Interactions between Proxy Mobile IPv6 (PMIPv6) and Mobile IPv6 (MIPv6): Scenarios and Related Issues
draft-ietf-netlmm-mip-interactions-07
The information below is for an old version of the document that is already published as an RFC.
| Document | Type |
This is an older version of an Internet-Draft that was ultimately published as RFC 6612.
|
|
|---|---|---|---|
| Author | Gerardo Giaretta | ||
| Last updated | 2015-10-14 (Latest revision 2010-10-28) | ||
| Replaces | draft-giaretta-netlmm-mip-interactions | ||
| RFC stream | Internet Engineering Task Force (IETF) | ||
| Intended RFC status | Informational | ||
| Formats | |||
| Reviews | |||
| Additional resources | Mailing list discussion | ||
| Stream | WG state | WG Document | |
| Document shepherd | (None) | ||
| IESG | IESG state | Became RFC 6612 (Informational) | |
| Action Holders |
(None)
|
||
| Consensus boilerplate | Unknown | ||
| Telechat date | (None) | ||
| Responsible AD | Jari Arkko | ||
| IESG note | |||
| Send notices to | (None) |
draft-ietf-netlmm-mip-interactions-07
NETLMM Working Group G. Giaretta, Ed.
Internet-Draft Qualcomm
Intended status: Informational October 28, 2010
Expires: May 1, 2011
Interactions between PMIPv6 and MIPv6: scenarios and related issues
draft-ietf-netlmm-mip-interactions-07
Abstract
The use of Proxy Mobile IPv6 (PMIPv6) and Mobile IPv6 (MIPv6) in the
same network requires some care. This document discusses scenarios
where such mixed usage is appropriate and points out the need for
interaction between the two mechanisms. Solutions and
recommendations to enable these scenarios are also described.
Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].
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 May 1, 2011.
Copyright Notice
Copyright (c) 2010 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
Giaretta Expires May 1, 2011 [Page 1]
Internet-Draft PMIPv6-MIPv6 Interactions October 2010
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.
This document may contain material from IETF Documents or IETF
Contributions published or made publicly available before November
10, 2008. The person(s) controlling the copyright in some of this
material may not have granted the IETF Trust the right to allow
modifications of such material outside the IETF Standards Process.
Without obtaining an adequate license from the person(s) controlling
the copyright in such materials, this document may not be modified
outside the IETF Standards Process, and derivative works of it may
not be created outside the IETF Standards Process, except to format
it for publication as an RFC or to translate it into languages other
than English.
Giaretta Expires May 1, 2011 [Page 2]
Internet-Draft PMIPv6-MIPv6 Interactions October 2010
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Overview of the scenarios and related issues . . . . . . . . . 5
3.1. Issues related to scenario A.1 . . . . . . . . . . . . . . 9
3.2. Issues related to scenario A.2 . . . . . . . . . . . . . . 9
3.3. Issues related to scenario B . . . . . . . . . . . . . . . 11
4. Analysis of possible solutions . . . . . . . . . . . . . . . . 12
4.1. Solutions related to scenario A.1 . . . . . . . . . . . . 12
4.2. Solutions related to scenario A.2 . . . . . . . . . . . . 14
4.2.1. Mobility from a PMIPv6 domain to a non-PMIPv6
domain . . . . . . . . . . . . . . . . . . . . . . . . 15
4.2.2. Mobility from a non-PMIPv6 domain to a PMIPv6
domain . . . . . . . . . . . . . . . . . . . . . . . . 16
4.3. Solutions related to scenario B . . . . . . . . . . . . . 17
5. Security Considerations . . . . . . . . . . . . . . . . . . . 17
6. IANA considerations . . . . . . . . . . . . . . . . . . . . . 17
7. Additional Authors . . . . . . . . . . . . . . . . . . . . . . 17
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 18
9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 18
9.1. Normative References . . . . . . . . . . . . . . . . . . . 18
9.2. Informative References . . . . . . . . . . . . . . . . . . 19
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 19
Giaretta Expires May 1, 2011 [Page 3]
Internet-Draft PMIPv6-MIPv6 Interactions October 2010
1. Introduction
Proxy Mobile IPv6 (PMIPv6) [RFC5213] is a network based IP mobility
protocol standardized by IETF. In some deployment scenarios this
protocol will be deployed together with Mobile IPv6 (MIPv6)
[RFC3775], for example with PMIPv6 as local mobility protocol and
MIPv6 as global mobility protocol. While the usage of a local
mobility protocol should not have implications of how global mobility
is managed, since PMIPv6 is partially based on MIPv6 signaling and
data structure, some considerations are needed to understand how the
protocols interact and how the different scenarios can be enabled.
