Network Working Group H. Yokota
Internet-Draft KDDI Lab
Intended status: Standards Track K. Chowdhury
Expires: January 15, 2009 R. Koodli
Starent Networks
B. Patil
Nokia
F. Xia
Huawei USA
July 14, 2008
Fast Handovers for PMIPv6
draft-yokota-mipshop-pfmipv6-03.txt
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Copyright Notice
Copyright (C) The IETF Trust (2008).
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Abstract
This document specifies the usage of FMIPv6 when Proxy Mobile IPv6 is
applied for the mobility management protocol. Necessary amendments
are shown for FMIPv6 to work under the condition that the mobile node
does not have IP mobility functionality and it is not involved with
either MIPv6 or FMIPv6 operations.
Table of Contents
1. Requirements notation . . . . . . . . . . . . . . . . . . . . 3
2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5
4. Proxy-based FMIPv6 Protocol Overview . . . . . . . . . . . . . 7
4.1. Protocol Operation . . . . . . . . . . . . . . . . . . . . 7
4.2. Handoff Type Considerations . . . . . . . . . . . . . . . 13
4.3. IPv4 Support Considerations . . . . . . . . . . . . . . . 14
5. Message Format . . . . . . . . . . . . . . . . . . . . . . . . 15
5.1. Handover Initiate (HI) . . . . . . . . . . . . . . . . . . 15
5.2. Handover Acknowledge (HAck) . . . . . . . . . . . . . . . 16
5.3. Context Request Option . . . . . . . . . . . . . . . . . . 18
5.4. Tunnel-ID Option . . . . . . . . . . . . . . . . . . . . . 19
5.5. Mobile Node Interface Identifier (MN IID) Option . . . . . 19
5.6. New option-code for the IP Address Option . . . . . . . . 20
5.7. IPv4 Address Option . . . . . . . . . . . . . . . . . . . 20
5.8. Vendor Specific Option . . . . . . . . . . . . . . . . . . 21
6. Mobility Header-based HI/HAck messages . . . . . . . . . . . . 23
6.1. Handover Initiate (HI) Mobility Header . . . . . . . . . . 23
6.2. Handover Acknowledge (HAck) Mobility Header . . . . . . . 23
7. IPv4 Transport Support . . . . . . . . . . . . . . . . . . . . 24
7.1. Handover Initiate (HI) . . . . . . . . . . . . . . . . . . 24
7.2. Handover Acknowledge (HAck) . . . . . . . . . . . . . . . 24
8. Security Considerations . . . . . . . . . . . . . . . . . . . 26
9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 27
9.1. Normative References . . . . . . . . . . . . . . . . . . . 27
9.2. Informative References . . . . . . . . . . . . . . . . . . 27
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 28
Intellectual Property and Copyright Statements . . . . . . . . . . 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 [1].
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2. Introduction
Proxy Mobile IPv6 [2] provides IP mobility to a mobile node that does
not have Mobile IPv6 [4] functionality. The proxy agent in the
network performs the signaling and does the mobility management on
behalf of the mobile node. Although the signaling between the mobile
node and the network can be saved, the basic performance for handover
such as handover latency is considered to be not different from that
of Mobile IPv6.
To improve handover latency due to Mobile IPv6 procedures, fast
handovers for MIPv6 is specified in FMIPv6[3]. By applying the
FMIPv6 solution to Proxy MIPv6 as well, it is expected that the
handover latency due to Proxy MIPv6 procedures will be improved as
much. However, Mobile IPv6 and Proxy MIPv6 are intrinsically
different in the sense that the mobile node is not involved with IP
mobility and hence does not directly handle the care-of address.
Hence, there are some issues in directly applying the original
specifications of FMIPv6 to Proxy MIPv6. This document identifies
those differences and specifies amendments to apply FMIPv6 solution
principles to Proxy MIPv6.
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3. Terminology
This document refers to [2][3][4] 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.
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 specify the MN and to help the PAR resolve
the NAR (e.g. the new access point or base station to which the
MN is moving to).
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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
To reduce the handover latency due to signaling between the MAGs
(Mobile Access Gateways) and the LMA (Local Mobility Anchor), FMIPv6
in this document specifies a bi-directional tunnel between the
Previous MAG (PMAG) and the New MAG (NMAG). To expedite sending the
Proxy Binding Update (PBU) by the NMAG, FMIPv6 protocol is also used
for context transfer, whereby the necessary information for sending
the PBU is 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 the MN is not directly involved with IP mobility, it is natural
to think that the MN is not directly involved with fast handover
procedures, either at least from the IP layer perspective.
