One document matched: draft-ietf-mipshop-pfmipv6-10.txt
Differences from draft-ietf-mipshop-pfmipv6-09.txt
Network Working Group H. Yokota
Internet-Draft KDDI Lab
Intended status: Standards Track K. Chowdhury
Expires: May 22, 2010 R. Koodli
Starent Networks
B. Patil
Nokia
F. Xia
Huawei USA
November 18, 2009
Fast Handovers for Proxy Mobile IPv6
draft-ietf-mipshop-pfmipv6-10.txt
Abstract
Mobile IPv6 (MIPv6) [RFC3775] provides a mobile node with IP mobility
when it performs a handover from one access router to another and
fast handovers for Mobile IPv6 (FMIPv6) [RFC5568] are specified to
enhance the handover performance in terms of latency and packet loss.
While MIPv6 (and FMIPv6 as well) requires the participation of the
mobile node in the mobility-related signaling, Proxy Mobile IPv6
(PMIPv6) [RFC5213] provides IP mobility to mobile nodes that either
have or do not have MIPv6 functionality without such involvement.
Nevertheless, the basic performance of PMIPv6 in terms of handover
latency and packet loss is considered not any different from that of
MIPv6.
When the fast handover is considered in such an environment, several
modifications are needed to FMIPv6 to adapt to the network-based
mobility management. This document specifies the usage of Fast
Mobile IPv6 (FMIPv6) when Proxy Mobile IPv6 is used as the mobility
management protocol. Necessary extensions are specified for FMIPv6
to support the scenario when the mobile node does not have IP
mobility functionality and hence is not involved with either MIPv6 or
FMIPv6 operations.
Status of this Memo
This Internet-Draft is submitted to IETF in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as Internet-
Drafts.
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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."
The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt.
The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html.
This Internet-Draft will expire on May 22, 2010.
Copyright Notice
Copyright (c) 2009 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 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.
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Table of Contents
1. Requirements notation . . . . . . . . . . . . . . . . . . . . 4
2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 5
3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 6
4. Proxy-based FMIPv6 Protocol Overview . . . . . . . . . . . . . 7
4.1. Protocol Operation . . . . . . . . . . . . . . . . . . . . 8
4.2. Inter-AR Tunneling Operation . . . . . . . . . . . . . . . 15
4.3. IPv4 Support Considerations . . . . . . . . . . . . . . . 17
5. PMIPv6-related Fast Handover Issues . . . . . . . . . . . . . 18
5.1. Manageability Considerations . . . . . . . . . . . . . . . 18
5.2. Expedited Packet Transmission . . . . . . . . . . . . . . 18
6. Message Formats . . . . . . . . . . . . . . . . . . . . . . . 20
6.1. Mobility Header . . . . . . . . . . . . . . . . . . . . . 20
6.1.1. Handover Initiate (HI) . . . . . . . . . . . . . . . . 20
6.1.2. Handover Acknowledge (HAck) . . . . . . . . . . . . . 22
6.2. Mobility Options . . . . . . . . . . . . . . . . . . . . . 24
6.2.1. Context Request Option . . . . . . . . . . . . . . . . 24
6.2.2. Local Mobility Anchor Address (LMAA) Option . . . . . 25
6.2.3. Mobile Node Interface Identifier (MN IID) Option . . . 26
6.2.4. Home Network Prefix Option . . . . . . . . . . . . . . 27
6.2.5. Link-local Address Option . . . . . . . . . . . . . . 27
6.2.6. GRE Key Option . . . . . . . . . . . . . . . . . . . . 27
6.2.7. IPv4 Address Option . . . . . . . . . . . . . . . . . 27
6.2.8. Vendor-Specific Mobility Option . . . . . . . . . . . 27
7. Security Considerations . . . . . . . . . . . . . . . . . . . 28
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 29
9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 30
10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 31
10.1. Normative References . . . . . . . . . . . . . . . . . . . 31
10.2. Informative References . . . . . . . . . . . . . . . . . . 31
Appendix A. Applicable Use Cases . . . . . . . . . . . . . . . . 32
A.1. PMIPv6 Handoff Indication . . . . . . . . . . . . . . . . 32
A.2. Local Routing . . . . . . . . . . . . . . . . . . . . . . 32
Appendix B. Change Log . . . . . . . . . . . . . . . . . . . . . 34
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 39
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1. Requirements notation
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119].
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2. Introduction
Proxy Mobile IPv6 [RFC5213] provides IP mobility to a mobile node
that does not support Mobile IPv6 [RFC3775] mobile node
functionality. A proxy agent in the network performs the mobility
management signaling on behalf of the mobile node. This model
transparently provides mobility for mobile nodes within a PMIPv6
domain. Nevertheless, the basic performance of PMIPv6 in terms of
handover latency and packet loss is considered not any different from
that of Mobile IPv6.
Fast Handovers for Mobile IPv6 (FMIPv6) [RFC5568] describes the
protocol to reduce the handover latency for Mobile IPv6 by allowing a
mobile node to send packets as soon as it detects a new subnet link
and by delivering packets to the mobile node as soon as its
attachment is detected by the new access router. This document
describes necessary extensions to FMIPv6 to minimize handover delay
and packet loss as well as to transfer network-resident context for a
PMIPv6 handover.
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3. Terminology
This document reuses terminology from [RFC5213], [RFC5568] and
[RFC3775]. The following terms and abbreviations are additionally
used in this document.
Access Network (AN):
A network composed of link-layer access devices such as access
points or base stations providing access to an Access Router
(AR) connected to it.
Previous Access Network (P-AN):
The access network to which the Mobile Node (MN) is attached
before handover.
New Access Network (N-AN):
The access network to which the Mobile Node (MN) is attached
after handover.
Previous Mobile Access Gateway (PMAG):
The MAG that manages mobility related signaling for the MN
before handover. In this document, the MAG and the Access
Router are co-located.
New Mobile Access Gateway (NMAG):
The MAG that manages mobility related signaling for the MN after
handover. In this document, the MAG and the Access Router (AR)
are co-located.
Local Mobility Anchor (LMA)
The topological anchor point for the mobile node's home network
prefix(es) and the entity that manages the mobile node's binding
state. This specification does not alter any capability or
functionality defined in [RFC5213].
HO-Initiate:
A generic signaling message, sent from the P-AN to the PMAG that
indicates a MN handover. While this signaling is dependent on
the access technology, it is assumed that HO-Initiate can carry
the information to identify the MN and to assist the PMAG
resolve the NMAG and the new access point or the base station to
which the MN is moving to. The details of this message are
outside the scope of this document.