Some standardization fora are also investigating more complex
scenarios where the mobility of some nodes is handled using Proxy
Mobile IPv6, while other nodes use Mobile IPv6; or the mobility of a
node is managed in turn by a host-based and a network-based
mechanism. This needs also to be analyzed as a possible deployment
scenario.
This document provides a taxonomy of the most common scenarios that
require direct interaction between MIPv6 and PMIPv6. The list is not
meant to be exhaustive. Moreover, this document presents and
identifies most of the issues pertained to these scenarios and
discusses possible means and mechanisms that are recommended to
enable them.
2. Terminology
General mobility terminology can be found in [RFC3753]. The
following acronyms are used in this document:
o AR (Access Router): first hop router.
o BCE (Binding Cache Entry): an entry of the MIPv6 or PMIPv6 Binding
Cache.
o LMA (Local Mobility Anchor): the PMIPv6 mobility anchor as
specified in [RFC5213]
o MAG (Mobility Access Gateway): the PMIPv6 client as specified in
[RFC5213]
o MN-HoA: the home address of a mobile node in a PMIPv6 domain.
o MN-HNP: the IPv6 prefix that is always present in the Router
Advertisements that the mobile node receives when it is attached
to any of the access links in that PMIPv6 domain. MN-HoA always
Giaretta Expires May 1, 2011 [Page 4]
Internet-Draft PMIPv6-MIPv6 Interactions October 2010
belongs to this prefix.
o MIPv6-HoA: the Home Address the MN includes in MIPv6 binding
update messages.
o MIPv6-CoA: the Care-of Address the MN includes in MIPv6 binding
update messages.
3. Overview of the scenarios and related issues
Several scenarios can be identified where MIPv6 and PMIPv6 are
deployed in the same network. This document not only focuses on
scenarios where the two protocols are used by the same mobile node to
manage local and global mobility, but also investigates more complex
scenarios where the protocols are more tightly integrated or where
there is a co-existence of nodes which do or do not implement MIPv6.
In particular the scenario space can be split into hierarchical
deployments and alternative deployments of Mobile IP (MIP) and Proxy
Mobile IP (PMIP). Hierarchical deployments are scenarios where the
two mobility protocols are used in the same network in a hierarchical
manner for global and local mobility management. Alternative
deployments are scenarios where only one of the two protocols is used
for mobility management of a given mobile node.
The following hierarchical scenarios are identified:
Scenario A.1 - in this scenario PMIPv6 is used as a network based
local mobility management protocol whereas MIPv6 is used as a global
mobility management protocol. This interaction is very similar to
the HMIPv6-MIPv6 interaction [RFC4140]; MIPv6 is used to manage
mobility among different access networks, while the mobility within
the access network is handled by PMIPv6. The address managed by
PMIPv6 (i.e. the MN-HoA) is registered as Care-of Address by the MN
at the HA. This means that the HA has a binding cache entry for
MIPv6-HoA that points to the MN-HoA.
Giaretta Expires May 1, 2011 [Page 5]
Internet-Draft PMIPv6-MIPv6 Interactions October 2010
The following figure illustrates this scenario.
