RFC 5213
Proxy Mobile IPv6
7. Mobile Node Operation
This non-normative section explains the mobile node's operation in a Proxy Mobile IPv6 domain.7.1. Moving into a Proxy Mobile IPv6 Domain
When a mobile node enters a Proxy Mobile IPv6 domain and attaches to an access network, the mobile access gateway on the access link detects the attachment of the mobile node and completes the binding
registration with the mobile node's local mobility anchor. If the binding update operation is successfully performed, the mobile access gateway will create the required state and set up the forwarding for the mobile node's data traffic. When a mobile node attaches to the access link, it will typically send a Router Solicitation message [RFC4861]. The mobile access gateway on the access link will respond to the Router Solicitation message with a Router Advertisement message. The Router Advertisement message will carry the mobile node's home network prefix(es), default-router address, and other address configuration parameters. If the mobile access gateway on the access link receives a Router Solicitation message from the mobile node, before it completes the signaling with the mobile node's local mobility anchor, the mobile access gateway may not know the mobile node's home network prefix(es) and may not be able to emulate the mobile node's home link on the access link. In such a scenario, the mobile node may notice a delay before it receives a Router Advertisement message. This will also affect mobile nodes that would be capable of handling their own mobility, or mobile nodes that do not need to maintain the same IP address through movements. If the received Router Advertisement message has the Managed Address Configuration flag set, the mobile node, as it would normally do, will send a DHCP Request [RFC3315]. The DHCP relay service enabled on that access link will ensure the mobile node can obtain one or more addresses from its home network prefix(es). If the received Router Advertisement message does not have the Managed Address Configuration flag set and if the mobile node is allowed to use autoconfigured address(es), the mobile node will be able to obtain IPv6 address(es) from each of its home network prefixes using any of the standard IPv6 address configuration mechanisms permitted for that mode. If the mobile node is IPv4-enabled and if the network permits, it will be able to obtain the IPv4 address configuration, as specified in the companion document [IPV4-PMIP6]. Once the address configuration is complete, the mobile node can continue to use this address configuration as long as it is attached to the network that is in the scope of that Proxy Mobile IPv6 domain.
7.2. Roaming in the Proxy Mobile IPv6 Domain
After obtaining the address configuration in the Proxy Mobile IPv6 domain, as the mobile node moves and changes its point of attachment from one mobile access gateway to the other, it can still continue to use the same address configuration. As long as the attached access link is in the scope of that Proxy Mobile IPv6 domain, the mobile node will always detect the same router advertising itself as a default-router and advertising the mobile node's home network prefix(es) on each connected link. If the mobile node has address configuration that it obtained using DHCP, it will be able to retain the address configuration and extend the lease lifetime.8. Message Formats
This section defines extensions to the Mobile IPv6 [RFC3775] protocol messages.8.1. Proxy Binding Update Message
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 # | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |A|H|L|K|M|R|P| Reserved | Lifetime | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | . . . Mobility options . . . | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ A Binding Update message that is sent by a mobile access gateway to a local mobility anchor is referred to as the "Proxy Binding Update" message. A new flag (P) is included in the Binding Update message. The rest of the Binding Update message format remains the same as defined in [RFC3775] and with the additional (R) and (M) flags, as specified in [RFC3963] and [RFC4140], respectively.
Proxy Registration Flag (P)
A new flag (P) is included in the Binding Update message to
indicate to the local mobility anchor that the Binding Update
message is a proxy registration. The flag MUST be set to the
value of 1 for proxy registrations and MUST be set to 0 for direct
registrations sent by a mobile node.
Mobility Options
Variable-length field of such length that the complete Mobility
Header is an integer multiple of 8 octets long. This field
contains zero or more TLV-encoded mobility options. The encoding
and format of defined options are described in Section 6.2 of
[RFC3775]. The local mobility anchor MUST ignore and skip any
options that it does not understand.
As per this specification, the following mobility options are
valid in a Proxy Binding Update message. These options can be
present in the message in any order. There can be one or more
instances of the Home Network Prefix options present in the
message. However, there cannot be more than one instance of any
of the following options.
Mobile Node Identifier option
Home Network Prefix option
Handoff Indicator option
Access Technology Type option
Timestamp option
Mobile Node Link-layer Identifier option
Link-local Address option
Additionally, there can be one or more instances of the Vendor-
Specific Mobility option [RFC5094].
For descriptions of other fields present in this message, refer to
Section 6.1.7 of [RFC3775].