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4. Proxy-based FMIPv6 Protocol Overview
This specification describes fast handover protocols for the network-
based mobility management protocol called Proxy Mobile IP (PMIPv6)
[RFC5213]. The core functional entities defined in PMIPv6 are the
LMA and the MAG. The LMA is the topological anchor point for the
MN's home network prefix(es). The MAG acts as an access router (AR)
for the MN and performs the mobility management procedures on its
behalf. The MAG is responsible for detecting the MN's movements to
and from the access link and for initiating binding registrations to
the MN's LMA. If the MAGs can be informed of the detachment and/or
attachment of the MN in a timely manner via e.g., the lower layer
signaling, it will become possible to optimize the handover
procedure, which involves establishing a connection on the new link
and signaling between mobility agents, compared to the baseline
specification of PMIPv6.
In order to further improve the performance during the handover, the
PFMIPv6 protocol in this document specifies a bi-directional tunnel
between the Previous MAG (PMAG) and the New MAG (NMAG) to tunnel
packets meant for the mobile node. In order to enable the NMAG to
send the Proxy Binding Update (PBU), the Handover Initiate (HI) and
Handover Acknowledge (HAck) messages in [RFC5568] are extended for
context transfer, in which parameters such as MN's Network Access
Identifier (NAI), Home Network Prefix (HNP), IPv4 Home Address, are
transferred from the PMAG. New flags 'P' and 'F' are defined for the
HI and HAck messages to distinguish from those in [RFC5568] and to
request packet forwarding, respectively.
In this document, the Previous Access Router (PAR) and New Access
Router (NAR) are interchangeable with the PMAG and NMAG,
respectively. The reference network is illustrated in Figure 1. The
access networks in the figure (i.e., P-AN and N-AN) are composed of
Access Points (APs) defined in [RFC5568], which are often referred to
as base stations in cellular networks.
Since a MN is not directly involved with IP mobility protocol
operations, it follows that the MN is not directly involved with fast
handover procedures either. Hence, the messages involving the MN in
[RFC5568] are not used when PMIPv6 is in use. More specifically, the
Router Solicitation for Proxy Advertisement (RtSolPr), the Proxy
Router Advertisement (PrRtAdv), Fast Binding Update (FBU), Fast
Binding Acknowledgment (FBack) and the Unsolicited Neighbor
Advertisement (UNA) messages are not applicable in the PMIPv6
context.
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+----------+
| LMA |
| |
+----------+
/ \
/ \
/ \
+........../..+ +..\..........+
. +-------+-+ .______. +-+-------+ .
. | PMAG |()_______)| NMAG | .
. | (PAR) | . . | (NAR) | .
. +----+----+ . . +----+----+ .
. | . . | .
. ___|___ . . ___|___ .
. / \ . . / \ .
. ( P-AN ) . . ( N-AN ) .
. \_______/ . . \_______/ .
. | . . | .
. +----+ . . +----+ .
. | MN | ----------> | MN | .
. +----+ . . +----+ .
+.............+ +.............+
Figure 1: Reference network for fast handover
4.1. Protocol Operation
There are two modes of operation in FMIPv6 [RFC5568]. In the
predictive mode of fast handover, a bi-directional tunnel between the
PMAG (PAR) and NMAG (NAR) is established prior to the MN's attachment
to the NMAG. In the reactive mode, this tunnel establishment takes
place after the MN attaches to the NMAG. In order to alleviate the
packet loss during a MN's handover (especially when the MN is
detached from both links), the downlink packets for the MN need to be
buffered either at the PMAG or NMAG, depending on when the packet
forwarding is performed. It is hence required that all MAGs have the
capability and enough resources to buffer packets for the MNs
accommodated by them. The buffer size to be prepared and the rate at
which buffered packets are drained are addressed in Section 5.4 of
[RFC5568]. Note that the protocol operation specified in the
document is transparent to the LMA, hence there is no new functional
requirement or change on the LMA.
Unlike MIPv6, the MN in the PMIPv6 domain is not involved with IP
mobility signaling; therefore, in order for the predictive fast
handover to work effectively, it is required that the MN is capable
of reporting lower-layer information to the AN at a short enough
interval, and the AN is capable of sending the HO-initiate to the
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PMAG at an appropriate timing. The sequence of events for the
predictive fast handover are illustrated in Figure 2.
PMAG NMAG
MN P-AN N-AN (PAR) (NAR) LMA
| | | | | |
| Report | | | | |
(a) |-(MN ID,-->| | | | |
| New AP ID)| | | | |
| | HO Initiate | | |
(b) | |--(MN ID, New AP ID)-->| | |
| | | | | |
| | | | | |
(c) | | | |----HI---->| |
| | | | | |
| | | | | |
(d) | | | |<---HAck---| |
| | | | | |
| | | | | |
| | | |HI/HAck(optional) |
(e) | | | |<- - - - ->| |
| | | #=|<===================|
(f) | | | #====DL data=>| |
| | | | | |
(g) ~~~ | | | | |
~~~ | | | | |
| MN-AN connection | AN-MAG connection | |
(h) |<---establishment---->|<----establishment----->| |
| | | (substitute for UNA) | |
| | | | | |
(i) |<==================DL data=====================| |
| | | | | |
(j) |===================UL data====================>|=# |
| | | #=|<============# |
| | | #=====================>|
/ | | | | | | \
|(k) | | | | |--PBU-->| |
| | | | | | | |
|(l) | | | | |<--PBA--| |
\ | | | | | | /
Figure 2: Predictive fast handover for PMIPv6 (PAR initiated)
The detailed descriptions are as follows:
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(a) The MN detects that a handover is imminent and reports the
identifications of itself (MN ID) and the New Access Point
Identifier (New AP ID) [RFC5568] to which the MN is most likely
to move. The MN ID could be the NAI or a Link Layer Address
(LLA), or any other suitable identifier. This step is access
technology specific. In some cases, the P-AN will determine
which AP ID the MN is moving to.
(b) The previous access network (P-AN), to which the MN is currently
attached, indicates the handover of the MN to the PMAG (PMAG).
Detailed definition and specification of this message are
outside the scope of this document.
(c) The PMAG sends the HI to the NMAG. The HI message MUST have the
P flag set and include the MN ID, the HNP(s), the MN IID and the
address of the LMA that is currently serving the MN. If there
is a valid (non-zero) MN Link-layer Identifier (MN LL-ID), that
information MUST also be included.
(d) The NMAG sends the HAck back to the PMAG with the P flag set.
(e) If it is preferred that the timing of buffering or forwarding
should be later than step (c), the NMAG may optionally request
the PMAG at a later and appropriate time to buffer or forward
packets by setting U flag [RFC5568] or F flag in the HI message,
respectively.
