NETEXT WG X. Zhou
Internet-Draft ZTE Corporation
Intended status: Standards Track J. Korhonen
Expires: November 20, 2013 Renesas Mobile
C. Williams
Consultant
S. Gundavelli
Cisco
CJ. Bernardos
UC3M
May 19, 2013
Prefix Delegation Support for Proxy Mobile IPv6
draft-ietf-netext-pd-pmip-08
Abstract
This specification defines extensions to Proxy Mobile IPv6 protocol
for allowing a mobile router in a Proxy Mobile IPv6 domain to obtain
delegated IP prefixes for its attached mobile networks. The mobility
entities in the network will provide network-based mobility
management support for those delegated IP prefixes just as how IP
mobility support is provided for the mobile node's home address.
Even as the mobile router performs an handoff and changes its network
point of attachment, mobility support is ensured for all the
delegated IP prefixes and for all the IP nodes in the mobile network
that use IP address configuration from those delegated IP prefixes.
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
Task Force (IETF). Note that other groups may also distribute
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
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on November 20, 2013.
Copyright Notice
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Copyright (c) 2013 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
(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.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Convention and Terminology . . . . . . . . . . . . . . . . . . 5
3. Solution Overview . . . . . . . . . . . . . . . . . . . . . . 7
3.1. Stated Assumptions . . . . . . . . . . . . . . . . . . . . 7
3.2. Deployment Models . . . . . . . . . . . . . . . . . . . . 7
3.2.1. Delegating Router Co-located with Mobile Access
Gateway . . . . . . . . . . . . . . . . . . . . . . . 7
3.2.2. Delegating Router Co-located with Local Mobility
Anchor . . . . . . . . . . . . . . . . . . . . . . . . 8
3.2.3. Static Configuration of Delegated Mobile Network
Prefixes . . . . . . . . . . . . . . . . . . . . . . . 9
4. Message formats . . . . . . . . . . . . . . . . . . . . . . . 11
4.1. Delegated Mobile Network Prefix Option . . . . . . . . . . 11
4.2. Status Codes . . . . . . . . . . . . . . . . . . . . . . . 12
5. Operational Details . . . . . . . . . . . . . . . . . . . . . 13
5.1. MAG Considerations . . . . . . . . . . . . . . . . . . . . 13
5.1.1. Extension to Binding Update List Entry Data
Structure . . . . . . . . . . . . . . . . . . . . . . 13
5.1.2. Signaling Considerations . . . . . . . . . . . . . . . 13
5.1.3. Packet Forwarding . . . . . . . . . . . . . . . . . . 17
5.2. LMA Considerations . . . . . . . . . . . . . . . . . . . . 18
5.2.1. Extensions to Binding Cache Entry Data Structure . . . 18
5.2.2. Signaling Considerations . . . . . . . . . . . . . . . 18
5.2.3. Packet Forwarding . . . . . . . . . . . . . . . . . . 20
5.3. Security Policy Database (SPD) Example Entries . . . . . . 20
6. Security Considerations . . . . . . . . . . . . . . . . . . . 22
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 23
8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 24
9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 25
9.1. Normative References . . . . . . . . . . . . . . . . . . . 25
9.2. Informative References . . . . . . . . . . . . . . . . . . 25
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 26
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1. Introduction
Proxy Mobile IPv6 [RFC5213] enables network-based mobility management
support for an IP host without requiring its participation in any IP
mobility signaling. The mobility elements in the network allow an IP
host to obtain an IPv4 address and/or a set of IPv6 addresses and be
able to obtain IP mobility support for those IP address(es) within
the Proxy Mobile IPv6 domain. In this context, the mobility
management support that is enabled is for an individual IP host,
which is the mobile node. The IPv4 home address, or the IPv6 home
network prefixes are logically bound to the link shared between the
mobile access gateway and the mobile node and only the mobile node
can use those IP address(es) by configuring them on the interface
attached to that link. Currently, there is no mobility support for
the mobile networks attached to a mobile router in a Proxy Mobile
IPv6 domain.
This specification defines extensions to the Proxy Mobile IPv6
protocol for allowing mobility support to the mobile networks
attached to a mobile router. The mobile router can request the
mobility entities in the Proxy Mobile IPv6 domain for one or more
delegated IP prefixes using DHCP Prefix Delegation extensions
[RFC3633], or through other mechanisms outside the scope of this
document. The mobility entities in the network will provide network-
based mobility management support for those delegated prefixes just
as how mobility is supported for an home address. The delegated
prefixes are hosted in the mobile network attached to the mobile
router. IP mobility is ensured for all the IP nodes in the mobile
network, even as the mobile router performs an handoff by changing
its point of network attachment within the Proxy Mobile IPv6 domain.