Therefore, among the messages for fast handovers defined in [3],
those that are initiated by and targeted to the MN 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
FMIPv6 [3] specifies two types of fast handovers; the predictive fast
handover and the reactive fast handover. In the predictive fast
handover, the MN sends the FBU to the PAR before handover, which then
triggers to establish a bi-directional tunnel between the PAR and NAR
to transfer packets for the MN. On the other hand, in the reactive
fast handover, the FBU is sent by the MN to the NAR after it has
moved to the new network, which is then transferred to the PAR to
trigger to send the Handover Initiate (HI) towards the NAR. Based on
the above observations, the fast handover procedures for PMIPv6 need
to work without the involvement of the MN. Figure 2 illustrates the
predictive fast handover procedures for PMIPv6, where the bi-
directional tunnel establishment is initiated by the PAR.
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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-HoA,MN IID,LMA) |
| | | | | |
(d) | | | |<---HAck---| |
| | | | (MN ID) | |
| | | | | |
| | | | HI/HAck | |
(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 | |
(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. These IDs can be
Link-Layer Addresses (LLAs) or any other types of IDs. This
step is access technology specific. In some cases, the P-AN
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will figure out 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-HoA, the MN-IID and the
address of the LMA that is currently serving the MN.
(d) The NAR sends back the Hack to the PAR.
(e) The NAR requests the PAR to buffer or forward packets by setting
U or F flags in the HI message, respectively.
(f) If F flag is set in the HI at 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 detunneling, those packets may be
buffered at the NAR. If the connection between the N-AN and NAR
has already been established, those packet may reach the N-AN
(access technology specific).
(g) The MN hands over 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, yet
(access technology specific). This can be regarded as a
substitute for the UNA.
(i) The NAR starts to transfer 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 can be obtained in (c). Steps (l) and (m) are not
part of the fast handover procedure, but shown for reference.
(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.
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According to Section 4 of [3], 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, so the PAR transfers the packets
for the MN to the NAR instead of the NCoA. The NAR then simply
detunnels (decapsulates) those packets and delivers them to the MN.
If the NAR obtains the LLA (=MN ID) and MN-HoA by the HI, it can
create the NCE for the MN and deliver packets to it before the MN
performs the ND. 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 [3]. 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: MN-HoA
Outer source address: IP address of the PAR (PMAG)
Outer destination address: IP address of the NAR (NMAG)
In (i),
Source address: IP address of the CN
Destination address: MN-HoA
In (j),
- from the MN to the NMAG,
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Source address: MN-HoA
Destination address: IP address of the CN
- from the NMAG to the PMAG,
Inner source address: 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: 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 in 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
sends the HI to the PAR after the MN has moved to the new network.
Figure 3 illustrates the reactive fast handover procedures for
PMIPv6, where the bi-directional tunnel establishment is initiated by
the NAR.
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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) | (MN ID) | |
| | |(substitute for UNA and FBU)| |
| | | | | |
| | | | HI | |
(c) | | | |<---(MN ID) ---| |
| | | | | |
| | | | HAck | |
(d) | | | |---(MN ID, --->| |
| | | MN-HoA,MN IID,LMA) |
| | | | | |
(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 hands over from the P-AN to the N-AN.
(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. This can be regarded as a substitute for
the UNA and FBU.
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(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 back the HAck to the NAR. The HAck message MUST
include the 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 transferred from the PAR to the NAR over this tunnel.
After detunneling, 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. Handoff Type Considerations
PMIPv6 [2] 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.
According to [2], the following handoff types are defined:
0) Reserved
1) Attachment over a new interface
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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 Identification (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.
4.3. IPv4 Support Considerations
The motivation and usage scenarios of IPv4 protocol support by PMIPv6
are described in [6]. 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-MH-HoA to the NMAG, which is the inner destination
address of the downlink forwarded packets. To this end, a new option
called IPv4 Address Option is defined in this document. As for 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 Section 5.7.
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5. Message Format
This document extends the HI and HAck to work with PMIPv6 and further
defines new options and option-codes for the IP Address option to
convey context information.
5.1. Handover Initiate (HI)
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+---------------+---------------+-------------------------------+
| Type | Code | Checksum |
+---------------+-+-+-+-+-------+-------------------------------+
| Subtype |S|U|P|F|Resv'd | Identifier |
+---------------+-+-+-+-+-------+-------------------------------+
| Options ...
+-------------------------
IP Fields:
Source Address
The IP address of PAR or NAR
Destination Address
The IP address of the peer AR
All the other fields follow [3].