(f) If the F flag is set in the previous step, a bi-directional
tunnel is established between the PMAG and NMAG and packets
destined for the MN are forwarded from the PMAG to the NMAG over
this tunnel. After decapsulation, those packets may be buffered
at the NMAG. If the connection between the N-AN and NMAG has
already been established, those packets may be forwarded towards
the N-AN, which then becomes responsible for them (e.g.,
buffering or delivering depending on the condition of the MN's
attachment); this is access technology specific.
(g) The MN undergoes handover to the New Access Network (N-AN).
(h) The MN establishes a physical link connection with the N-AN
(e.g., radio channel assignment), which in turn triggers the
establishment of a link-layer connection between the N-AN and
NMAG if not yet established. An IP layer connection setup may
be performed at this time (e.g., PPP IPv6CP) or at a later time
(e.g., stateful or stateless auto address configuration). This
step can be a substitute for the UNA in [RFC5568]. If the NMAG
acquires a valid new MN LL-ID via the N-AN and a valid old MN
LL-ID from the PMAG at step (c), these IDs SHOULD be compared to
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determine whether the same interface is used before and after
handover. When the connection between the MN and NMAG is PPP
and the same interface is used for the handover, the NMAG SHOULD
confirm that the same interface identifier (IID), which is
transferred by the MN-IID option at step (c), is assigned to the
MN's interface during the Configure-Request/Ack exchange.
(i) The NMAG starts to forward packets destined for the MN via the
N-AN.
(j) The uplink packets from the MN are sent to the NMAG via the N-AN
and the NMAG forwards them to the PMAG. The PMAG then sends the
packets to the LMA that is currently serving the MN.
(k) The NMAG (NAR) sends the Proxy Binding Update (PBU) to the LMA,
whose address is provided in (c). Steps (k) and (l) are not
part of the fast handover procedure, but shown for reference.
(l) The LMA sends back the Proxy Binding Acknowledgment (PBA) to the
NMAG (NMAG). From this time on, the packets to/from the MN go
through the NMAG instead of the PMAG.
According to Section 4 of [RFC5568], the PMAG establishes a binding
between the Previous Care-of Address (PCoA) and New Care-of Address
(NCoA) to forward packets for the MN to the NAR, and the NMAG creates
a proxy neighbor cache entry to receive those packets for the NCoA
before the MN arrives. In the case of PMIPv6, however, the only
address that is used by the MN is MN-HoA (Mobile Node's Home
Address). Hence the PMAG forwards MN's packets to the NMAG instead
of the NCoA. FMIPv4 [RFC4988] specifies forwarding when the MN uses
the home address as its on-link address rather than the care-of
address. The usage in PMIPv6 is similar to that in FMIPv4, where the
address is used by the MN is based on Home Network Prefix. Hence the
PMAG forwards MN's packets to the NMAG instead of the NCoA. The NMAG
then simply decapsulates those packets and delivers them to the MN.
Since the NMAG obtains the Link-layer address (MN LL-ID), the
interface identifier (MN-IID) and HNP(s) by the HI, it can create the
Neighbor Cache Entry for the MN and deliver packets to it even before
the MN can perform Neighbor Discovery. For the uplink packets from
the MN after handover in (j), the NMAG forwards the packets to the
PMAG through the tunnel established in step (f). The PMAG then
decapsulates and sends them to the LMA.
The timing of the context transfer and that of packet forwarding may
be different. Thus, a new flag 'F' and Option Code values for it in
the HI and HAck messages are defined to request forwarding. To
request buffering, 'U' flag has already been defined in [RFC5568].
If the PMAG receives the HI message with the F flag set, it starts
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forwarding packets for the MN. The HI message with the U flag set
may be sent earlier if the timing of buffering is different from that
of forwarding. If packet forwarding is completed, the PMAG MAY send
the HI message with the F flag set and the Option Code value being 2.
By this message, the ARs on both ends can tear down the forwarding
tunnel synchronously.
The IP addresses in the headers of those user packets are summarized
below:
In Step (f),
Inner source address: IP address of the CN
Inner destination address: HNP or Mobile Node's IPv4 Home
Address (IPv4-MN-HoA)
Outer source address: IP address of the PMAG (PAR)
Outer destination address: IP address of the NMAG (NAR)
In Step (i),
Source address: IP address of the CN
Destination address: HNP or IPv4-MN-HoA
In Step (j),
- from the MN to the NMAG,
Source address: HNP or IPv4-MN-HoA
Destination address: IP address of the CN
- from the NMAG to the PMAG,
Inner source address: HNP or IPv4-MN-HoA
Inner destination address: IP address of the CN
Outer source address: IP address of the NMAG (NAR)
Outer destination address: IP address of the PMAG (PAR)
- from the PMAG to the LMA,
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Inner source address: HNP or IPv4-MN-HoA
Inner destination address: IP address of the CN
Outer source address: IP address of the PMAG (PAR)
Outer destination address: IP address of the LMA
In the case of the reactive handover for PMIPv6, since the MN does
not send either the FBU or UNA, it would be more natural that the
NMAG sends the HI to the PMAG after the MN has moved to the new link.
The NMAG then needs to obtain the information of the PMAG beforehand.
Such information could be provided, for example, by the MN sending
the AP-ID on the old link and/or by the lower-layer procedures
between the P-AN and N-AN. The exact method is not specified in this
document. Figure 3 illustrates the reactive fast handover procedures
for PMIPv6, where the bi-directional tunnel establishment is
initiated by the NMAG.
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PMAG NMAG
MN P-AN N-AN (PAR) (NAR) LMA
| | | | | |
(a) ~~~ | | | | |
~~~ | | | | |
| MN-AN connection | AN-MAG connection | |
(b) |<--establishment-->|<-------establishment------>| |
|(MN ID, Old AP ID) | (MN ID, Old AP ID) | |
| | |(substitute for UNA and FBU)| |
| | | | | |
| | | | | |
(c) | | | |<-----HI-------| |
| | | | | |
| | | | | |
(d) | | | |-----HAck----->| |
| | | | | |
| | | | | |
(e) | | | #=|<=======================|
| | | #================>|=# |
|<====================DL data======================# |
| | | | | |
(f) |=====================UL data===================>|=# |
| | | #=|<================# |
| | | #=========================>|
| | | | | |
/ | | | | | | \
|(g) | | | | |--PBU-->| |
| | | | | | | |
|(h) | | | | |<--PBA--| |
\ | | | | | | /
Figure 3: Reactive fast handover for PMIPv6 (NAR initiated)
The detailed descriptions are as follows:
(a) The MN undergoes handover from the P-AN to the N-AN. The AP-ID
on the old link may be provided by the MN to help identify the
PMAG on the new link.