The local mobility anchor in the Proxy Mobile IPv6 domain will not
track the individual IP sessions for all the IP nodes in the mobile
network, it only tracks a single mobile router session that is
hosting the mobile network and associates the delegated IP prefixes
with that session.
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_----_
+-------+ _( )_
| |---( Internet )
| LMA | (_ _)
| | '----'
+-------+
|
=== === ===
== Proxy ==
== Mobile IPv6 ==
== Domain ==
=== === ===
___________|___________
| |
+-------+ +-------+
| MAG | | MAG |
+-------+ +-------+
.
.
- - - - - - - -
| +------+ |
| | MR | |
| +------+ |
| | |
| ------- |
| | | |
| LFN LFN |
- - - - - - - -
Figure 1: Mobile Router in Proxy Mobile IPv6 Domain
Within the context of this document, the definition of a mobile
router extends that of a mobile node definition from [RFC5213], by
adding routing capability for routing IP packets between its egress
interface (interface used for attachment to the mobile access
gateway) and any of its ingress interfaces (interface used for
attachment to the mobile network). The network of nodes part of the
mobile network are referred to as locally fixed nodes (LFN) and they
all move with the mobile router as a single cluster. Figure 1
illustrates a mobile router in a Proxy Mobile IPv6 domain.
The rest of the document identifies the protocol extensions and the
operational details of the local mobility anchor and mobile access
gateway for supporting this specification.
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2. Convention and 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].
All the mobility related terms used in this document are to be
interpreted as defined in Proxy Mobile IPv6 specifications [RFC5213]
and [RFC5844]. All the DHCP related terms are to be interpreted as
defined in DHCPv6-PD for NEMO [RFC6276], DHCPv6-PD [RFC3633] and
Subnet Allocation Option for DHCPv4 [RFC6656]. This document also
provides a context-specific explanation to the following terms used
in this document.
Mobile Router (MR)
The term mobile router is used to refer to an IP router whose
mobility is managed by the network while being attached to a Proxy
Mobile IPv6 domain. The mobile router is a mobile node as defined
in [RFC5213], but with additional capabilities for supporting an
attached mobile network. The mobility entities in the Proxy
Mobile IPv6 domain provide mobility for the IPv4/IPv6 address(es)
assigned to the mobile node's egress link and also mobility
support to the network prefixes hosted in the network attached to
the mobile router.
Mobile Network
It is an IP network attached to a mobile router. There can be
many IP nodes in this IP network. The mobile router is a gateway
for these IP nodes for reaching other IP networks or the Internet.
The mobile router and the attached IP networks move as a single
cluster.
Delegated Mobile Network Prefix (DMNP)
The Delegated Mobile Network Prefix is an IPv4/IPv6 prefix
delegated to a mobile router and is hosted in the mobile network.
The IP nodes in the mobile network will be able to obtain IP
address configuration from the delegated mobile network prefix and
will have IP mobility support for that address configuration. The
DMNP is topologically anchored on the local mobility anchor and
the mobility elements in the Proxy Mobile IPv6 domain provide IP
mobility support for the prefix, by forwarding the mobile network
traffic to the mobile router.
Locally Fixed Node (LFN)
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A Locally Fixed Node is an IP node in the mobile network. As the
mobile router performs an handoff and changes its network point of
attachement, the locally fixed node moves along with the mobile
router.
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3. Solution Overview
This section provides an overview of the operation of this
specification, as well as lists the stated assumptions. This
specification references three different deployment scenarios and
explains the protocol operation.
3.1. Stated Assumptions
o The mobile router is a mobile node as defined in [RFC5213], but
with additional capabilities for routing IP packets between its
egress interface (interface used for attachment to the mobile
access gateway) and any of its ingress interfaces (interface used
for attachment to the mobile network).
o The specification assumes that a mobile router is an IPv4 and/or
IPv6 router without any capability for mobility management.
o The mobile router can obtain the delegated IP prefix(es) for its
attached mobile networks using DHCPv6, or using mechanisms outside
of this document (Example: Static Configuration, or access
technology specific mechanisms). This document makes no
assumption on the support of any one specific approach. However,
it explains the protocol operation using DHCPv6-based prefix
delegation as specified in [RFC3633] and with the use of Prefix
Exclude Option for DHCPv6-PD as described in [RFC6603]. It
defines an interworking between the mobility entities and the
DHCPv6 functional elements in a non-normative way.
o The mobile router obtains the IP address configuration for its
egress roaming interface as specified in [RFC5213] and [RFC5844].
The mobile router along with its mobile networks will be able to
perform handoff and change its point of attachment in the network
and will be able to retain IP mobility support.