+----+
| HA | MIPv6-HoA -> MN-HoA
+----+
/\
/ \
+-------------/----\--------------+
( / \ ) Global Mobile IPv6
( / \ ) Domain
+----------/----------\-----------+
/ \
+----+ +----+
MN-HoA -> MAG1 |LMA1| |LMA2|
+----+ +----+
//\\ \\
+----//--\\---+ +-----\\------+
( // \\ ) ( \\ ) Local Mobility Network
( // \\ ) ( \\ ) PMIPv6 domain
+-//--------\\+ +--------\\---+
// \\ \\
// \\ \\
// \\ \\
+----+ +----+ +----+
|MAG1| |MAG2| |MAG3|
+----+ +----+ +----+
| | |
[MN]
Figure 1 - Scenario A.1
Scenario A.2 - in this scenario the mobile node is moving across
different access networks, some of them supporting PMIPv6 and some
others not supporting it. Therefore the mobile node is roaming from
an access network where the mobility is managed through a network-
based solution to an access network where a host-based management
(i.e. Mobile IPv6) is needed. This scenario may have different sub-
scenarios depending on the relations between the MIPv6 home network
and the PMIPv6 domain. The following figure illustrates an example
of this scenario, where the MN is moving from an access network where
PMIPv6 is supported (i.e. MAG functionality is supported) to a
network where PMIPv6 is not supported (i.e. MAG functionality is not
supported by the AR). This implies that the home link of the MN is
actually a PMIPv6 domain. In this case the MIPv6-HoA is equal to the
MN-HoA (i.e. the address managed by PMIPv6).
Giaretta Expires May 1, 2011 [Page 6]
Internet-Draft PMIPv6-MIPv6 Interactions October 2010
MIPv6-HoA == MN-HoA -> MAG1
+------+
|HA/LMA|-----------------------+
+------+ |
//\\ |
+-------//--\\--------+ |
( // \\ PMIPv6 ) |
( // \\ domain) +--------------+
+----//--------\\-----+ ( Non-PMIPv6 )
// \\ ( domain )
// \\ +--------------+
// \\ |
+----+ +----+ +----+
|MAG1| |MAG2| | AR |
+----+ +----+ +----+
| | |
[MN]
Figure 2 - Scenario A.2
In the scenario illustrated in Figure 2 the non-PMIPv6 domain can
actually be also a different PMIPv6 domain that handles a different
MN_HoA. The following figure illustrates this sub-case: the MIPv6-
HoA is equal to the MN_HoA; however when the MN hands over to MAG3 it
gets a different IP address (managed by LMA2 using PMIPv6) and
registers it as a MIPv6 CoA.
Giaretta Expires May 1, 2011 [Page 7]
Internet-Draft PMIPv6-MIPv6 Interactions October 2010
MIPv6-HoA == MN-HoA -> MAG_1
+-------+
|HA/LMA1|-----------------------+
+-------+ |
//\\ +----+
+-------//--\\--------+ |LMA2|
( // \\ home ) +----+
( // \\ PMIPv6) +------||------+
( // \\domain) ( ||visited)
+---//----------\\----+ ( ||PMIPv6 )
// \\ ( ||domain )
// \\ +------||------+
+----+ +----+ +----+
|MAG1| |MAG2| |MAG3|
+----+ +----+ +----+
| | |
[MN]
(a)
MIPv6-HoA -> MN_CoA
+-------+
|HA/LMA1|-----------------------+
+-------+ |
//\\ +----+
+-------//--\\--------+ |LMA2| MN_CoA -> MAG3
( // \\ home ) +----+
( // \\ PMIPv6) +------||------+
( // \\domain) ( ||visited)
+---//----------\\----+ ( ||PMIPv6 )
// \\ ( ||domain )
// \\ +------||------+
+----+ +----+ +----+
|MAG1| |MAG2| |MAG3|
+----+ +----+ +----+
| | |
[MN]
(b)
Figure 3 - Scenario A.2 with visited PMIPv6 domain
The following alternative deployment has been identified:
Scenario B - in this scenario some mobile nodes use MIPv6 to manage
their movements while others rely on a network-based mobility
solution provided by the network as they don't support Mobile IPv6.
Giaretta Expires May 1, 2011 [Page 8]
Internet-Draft PMIPv6-MIPv6 Interactions October 2010
There may be a common mobility anchor that acts as MIPv6 Home Agent
and PMIPv6 LMA, depending on the type of the node as depicted in the
figure. However, the LMA and HA can also be separated and this has
no impacts to the mobility of the nodes.