(b) The MN establishes a connection (e.g., radio channel) with the
N-AN, which triggers the establishment of the connection between
the N-AN and NMAG. The MN ID is transferred to the NMAG for the
subsequent procedures. The AP-ID on the old link may also be
provided by the MN to help identify the PMAG on the new link.
This can be regarded as a substitute for the UNA and FBU.
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(c) The NMAG sends the HI to the PMAG. The HI message MUST have the
P flag set and include the MN ID. The Context Request Option
MAY be included to request additional context information on the
MN to the PMAG.
(d) The PMAG sends the HAck back to the NMAG with the P flag set.
The HAck message MUST include the HNP(s) and/or IPv4-MN-HoA that
is corresponding to the MN ID in the HI message and SHOULD
include the MN LL-ID, only if it is valid (non zero), and the
LMA address that is currently serving the MN. The context
information requested by the NMAG MUST be included. If the
requested context is not available for some reason, the PMAG
MUST return the HAck with the Code value 131. If the F flag is
set in the HI at step (c) and forwarding is nevertheless not
executable for some reason, the PMAG MUST return the HAck with
the Code value 132.
(e) If the F flag in the HI is set at step (c), a bi-directional
tunnel is established between the PMAG and NMAG and packets
destined for the MN are forwarded from the PMAG to the NMAG over
this tunnel. After decapsulation, those packets are delivered
to the MN via the N-AN.
(f) The uplink packets from the MN are sent to the NMAG via the N-AN
and the NMAG forwards them to the PMAG. The PMAG then sends the
packets to the LMA that is currently serving the MN.
Steps (g)-(h) are the same as (k)-(l) in the predictive fast handover
procedures.
In step (c), The IP address of the PMAG needs to be resolved by the
NMAG to send the HI to the PMAG. This information may come from the
N-AN or some database that the NMAG can access.
4.2. Inter-AR Tunneling Operation
When the PMAG (PAR) or NMAG (NAR), depending on the fast handover
mode, receives the HI message with the F flag set, it prepares to
send/receive the MN's packets to/from the other MAG and returns the
HAck message with the same sequence number. The both MAGs SHOULD
support the following encapsulation modes for the user packets, which
are also defined for the tunnel between the LMA and MAG:
o IPv4-or-IPv6-over-IPv6 [IPv4PMIPv6]
o IPv4-or-IPv6-over-IPv4 [IPv4PMIPv6]
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o IPv4-or-IPv6-over-IPv4-UDP [IPv4PMIPv6]
o TLV-header UDP tunneling [GREKEY]
o GRE tunneling with or without GRE key(s) [GREKEY]
The PMAG and the NMAG MUST use the same tunneling mechanism for the
data traffic tunneled between them. The encapsulation mode to be
employed SHOULD be configurable. This specification recommends the
following:
1. As the default behavior, the inter-MAG tunnel uses the same
encapsulation mechanism as that for the PMIPv6 tunnel between the
LMA and the MAGs. The PMAG and NMAG automatically start using
the same encapsulation mechanism without a need for a special
configuration on the MAGs or a dynamic tunneling mechanism
negotiation between them.
2. Configuration on the MAGs can override the default mechanism
specified in #1 above. The PMAG and NMAG MUST be configured with
the same mechanism and this configuration is most likely to be
uniform throughout the PMIPv6 domain. If the packets on the
PMIPv6 tunnel cannot be uniquely mapped on to the configured
inter-MAG tunnel, this scenario is not applicable and scenario #3
below SHOULD directly be applied.
3. An implicit or explicit tunnel negotiation mechanism between the
MAGs can override the default mechanism specified in #1 above.
The employed tunnel negotiation mechanism is outside the scope of
this document.
The necessary information MUST be transferred in the HI/HAck messages
to distinguish MN's packets for forwarding in advance or at this
time. Such information includes the HNP(s) (or IPv4-MN-HoA) and/or
GRE key(s). In the case of GRE tunneling with GRE keys being used,
for each mobility session, the NMAG selects the GRE key for the
downlink packets and the PMAG selects the GRE key for the uplink
packets. These GRE keys are exchanged between the PMAG and the NMAG
using the GRE Key option as described in [GREKEY], e.g., In the case
of the reactive mode as shown in Figure 3, the DL GRE key is
communicated in the HI message while the UL GRE key is sent in the
HAck message. For the downlink packets, the PMAG redirects MN's
packets from the LMA towards the NMAG and if the MN is ready to
receive those packets or the N-AN can handle them regardless of the
state of the MN, the NMAG should immediately send them towards the
N-AN; otherwise it should buffer them until the MN is ready. For the
uplink packets, the NMAG SHOULD reverse-tunnel them from the MN
towards the PMAG and the PMAG sends them to the LMA.
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When the PMAG or NMAG receives the HI message with the U flag set, it
prepares to buffer the MN's packets and returns the HAck message with
the same sequence number. It MUST be followed by another HI message
with the F flag set at an appropriate time to forward the buffered
packets.
If the MAG that received the HI message encounters an erroneous
situation (e.g., insufficient buffer space), it SHOULD immediately
send the HAck message with the cause of the error and cancel all
tunneling operation.
4.3. IPv4 Support Considerations
The motivation and usage scenarios of IPv4 protocol support by PMIPv6
are described in [IPv4PMIPv6]. The scope of IPv4 support covers the
following two features:
o IPv4 Home Address Mobility Support, and
o IPv4 Transport Support.
As for IPv4 Home Address Mobility Support, the MN acquires IPv4 Home
Address (IPv4-MN-HoA) and in the case of handover, the PMAG needs to
transfer IPv4-MN-HoA to the NMAG, which is the inner destination
address of the packets forwarded on the downlink. For this purpose,
IPv4 Address Option described in Section 6.2.7 is used. In order to
provide IPv4 Transport Support, the NMAG needs to know the IPv4
address of the LMA (IPv4-LMAA) to send PMIPv6 signaling messages to
the LMA in the IPv4 transport network. For this purpose, a new
option called LMA Address (LMAA) Option is defined in Section 6.2.2
so as to convey IPv4-LMAA from the PMAG to NMAG.
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5. PMIPv6-related Fast Handover Issues
5.1. Manageability Considerations
This specification does not require any additional IP-level
functionality on the LMA and the MN running in the PMIPv6 domain. A
typical network interface that the MN could be assumed to have is one
with the cellular network, where the network controls the movement of
the MN. Different types of interfaces could be involved such as
different generations (3G and 3.9G) or different radio access
systems. This specification supports a MN with the single radio
mode, where only one interface is active at any given time. The
assigned IP address is preserved whether the physical interface
changes or not and the MN can identify which interface should be used
if there are multiple ones.
