Network Working Group H. Yokota
Internet-Draft KDDI Lab
Intended status: Standards Track K. Chowdhury
Expires: August 22, 2009 R. Koodli
Starent Networks
B. Patil
Nokia
F. Xia
Huawei USA
February 18, 2009
Fast Handovers for Proxy Mobile IPv6
draft-ietf-mipshop-pfmipv6-02.txt
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Copyright Notice
Copyright (c) 2009 IETF Trust and the persons identified as the
document authors. All rights reserved.
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to this document.
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Abstract
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.
Table of Contents
1. Requirements notation . . . . . . . . . . . . . . . . . . . . 4
2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 5
3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 6
4. Proxy-based FMIPv6 Protocol Overview . . . . . . . . . . . . . 8
4.1. Protocol Operation . . . . . . . . . . . . . . . . . . . . 8
4.2. IPv4 Support Considerations . . . . . . . . . . . . . . . 14
5. Other Considerations . . . . . . . . . . . . . . . . . . . . . 16
6. Message Formats . . . . . . . . . . . . . . . . . . . . . . . 17
6.1. Mobility Header . . . . . . . . . . . . . . . . . . . . . 17
6.1.1. Handover Initiate (HI) . . . . . . . . . . . . . . . . 17
6.1.2. Handover Acknowledge (HAck) . . . . . . . . . . . . . 18
6.2. Mobility Options . . . . . . . . . . . . . . . . . . . . . 20
6.2.1. Context Request Option . . . . . . . . . . . . . . . . 20
6.2.2. Local Mobility Anchor Address (LMAA) Option . . . . . 21
6.2.3. IPv4 Address Option . . . . . . . . . . . . . . . . . 22
6.2.4. Home Network Prefix Option . . . . . . . . . . . . . . 22
6.2.5. Mobile Node Interface Identifier (MN IID) Option . . . 23
6.2.6. Link-local Address Option . . . . . . . . . . . . . . 23
6.2.7. GRE Key Option . . . . . . . . . . . . . . . . . . . . 23
6.2.8. Vendor-Specific Mobility Option . . . . . . . . . . . 23
7. Security Considerations . . . . . . . . . . . . . . . . . . . 24
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 25
9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 26
9.1. Normative References . . . . . . . . . . . . . . . . . . . 26
9.2. Informative References . . . . . . . . . . . . . . . . . . 26
Appendix A. Handoff Type Considerations . . . . . . . . . . . . . 27
Appendix B. Change Log . . . . . . . . . . . . . . . . . . . . . 28
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 29
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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 possess Mobile IPv6 [RFC3775] 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 is specified in [RFC5268bis]. This
document applies the same Fast Handovers protocol for Proxy Mobile
IPv6 (PFMIPv6), in order to provide handover delay, packet loss and
transfer of network-resident contexts. This document also specifies
necessary extensions to FMIPv6 for operation in a PMIPv6 domain.
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3. Terminology
This document refers to [RFC5213][RFC5268bis][RFC3775] for
terminology. The following terms and abbreviations are additionally
used in this document. The reference network is illustrated in
Figure 1.
Previous Access Network (P-AN):
The access network to which the MN is attached before handover.
New Access Network (N-AN):
The access network to which the 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 (AR) are collocated.
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 collocated.
HO-Initiate:
A generic signaling that indicates the handover of the MN sent
from the P-AN to the PMAG. 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 PAR resolve
the NAR (e.g., the new access point or base station to which the
MN is moving).
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+----------+
| LMA |
| |
+----------+
/ \
/ \
/ \
+........../..+ +..\..........+
. +-------+-+ .______. +-+-------+ .
. | PAR |()_______)| NAR | .
. | (PMAG) | . . | (NMAG) | .
. +----+----+ . . +----+----+ .
. | . . | .
. ___|___ . . ___|___ .
. / \ . . / \ .
. ( P-AN ) . . ( N-AN ) .
. \_______/ . . \_______/ .
. | . . | .
. +----+ . . +----+ .
. | MN | ----------> | MN | .
. +----+ . . +----+ .
