router to unicast DHCPv6 messages to the DHCPv6 server. The
relay agent MUST be configured with the address of the DHCPv6 server. relay agent MUST be configured with the address of the DHCPv6 server.
For the purposes of this specification, the relay agent assumes that For the purposes of this specification, the relay agent assumes that
the home agent for the mobile router hosts the DHCPv6 server. the home agent for the mobile router hosts the DHCPv6 server.
Therefore, the mobile router MUST configure the DHCPv6 relay agent to Therefore, the mobile router MUST configure the DHCPv6 relay agent to
forward DHCPv6 messages to the home agent. forward DHCPv6 messages to the home agent.
The DHCPv6 specification supports in certain scenarios the use of The DHCPv6 specification supports in certain scenarios the use of
unicast between the client and the server. However its use presents unicast between the client and the server. However, its use presents
some difficulties, as the client has to first receive a Server some difficulties, as the client has to first receive a Server
Unicast option (section 22.12 of [RFC3315]) from the server, which Unicast option (Section 22.12 of [RFC3315]) from the server, which
means that a Solicit/Advertise message exchange is required in means that a Solicit/Advertise message exchange is required in
advance. That signaling exchange would require the presence of a advance. That signaling exchange would require the presence of a
relay agent on the mobile router, and therefore little gain would be relay agent on the mobile router, and therefore little gain would be
achieved in this case from the use of the Server Unicast option. achieved in this case from the use of the Server Unicast option.
3.1.2. Transmission of DHCPv6 messages 3.1.2. Transmission of DHCPv6 Messages
When the DHCPv6 client in the mobile router sends a message, it MUST When the DHCPv6 client in the mobile router sends a message, it MUST
hand the message to the DHCPv6 relay agent in the mobile router. The hand the message to the DHCPv6 relay agent in the mobile router. The
way in which the message is passed to the DHCP relay agent is beyond way in which the message is passed to the DHCP relay agent is beyond
the scope of this document. The relay agent encapsulates the message the scope of this document. The relay agent encapsulates the message
from the client according to [RFC3315] in a Relay-forward message and from the client according to [RFC3315] in a Relay-forward message and
sends the resulting DHCPv6 message to the home agent. The relay sends the resulting DHCPv6 message to the home agent. The relay
agent sets the fields in the Relay-forward message as follows: agent sets the fields in the Relay-forward message as follows:
msg-type RELAY-FORW msg-type RELAY-FORW
hop-count 1 hop-count 1
link-address The home address of the mobile router link-address The home address of the mobile router
peer-address The home address of the mobile router peer-address The home address of the mobile router
options MUST include a "Relay Message option" [RFC3315]; MAY options MUST include a "Relay Message option" [RFC3315]; MAY
include other options added by the relay agent. include other options added by the relay agent.
3.1.3. Receipt of DHCPv6 messages 3.1.3. Receipt of DHCPv6 Messages
Messages from the DHCPv6 server will be returned to the DHCPv6 relay Messages from the DHCPv6 server will be returned to the DHCPv6 relay
agent, with the message for the DHCPv6 client encapsulated in the agent, with the message for the DHCPv6 client encapsulated in the
Relay Message option [RFC3315] in a Relay-reply message. The relay Relay Message option [RFC3315] in a Relay-reply message. The relay
agent function MUST extract the message for the client from the Relay agent function MUST extract the message for the client from the Relay
Message option and hand the message to the DHCPv6 client in the Message option and hand the message to the DHCPv6 client in the
mobile router. The way in which the message is passed to the client mobile router. The way in which the message is passed to the client
is beyond the scope of this document. is beyond the scope of this document.
3.2. Exchanging DHCPv6 messages when the mobile router is at home 3.2. Exchanging DHCPv6 Messages When the Mobile Router Is at Home
When the mobile router is on its home link, the home agent MUST use When the mobile router is on its home link, the home agent MUST use
the home link to exchange DHCPv6PD messages with the mobile router the home link to exchange DHCPv6PD messages with the mobile router
(Figure 3). In this case, the DHCPv6 co-located relay function MUST (Figure 3). In this case, the DHCPv6 co-located relay function MUST
be disabled. It is the responsibility of the implementation to be disabled. It is the responsibility of the implementation to
determine when the mobile router is on its home link. The Home Link determine when the mobile router is on its home link. The Home Link
Detection mechanism is described in the section 11.5.2 of Detection mechanism is described in Section 11.5.2 of [RFC6275].