5.2. Expedited Packet Transmission
The protocol specified in this document enables the NMAG to obtain
parameters which would otherwise be available only by communicating
with the LMA. For instance, the HNP(s) and/or IPv4-MN-HoA of a MN
are made available to the NMAG through context transfer. This allows
the NMAG to perform some procedures that may be beneficial. The
NMAG, for example, could send a Router Advertisement (RA) with the
HNP option to the MN as soon as its link attachment is detected
(e.g., via receipt of a Router Solicitation message). Such an RA is
recommended, for example, in scenarios where the MN uses a new radio
interface while attaching to the NMAG; since the MN does not have
information regarding the new interface, it will not be able to
immediately send packets without first receiving an RA with HNP(s).
Especially, in the reactive fast handover, the NMAG gets to know the
HNP(s) assigned to the MN on the previous link at step (d) in
Figure 3. In order to reduce the communication disruption time, the
NMAG SHOULD expect the MN to keep using the same HNP and to send
uplink packets before that step upon the MN's request. However, if
the HAck from the PMAG returns a different HNP or the subsequent
PMIPv6 binding registration for the HNP fails for some reason, then
the NMAG MUST withdraw the advertised HNP by sending another RA with
zero prefix lifetime for the HNP in question. This operation is the
same as described in Section 6.12 of [RFC5213].
The protocol specified in this document is applicable regardless of
whether link-layer addresses are used between a MN and its access
router. A MN should be able to continue sending packets on the
uplink even when it changes link. When link-layer addresses are
used, the MN performs Neighbor Unreachability Detection (NUD)
[RFC4861], after attaching to a new link, probing the reachability of
its default router. The new router should respond to the NUD probe,
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providing its link-layer address in the solicited Neighbor
Advertisement, which is common in the PMIPv6 domain. Implementations
should allow the MN to continue to send uplink packets while it is
performing NUD.
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6. Message Formats
This document defines new Mobility Header messages for the extended
HI and Hack and new mobility options for conveying context
information.
6.1. Mobility Header
6.1.1. Handover Initiate (HI)
This section defines extensions to the HI message in [RFC5568]. The
format of the Message Data field in the Mobility Header 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
+-------------------------------+
| Sequence # |
+-+-+-+-+-------+---------------+-------------------------------+
|S|U|P|F|Resv'd | Code | |
+-+-+-+-+-------+---------------+ |
| |
. .
. Mobility options .
. .
| |
+---------------------------------------------------------------+
(Note:P=1)
IP Fields:
Source Address
The IP address of PMAG or NMAG
Destination Address
The IP address of the peer MAG
Message Data:
Sequence # Same as [RFC5568].
S flag Defined in [RFC5568] and MUST be set to zero in this
specification.
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U flag Buffer flag. Same as [RFC5568].
P flag Proxy flag. Used to distinguish the message from that
defined in [RFC5568] and MUST be set in all new message
formats defined in this document when using this protocol
extension.
F flag Forwarding flag. Used to request to forward the packets
for the MN.
Reserved Same as [RFC5568].
Code [RFC5568] defines this field and its values 0 and 1. In
this specification, with the P flag set, this field can
be set to zero by default or the following values:
2: Indicate the completion of forwarding
3: All available context transferred
Code value 3 is set when the transfer of all necessary
context information is completed with this message. This
Code value is used in both cases where the context
information is fragmented into several pieces and the
last fragment is contained in this message and where the
whole information is transferred in one piece.
Mobility options:
This field contains one or more mobility options, whose encoding and
formats are defined in [RFC3775].
Requested option
In order to uniquely identify the target MN, the MN
Identifier MUST be contained in the Mobile Node Identifier
Option.
The transferred context MUST be for one MN per message. In addition,
the NMAG can request necessary mobility options by the Context
Request Option defined in this document.
Context Request Option
This option MAY be present to request context information
typically by the NMAG to the PMAG in the NAR-initiated fast
handover.
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6.1.2. Handover Acknowledge (HAck)
This section defines extensions to the HAck message in[RFC5568]. The
format of the Message Data field in the Mobility Header 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
+-------------------------------+
| Sequence # |
+-+-+-+---------+---------------+-------------------------------+
|U|P|F|Reserved | Code | |
+-+-+-+---------+---------------+ |
| |
. .
. Mobility options .
. .
| |
+---------------------------------------------------------------+
(Note:P=1)
IP Fields:
Source Address
Copied from the destination address of the
Handover Initiate message to which this message
is a response.
Destination Address
Copied from the source address of the Handover
Initiate message to which this message is a
response.
Message Data:
The usages of Sequence # and Reserved fields are exactly the same as
those in [RFC5568].
U flag Same as defined in Section 6.1.1.
P flag Used to distinguish the message from that defined in
[RFC5568] and MUST be set in all new message formats
defined in this document when using this protocol
extension.
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F flag Same as defined in Section 6.1.1.
Code
Code values 0 through 4 and 128 through 130 are defined
in [RFC5568]. In this specification, the meaning of Code
value 0 is modified, 128 through 130 are reused, and 5,
6, 131 and 132 are newly defined.
0: Handover Accepted or Successful
5: Context Transfer Accepted or Successful
6: All available Context Transferred
128: Handover Not Accepted, reason unspecified
129: Administratively prohibited
130: Insufficient resources
131: Requested Context Not Available
132: Forwarding Not Available
Mobility options:
This field contains one or more mobility options, whose encoding and
formats are defined in [RFC3775]. The mobility option that uniquely
identifies the target MN MUST be copied from the corresponding HI
message and the transferred context MUST be for one MN per message.
Requested option(s) All the context information requested by the
Context Request Option in the HI message SHOULD be present
in the HAck message. The other cases are described below.
In the case of the PAR-initiated fast handover, when the PMAG sends
the HI message to the NMAG with the context information and the NMAG
successfully receives it, the NMAG returns the HAck message with Code
value 5. In the case of the NAR-initiated fast handover, when the
NMAG sends the HI message to the PMAG with or without Context Request
Option, the PMAG returns the HAck message with the requested or
default context information (if any). If all available context
information is transferred, the PMAG sets the Code value in the HAck
message to 6. If more context information is available, the PMAG
sets the Code value in the HAck to 5 and the NMAG MAY send new HI
message(s) to retrieve the rest of the available context information.
If none of the requested context information is available, the PMAG
returns the HAck message with Code value 131 without any context
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information.