+.............+ +.............+
Figure 1: Reference network for fast handover
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4. Proxy-based FMIPv6 Protocol Overview
In order to improve the performance during handover (when operations
such as attachment to a new network and signaling between mobility
agents are involved), the PFMIPv6 protocol in this document specifies
a bi-directional tunnel between the Previous MAG (PMAG) and the New
MAG (NMAG). In order to enable the NMAG to send the Proxy Binding
Update (PBU), the Handover Initiate (HI) and Handover Acknowledge
(HAck) messages in [RFC5268bis] are used for context transfer, in
which parameters such as MN's NAI, Home Network Prefix (HNP), IPv4
Home Address, are transferred from the PMAG.
In this document, the Previous Access Router (PAR) and New Access
Router (NAR) are interchangeable with the PMAG and NMAG,
respectively.
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
[RFC5268bis] are not used when PMIPv6 is in use. Such messages are
the Router Solicitation for Proxy Advertisement (RtSolPr), Proxy
Router Advertisement (PrRtAdv), Fast Binding Update (FBU), Fast
Binding Acknowledgment (FBack) and Unsolicited Neighbor Advertisement
(UNA).
4.1. Protocol Operation
There are two modes of operation in FMIPv6 [RFC5268bis]. In the
predictive mode of fast handover, a bi-directional tunnel between the
PAR and NAR is established prior to the MN's attachment to the NAR.
In the reactive mode, this tunnel establishment takes place after the
MN attaches to the NAR. Since the MN is not involved in IP mobility
signaling in PMIPv6, the sequence of events illustrating the
predictive fast handover are shown in Figure 2.
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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)-->| | |
| | | | | |
| | | | HI | |
(c) | | | |-(MN ID, ->| |
| | | | MN IID, LMAA) |
| | | | | |
(d) | | | |<---HAck---| |
| | | | (MN ID) | |
| | | | | |
| | | |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====================>|# |
| | | #|<==========|# |
| | | #|===================>|
| | | |HI/HAck(optional) |
(k) | | | |<- - - - ->| |
/ | | | | | | \
|(l) | | | | |--PBU-->| |
| | | | | | | |
|(m) | | | | |<--PBA--| |
\ | | | | | | /
Figure 2: Predictive fast handover for PMIPv6 (PAR initiated)
The detailed descriptions are as follows:
(a) The MN detects that a handover is imminent and reports the
identifications of itself (MN ID) and the access point (New AP
ID) 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
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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 PAR (PMAG).
(c) The PAR sends the HI to the NAR. The HI message MUST include
the MN ID and SHOULD include the MN-HNP, the MN-IID and the
address of the LMA that is currently serving the MN.
(d) The NAR sends the HAck back to the PAR.
(e) The NAR may optionally request the PAR to buffer or forward
packets by setting U or F flags in the HI message, respectively.
This step may be combined with steps (c) and (d).
(f) If the F flag is set in the previous step, a bi-directional
tunnel is established between the PAR and NAR and packets
destined for the MN are forwarded from the PAR to the NAR over
this tunnel. After decapsulation, those packets may be buffered
at the NAR. If the connection between the N-AN and NAR has
already been established, those packet may be forwarded towards
the N-AN; this is access technology specific.
(g) The MN undergoes handover to the New Access Network (N-AN).
(h) The MN establishes a connection (e.g., radio channel) with the
N-AN, which in turn triggers the establishment of the connection
between the N-AN and NAR if it has not been established already
(access technology specific). This can be regarded as a
substitute for the UNA.
(i) The NAR starts to forward packets destined for the MN via the
N-AN.
(j) The uplink packets from the MN are sent to the NAR via the N-AN
and the NAR forwards them to the PAR. The PAR then sends the
packets to the LMA that is currently serving the MN.
(k) The PAR MAY send the HI message to indicate that the packet
forwarding is completed.
(l) The NAR (NMAG) sends the Proxy Binding Update (PBU) to the LMA,
whose address is provided in (c). Steps (l) and (m) are not
part of the fast handover procedure, but shown for reference.
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(m) The LMA sends back the Proxy Binding Acknowledgment (PBA) to the
NAR (NMAG). From this time on, the packets to/from the MN go
through the NAR instead of the PAR.