+--------+
| HA/LMA |
+--------+
+------+ +------+
| MAG1 | | MAG2 |
+------+ +------+
+-----------+
| IPv6 host | ----------------->
+-----------+ movement
+----------+
| MIPv6 MN | ----------------->
+----------+ movement
Figure 4 - Scenario B
Note that some of the scenarios can be combined. For instance,
scenario B can be combined with scenario A.1 or scenario A.2.
The following sections describe some possible issues for each
scenario. Respective recommendations are described in Section 4.3.
The specifications considered as a baseline for the analysis are the
following: [RFC3775], [RFC4877] and [RFC5213].
3.1. Issues related to scenario A.1
This scenario is very similar to other hierarchical mobility schemes,
including a HMIPv6-MIPv6 scheme. No issues have been identified in
this scenario. Note that a race condition where the MN registers the
CoA at the HA before the CoA is actually bound to the MAG at the LMA
is not possible. The reason is that per PMIPv6 specification the MAG
does not forward any packets sent by the MN until the PMIPv6 tunnel
is up, regardless the mechanism used for address allocation.
Section 4.1 describes one message flow in case PMIPv6 is used as a
local mobility protocol and MIPv6 is used as a global mobility
protocol.
3.2. Issues related to scenario A.2
This section highlights some considerations that are applicable to
scenario A.2.
Giaretta Expires May 1, 2011 [Page 9]
Internet-Draft PMIPv6-MIPv6 Interactions October 2010
1. HoA management and lookup key in the binding cache
* In MIPv6 [RFC3775] the lookup key in the Binding Cache is the
Home Address of the MN. In particular, the base specification
[RFC3775] doesn't require the MN to include any identifier,
such as the MN-ID [RFC4283], in the Binding Update message
other than its Home Address. As described in [RFC4877], the
identifier of the MN is known by the Home Agent after the
IKEv2 exchange, but this is not used in the MIPv6 signaling,
nor as a lookup key for the binding cache. On the other hand,
as specified in [RFC5213], a Proxy Binding Update contains the
Home Prefix of the MN, the MN-ID and does not include the Home
Address of the MN (since it may not be known by the MAG and
consequently by the HA/LMA). The lookup key in the binding
cache of the LMA is either the home prefix or the MN-ID. This
implies that lookup keys for MIPv6 and PMIPv6 registrations
are different. Because of that, when the MN moves from its
home network (i.e. from the PMIPv6 domain) to the foreign
link, the Binding Update sent by the MN is not identified by
the HA as an update of the Proxy Binding Cache Entry
containing the home prefix of the MN, but a new binding cache
entry is created. Therefore PMIPv6 and MIPv6 will always
create two different binding cache entries in the HA/LMA which
implies that the HA and LMA are logically separated. How to
handle the presence of the two binding cache entries for the
same MN is described in Section 4.2.
2. MIPv6 de-registration Binding Update deletes PMIPv6 binding cache
entry
* When the mobile node moves from a MIPv6 foreign network to the
PMIPv6 home domain, the MAG registers the mobile node at the
LMA by sending a Proxy Binding Update. Subsequently, the LMA
updates the mobile node's binding cache entry with the MAG
address and the MAG emulates the mobile node's home link.
Upon detection of the home link, the mobile node will send a
de-registration Binding Update to its home agent. It is
necessary to make sure that the de-registration of the MIPv6
BU does not change the PMIPv6 binding cache entry just created
by the MAG.
3. Race condition between Binding Update and Proxy Binding Update
messages (Sequence Numbers and Timestamps)
* MIPv6 and PMIPv6 use different mechanisms for handling re-
ordering of registration messages and they are sent by
different entities. In MIPv6, Binding Update messages that
are sent by the mobile node to the home agent are ordered by
Giaretta Expires May 1, 2011 [Page 10]
Internet-Draft PMIPv6-MIPv6 Interactions October 2010
the sequence numbers. The other side, in PMIP, Proxy Binding
Update messages that are sent by the MAG to the LMA are
ordered by a timestamp option. When the mobile node moves
from one access where Mobile IP is used to another access when
Proxy Mobile IP is used, delay in the mobility signaling sent
may imply adverse situations. For example if the mobile node
sends a Mobile IP binding update from access A before moving
to access B and this binding update gets delayed (e.g. a
refresh binding update), the binding update may reach the
combined LMA/HA after the proxy binding update sent by the
MAG, re-directing packets to access A even after the mobile
has moved to access B.