[I-D.ietf-mext-rfc3775bis].
-------- -------- -------- --------
| MR | | HA | | MR | | HA |
| (RR) | | (DR) | | (RR) | | (DR) |
-------- -------- -------- --------
| | | |
| DHCPv6 Solicit | | DHCPv6 Solicit |
|------------------------>| |------------------------>|
| | | |
| DHCPv6 Advertise | | DHCPv6 Advertise |
skipping to change at page 9, line 26 skipping to change at page 9, line 26
| DHCPv6 Request | | DHCPv6 Request |
|------------------------>| |------------------------>|
| | | |
| DHCPv6 Reply | | DHCPv6 Reply |
|<------------------------| |<------------------------|
| (Mobile Network Prefix) | | (Mobile Network Prefix) |
| | | |
Figure 3: Signaling sequence for the case the home agent is at home Figure 3: Signaling sequence for the case the home agent is at home
3.3. Selecting a home agent that provides DHCPv6PD 3.3. Selecting a Home Agent That Provides DHCPv6PD
Not all nodes that are willing to act as a home agent are required to Not all nodes that are willing to act as a home agent are required to
provide DHCPv6PD. Therefore, when selecting a home agent, a mobile provide DHCPv6PD. Therefore, when selecting a home agent, a mobile
router that requires DHCPv6PD service MUST identify a home agent that router that requires DHCPv6PD service MUST identify a home agent that
will provide the service. The mobile router can determine if a home will provide the service. The mobile router can determine if a home
agent provides DHCPv6PD by initiating a DHCPv6 message exchange agent provides DHCPv6PD by initiating a DHCPv6 message exchange
(i.e., sending a Solicit message) in which the mobile router requests (i.e., sending a Solicit message) in which the mobile router requests
delegated prefix(es). If the home agent does not respond or responds delegated prefix(es). If the home agent does not respond or responds
but does not delegate any prefix(es) in its response, the mobile but does not delegate any prefix(es) in its response, the mobile
router assumes that the home agent does not provide DHCPv6PD service. router assumes that the home agent does not provide DHCPv6PD service.
skipping to change at page 10, line 15 skipping to change at page 10, line 15
the mobile router discontinues sending Solicit messages to the home the mobile router discontinues sending Solicit messages to the home
agent after sending 6 Solicit messages, and conclude that the home agent after sending 6 Solicit messages, and conclude that the home
agent will not provide DHCPv6PD service. Sending 6 queries provides agent will not provide DHCPv6PD service. Sending 6 queries provides
enough reliability for scenarios in which the wireless connectivity enough reliability for scenarios in which the wireless connectivity
is lost for a short period after sending the first Binding Update is lost for a short period after sending the first Binding Update
message. message.
It is RECOMMENDED that the mobile router uses a sequential probing of It is RECOMMENDED that the mobile router uses a sequential probing of
the home agents for DHCPv6PD service. the home agents for DHCPv6PD service.
3.4. Minimizing DHCPv6PD messages 3.4. Minimizing DHCPv6PD Messages
The use DHCPv6PD in a mobile network can be combined with the Rapid The use DHCPv6PD in a mobile network can be combined with the Rapid
Commit option [RFC3315] to provide DHCPv6 prefix delegation with a Commit option [RFC3315] to provide DHCPv6 prefix delegation with a
two message exchange between the mobile router and the DHCPv6PD two-message exchange between the mobile router and the DHCPv6PD
delegating router. delegating router.
3.5. Other DHCPv6 functions 3.5. Other DHCPv6 Functions
The DHCPv6 messages exchanged between the mobile router and the home The DHCPv6 messages exchanged between the mobile router and the home
agent MAY also be used for other DHCPv6 functions in addition to agent MAY also be used for other DHCPv6 functions in addition to
DHCPv6PD. For example, the home agent MAY assign global addresses to DHCPv6PD. For example, the home agent MAY assign global addresses to
the mobile router and MAY pass other configuration information such the mobile router and MAY pass other configuration information such
as a list of available DNS recursive name servers [RFC3646] to the as a list of available DNS recursive name servers [RFC3646] to the
mobile router using the same DHCPv6 messages as used for DHCPv6PD. mobile router using the same DHCPv6 messages as used for DHCPv6PD.