According to Section 4 of [RFC5268bis], the PAR establishes a binding
between the PCoA and NCoA to forward packets for the MN to the NAR,
and the NAR creates a proxy NCE 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. Hence the PAR forwards
MN's packets to the NAR instead of the NCoA. FMIPv4 [RFC4988]
specifies forwarding when the MN uses HoA 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 PAR forwards MN's packets to the NAR
instead of the NCoA. The NAR then simply decapsulates those packets
and delivers them to the MN. Since the NAR obtains the LLA (MN IID)
and MN-HNP by the HI, it can create the NCE 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 NAR
forwards the packets to the PAR through the tunnel established in
step (f). The PAR 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 the Option Code values for it
in the HI message are defined to request forwarding. To request
buffering, 'U' flag has already been defined in [RFC5268bis]. If the
PAR receives the HI message with F flag set and the Option Code value
being 2, it starts forwarding packets for the MN. The HI message
with U flag set may be sent earlier if the timing of buffering is
different from that of forwarding. If packet forwarding is
completed, the PAR MAY send the HI message with F flag set and the
Option Code value being 3. 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 (f),
Inner source address: IP address of the CN
Inner destination address: HNP or IPv4-MN-HoA
Outer source address: IP address of the PAR (PMAG)
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Outer destination address: IP address of the NAR (NMAG)
In (i),
Source address: IP address of the CN
Destination address: HNP or IPv4-MN-HoA
In (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 NAR (NMAG)
Outer destination address: IP address of the PAR (PMAG)
- from the PMAG to the LMA,
Inner source address: HNP or IPv4-MN-HoA
Inner destination address: IP address of the CN
Outer source address: IP address of the PAR (PMAG)
Outer destination address: IP address of the LMA
If the network that the MN has moved to does not support PMIPv6 but
only MIPv6 (i.e. there exists a MIPv6 HA) and the MN supports MIPv6
at the same time, the MN and HA can exchange BU/BA instead of PBU/PBA
in steps (j) and (k). If this is the case, the LMA and HA will most
likely be collocated and the LMA (HA) address should be maintained in
the new network for communication continuity. Since the LMA (HA)
address is transferred to the NAR in step (c), the MN can retrieve it
at or after step (g) by e.g. the authentication or DHCP procedure
(not shown in the figure).
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 NAR
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sends the HI to the PAR after the MN has moved to the new link. The
NAR then needs to obtain the information of the PAR 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 NAR.
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)| |
| | | | | |
| | | | HI | |
(c) | | | |<---(MN ID) ---| |
| | | | | |
| | | | HAck | |
(d) | | | |---(MN ID, --->| |
| | | | MN IID, LMAA) | |
| | | | | |
(e) | | | |===DL data====>|# |
|<====================DL data====================|# |
| | | | | |
(f) |=====================UL data===================>|# |
| | | #=|<==============|# |
| | | #=|=======================>|
(g) | | | |<---HI/HAck--->| |
| | | | | |
/ | | | | | | \
|(h) | | | | |--PBU-->| |
| | | | | | | |
|(i) | | | | |<--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.
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(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 NAR. The MN ID is transferred to the NAR 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.
(c) The NAR sends the HI to the PAR. The HI message MUST include
the MN ID. The Context Request Option MAY be included to
request additional context information on the MN to the PAR.
(d) The PAR sends the HAck back to the NAR. The HAck message MUST
include the HNP and/or IPv4-MN-HoA that is corresponding to the
MN ID in the HI message and SHOULD include the MN-IID and the
LMA address that is currently serving the MN. The context
information requested by the NAR MUST be included.
(e) If F flag in the HI is set, a bi-directional tunnel is
established between the PAR and NAR and packets destined for the
MN are forwarded from the PAR to the NAR 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 NAR via the N-AN
and the NAR forwards them to the PAR. The PAR then sends the
packets to the LMA that is currently serving the MN.
(g) The PAR MAY send the HI message to indicate that the packet
forwarding is completed.
Steps (h)-(i) are the same as (l)-(m) in the predictive fast handover
procedures.
In step (c), The IP address of the PAR needs to be resolved by the
NAR to send the HI to the PAR. This information may come from the
N-AN or some database that the NAR can access.
Also, in step (c), the NAR could send an unsolicited HAck message to
the PAR, which then triggers the HI message from the PAR. By doing
so, the directions of HI/HAck messages are aligned with the
predictive (PAR-initiated) fast handover. Further study is needed if
this call flow is more appropriate than the current one.