4. Threat of compromised MAG
* In MIPv6 base specification [RFC3775] there is a strong
binding between the Home Address registered by the mobile node
and the Security Association used to modify the corresponding
binding cache entry.
* In PMIPv6 specification, the MAG sends proxy binding updates
on behalf of a mobile node to update the binding cache entry
that corresponds to the mobile node's home address. Since the
MAG sends the binding updates, PMIPv6 requires security
associations between each MAG and the LMA.
* As described in [RFC4832], in PMIPv6 the MAG compromise or
impersonation is an issue. RFC4832, section 2.2, describes
how a compromised MAG can harm the functionality of LMA, e.g.
manipulating LMA's routing table (or binding cache).
* In this mixed scenario, both host-based and network-based
security associations are used to update the same binding
cache entry at the HA/LMA (but see the first bullet of this
list, as the entry may not be the same). Based on this
consideration, the threat described in [RFC4832] is worse as
it affects also hosts that are using the LMA/HA as MIPv6 HA
and are not using PMIPv6
3.3. Issues related to scenario B
In this scenario there are two types of nodes in the access network:
some nodes support MIPv6 while some others do not. The rationale
behind such a scenario is that the nodes implementing MIPv6 manage
their own mobility to achieve better performance, e.g. for inter-
technology handovers. Obviously, nodes that do not implement MIPv6
must rely on the network to manage their mobility: therefore Proxy
MIPv6 is used for those nodes.
Giaretta Expires May 1, 2011 [Page 11]
Internet-Draft PMIPv6-MIPv6 Interactions October 2010
Based on the current PMIPv6 solution described in [RFC5213], in any
link of the PMIPv6 domain the MAG emulates the mobile node's home
link, advertising the home link prefix to the MN in a unicast Router
Advertisement message. This ensures that the IP address of the MN is
still considered valid by the MN itself. The home network prefix
(and any other information needed to emulate the home link) is
included in the mobile node's profile that is obtained by the MAG via
context transfer or via a policy store.
However, in case there are nodes that implement MIPv6 and want to use
this protocol, the network must offer MIPv6 service to them. In such
case the MAG should not emulate the home link. Instead of
advertising the MN-HNP, the MAG should advertise the topologically
correct local IP prefix, i.e. the prefix belonging to the MAG, so
that the MN detects an IP movement, configures a new CoA and sends a
MIPv6 Binding Update based on [RFC3775].
4. Analysis of possible solutions
4.1. Solutions related to scenario A.1
As mentioned in Section 3.1, there are no significant issues in this
scenario.
Figures 5 and 6 show a scenario where a mobile node is moving from
one PMIPv6 domain to another, based on the scenario of Figure 1. In
Figure 5, the mobile node moves from an old MAG to MAG2 in the same
PMIPv6 domain: this movement triggers a PBU to LMA1 and the updating
of the binding cache at the LMA1; there is no MIPv6 signaling as the
CoA_1 registered at the HA is the Home Address for the PMIPv6
session. In Figure 6, the mobile node moves from MAG2 in the LMA1
PMIPv6 domain to MAG3 in a different PMIPv6 domain: this triggers the
PMIPv6 signaling and the creation of a binding at the LMA2. On the
other hand, the local address of the mobile node is changed, as the
LMA has changed, and therefore the mobile node sends a MIPv6 Binding
Update to the HA with the new CoA_2.