3.2. Deployment Models
This section explains the protocol operation for supporting prefix
delegation support in Proxy Mobile IPv6 for the following three
deployment_models. The high-level message call flows between the
mobile router, mobile access gateway and the local mobility anchor
are presented.
3.2.1. Delegating Router Co-located with Mobile Access Gateway
o The delegating router (DR) function, as specified in [RFC3633], is
co-located with the mobile access gateway.
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o The requesting router (RR) function, as specified in [RFC3633], is
enabled on the mobile router.
+-----+ +-----+ +-----+
| MR | | MAG | | LMA |
|(RR) | | (DR)| | |
+-----+ +-----+ +-----+
1) |-- MN Attach -----| |
| |--------- PBU ----------->|
| | |
| |<-------- PBA ------------|
| | |
| |o========================o|
2) | | PMIPv6 tunnel |
| |o========================o|
3) |-- Solicit for -->| |
| delegated prefix | |
4) | |----------PBU------------>|
| | |
5) | |<---------PBA (DMNP)------|
| | |
- -<---+ |
6) |<- Advertise -----| | |
| | | |
7) |-- Request ------>| Optional |
| | | |
- -<---+ |
8) |<-- Reply (DMNP) -| |
| | |
| | |
Figure 2: Delegating Router Co-located with Mobile Access Gateway
3.2.2. Delegating Router Co-located with Local Mobility Anchor
o The delegating router (DR) function, as specified in [RFC3633], is
co-located with the local mobility anchor.
o A DHCPv6 Relay Agent (DRA) function, as specified in [RFC3315], is
co-located on the mobile access gateway.
o The requesting router (RR) function, as specified in [RFC3633], is
enabled on the mobile router.
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+-----+ +-----+ +-----+
| MR | | MAG | | LMA |
|(RR) | |(DRA)| |(DR) |
+-----+ +-----+ +-----+
1) |-- MN Attach -----| |
| |--------- PBU ----------->|
| | |
| |<-------- PBA ------------|
| | |
| |o========================o|
2) | | PMIPv6 tunnel |
| |o========================o|
3) |-- Solicit for -->| |
| delegated prefix | |
4) | |--- Solicit ------------->|
- - - <---+
5) | |<-- Advertise ------------| |
| | | |
6) |<- Advertise -----| | |
| | | Optional
7) |-- Request ------>| | |
| | | |
8) | |--- Request ------------->| |
- - - <---+
9) | |<-- Reply (DMNP) ---------|
| | |
10) | |----------PBU (DNMP)----->|
| | |
11) | |<---------PBA (DMNP)------|
| | |
12) |<-- Reply (DMNP) -| |
| | |
Figure 3: Delegating Router Co-located with Local Mobility Anchor
3.2.3. Static Configuration of Delegated Mobile Network Prefixes
o The delegated mobile network prefixes of the mobile router are
statically configured in the mobile node's policy profile
[RFC5213].
o The delegated mobile network prefixes are statically configured in
the mobile network attached to the mobile router. The mobile
router is the default-router for the mobile networks.
o The mobile access gateway obtains statically configured mobile
network prefixes from the policy profile and registers them with
the local mobility anchor using the extensions specified in this
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document. There is no explicit trigger from the mobile router
from registering, or de-registering those prefixes. As long as
there is a mobility session for the mobile router's home address,
the local mobility anchor enables mobility support for the mobile
network prefixes.
+-----+ +-----+ +-----+
| MR | | MAG | | LMA |
| | | | | |
+-----+ +-----+ +-----+
1) |-- MN Attach -----| |
2) | - (Policy Profile) |
| | |
3) | |--------- PBU (DMNP) ---->|
| | |
4) | |<-------- PBA (DMNP) -----|
| | |
| |o========================o|
5) | | PMIPv6 tunnel |
| |o========================o|
| | |
Figure 4: Delegating Router Co-located with Local Mobility Anchor
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4. Message formats
This section defines extensions to Proxy Mobile IPv6 [RFC5213]
protocol messages.
4.1. Delegated Mobile Network Prefix Option
A new mobility header option, Delegated Mobile Network Prefix option
is defined for use with Proxy Binding Update and Proxy Binding
Acknowledgment messages exchanged between a local mobility anchor and
a mobile access gateway. This option is used for exchanging the
mobile router's IPv4/IPv6 delegated mobile network prefix. There can
be multiple instances of the Delegated Mobile Network Prefix option
present in a message.
The Delegated Mobile Network Prefix option has an alignment
requirement of 8n+2. Its format is as follows:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length |V| Reserved | Prefix Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ +
| |
. .
+ IPv4 or IPv6 Delegated Mobile Network Prefix +
| (DMNP) |
+ +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type
<IANA-1>: To be assigned by IANA.