4.2. 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:
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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. In order to
support IPv4-MN-HoA, a new option called IPv4 Address Option is
defined in this document. 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. The above IPv4 Address Option is defined so as to
be able to convey IPv4-LMAA. The details of this option are
described in [IPv4PMIPv6].
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5. Other Considerations
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 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 which may be beneficial. For
instance, the NMAG could send a Router Advertisement (RA) with the
HNP option to the MN as soon as it's 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.
However, if 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 that 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. If the new router's interface is configured to
respond to queries sent to link-layer addresses than its own (e.g.,
set to promiscuous mode), then it can respond to the NUD probe,
providing its link-layer address in the solicited Neighbor
Advertisement. While the MN is performing NUD, it can continue to
send uplink packets.
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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 [RFC5268bis].
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|F| Reserved | Code |
+-+-+-+-----------------------------------------+---------------+
| |
. .
. Mobility options .
. .
| |
+---------------------------------------------------------------+
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 [RFC5268bis].
S flag Must be set to zero (defined in [RFC5268bis]).
U flag Buffer flag. Same as [RFC5268bis].
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F flag Forwarding flag. Used to request to forward the packets
for the MN.
Reserved These fields are unused. They MUST be initialized to
zero by the sender and MUST be ignored by the receiver.
Code If F flag is not set, the Code MUST be set to zero.
Otherwise, the Code value has the following meaning:
0: Reserved
1: Forwarding is not requested
2: Request forwarding
3: Indicate the completion of forwarding
Mobility options:
This field contains one or more mobility options, whose encoding and
formats are defined in [RFC3775]. At least one mobility option MUST
uniquely identify the target MN (e.g., the Mobile Node Identifier
Option defined in RFC4283) and the transferred context MUST be for
one MN per message. In addition, the NAR can request necessary
mobility options by the Context Request Option defined in this
document.
Context Request Option
This option is used to request context information typically
by the NAR to the PAR in the NAR-initiated fast handover.
6.1.2. Handover Acknowledge (HAck)
This section defines extensions to the HAck message in [RFC5268bis].
The format of the Message Data field in the Mobility Header is as
follows:
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0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+---------------+---------------+
| Sequence # |
+-------------------------------+---------------+---------------+
| Reserved | Code |
+-----------------------------------------------+---------------+
| |
. .
. Mobility options .
. .
| |
+---------------------------------------------------------------+
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:
Sequence # Same as [RFC5268bis].
Reserved These fields are unused. They MUST be initialized to
zero by the sender and MUST be ignored by the receiver.
Code:
0: Handover Accepted
5: Context Transferred successfully, more context
available
6: Context Transferred successfully, no more
context available
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128: Handover Not Accepted
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 MUST be present in
the HAck message. Otherwise, the Code value MUST be set to
131.
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.
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 |
+---------------------------------------------------------------+
| ... |
Context Request Option is typically used for the reactive (NAR-
initiated) fast handover mode to retrieve the context information
from the PAR. When this option is included in the HI message, the
requested option(s) MUST be included in the HAck message.
Option-Type TBD1
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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.
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 context is the Vendor-
Specific Option defined in Section 6.2.8, the requested option format
looks as follows:
| ... |
+---------------+---------------+-------------------------------+
| Req-type-N=19 | Req-length-N=6| Vendor-ID |
+-------------------------------+-------------------------------+
| Vendor-ID | Sub-Type |
+---------------------------------------------------------------+
| ... |
6.2.2. Local Mobility Anchor Address (LMAA) Option
This option is used to transfer the Local Mobility Anchor Address
(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 | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ +
| |
+ Local Mobility Anchor Address +
| |
+ +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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Option-Type TBD2
Option-Length 18
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
The LMA address, with which the MN is currently
registered.
6.2.3. IPv4 Address Option
As described in Section 4.2, if the MN is IPv4-only mode or dual-
stack mode, the MN requires IPv4 home address (IPv4-MN-HoA). The
IPv4 address of the LMA (IPv4-LMAA) is also needed to send PMIP
signaling messages when the ARs and LMA are in an IPv4 transport
network. This option has alignment requirement of 4n.
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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv4 Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Option-Type TBD3
Option-Length 6
Option-Code
0 IPv4-MN-HoA
1 IPv4-LMAA
Reserved This field is unused. It MUST be initialized to zero
by the sender and MUST be ignored by the receiver.