Giaretta Expires May 1, 2011 [Page 12]
Internet-Draft PMIPv6-MIPv6 Interactions October 2010
+----+ +------+ +------+ +----+
| MN | | MAG2 | | LMA1 | | HA |
+----+ +------+ +------+ +----+
| | | |
| | | +-----------------+
| | | | HoA -> CoA_1 |
| | | | binding present |
| | | +-----------------+
| | | |
| CoA conf/confirm | PBU(CoA_1,MAG_2) | |
| <--------------->| ----------------->| |
| | +-----------------+|
| | | CoA_1 -> MAG_2 ||
| | | binding updated ||
| | +-----------------+|
| | PBA | |
| | <----------------| |
| | | |
Figure 5 - Local Mobility Message Flow
+----+ +------+ +------+ +----+
| MN | | MAG3 | | LMA2 | | HA |
+----+ +------+ +------+ +----+
| CoA config | PBU(CoA_2,MAG_3) | |
|<---------------->|------------------->| |
| | +-----------------+ |
| | | CoA_2 -> MAG_3 | |
| | | binding created | |
| | +-----------------+ |
| | PBA | |
| |<-------------------| |
| | | |
| | BU (HoA, CoA_2) | |
|---------------------------------------------------->|
| | | |
| | | +-----------------+
| | | | HoA -> CoA_2 |
| | | | binding updated |
| | | +-----------------+
| | BA | |
|<----------------------------------------------------|
Figure 6 - Global Mobility Message Flow
Giaretta Expires May 1, 2011 [Page 13]
Internet-Draft PMIPv6-MIPv6 Interactions October 2010
4.2. Solutions related to scenario A.2
As described in Section 3.2, in this scenario the mobile node relies
on PMIPv6 as long as it is in the PMIPv6 domain. The mobile node
then uses MIPv6 whenever it moves out of the PMIPv6 domain which
basically implies that the MIPv6 home link is a PMIPv6 domain.
Analyzing the issues described in Section 3.2, it is clear that most
of them are applicable only to the case where there is a common
binding cache entry for the PMIPv6 registration and the MIPv6
registration. The issue 1 on how the two protocols identify the
binding cache entry is valid only in case we assume that a PMIPv6
message has any value for a MIPv6 BCE. Also the issues 2 and 3 are
not applicable in case different logical BCEs are used by the LMA and
the HA. For this reason, it is recommended that when the MIPv6 home
link is implemented as a PMIPv6 domain, the HA/LMA implementation
treats the two protocol as independent.
More in details the following principles should be followed by the
HA/LMA implementation:
o PMIPv6 signaling does not overwrite any MIPv6 BCE. In particular,
when a PMIPv6 binding cache entry is created for a mobile node
which has previously created a MIPv6 BCE, the MIPv6 binding cache
entry of the MN is not overwritten and a new PMIPv6 binding cache
entry is created.
o The downlink packets in the case where both the MIPv6 binding
cache entry and PMIPv6 binding cache entry exist are processed as
follows:
1. The MIPv6 binding cache entry is processed first. If the
destination address of the received downlink packet matches
the the binding cache entry of the HA, the packet is forwarded
by encapsulating it with the care-of-address contained in the
BCE.
2. If the destination address does not match the MIPv6 BCE, the
binding cache entry created by PMIPv6 is applied and the
packet are encapsualted to the registered MAG.
The following subsections provide a description of the procedures
which will be followed by the mobile node and HA/LMA based on the
above principles. The analysis is performed in two different
subsections, depending if the mobile node moves from a PMIPv6 domain
to a non-PMIPv6 domain or vice versa.
Giaretta Expires May 1, 2011 [Page 14]
Internet-Draft PMIPv6-MIPv6 Interactions October 2010
4.2.1. Mobility from a PMIPv6 domain to a non-PMIPv6 domain
Let's assume the mobile node is attached to a PMIPv6 domain and there
is a valid Proxy Binding Cache entry at the LMA. Then the mobile
node moves to a different access network and starts using MIPv6 (e.g.
because PMIPv6 is not supported). The mobile node needs to bootstrap
MIPv6 parameters and send a MIPv6 Binding Update in order to have
service continuity. Therefore the following steps must be performed
by the UE:
o HA/LMA address discovery: the mobile node needs to discover the IP
address of the LMA which has a valid binding cache entry for its
home network prefix. This is described in Section 3.2 as issue 4.
o Security Association establishment: the mobile node needs to
establish an IPsec Security Association with the HA/LMA as
described in [RFC4877]
o HoA or home network prefix assignment: as part of the MIPv6
bootstrapping procedure the HA assigns a MIPv6 HoA to the MN.
This address must be the same the mobile node was using in the
PMIPv6 domain.