Length
8-bit unsigned integer indicating the length of the option in
octets, excluding the type and length fields.
IPv4 Prefix (V)
If the IPv4 Prefix (V) flag is set to a value of (1), then it
indicates that the prefix that is included in the DMNP field is an
IPv4 prefix. If the IPv4 Prefix (V) flag is set to a value of
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(0), then it indicates that the prefix that is included in the
DMNP field is an IPv6 prefix.
Reserved
This field is unused for now. The value MUST be initialized to 0
by the sender and MUST be ignored by the receiver.
Prefix Length
8-bit unsigned integer indicating the prefix length of the prefix
contained in the option.
Delegated Mobile Network Prefix
Contains a mobile router's 4-byte IPv4 or a 16-byte IPv6 Delegated
Mobile Network Prefix.
4.2. Status Codes
This document defines the following new status code values for use in
the Proxy Binding Acknowledgement message. These values have been
allocated from the same number space as defined in Section 6.1.8 of
[RFC6275].
NOT_AUTHORIZED_FOR_DELEGATED_MNP: <IANA-2>
Not Authorized for delegated mobile network prefix
REQUESTED_DMNP_IN_USE: <IANA-3>
Requested delegated mobile network prefix is in use
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5. Operational Details
5.1. MAG Considerations
5.1.1. Extension to Binding Update List Entry Data Structure
In order to support this specification, the conceptual Binding Update
List Entry (BULE) data structure [RFC5213] needs to be extended to
include delegated mobile network prefix (DMNP) list. Each entry in
the list is used for storing an IPv4/IPv6 mobile network prefix
delegated to the mobile router.
5.1.2. Signaling Considerations
o The mobile node's policy profile defined in [RFC5213] is extended
to include a parameter which indicates Delegated Prefix support.
During the mobile router's initial attachment procedure, the
mobile access gateway obtains the mobile router's policy profile,
as per the procedures defined in [RFC5213]. If the policy profile
indicates that the mobile router is authorized for Delegated
Prefix support, then the following considerations apply.
o For requesting the local mobility anchor to allocate delegated
mobile network prefix(es) for the mobile router, the mobile access
gateway MUST include one or more Delegated Mobile Network Prefix
(DMNP) options in the Proxy Binding Update message.
* There MUST be exactly one instance of the Delegated Mobile
Network Prefix option with ALL_ZERO value and with the (V) flag
set to a value of (0). This serves as a request to the local
mobility anchor to allocate a set of delegated IPv6 mobile
network prefixes.
* There MUST be exactly one instance of the Delegated Mobile
Network Prefix option with ALL_ZERO value and with the (V) flag
set to a value of (1). This serves as a request to the local
mobility anchor to allocate a set of delegated IPv4 mobile
network prefixes.
* There MUST be exactly one instance of the Delegated Mobile
Network Prefix option with NON_ZERO prefix value for each of
the mobile network prefixes that the mobile access gateway is
requesting the local mobility anchor to allocate. The prefix
value in the option is the prefix that is either statically
configured for that mobile router, or obtained via DHCP prefix
delegation. This serves as a request to the local mobility
anchor to allocate the requested IPv4/IPv6 prefix.
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o If the received Proxy Binding Acknowledgement message has the
status field value set to NOT_AUTHORIZED_FOR_DELEGATED_MNP (Not
Authorized for delegated mobile network prefix), the mobile access
gateway MUST NOT enable mobility support for any of the prefixes
in the mobile network and prefix delegation support has to be
disabled.
o If the received Proxy Binding Acknowledgement message has the
status field value set to REQUESTED_DMNP_IN_USE (Requested
delegated mobile network prefix is in use), the mobile access
gateway MUST NOT enable mobility support for the requested
prefixes. The mobile access gateway MAY choose to send Proxy
Binding Acknowledgement message requesting the local mobility
anchor to perform the prefix assignment.
o If the received Proxy Binding Acknowledgement message has the
status field value set to 0 (Proxy Binding Update accepted), the
mobile access gateway has to apply the following considerations.
* The delegated mobile network prefix (DMNP) list in the mobile
router's Binding Update List entry has to be updated with the
allocated prefix(es). However, if the received message was in
response to a de-registration request with a lifetime value of
(0), then the delegated mobile network prefix list has to be
removed along with the Binding Update List entry.
* The mobile access gateway has to set up a policy-based route
for forwarding the IP packets received from the mobile network
(with the source IP address from any of the delegated IPv4/IPv6
mobile network prefixes) through the bidirectional tunnel set
up for that mobile router. However, if the received message
was in response to a de-registration request with a lifetime
value of (0), then the created forwarding state has to be
removed.