IPv4 Address IPv4 address specified in Option-Code
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 format of this option follows
the Home Network Prefix Option defined in [RFC5213].
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6.2.5. 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. The format of this option follows the
Mobile Node Interface Identifier Option defined in [RFC5213].
6.2.6. Link-local Address Option
This option is used to transfer the link-local address of the PAR
(PMAG). The format of this option follows the Link-local Address
Option defined in [RFC5213].
6.2.7. 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 PAR and NAR. 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.
6.2.8. Vendor-Specific Mobility Option
This option is used to transfer any other information defined in this
document. The format of this option follows the Vendor-Specific
Mobility Option defined in [RFC5094]. The exact values in the Vendor
ID, Sub-Type and Data fields are outside the scope of this document.
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7. Security Considerations
Security issues for this document follow those for PMIPv6[RFC5213]
and FMIPv6[RFC5268bis]. In PMIPv6, MAG and LMA are assumed to share
security association. In FMIPv6, the access routers (i.e., the PMAG
and NMAG in this document) are assumed to share security association.
No new security risks are identified. Support for integrity
protection using IPsec is required, but support for confidentiality
is not necessary.
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8. IANA Considerations
This document defines two new mobility options, which are described
in Section 6.2. The Type value for these options are assigned from
the same numbering space as allocated for the other mobility options,
as defined in [RFC3775].
Mobility Options
Value Description Reference
----- ------------------------------------- -------------
TBD1 Context Request Option Section 6.2.1
TBD2 Local Nobility Anchor Address Option Section 6.2.2
TBD3 IPv4 Address Option Section 6.2.3
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9. References
9.1. 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.
[RFC5268bis]
Koodli, R., Ed., "Mobile IPv6 Fast Handovers",
draft-ietf-mipshop-rfc5268bis-00.txt, February 2009.
[RFC3775] Johnson, D., "Mobility Support in IPv6", RFC 3775,
June 2004.
[RFC4988] Koodli, R. and C. Perkins, "Mobile IPv4 Fast Handovers",
RFC 4988, October 2007.
[RFC5094] Devarapalli, V., Patel, A., and K. Leung, "Mobile IPv6
Vendor Specific Option", RFC 5094, December 2007.
9.2. Informative References
[RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman,
"Neighbor Discovery for IP version 6 (IPv6)", RFC 4861,
September 2007.
[IPv4PMIPv6]
Wakikawa, R., Ed. and S. Gundavelli, "IPv4 Support for
Proxy Mobile IPv6",
draft-ietf-netlmm-pmip6-ipv4-support-09.txt,
January 2009.
[GREKEY] Muhanna, A., Ed., "GRE Key Option for Proxy Mobile IPv6",
draft-ietf-netlmm-grekey-option-03.txt, January 2009.
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Appendix A. Handoff Type Considerations
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)
By using the MN Interface Identifier (MN IID) option, which is
defined in this document, the following solution can be considered.
When the NMAG receives the MN IID used in the P-AN from the PMAG via
the HI or HAck messages, the NMAG compares it with the new MN IID
that is obtained from the MN in the N-AN. If these two MN IIDs are
the same, the handover type falls into 3) and the Handoff Indicator
value is set to 3. If these two MN IIDs are different, the handover
is likely to be 2) since the HI/HAck message exchange implies that
this is a handover 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 new
network, 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, the NMAG
may set the value to 4.
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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 [RFC5268bis].
* Revised Section 8 removing the request for the type assignment
of HI/HAck Mobility Headers.
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Authors' Addresses
Hidetoshi Yokota
KDDI Lab
2-1-15 Ohara, Fujimino
Saitama, 356-8502
JP
Email: yokota@kddilabs.jp
Kuntal Chowdhury
Starent Networks
30 International Place
Tewksbury, MA 01876
US
Email: kchowdhury@starentnetworks.com
Rajeev Koodli
Starent Networks
30 International Place
Tewksbury, MA 01876
US
Email: rkoodli@starentnetworks.com
Basavaraj Patil
Nokia
6000 Connection Drive
Irving, TX 75039
US
Email: basavaraj.patil@nokia.com
Frank Xia
Huawei USA
1700 Alma Dr. Suite 500
Plano, TX 75075
US
Email: xiayangsong@huawei.com
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