Since all these steps must be performed by the mobile node before
sending the Binding Update, they have an impact on the handover
latency experienced by the MN. For this reason it is recommended
that the mobile node establishes the IPsec security association (and
consequently is provided by the HA/LMA with a MIPv6-HoA) when it is
initialized. This implies that the mobile node has MIPv6 stack
active while in the PMIPv6 domain, but as long as it is attached to
the same PMIPv6 domain, it will appear to the mobile node as if it is
attached to the home link.
In order to establish the security association with the HA/LMA, the
mobile node needs to discover the IP address of the LMA/HA while in
the PMIPv6 domain. This can be done either based on DNS or based on
DHCPv6, as described in [RFC5026] and [boot-integrated]. The network
should be configured so that the mobile node discovers or gets
assigned the same HA/LMA that was serving as the LMA in the PMIPv6
domain. Details of the exact procedure are out of scope of this
document.
When the mobile node establishes the security association, it
acquires a home address based on [RFC5026]. However, based on PMIPv6
operations, the LMA knows only the Home Network Prefix used by the
mobile node and does not know the MN-HoA.For this reason, the mobile
node must be configured to propose MN-HoA as the home address in the
IKEv2 INTERNAL_IP6_ADDRESS attribute during the IKEv2 exchange with
Giaretta Expires May 1, 2011 [Page 15]
Internet-Draft PMIPv6-MIPv6 Interactions October 2010
the HA/LMA. Alternatively the HA/LMA can be configured to provide
the entire Home Network Prefix via the MIP6_HOME_LINK attribute to
the mobile node as specified in [RFC5026]; based on this Home Network
Prefix the mobile node can configure a home address. Note that the
security association must be bound to the MN-HoA used in the PMIPv6
domain as per [RFC4877]. Note that the home network prefix is shared
between the LMA and HA and this implies that there is an interaction
between the LMA and the HA in order to assign a common home network
prefix when triggered by PMIPv6 and MIPv6 signaling
When the mobile node hands over to an access network which does not
support Proxy Mobile IPv6, it sends a Binding Update to the HA. The
mobile node may set the R bit defined in NEMO specification (implicit
mode) [RFC3963]in order to indicate that the entire HNP is moved to
the new CoA. A MIPv6 binding cache entry is created irrespective of
the existing PMIPv6 BCE. Packets matching the MIPv6 binding cache
entry are sent to the CoA present in the MIPv6 BCE. The PMIPv6
binding cache entry will expire in case the MAG does not send a
refresh PBU.
4.2.2. Mobility from a non-PMIPv6 domain to a PMIPv6 domain
In this section it is assumed that the mobile node is in a non-PMIPv6
access network and it has bootstrapped MIPv6 operations based on
[RFC5026]; therefore there is valid binding cache for its MIPv6-HoA
(or HNP in case of NEMO) at the HA. Then the mobile node moves to a
PMIPv6 domain which is configured to be the home link for the MIPv6-
HoA the mobile node has been assigned.
In order to provide session continuity, the MAG needs to send a PBU
to the HA/LMA that was serving the MN. The MAG needs to discover the
HA/LMA; however the current version of [RFC5213] assumes that the LMA
is assigned to the MAG or discovered by the MAG when the mobile node
attaches to the MAG. the exact mechanism is not specified in
[RFC5213]. A detailed description of the necessary procedure is out
of the scope of this document. Note that the MAG may also rely on
static configuration or lower layer information provided by the
mobile node in order to select the correct HA/LMA.
The PBU sent by the MAG creates a PMIPv6 binding cache entry for the
mobile node which is independent of the MIPv6 BCE. Traffic destined
to the MIPv6-HoA (or to the HNP in case the mobile node had set the
flag R in the last BU) is still forwarded to the CoA present in the
MIPv6 BCE. When the mobile node wants to use the HoA directly from
the home link, it sends a de-registration message and at that point
only the PMIPv6 binding cache entry is present.