ICMP Fields:
Code If P flag is not set, the Code value follows [3]. If P
flag is set but F flag is not set, the Code MUST be set to
zero. If both P flag and F flag are set, the Code value
has the following meaning:
0, 1: See [3].
2: Request forwarding
3: Indicate the completion of forwarding
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S flag not used when P flag is set and MUST be set to zero.
U flag Buffer flag. Same as [3].
P flag Proxy flag. When set, PMIPv6 instead of MIPv6 is assumed
for the mobility management protocol. All the involved
nodes MUST perform based on this document for fast handover
procedures.
F flag Forwarding flag. Used to request to forward the packets
for the MN.
All the other fields follow [3].
Valid options:
MN ID This identifier can be the link-layer address of the MN or
any other type of information that can uniquely identify
the MN. If the link-layer address is used as the MN ID,
the Link-Layer Address (LLA) option defined in [3] MUST be
used.
MN-HoA This information is stored in the IP Address option.
MN-IID This information is stored in the MN Interface Identifier
option.
Context Request Option Context Request Option This option is used to
request context information typically by the NAR to the PAR
in the NAR-initiated fast handover.
5.2. Handover Acknowledge (HAck)
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+---------------+---------------+--------------------------------+
| Type | Code | Checksum |
+---------------+-+-------------+--------------------------------+
| Subtype |P| Reserved | Identifier |
+---------------+-+-------------+--------------------------------+
| Options ...
+------------------------
IP Fields:
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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.
All the other fields follow [3].
ICMP Fields:
Code:
0: Handover Accepted
5: Context Transferred successfully, more context
available
6: Context Transferred successfully, no more
context available
128: Handover Not Accepted
129: Administratively prohibited
130: Insufficient resources
131: No context available
132: Forwarding Not Available
P flag Proxy flag. When set, PMIPv6 instead of MIPv6 is assumed
for the mobility management protocol. All the involved
nodes MUST perform based on this document for fast handover
procedures.
Valid options:
MN ID Copied from the corresponding HI message.
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MN-HoA Stored in the IP Address option so that the NAR can use
this address for the PBU.
MN-IID This information is stored in the MN Interface Identifier
option.
LMA Stored in the IP Address option so that the NAR can use
this address for the PBU.
Requested option(s) All the other context information requested by
the Context Request Option in the HI message.
5.3. 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
+---------------+---------------+---------------+---------------+
| Type | Length | Option-Code | Reserved |
+---------------------------------------------------------------+
| Reserved |
+---------------+---------------+-------------------------------+
| Req-type-1 | Req-option-1 | Padding |
+---------------------------------------------------------------+
| Padding |
+---------------------------------------------------------------+
| ... |
+---------------+---------------+-------------------------------+
| Req-type-N | Req-option-N | Vendor/Org-ID |
+-------------------------------+-------------------------------+
| Vendor/Org-ID | VS-Type |
+---------------------------------------------------------------+
| ... |
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.
Type TBD
Length Number of requested context(s)+1.
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Option-Code 0
Req-type-n The Type value for the requested option.
Req-option-n The Option-Code for the requested option.
Padding 6 octets of padding are added if the requested type is
not the Vendor-Specific Option. MUST be set to zero.
Vendor/Org-ID When the Vendor Specific Option is requested, the 3rd
to 6th octets are used for the Vendor/Org-ID defined
in Section 5.8.
VS-Type When the Vendor Specific Option is requested, the 7th
to 8th octets are used for the VS-Type defined in
Section 5.8.
5.4. Tunnel-ID Option
This option is used to transfer additional information that
associates the MN with the tunnel used by the MN. The exact format
of the Tunnel-ID is outside the scope of this document.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+---------------+---------------+---------------+---------------+
| Type | Length | Option-Code | TID-Length |
+---------------------------------------------------------------+
| Tunnel-ID ...
+------------------------------
Type TBD
Length The size of this option is in 8 octets including the
Type, Length and Option-Code.
Option-Code 0
TID-Length The length of the Tunnel-ID in octets
Tunnel-ID The Tunnel-ID value.
5.5. 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 the interface identifier
follows the Mobile Node Interface Identifier Option defined in [2].
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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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | Option-Code | MN IID-Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ Interface Identifier +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type TBD
Length The size of this option is in 8 octets including the
Type, Length and Option-Code.
Option-Code 0
MN IID-Length The length of the MN IID in octets
Interface Identifier
The Interface Identifier value of the MN that is used
in the P-AN.