8.2. Proxy Binding Acknowledgement Message
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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Status |K|R|P|Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Sequence # | Lifetime | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | . . . Mobility options . . . | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ A Binding Acknowledgement message that is sent by a local mobility anchor to a mobile access gateway is referred to as the "Proxy Binding Acknowledgement" message. A new flag (P) is included in the Binding Acknowledgement message. The rest of the Binding Acknowledgement message format remains the same as defined in [RFC3775] and with the additional (R) flag as specified in [RFC3963]. Proxy Registration Flag (P) A new flag (P) is included in the Binding Acknowledgement message to indicate that the local mobility anchor that processed the corresponding Proxy Binding Update message supports proxy registrations. The flag is set to a value of 1 only if the corresponding Proxy Binding Update had the Proxy Registration Flag (P) set to value of 1. Mobility Options A variable-length field of such length that the complete Mobility Header is an integer multiple of 8 octets long. This field contains zero or more TLV-encoded mobility options. The encoding and format of defined options are described in Section 6.2 of [RFC3775]. The mobile access gateway MUST ignore and skip any options that it does not understand. As per this specification, the following mobility options are valid in a Proxy Binding Acknowledgement message. These options can be present in the message in any order. There can be one or
more instances of the Home Network Prefix options present in the
message. However, there cannot be more than one instance of any
of the following options.
Mobile Node Identifier option
Home Network Prefix option
Handoff Indicator option
Access Technology Type option
Timestamp option
Mobile Node Link-layer Identifier option
Link-local Address option
Additionally, there can be one or more instances of the Vendor-
Specific Mobility option [RFC5094].
Status
An 8-bit unsigned integer indicating the disposition of the Proxy
Binding Update. Values of the Status field less than 128 indicate
that the Proxy Binding Update was accepted by the local mobility
anchor. Values greater than or equal to 128 indicate that the
Proxy Binding Update message was rejected by the local mobility
anchor. Section 8.9 defines the Status values that can used in
Proxy Binding Acknowledgement message.
For descriptions of other fields present in this message, refer to
Section 6.1.8 of [RFC3775].
8.3. Home Network Prefix Option
A new option, Home Network Prefix option is defined for use with the
Proxy Binding Update and Proxy Binding Acknowledgement messages
exchanged between a local mobility anchor and a mobile access
gateway. This option is used for exchanging the mobile node's home
network prefix information. There can be multiple Home Network
Prefix options present in the message.
The Home Network Prefix Option has an alignment requirement of 8n+4.
Its format is as follows:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | Reserved | Prefix Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ +
| |
+ Home Network Prefix +
| |
+ +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type
22
Length
8-bit unsigned integer indicating the length of the option
in octets, excluding the type and length fields. This field
MUST be set to 18.
Reserved (R)
This 8-bit field is unused for now. The value MUST be
initialized to 0 by the sender and MUST be ignored by the
receiver.
Prefix Length
8-bit unsigned integer indicating the prefix length of the
IPv6 prefix contained in the option.
Home Network Prefix
A sixteen-byte field containing the mobile node's IPv6 Home
Network Prefix.
8.4. Handoff Indicator Option
A new option, Handoff Indicator option is defined for use with the
Proxy Binding Update and Proxy Binding Acknowledgement messages
exchanged between a local mobility anchor and a mobile access
gateway. This option is used for exchanging the mobile node's
handoff-related hints.
The Handoff Indicator option has no alignment requirement. Its
format is as follows:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | Reserved (R) | HI |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type
23
Length
8-bit unsigned integer indicating the length of the option
in octets, excluding the type and length fields. This field
MUST be set to 2.
Reserved (R)
This 8-bit field is unused for now. The value MUST be
initialized to 0 by the sender and MUST be ignored by the
receiver.
Handoff Indicator (HI)
An 8-bit field that specifies the type of handoff. The values
(0 - 255) will be allocated and managed by IANA. The following
values are currently 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)
8.5. Access Technology Type Option
A new option, Access Technology Type option is defined for use with
the Proxy Binding Update and Proxy Binding Acknowledgement messages
exchanged between a local mobility anchor and a mobile access
gateway. This option is used for exchanging the type of the access
technology by which the mobile node is currently attached to the
mobile access gateway.
The Access Technology Type Option has no alignment requirement. Its
format is as follows:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | Reserved (R) | ATT |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type
24
Length
8-bit unsigned integer indicating the length of the option
in octets, excluding the type and length fields. This field
MUST be set to 2.
Reserved (R)
This 8-bit field is unused for now. The value MUST be
initialized to 0 by the sender and MUST be ignored by the
receiver.
Access Technology Type (ATT)
An 8-bit field that specifies the access technology through
which the mobile node is connected to the access link on the
mobile access gateway.
The values (0 - 255) will be allocated and managed by IANA. The
following values are currently reserved for the below specified
access technology types.