6.2. Mobility Options
6.2.1. Context Request Option
This option is sent in the HI message to request context information
on the MN. If a default set of context information is defined and
always sufficient, this option is not used. This option is more
useful to retrieve additional or dynamically selected context
information.
Context Request Option is typically used for the reactive (NAR-
initiated) fast handover mode to retrieve the context information
from the PMAG. When this option is included in the HI message, all
the requested context information SHOULD be included in the HAck
message in the corresponding mobility option(s) (e.g., HNP, LMAA or
MN IID mobility options).
The default context information to request is the Home Network Prefix
Option. If the Mobile Node link-layer is available and used, the
Mobile Node Link-layer Identifier Option MUST also be requested.
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
+---------------+---------------+---------------+---------------+
| Option-Type | Option-Length | Reserved |
+---------------+---------------+-------------------------------+
| Req-type-1 | Req-length-1 | Req-type-2 | Req-length-2 |
+---------------------------------------------------------------+
| Req-type-3 | Req-length-3 | Req-option-3 |
+---------------------------------------------------------------+
| ... |
Option-Type TBD1
Option-Length The length in octets of this option, not including the
Option Type and Option Length fields.
Reserved This field is unused. It MUST be initialized to zero
by the sender and MUST be ignored by the receiver.
Req-type-n The type value for the n'th requested option.
Req-length-n The length of the n'th requested option excluding the
Req-type-n and Req-length-n fields.
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Req-option-n The optional data to uniquely identify the requested
context for the n'th requested option.
In the case where there are only Req-type-n and Req-length-n fields,
the value of the Req-length-n is set to zero. If additional
information besides the Req-type-n is necessary to uniquely specify
the requested context, such information follows after the
Req-length-n. For example, when the requested contexts start with
the HNP Option (type=22), the MN Link-layer ID Option (type=25) and
the Vendor-Specific Option (type=19), the requested option format
looks as follows:
| ... |
+---------------+---------------+---------------+---------------+
|Option-Type=CRO| Option-Length | Reserved |
+---------------+---------------+---------------+---------------+
| Req-type-N=22 | Req-length-N=0| Req-type-N=25 | Req-length-N=0|
+---------------+---------------+-------------------------------+
| Req-type-N=19 | Req-length-N=5| Vendor-ID |
+-------------------------------+---------------+---------------+
| Vendor-ID | Sub-Type | |
+-----------------------------------------------+ |
| ... |
The first two options can uniquely identify the requested contexts
(i.e., the HNP and MN Link-layer ID) by the Req-type, so the Req-
length is set to zero; however, the subsequent Vendor-Specific Option
further needs the Vendor-ID and Sub-type to identify the requested
context, so these parameters follow and the Req-length is set to 5.
Note that the exact values in the Vendor-ID ans Sub-Type follow
[RFC5094].
6.2.2. Local Mobility Anchor Address (LMAA) Option
This option is used to transfer the Local Mobility Anchor IPv6
Address (LMAA) or its IPv4 Address (IPv4-LMAA), with which the MN is
currently registered. The detailed definition of the LMAA is
described in [RFC5213].
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Option-Type | Option-Length | Option-Code | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Local Mobility Anchor Address ... |
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Option-Type TBD2
Option-Length 18 or 6
Option-Code
0 Reserved
1 IPv6 address of the LMA (LMAA)
2 IPv4 address of the LMA (IPv4-LMAA)
Reserved This field is unused. It MUST be initialized to zero
by the sender and MUST be ignored by the receiver.
Local Mobility Anchor Address
If Option-Code is 1, the LMA IPv6 address (LMAA) is
inserted. If Option-Code is 2, the LMA IPv4 address
(IPv4-LMA) is inserted.
6.2.3. Mobile Node Interface Identifier (MN IID) Option
This option is used to transfer the interface identifier of the MN
that is used in the P-AN.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Option-Type | Option-Length | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ Interface Identifier +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Option-Type TBD3
Option-Length 10
Reserved This field is unused. It MUST be initialized to zero
by the sender and MUST be ignored by the receiver.
Interface Identifier
The Interface Identifier value of the MN that is used
in the P-AN.
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6.2.4. Home Network Prefix Option
This option is used to transfer the home network prefix that is
assigned to the MN in the P-AN. The Home Network Prefix Option
defined in [RFC5213] is used for this.
6.2.5. Link-local Address Option
This option is used to transfer the link-local address of the PMAG
(PMAG). The Link-local Address Option defined in [RFC5213] is used
for this.
6.2.6. GRE Key Option
This option is used to transfer the GRE Key for the MN's data flow
over the bi-directional tunnel between the PMAG and NMAG. The
message format of this option follows the GRE Key Option defined in
[GREKEY]. The GRE Key value uniquely identifies each flow and the
sender of this option expects to receive packets of the flow from the
peer AR with this value.
6.2.7. IPv4 Address Option
As described in Section 4.3, if the MN runs in IPv4-only mode or
dual-stack mode, it requires IPv4 home address (IPv4-MN-HoA). This
option is used to transfer the IPv4 home address if assigned on the
previous link. The format of this option follows the IPv4 Home
Address Request Option defined in [IPv4PMIPv6].
6.2.8. Vendor-Specific Mobility Option
This option is used to transfer any other information defined in this
document. The format and used values of this option follow the
Vendor-Specific Mobility Option defined in [RFC5094].
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7. Security Considerations
Security issues for this document follow those for PMIPv6 [RFC5213]
and FMIPv6 [RFC5568]. In PMIPv6, the MAG and LMA are assumed to
share security associations. In FMIPv6, the access routers (i.e.,
the PMAG and NMAG in this document) are assumed to share security
associations.
The Handover Initiate (HI) and Handover Acknowledge (HAck) messages
exchanged between the PMAG and NMAG MUST be protected using end-to-
end security association(s) offering integrity and data origin
authentication. The PMAG and the NMAG MUST implement IPsec [RFC4301]
for protecting the HI and HAck messages. IPsec Encapsulating
Security Payload (ESP) [RFC4303] in transport mode with mandatory
integrity protection SHOULD be used for protecting the signaling
messages. Confidentiality protection SHOULD be used if sensitive
context related to the mobile node is transferred.
IPsec ESP [RFC4303] in tunnel mode SHOULD be used to protect the MN's
packets at the time of forwarding if the link between the PMAG and
NMAG exposes the MN's packets to more threats than if they had
followed their normal routed path.
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8. IANA Considerations
This document defines new flags and status codes in the HI and HAck
messages as well as three new mobility options. The Type values for
these mobility options are assigned from the same numbering space as
allocated for the other mobility options defined in [RFC3775].