5.6. New option-code for the IP Address Option
To convey the MN-HoA and LMA in the HI or HAck message, new Option-
Codes for the IP Address Option[3] are defined:
Option-Code
4 MN-HoA
5 LMA
5.7. IPv4 Address Option
As described in Section 4.3, 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.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | Option-Code | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv4 Address |
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type TBD
Length 1
Option-Code
0 IPv4-MN-HoA
1 IPv4-LMAA
IPv4 Address IPv4 address specified in Option-Code
5.8. Vendor Specific Option
This option is to send other information than defined in this
document. Many of the context information can be vendor specific
(access technology specific). This option is used for such
information.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+---------------+---------------+---------------+---------------+
| Type | Length | Option-Code | Reserved |
+---------------------------------------------------------------+
| Vendor/Org-ID |
+-------------------------------+-------------------------------+
| VS-Type | VS-Length |
+---------------------------------------------------------------+
| VS-Value ...
+------------------------------
Type TBD
Length The size of this option is in 8 octets including the
Type, Length and Option-Code.
Option-Code 0
Vendor/Org-ID The SMI Network Management Private Enterprise Code of
the Vendor/Organization as defined by IANA.
VS-Type The type of the Vendor-Specific information carried in
this option. The type value is defined by the vendor
or organization specified by Vendor/Org-ID.
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VS-Length The length of the Vendor-Specific information carried
in this option.
VS-Value The value of the Vendor-Specific information carried
in this option.
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6. Mobility Header-based HI/HAck messages
If ICMPv6 is not allowed between the PAR and NAR for security reason
(e.g. blocked by the firewall), the HI and HAck messages MAY be
exchanged in the form of the Mobility Header [4]. Which type of HI/
HAck message is used MUST be preconfigured both in the PAR and NAR.
6.1. Handover Initiate (HI) Mobility Header
The MH Type value of the HI Mobility Header is TBD1. 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
+---------------+---------------+
| Type | Code |
+---------------+-+-+-+-+-------+---------------+---------------+
| Subtype |S|U|P|F| Resv'd| Identifier |
+---------------+-+-+-+-+-------+-------------------------------+
| Options ...
+------------------------
The usages of all the above fields are the same as those in the
original HI message.
6.2. Handover Acknowledge (HAck) Mobility Header
The MH Type value of the HAck Mobility Header is TBD2. 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
+---------------+---------------+
| Type | Code |
+---------------+-+-------------+---------------+---------------+
| Subtype |P| Reserved | Identifier |
+---------------+-+-------------+-------------------------------+
| Options ...
+------------------------
The usages of all the above fields are the same as those in the
original HAck message.
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7. IPv4 Transport Support
If the connection between the PAR and NAR only supports IPv4, then
the HI/HAck messages MAY be transferred by ICMPv4. Which version of
ICMP is used MUST be preconfigured in both the PAR and NAR.
7.1. Handover Initiate (HI)
The message format is the same as in Section 5.1.
IP fields:
Source address: the IPv4 address of PAR or NAR
Destination address: the IPv4 address of the peer AR
Time-to-Live: At least 1. See Section 5.5 in [5]
ICMP fields:
Same as in Section 5.1 except for the following:
Type: 41. See Section 5.5 in [5]
Checksum: See Section 5.5 in [5]
Subtype: assigned by IANA
7.2. Handover Acknowledge (HAck)
The message format is the same as in Section 5.2.
IP fields:
Source address: See Section 5.2
Destination address: See Section 5.2
Time-to-Live: At least 1. See Section 5.6 in [5]
ICMP fields:
Same as in Section 5.2 except for the following:
Type: 41. See Section 5.6 in [5]
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Checksum: See Section 5.6 in [5]
Subtype: assigned by IANA
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8. Security Considerations
Security issues for this document follow those for PMIPv6[2] and
FMIPv6[3]. In this document, it is assumed that the PAR (PMAG), NAR
(NMAG) and LMA have trust relationship with each other and the
connection between any pair is securely protected.
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9. References
9.1. Normative References
[1] Bradner, S., "Key words for use in RFCs to Indicate Requirement
Levels", BCP 14, RFC 2119, March 1997.
[2] Gundave, S., Ed., "Proxy Mobile IPv6",
draft-ietf-netlmm-proxymip6-18.txt, May 2008.
[3] Koodli, R., Ed., "Mobile IPv6 Fast Handovers", RFC 5268,
June 2008.
[4] Johnson, D., "Mobility Support in IPv6", RFC 3775, June 2004.
[5] Koodli, R. and C. Perkins, "Mobile IPv4 Fast Handovers",
RFC 4988, October 2007.
9.2. Informative References
[6] Wakikawa, R., Ed. and S. Gundavelli, "IPv4 Support for Proxy
Mobile IPv6", draft-ietf-netlmm-pmip6-ipv4-support-02.txt,
November 2007.
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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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