5.1.2.1. DHCP - MAG Interactions
This section describes the interactions between the DHCP and PMIPv6
logical entities running on the mobile access gateway. This section
is applicable only for deployments that use DHCPv6-based prefix
delegation. As described next, these interactions vary slightly
depending on the considered deployment model at the mobile access
gateway (described in Section 3.2).
The mobile router, acting as a "Requesting Router" as described in
[RFC3633], sends a SOLICIT message including one or more IA_PD
option(s) to the Delegating Router/DHCPv6 Relay Agent collocated on
the mobile access gateway. This message provides the needed trigger
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for the mobile access gateway for requesting the local mobility
anchor to enable delegated mobile network prefix support for that
mobility session.
o Delegating router co-located with mobile access gateway
* The mobile access gateway applies the considerations in
Section 5.1.2 for requesting the local mobility anchor to
enable delegated prefix support. For example, if the mobile
router is soliciting an IPv4 prefix, the mobile access gateway
includes in the Proxy Binding Update signaling a Delegated
Mobile Network Prefix option with ALL_ZERO value and with the
(V) flag set to a value of (1).
* The mobile access gateway, upon successfully completing the
Proxy Binding Update signaling with the local mobility anchor
(following the considerations described in Section 5.1.2), adds
the delegated mobile network prefixes to the binding update
list. Then, the mobile access gateway provides the obtained
prefixes to the DHCPv6 Delegating Router for prefix assignment.
The way in which the mobile access gateway provides the DHCPv6
Delegating Router with this information is beyond the scope of
this document.
+ In case the Proxy Binding Update signaling with the local
mobility anchor is not completed successfully, for example
because the local mobility anchor is not authorized for
delegated mobile network prefix or the requested prefix is
in use, the DHCPv6 Delegating Router will send a Reply
message to the Requesting Router containing the IA_PD with
the lifetimes of the prefixes in the IA_PD set to zero.
* The standard DHCPv6 considerations will be applied with respect
to the interactions between the Delegating Router and the
Requesting Router. The Delegating Router is provided with the
delegated prefix(es), which can then be then advertised in the
mobile network, and therefore used by the locally fixed nodes
to auto configure IP addresses allowing to gain access to the
Internet.
* Any time, the Requesting Router releases the delegated
prefixes, the Delegating Router removes the assigned prefixes.
To do so, the mobile access gateway will send an Updated Proxy
Binding Update following the considerations described in
Section 5.1.2 for deregistering those prefixes. The way in
which the DHCPv6 Delegating Router triggers the mobile access
gateway in order to deregister the prefixes is beyond the scope
of this document.
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* In case the mobile router performs a handover and attaches to a
different mobile access gateway, the following cases are
possible:
+ The new mobile access gateway does not support the
delegation of mobile network prefixes described in this
specification. In this case, forwarding of the previously
delegated mobile network prefixes is no longer performed.
+ The new mobile access gateway supports the delegation of
mobile network prefixes described in this specification. In
this case, the Delegating Router, upon the reception of the
SOLICIT message, will learn the delegated mobile network
prefixes from the Proxy Binding Update signaling performed
with the local mobility anchor.
o Delegating router co-located with local mobility anchor
* A DHCPv6 Relay Agent function running on the mobile access
gateway will forward the DHCP messages to the local mobility
anchor which has the co-located Delegating Router function.
The Requesting Router and the Delegating Router complete the
DHCP messages related to prefix delegation.
* During the DHCPv6 exchange, the standard DHCPv6 considerations
apply with respect to the interactions between the Delegating
Router, DHCPv6 Relay Agent and the Requesting Router.
* The mobile access gateway learns from the co-located DHCPv6
Relay Agent the prefixes allocated by the Delegating Router.
The way in which the mobile access gateway learns obtains this
information from the DHCPv6 Relay Agent is beyond the scope of
this document.
* The mobile access gateway will apply the considerations in
Section 5.1.2 for requesting the local mobility anchor to
enable delegated prefix support. The mobile access gateway
will include exactly one instance of the Delegated Mobile
Network Prefix option with NON_ZERO prefix value for each of
the mobile network prefixes that the mobile access gateway is
requesting the local mobility anchor to allocate. The prefix
value(s) in the option will be the prefix(es) obtained via DHCP
prefix delegation.
* The mobile access gateway, upon successfully completing the
Proxy Binding Update signaling with the local mobility anchor,
will provide the obtained prefixes to the DHCPv6 Relay Agent
for prefix assignment. The Delegating Router is provided with
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the delegated prefix(es) completing the standard DHCPv6
signaling. These prefixes can then be then advertised in the
mobile network, and therefore used by the locally fixed nodes
to auto configure IP addresses allowing to gain access to the
Internet.