Mobility Options
Value Description Reference
----- ------------------------------------- -------------
TBD1 Context Request Option Section 6.2.1
TBD2 Local Mobility Anchor Address Option Section 6.2.2
TBD3 Mobile Node Interface Identifier Option Section 6.2.3
Handover Initiate Flags
Flag Value Description Reference
---- ----- ------------------------------- -------------
P 0x20 Proxy flag Section 6.1.1
F 0x10 Forwarding flag Section 6.1.1
Handover Acknowlede Flags
Flag Value Description Reference
---- ----- ------------------------------- -------------
P 0x40 Proxy flag Section 6.1.2
F 0x20 Forwarding flag Section 6.1.2
Handover Initiate Status Codes
Code Description Reference
---- -------------------------------------- -------------
2 Indicate the completion of forwarding Section 6.1.1
3 All available context transferred Section 6.1.1
Handover Acknowledge Status Codes
Code Description Reference
---- -------------------------------------- -------------
0 Handover Accepted or Successful Section 6.1.2
5 Context Transfer Accepted or Successful Section 6.1.2
6 All available Context Transferred Section 6.1.2
131 Requested Context Not Available Section 6.1.2
132 Forwarding Not Available Section 6.1.2
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9. Acknowledgments
The authors would like to specially thank Vijay Devarapalli and Sri
Gundavelli for their thorough reviews of this document.
The authors would also like to thank Charlie Perkins, Desire Oulai,
Ahmad Muhanna, Giaretta Gerardo, Domagoj Premec, Marco Liebsch, Fan
Zhao, Julien Laganier and Pierrick Seite for their passionate
discussions in the working group mailing list.
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10. References
10.1. Normative References
[RFC5213] Gundavelli, S., Leung, K., Devarapalli, V., Chowdhury, K.,
and B. Patil, "Proxy Mobile IPv6", RFC 5213, August 2008.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC5568] Koodli, R., "Mobile IPv6 Fast Handovers", RFC 5568,
July 2009.
[RFC3775] Johnson, D., Perkins, C., and J. Arkko, "Mobility Support
in IPv6", RFC 3775, June 2004.
[RFC4301] Kent, S. and K. Seo, "Security Architecture for the
Internet Protocol", RFC 4301, December 2005.
[RFC4303] Kent, S., "IP Encapsulating Security Payload (ESP)",
RFC 4303, December 2005.
[RFC5094] Devarapalli, V., Patel, A., and K. Leung, "Mobile IPv6
Vendor Specific Option", RFC 5094, December 2007.
[IPv4PMIPv6]
Wakikawa, R., Ed. and S. Gundavelli, "IPv4 Support for
Proxy Mobile IPv6",
draft-ietf-netlmm-pmip6-ipv4-support-17.txt,
Semptember 2009.
[GREKEY] Muhanna, A., Ed., "GRE Key Option for Proxy Mobile IPv6",
draft-ietf-netlmm-grekey-option-09.txt, May 2009.
10.2. Informative References
[RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman,
"Neighbor Discovery for IP version 6 (IPv6)", RFC 4861,
September 2007.
[RFC4988] Koodli, R. and C. Perkins, "Mobile IPv4 Fast Handovers",
RFC 4988, October 2007.
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Appendix A. Applicable Use Cases
A.1. PMIPv6 Handoff Indication
PMIPv6 [RFC5213] defines the Handoff Indicator Option and describes
the type of the handoff and the values to set to the option. This
document proposes one approach to determining the handoff type by the
NMAG when the handoff of the MN is executed.
According to [RFC5213], the following handoff types are defined:
0) Reserved
1) Attachment over a new interface
2) Handoff between two different interfaces of the mobile node
3) Handoff between mobile access gateways for the same interface
4) Handoff state unknown
5) Handoff state not changed (Re-registration)
Assuming that there is a valid MN Link-layer Identifier (MN LL-ID),
the following solution can be considered. When the NMAG receives the
MN LL-ID from the PMAG in the MN LL-ID option via the HI or HAck
message, the NMAG compares it with the new MN LL-ID that is obtained
from the MN in the N-AN. If these two MN LL-IDs are the same, the
handoff type falls into 3) and the Handoff Indicator value is set to
3. If these two MN LL-IDs are different, the handoff is likely to be
2) since the HI/HAck message exchange implies that this is a handoff
not a multi-homing, therefore the Handoff Indicator value can be set
to 2. If there is no HI/HAck exchange performed prior to the network
attachment of the MN in the N-AN, the NMAG may infer that this is a
multi-homing case and set the Handoff Indicator value to 1. In the
case of re-registration, the MAG, to which the MN is attached, can
determine if the handoff state is not changed, so the MAG can set the
HI value to 5 without any additional information. If none of them
can be assumed or there is no valid MN LL-ID available, the NMAG may
set the value to 4.
A.2. Local Routing
Section 6.10.3 in [RFC5213] describes that if EnableMAGLocalRouting
flag is set, when two mobile nodes are attached to one MAG, the
traffic between them may be locally routed. If one mobile node moves
from this MAG (PMAG) to another MAG (NMAG) and if the PMAG does not
detect the MN's detachment, it will continue to forward packets
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locally forever. This situation is more likely to happen in the
reactive fast handover with WLAN access, which does not have the
capability to detect the detachment of the MN in a timely manner.
PFMIPv6 can be applied to handle this case. When the MN attaches to
the NMAG, the NMAG sends the HI message to the PMAG with the 'F' flag
set, which makes the PMAG realize the detachment of the MN and
establish the inter-MAG tunnel. The PMAG immediately stops the local
routing and sends the packets for the MN to the NMAG via that tunnel,
which are then delivered to the MN on the new link.
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Appendix B. Change Log
Changes at -00
* Added separate sections for MH and ICMP.
* Clarified usage of HNP and IPv4-MN-HoA throughout the document.
* Added IANA Considerations.
* Added section on Other Considerations, including operation of
uplink packets when using link-layer addresses, multiple
interface usage and transmission of RA to withdraw HNP in the
event of failure of PMIP6 registration.
* Revised Security Considerations.
Changes from -00 to -01
* Removed ICMPv6-based message format.
* Clarified HI/HAck exchange in the predictive mode (step (e) in
Figure 2).
* Clarified information retrieval about the PMAG in the reactive
mode.
* Removed the extension to the GRE Key Option.
* Clarified the handoff type considerations in Appendix A.
* Home Network Prefix Option, Link-local Address Option and
Vendor-Specific Mobility Option are added.
Changes from -01 to -02
* Aligned HI/HAck message formats with
draft-ietf-mipshop-rfc5268bis-00.txt.
* Revised Section 8 removing the request for the type assignment
of HI/HAck Mobility Headers.