The home agent MAY act as a DHCPv6 relay agent for mobile nodes while The home agent MAY act as a DHCPv6 relay agent for mobile nodes while
it acts as a delegating router for mobile routers. it acts as a delegating router for mobile routers.
skipping to change at page 12, line 15 skipping to change at page 12, line 15
home agent SAD: home agent SAD:
- SA2(OUT, spi_b, home_address_1, ESP, TRANSPORT): - SA2(OUT, spi_b, home_address_1, ESP, TRANSPORT):
local_address = home_agent_1 & local_address = home_agent_1 &
remote_address = home_address_1 & remote_address = home_address_1 &
proto = UDP & local_port = DHCP proto = UDP & local_port = DHCP
- SA1(IN, spi_a, home_agent_1, ESP, TRANSPORT): - SA1(IN, spi_a, home_agent_1, ESP, TRANSPORT):
local_address = home_address_1 & local_address = home_address_1 &
remote_address = home_agent_1 & remote_address = home_agent_1 &
proto = UDP & remote_port = DHCP proto = UDP & remote_port = DHCP
5. IANA Considerations 5. Acknowledgments
This document describes the use of DHCPv6 for prefix delegation in
mobile networks. It does not introduce any additional IANA
considerations.
6. Acknowledgments
The authors would like to thank people who have given valuable The authors would like to thank people who have given valuable
comments on the mailing list. Specific suggestions from Ryuji comments on the mailing list. Specific suggestions from Ryuji
Wakikawa, George Tsirtsis, Alexandru Petrescu, Vijay Devarapalli and Wakikawa, George Tsirtsis, Alexandru Petrescu, Vijay Devarapalli, and
Marcelo Bagnulo were incorporated into this document. Marcelo Bagnulo were incorporated into this document.
The authors would like to thank Julien Laganier, Michaela Vanderveen The authors would like to thank Julien Laganier, Michaela Vanderveen,
and Jean-Michel Combes for their review of previous versions of this and Jean-Michel Combes for their review of previous versions of this
document. document.
7. Change Log 6. References
This section MUST be removed before this document is published as an
RFC.
7.1. Revision -00
This document is based on draft-ietf-nemo-dhcpv6-pd-03 and includes
the use of the DHCPv6 relay agent in the MR from
draft-dupont-mext-dhcrelay-00.
7.2. Revision -01
Added detail in Section 4, "Security Considerations", describing
protection required for DHCPv6 and a mechanism for protecting traffic
between the DHCPv6 relay agent and server.
Corrected minor typos.
7.3. Revision -02
Removed text describing extensions to DHAAD for discovery of HA that
will provide PD.
Added Section 3.3, "Selecting an HA that provides DHCPv6PD," which
describes how an MR can discover DHCPv6PD service through polling of
multiple HAs.
Added text to Section 4, "Security Considerations", giving detail
about the use of IPsec.
7.4. Revision -04
Added some figures to better explaining considered topologies and
message exchanges. Credits to Alex Petrescu.
Added some text to clarify that two BUs are required, one to set up
the tunnel to the HA so the DHCPv6 signaling can be sent, and one to
register the delegated prefixes as MNPs at the HA. This updates RFC
3963 behavior (note added).
Text added to address some comments received on the MEXT mailing list
Corrected minor typos.
Enlisted Carlos J. Bernardos as co-author
7.5. Revision -05
Only implicit BU mode supported.
Only DHCPv6 relay agent in the MR co-located with the DHCPv6 client
function is supported as mode of operation when the MR is away from
home.
Security considerations include now the issue of the HA enforcing
that the MR registers the prefixes that were delegated to it via
DHCPv6PD.
Since [I-D.ietf-mext-rfc3775bis] specifies that MR and HA operate in
RO mode when sending traffic between them, the term tunnel has been
removed.
Some typos detected and corrected.
7.6. Revision -06
Some nits fixed.
7.7. Revision -07
Fixes and clarifying text as suggested during IESG review.