+ In case the Proxy Binding Update signalling with the local
mobility anchor is not completed successfully, for example
because the local mobility anchor is not authorized for
delegated mobile network prefix, the requeted prefix is in
use, or the delegated prefix(es) do not match the ones
allocated by DHCP prefix delegation, the DHCPv6 Relay Agent
MAY send a Reply message to the Requesting Router containing
the IA_PD with the lifetimes of the prefixes in the IA_PD
set to zero.
* In case the mobile router performs a handover and attaches to a
different mobile access gateway, the following cases are
possible:
+ The new mobile access gateway does not support the
delegation of mobile network prefixes described in this
specification. In this case, forwarding of the previously
delegated mobile network prefixes is no longer performed.
+ The new mobile access gateway supports the delegation of
mobile network prefixes described in this specification. In
this case, the DHCPv6 Relay Agent, upon the reception of the
SOLICIT message, will learn the delegated mobile network
prefixes from the Proxy Binding Update signaling performed
with the local mobility anchor.
5.1.3. Packet Forwarding
o On receiving an IP packet from a mobile router, the mobile access
gateway before tunneling the packet to the local mobility anchor
MUST ensure that there is an established binding for the mobile
router and the source IP address of the packet is a prefix
delegated to that mobile router. If the source address of the
received IP packet is not part of the delegated mobile network
prefix, then the mobile access gateway MUST NOT tunnel the packet
to the local mobility anchor.
o On receiving an IP packet from the bi-directional tunnel
established with the local mobility anchor, the mobile access
gateway MUST first decapsulate the packet (removing the outer
header) and then use the destination address of the (inner) packet
to forward it on the interface through which the mobile router is
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reachable.
o The above forwarding considerations are not applicable to the IP
traffic sent/received to/from the mobile router's home address
(IPv4 HOA/HNP). For the mobile router's home address traffic,
forwarding considerations from [RFC5213] and [RFC5844] continue to
apply.
5.2. LMA Considerations
5.2.1. Extensions to Binding Cache Entry Data Structure
In order to support this specification, the conceptual Binding Cache
Entry (BCE) data structure [RFC5213] needs to be extended to include
the delegated mobile network prefix (DMNP) list. Each entry in the
list represents a delegated mobile network prefix.
5.2.2. Signaling Considerations
o If the Proxy Binding Update message does not include any Delegated
Mobile Network Prefix option(s) (Section 4.1), then the local
mobility anchor MUST NOT enable Delegated Prefix support for the
mobility session, and the Proxy Binding Acknowledgment message
that is sent in response MUST NOT contain any Delegated Mobile
Network Prefix option(s).
o If the Proxy Binding Update message includes one or more Delegated
Mobile Network Prefix options, but either the local mobility
anchor is not configured to support Delegated Prefix support, then
the local mobility anchor will ignore the option(s) and process
the rest of the option as specified in [RFC5213]. This would have
no effect on the operation of the rest of the protocol. The Proxy
Binding Acknowledgement message that is sent in response will not
include any Delegated Mobile Network Prefix option(s).
o If the Proxy Binding Update message has the Delegated Mobile
Network Prefix option(s) and if the local mobility anchor is
configured for Delegated Prefix support, then the local mobility
anchor MUST enable Delegated Mobile Network Prefix option for that
mobility session. The Proxy Binding Acknowledgement message that
is sent in response MUST include the Delegated Mobile Network
Prefix option(s). The following considerations apply.
* If there is at least one instance of the Delegated Mobile
Network Prefix option with a ALL_ZERO [RFC5213] prefix value,
then this serves as a request for the local mobility anchor to
perform the assignment of one or more delegated mobile network
prefixes.
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+ A Delegated Mobile Network option with ALL_ZERO value and
with the (V) flag set to a value of (0), is a request for
the local mobility anchor to allocate one or more IPv6
prefixes.
+ A Delegated Mobile Network option with ALL_ZERO value and
with the (V) flag set to a value of (1), is a request for
the local mobility anchor to allocate one or more IPv4
prefixes.
+ Inclusion of multiple instances of Delegated Mobile Network
options with ALL_ZERO value, one with the (V) flag set to a
value of (1), and another instance with the (V) flag set to
a value of (0) is a request to allocate both IPv4 and IPv6
prefixes.
* If there are no instances of the Delegated Mobile Network
Prefix option present in the request with ALL_ZERO value, but
has a specific prefix value, then this serves as a request for
the local mobility anchor to perform the allocation of the
requested prefix(es).