Giaretta Expires May 1, 2011 [Page 16]
Internet-Draft PMIPv6-MIPv6 Interactions October 2010
4.3. Solutions related to scenario B
The solution for this scenario depends on the access network being
able to determine that a particular mobile node wants to use Mobile
IPv6. This requires a solution at the system level for the access
network and may require knowledge of the detailed configuration and
software capabilities of every mobile node in the system. These
issues are out of scope of this document
5. Security Considerations
Scenario A.1 does not introduce any new security issues in addition
to those described in [RFC5213] or [RFC3775].
For scenario A.2, this document requires that the a home agent that
also implements the PMIPv6 LMA functionality should allow both the
mobile node and the authorized MAGs to modify the binding cache
entries for the mobile node. Note that the compromised MAG threat
described in [RFC4832] applies also here in a more severe form as
explained in Section 3.2. Scenario B relies on the secure
identification of mobile nodes and their capabilities so that the
right service can be provided for the right mobile nodes. For
instance, a malicious mobile node should not get the home address of
some other node assigned to it, and a mobile node that desires to
employ its own mobility management should be able to do so. The
ability to identify nodes is already a requirement in [RFC5213], but
scenario B adds a requirement on identification of node capabilities.
6. IANA considerations
This document has no IANA actions.
7. Additional Authors
Chowdhury, Kuntal - kchowdhury@starentnetworks.com
Hesham Soliman - Hesham@elevatemobile.com
Vijay Devarapalli - vijay.devarapalli@azairenet.com
Sri Gundavelli - sgundave@cisco.com
Kilian Weniger - Kilian.Weniger@googlemail.com
Genadi Velev - Genadi.Velev@eu.panasonic.com
Giaretta Expires May 1, 2011 [Page 17]
Internet-Draft PMIPv6-MIPv6 Interactions October 2010
Ahmad Muhanna - amuhanna@nortel.com
George Tsirtsis - tsirtsis@googlemail.com
Suresh Krishnan - suresh.krishnan@ericsson.com
8. Acknowledgements
This document is a merge of four different Internet Drafts:
draft-weniger-netlmm-pmipv6-mipv6-issues-00,
draft-devarapalli-netlmm-pmipv6-mipv6-01,
draft-tsirtsis-logically-separate-lmaha-01and
draft-giaretta-netlmm-mip-interactions-00. Thanks to the authors and
editors of those drafts.
The authors would also like to thank Jonne Soininen and Vidya
Narayanan, NETLMM WG chairs, for their support.
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.
[RFC3775] Johnson, D., Perkins, C., and J. Arkko, "Mobility Support
in IPv6", RFC 3775, June 2004.
[RFC3963] Devarapalli, V., "Network Mobility (NEMO) Basic Support
Protocol", January 2005,
<http://www.rfc-editor.org/rfc/rfc3963.txt>.
[RFC4140] Soliman, H., "Hierarchical Mobile IPv6 Mobility Management
(HMIPv6)", August 2005,
<http://www.rfc-editor.org/rfc/rfc4140.txt>.
[RFC4832] Vogt, C. and J. Kempf, "Security Threats to Network-Based
Localized Mobility Management (NETLMM)", April 2007.
[RFC4877] Devarapalli, V. and F. Dupont, "Mobile IPv6 Operation with
IKEv2 and the Revised IPsec Architecture", 2005.
[RFC5026] Giaretta, G., Kempf, J., and V. Devarapalli, "Mobile IPv6
Bootstrapping in Split Scenario", RFC 5026, October 2007.
[RFC5213] Gundavelli, S., "Proxy Mobile IPv6", August 2008.
Giaretta Expires May 1, 2011 [Page 18]
Internet-Draft PMIPv6-MIPv6 Interactions October 2010
[boot-integrated]
Chowdhury, K., Ed., "MIP6-bootstrapping for the Integrated
Scenario", 2007.
9.2. Informative References
[RFC3753] Manner, J. and M. Kojo, "Mobility Related Terminology",
RFC 3753, June 2004.
[RFC4283] Patel, A., Leung, K., Khalil, M., Akhtar, H., and K.
Chowdhury, "Mobile Node Identifier Option for Mobile IPv6
(MIPv6)", RFC 4283, November 2005.
Author's Address
Gerardo Giaretta (editor)
Qualcomm
Email: gerardog@qualcomm.com
Giaretta Expires May 1, 2011 [Page 19]