8. References
8.1. Normative References
[I-D.ietf-mext-rfc3775bis] 6.1. Normative References
Perkins, C., Johnson, D., and J. Arkko, "Mobility Support
in IPv6", draft-ietf-mext-rfc3775bis-10 (work in
progress), October 2010.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997. Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC3315] Droms, R., Bound, J., Volz, B., Lemon, T., Perkins, C., [RFC3315] Droms, R., Bound, J., Volz, B., Lemon, T., Perkins, C.,
and M. Carney, "Dynamic Host Configuration Protocol for and M. Carney, "Dynamic Host Configuration Protocol for
IPv6 (DHCPv6)", RFC 3315, July 2003. IPv6 (DHCPv6)", RFC 3315, July 2003.
[RFC3633] Troan, O. and R. Droms, "IPv6 Prefix Options for Dynamic [RFC3633] Troan, O. and R. Droms, "IPv6 Prefix Options for Dynamic
Host Configuration Protocol (DHCP) version 6", RFC 3633, Host Configuration Protocol (DHCP) version 6", RFC 3633,
skipping to change at page 15, line 5 skipping to change at page 13, line 12
Thubert, "Network Mobility (NEMO) Basic Support Protocol", Thubert, "Network Mobility (NEMO) Basic Support Protocol",
RFC 3963, January 2005. RFC 3963, January 2005.
[RFC4291] Hinden, R. and S. Deering, "IP Version 6 Addressing [RFC4291] Hinden, R. and S. Deering, "IP Version 6 Addressing
Architecture", RFC 4291, February 2006. Architecture", RFC 4291, February 2006.
[RFC4877] Devarapalli, V. and F. Dupont, "Mobile IPv6 Operation with [RFC4877] Devarapalli, V. and F. Dupont, "Mobile IPv6 Operation with
IKEv2 and the Revised IPsec Architecture", RFC 4877, IKEv2 and the Revised IPsec Architecture", RFC 4877,
April 2007. April 2007.
8.2. Informative References [RFC6275] Perkins, C., Johnson, D., and J. Arkko, "Mobility Support
in IPv6", RFC 6275, July 2011.
6.2. Informative References
[RFC4885] Ernst, T. and H-Y. Lach, "Network Mobility Support [RFC4885] Ernst, T. and H-Y. Lach, "Network Mobility Support
Terminology", RFC 4885, July 2007. Terminology", RFC 4885, July 2007.
Authors' Addresses Authors' Addresses
Ralph Droms Ralph Droms
Cisco Cisco
1414 Massachusetts Avenue 1414 Massachusetts Avenue
Boxborough, MA 01719 Boxborough, MA 01719
USA USA
Phone: +1 978.936.1674 Phone: +1 978.936.1674
Email: rdroms@cisco.com EMail: rdroms@cisco.com
Pascal Thubert Pascal Thubert
Cisco Cisco
Village d'Entreprises Green Side Village d'Entreprises Green Side
400, Avenue Roumanille 400, Avenue Roumanille
Biot - Sophia Antipolis 06410 Biot - Sophia Antipolis 06410
FRANCE FRANCE
Email: pthubert@cisco.com EMail: pthubert@cisco.com
Francis Dupont Francis Dupont
ISC Internet Systems Consortium
Email: Francis.Dupont@fdupont.fr EMail: fdupont@isc.org
Wassim Haddad Wassim Haddad
Ericsson Ericsson
6210 Spine Road 6210 Spine Road
Boulder, CO 80301 Boulder, CO 80301
USA USA
Phone: +1 303.473.6963 Phone: +1 303.473.6963
Email: Wassim.Haddad@ericsson.com EMail: Wassim.Haddad@ericsson.com
Carlos J. Bernardos Carlos J. Bernardos
Universidad Carlos III de Madrid Universidad Carlos III de Madrid
Av. Universidad, 30 Av. Universidad, 30
Leganes, Madrid 28911 Leganes, Madrid 28911
Spain Spain
Phone: +34 91624 6236 Phone: +34 91624 6236
Email: cjbc@it.uc3m.es EMail: cjbc@it.uc3m.es
URI: http://www.it.uc3m.es/cjbc/ URI: http://www.it.uc3m.es/cjbc/
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