+ If any one of the requested prefixes are assigned to some
other mobility node, or not from an authorized pool that the
local mobility can allocate for that mobility session, then
the Proxy Binding Update MUST be rejected by sending a Proxy
Binding Acknowledgement message with Status field set to
REQUESTED_DMNP_IN_USE (Requested delegated mobile network
prefix is in use).
o Upon accepting the Proxy Binding Update, the local mobility anchor
MUST send a Proxy Binding Acknowledgement message with the Status
field set to 0 (Proxy Binding Update accepted).
* The message MUST include one instance of the Delegated Mobile
Network Prefix option for each of the allocated IPv4/IPv6
delegated mobile network prefixes.
* The delegated mobile network prefix (DMNP) list in the mobile
router's Binding Cache entry has to be updated with the
allocated prefix(es). However, if the request is a de-
registration request with a lifetime value of (0), the
delegated mobile network prefix list has to be removed along
with the Binding Cache entry.
* A route (or a platform-specific equivalent function that sets
up the forwarding) for each of the allocated prefixes over the
tunnel has to be added. However, if the request is a de-
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registration request, with a lifetime value of (0), all the
IPv4/IPv6 delegated prefix routes created for that session have
to be removed.
5.2.3. Packet Forwarding
o The local mobility anchor MUST advertise a connected route into
the Routing Infrastructure for the IP prefixes delegated to all of
the mobile routers that it is serving. This step essentially
enables the local mobility anchor to be a routing anchor for those
IP prefixes and be able to intercept IP packets sent to those
mobile networks.
o On receiving a packet from a correspondent node with the
destination address matching any of the mobile router's delegated
mobile network prefixes, the local mobility anchor MUST forward
the packet through the bi-directional tunnel set up with the
mobile access gateway where the mobile router is attached.
o On receiving an IP packet from the bi-directional tunnel
established with the mobile access gateway, the local mobility
anchor MUST first decapsulate the packet (removing the outer
header) and then use the destination address of the (inner) packet
for forwarding decision. The local mobility anchor MUST ensure
that there is an established binding for the mobile router and the
source IP address of the packet is a prefix delegated to a mobile
router reachable over that bi-directional tunnel.
o The above forwarding considerations are not applicable to the IP
traffic sent/received to/from the mobile router's home address
(IPv4 HOA/HNP). For the mobile router's home address traffic,
forwarding considerations from [RFC5213] and [RFC5844] continue to
apply.
5.3. Security Policy Database (SPD) Example Entries
The use of DHCPv6, as described in this document, requires message
integrity protection and source authentication. The IPsec security
mechanism used by Proxy Mobile IPv6 [RFC5213] for securing the
signaling messages between the mobile access gateway and the local
mobility anchor can be used for securing the DHCP signaling between
the mobile access gateway and the local mobility anchor.
The Security Policy Database (SPD) and Security Association Database
(SAD) entries necessary to protect the DHCP signaling is specified
below. The format of these entries is based on [RFC4877]
conventions. The SPD and SAD entries are only example
configurations. A particular implementation of mobile access gateway
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and local mobility anchor implementation can configure different SPD
and SAD entries as long as they provide the required security for
protecting DHCP signaling messages.
For the examples described in this document, a mobile access gateway
with address "mag_address_1", and a local mobility anchor with
address "lma_address_1" are assumed.
mobile access gateway SPD-S:
- IF local_address = mag_address_1 &
remote_address = lma_address_1 & proto = UDP &
local_port = any & remote_port = DHCP
Then use SA1 (OUT) and SA2 (IN)
mobile access gateway SAD:
- SA1(OUT, spi_a, lma_address_1, ESP, TRANSPORT):
local_address = mag_address_1 &
remote_address = lma_address_1 &
proto = UDP & remote_port = DHCP
- SA2(IN, spi_b, mag_address_1, ESP, TRANSPORT):
local_address = lma_address_1 &
remote_address = mag_address_1 &
proto = UDP & local_port = DHCP
local mobility anchor SPD-S:
- IF local_address = lma_address_1 &
remote_address = mag_address_1 & proto = UDP &
local_port = DHCP & remote_port = any
Then use SA2 (OUT) and SA1 (IN)
local mobility anchor SAD:
- SA2(OUT, spi_b, mag_address_1, ESP, TRANSPORT):
local_address = lma_address_1 &
remote_address = mag_address_1 &
proto = UDP & local_port = DHCP
- SA1(IN, spi_a, lma_address_1, ESP, TRANSPORT):
local_address = mag_address_1 &
remote_address = lma_address_1 &
proto = UDP & remote_port = DHCP
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6. Security Considerations
The Delegated Mobile Network Prefix Option defined in this
specification is for use in Proxy Binding Update and Proxy Binding
Acknowledgement messages. This option is carried like any other
mobility header option as specified in [RFC5213]. Therefore, it
inherits from [RFC5213] its security guidelines and does not require
any additional security considerations.