Changes from -02 to -03
* Updated HI/HAck message formats according to
draft-ietf-mipshop-rfc5268bis-01.txt.
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* Cleaned up Figure 2 and Figure 3.
* Moved PMIP domain boundary crossing situation in Section 4.1 to
Appendix A.3.
* Removed the alternative protocol operation with an unsolicited
HAck from Section 4.1.
* Modified Code values in the HAck message in order to avoid
collision with those in draft-ietf-mipshop-rfc5268bis-01.txt.
* Clarified the usage scenarios of Context Request Option.
* Modified the description of Code values in the HAck message.
* Changed the container for the IPv4-LMAA from IPv4 Address
option to the LMAA option.
* Made Confidentiality protection "SHOULD" for context transfer.
Changes from -03 to -04
* Added more explanations about MIPv6, FMIPv6 and PMIPv6 in
Abstract.
* Moved Figure 1 to Section 4.
* More clearly indicated the FMIPv6 messages that are not
applicable in the PMIPv6 context.
* Mandated the support of IP Sec on the PMAG and NMAG in order to
protect signaling and user packets and the context information.
* Added a new section for the inter-AR tunneling operation
(Section 4.2).
* Added descriptions about the encapsulation type in Sections 4.1
and 4.3.
* Added a description about buffering requirements on the MAG in
Section 4.1.
* Added a description about the timing of L2 and L3 connection
establishments in Section 4.1.
* Added a new section for PMIPv6-related fast handover issues
(Section 5) and a description about preferable behaviors of the
MN and MAG to reduce packet loss.
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* Added Acknowledgments section (Section 9).
* Added a new section for local routing in Appendix (A.2).
Changes from -04 to -05
* Fixed Figure 2 (step (i)).
* Defined the Mobile Network Interface Identifier (MN-IID)
mobility option in Section 6.2.4 (swapped with old Section
6.2.5), and added it to IANA considerations (Section 8).
* Changed from SHOULD to MUST regarding the inclusion of the
MN-ID, MN-HNP, MN-IID and the LMAA options in the HI message
(step (c) in Section 4.1).
* The optional behavior of the NMAG that allows it to send uplink
packets directly to the LMA before the PBU/PBA exchange was
removed from section 4.2 (as out of scope).
* In Section A.3, the description about the HA address assignment
from the NAR to the MN was removed (as out of scope).
Changes from -05 to -06
* Added 'P' flag in the HI and Hack messages to distinguish them
from those in FMIPv6.
* Made editorial corrections in Section 2 (Introduction), Section
3 (Terminology), Section 4 (Protocol Overview) and Section 4.2
(Inter-AR Tunneling Operation).
* Added a description on how forwarded packets should be handled
in the access network at step (f) in Section 4.1.
* Added all types of encapsulation methods that should be
supported in Section 4.1.
* Revised the Code values for the HI message in Section 6.1.1.
* Revised the Code values for the HAck message in Section 6.1.2
and added a description of its usage at step (d) of the
reactive handover mode in Section 4.1.
* Removed the definition of the IP Address Option in Section
6.2.3 and moved to Section 6.2.7, which currently refers to the
IPv4 Home Address Option defined by RFC5555. Revised the IANA
Consideration section accordingly.
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* Removed the Option-Code from the Mobile Node Identifier (MN
IID) Option.
* Removed Appendix A.3 (Handling of PMIPv6/MIPv6 switching).
Changes from -06 to -07
* Added explanations about defining and setting the 'P' flag for
the HI and Hack messages in Sections 4 and 4.1.
* Corrected the references for the encapsulation types in Section
4.1.
* Modified the Code values for the HI message in Section 6.1.1 to
avoid overlapping with those in
draft-ietf-mipshop-rfc5268bis-01.txt.
* Modified the reference for the IPv4 Address Option from RFC5555
to [IPv4PMIPv6] in Section 6.2.7.
Changes from -07 to -08
* Corrected the reference for the TLV-header UDP encapsulation in
Section 4.1.
* Updated the version number of the reference document
[IPv4PMIPv6] and the option name defined by that document in
Section 6.2.7.
Changes from -08 to -09
* Added a paragraph at the beginning of Section 4 describing the
assumption related to the lower layer signaling.
* Added a new section on the manageability considerations in
Section 5 describing the configurations on the network and the
mobile node assumed in this document.
* Modified the assumed configuration of the MAG regarding its
link-layer address in Section 5 (Section 5.2 in version -09).
* Specified the requested option to identify the target MN for
the inter-AR tunneling in Section 6.1.1.
* Specified the default context information in the Context
Request Option in Section 6.2.1.
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Changes from -09 to -10
* Revised the document based on the comments from TSV-DIR, SEC-
DIR, OPS-DIR and GEN-ART.
+ Split the abstract section in half for readability.
+ Added the definition of Localized Mobility Anchor (LMA) in
Section 3.
+ Added the purpose of this document at the beginning of
Section 4 to make the paragraph more complete.
+ Revised the third paragraph of the Security Consideration
section for more precise expression.
+ Moved the description about the requirement to set the 'P'
flag in HI/HAck to Sections 6.1.1 and 6.1.2. Also, noted
the 'P' flag setting below the message formats.
+ Described the both 'P' and 'F' flags as newly defined ones
in Section 4.
+ Clarified the usage of the Context Request Option if a
default set of context information is defined in Section
6.2.1 (changed from "not mandatory" to "not used").
+ Modified the identifier for the interface on the MN to the
MN's link-layer ID (MN LL-ID).
+ Corrected the local routing operation of the PMAG in
Appendix A.2.
* Revised the descriptions about the encapsulation mechanism for
the inter-MAG tunnel in Section 4.2 and other related parts for
clarification.
* Also listed the new flags and status codes for the HI/HAck
messages in the IANA Considerations section.
* Elaborated on the example use of the Context Request Option in
Section 6.2.1.
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Authors' Addresses
Hidetoshi Yokota
KDDI Lab
2-1-15 Ohara, Fujimino
Saitama, 356-8502
Japan
Email: yokota@kddilabs.jp
Kuntal Chowdhury
Starent Networks
30 International Place
Tewksbury, MA 01876
USA
Email: kchowdhury@starentnetworks.com
Rajeev Koodli
Starent Networks
30 International Place
Tewksbury, MA 01876
USA
Email: rkoodli@starentnetworks.com
Basavaraj Patil
Nokia
6000 Connection Drive
Irving, TX 75039
USA
Email: basavaraj.patil@nokia.com
Frank Xia
Huawei USA
1700 Alma Dr. Suite 500
Plano, TX 75075
USA
Email: xiayangsong@huawei.com
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