The use of DHCPv6 in this specification is as defined in DHCPv6 base
specification [RFC3315] and DHCPv6 Prefix Delegation specifications
[RFC3633]. The security considerations specified in those
specifications apply to this specification.
If IPsec is used, the IPsec security association that is used for
protecting the Proxy Binding Update and Proxy Binding
Acknowledgement, also needs to be used for protecting the DHCPv6
signaling between the mobile access gateway and the local mobility
anchor. Considerations specified in Section 5.3 identify the
extensions to security policy entries [RFC4301]
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7. IANA Considerations
This document requires the following IANA actions.
o Action-1: This specification defines a new Mobility Header option,
Delegated Mobile Network Prefix option. This mobility option is
described in Section 4.1. The type value <IANA-1> for this
message needs to be allocated from the Mobility Header Types
registry at http://www.iana.org/assignments/mobility-parameters.
RFC Editor: Please replace <IANA-1> in Section 4.1 with the
assigned value, and update this section accordingly.
o Action-2: This document also defines two new status code values
for use in the Proxy Binding Acknowledgement message, as described
in Section 4.2. These status codes are,
NOT_AUTHORIZED_FOR_DELEGATED_MNP (Not Authorized for delegated
mobile network prefix) with a status code value of <IANA-2>, and
REQUESTED_DMNP_IN_USE (Requested delegated mobile network prefix
is in use) with a status code value of <IANA-3>. These values
have to be assigned from the same number space as allocated for
other status codes [RFC6275] and update this section accordingly.
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8. Acknowledgments
The authors would like to Acknowledge Ryuji Wakikawa, Alexandru
Petrescu, Behcet Sarikaya, Seil Jeon and Basavaraj Patil for all the
discussions and reviews of this draft.
The work of Carlos J. Bernardos has also been partially supported by
the European Community's Seventh Framework Programme (FP7-ICT-2009-5)
under grant agreement n. 258053 (MEDIEVAL project) and by the
Ministry of Science and Innovation of Spain under the QUARTET project
(TIN2009-13992-C02-01).
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9. References
9.1. 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.
[RFC3633] Troan, O. and R. Droms, "IPv6 Prefix Options for Dynamic
Host Configuration Protocol (DHCP) version 6", RFC 3633,
December 2003.
[RFC4301] Kent, S. and K. Seo, "Security Architecture for the
Internet Protocol", RFC 4301, December 2005.
[RFC4877] Devarapalli, V. and F. Dupont, "Mobile IPv6 Operation with
IKEv2 and the Revised IPsec Architecture", RFC 4877,
April 2007.
[RFC5213] Gundavelli, S., Leung, K., Devarapalli, V., Chowdhury, K.,
and B. Patil, "Proxy Mobile IPv6", RFC 5213, August 2008.
[RFC5844] Wakikawa, R. and S. Gundavelli, "IPv4 Support for Proxy
Mobile IPv6", RFC 5844, May 2010.
[RFC6275] Perkins, C., Johnson, D., and J. Arkko, "Mobility Support
in IPv6", RFC 6275, July 2011.
[RFC6276] Droms, R., Thubert, P., Dupont, F., Haddad, W., and C.
Bernardos, "DHCPv6 Prefix Delegation for Network Mobility
(NEMO)", RFC 6276, July 2011.
[RFC6603] Korhonen, J., Savolainen, T., Krishnan, S., and O. Troan,
"Prefix Exclude Option for DHCPv6-based Prefix
Delegation", RFC 6603, May 2012.
9.2. Informative References
[RFC6656] Johnson, R., Kinnear, K., and M. Stapp, "Description of
Cisco Systems' Subnet Allocation Option for DHCPv4",
RFC 6656, July 2012.
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Authors' Addresses
Xingyue Zhou
ZTE Corporation
No.50 Software Avenue, Yuhuatai District
Nanjing
China
Phone: +86-25-8801-4634
Email: zhou.xingyue@zte.com.cn
Jouni Korhonen
Renesas Mobile
Porkkalankatu 24
Helsinki FIN-00180
Finland
Email: jouni.nospam@gmail.com
Carl Williams
Consultant
San Jose, CA
USA
Email: carlw@mcsr-labs.org
Sri Gundavelli
Cisco
170 West Tasman Drive
San Jose, CA 95134
USA
Email: sgundave@cisco.com
Carlos J. Bernardos
Universidad Carlos III de Madrid
Av. Universidad, 30
Leganes, Madrid 28911
Spain
Phone: +34 91624 6236
Email: cjbc@it.uc3m.es
URI: http://www.it.uc3m.es/cjbc/
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