0: Reserved ("Reserved")
1: Virtual ("Logical Network Interface")
2: PPP ("Point-to-Point Protocol")
3: IEEE 802.3 ("Ethernet")
4: IEEE 802.11a/b/g ("Wireless LAN")
5: IEEE 802.16e ("WIMAX")
8.6. Mobile Node Link-layer Identifier Option
A new option, Mobile Node Link-layer Identifier option is defined for use with the Proxy Binding Update and Proxy Binding Acknowledgement messages exchanged between a local mobility anchor and a mobile access gateway. This option is used for exchanging the mobile node's link-layer identifier. The format of the Link-layer Identifier option is shown below. Based on the size of the identifier, the option MUST be aligned appropriately, as per mobility option alignment requirements specified in [RFC3775]. 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 | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | + Link-layer Identifier + . ... . | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Type 25 Length 8-bit unsigned integer indicating the length of the option in octets, excluding the type and length fields. Reserved This field is unused for now. The value MUST be initialized to 0 by the sender and MUST be ignored by the receiver. Link-layer Identifier A variable length field containing the mobile node's link-layer identifier. The content and format of this field (including byte and bit ordering) is as specified in Section 4.6 of [RFC4861] for carrying link-layer addresses. On certain access links, where the link-layer address is not used or cannot be determined, this option cannot be used.
8.7. Link-local Address Option
A new option, Link-local Address option is defined for use with the Proxy Binding Update and Proxy Binding Acknowledgement messages exchanged between a local mobility anchor and a mobile access gateway. This option is used for exchanging the link-local address of the mobile access gateway. The Link-local Address option has an alignment requirement of 8n+6. Its format is as follows: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | + + | | + Link-local Address + | | + + | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Type 26 Length 8-bit unsigned integer indicating the length of the option in octets, excluding the type and length fields. This field MUST be set to 16. Link-local Address A sixteen-byte field containing the link-local address.8.8. Timestamp Option
A new option, Timestamp option is defined for use in the Proxy Binding Update and Proxy Binding Acknowledgement messages. The Timestamp option has an alignment requirement of 8n+2. Its format is as follows:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ Timestamp +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type
27
Length
8-bit unsigned integer indicating the length in octets of
the option, excluding the type and length fields. The value
for this field MUST be set to 8.
Timestamp
A 64-bit unsigned integer field containing a timestamp. The
value indicates the number of seconds since January 1, 1970,
00:00 UTC, by using a fixed point format. In this format, the
integer number of seconds is contained in the first 48 bits of
the field, and the remaining 16 bits indicate the number of
1/65536 fractions of a second.
8.9. Status Values
This document defines the following new Status values for use in
Proxy Binding Acknowledgement messages. These values are to be
allocated from the same number space, as defined in Section 6.1.8 of
[RFC3775].
Status values less than 128 indicate that the Proxy Binding Update
message was accepted by the local mobility anchor. Status values
greater than 128 indicate that the Proxy Binding Update was rejected
by the local mobility anchor.
PROXY_REG_NOT_ENABLED: 152
Proxy registration not enabled for the mobile node
NOT_LMA_FOR_THIS_MOBILE_NODE: 153
Not local mobility anchor for this mobile node
MAG_NOT_AUTHORIZED_FOR_PROXY_REG: 154
The mobile access gateway is not authorized to send proxy binding
updates
NOT_AUTHORIZED_FOR_HOME_NETWORK_PREFIX: 155
The mobile node is not authorized for one or more of the
requesting home network prefixes
TIMESTAMP_MISMATCH: 156
Invalid timestamp value (the clocks are out of sync)
TIMESTAMP_LOWER_THAN_PREV_ACCEPTED: 157
The timestamp value is lower than the previously accepted value
MISSING_HOME_NETWORK_PREFIX_OPTION: 158
Missing home network prefix option
BCE_PBU_PREFIX_SET_DO_NOT_MATCH: 159
All the home network prefixes listed in the BCE do not match all
the prefixes in the received PBU
MISSING_MN_IDENTIFIER_OPTION: 160
Missing mobile node identifier option
MISSING_HANDOFF_INDICATOR_OPTION: 161
Missing handoff indicator option
MISSING_ACCESS_TECH_TYPE_OPTION: 162
Missing access technology type option
Additionally, the following Status values defined in [RFC3775] can also be used in a Proxy Binding Acknowledgement message. 0 Proxy Binding Update accepted 128 Reason unspecified 129 Administratively prohibited 130 Insufficient resources9. Protocol Configuration Variables
9.1. Local Mobility Anchor - Configuration Variables
The local mobility anchor MUST allow the following variables to be configured by the system management. The configured values for these protocol variables MUST survive server reboots and service restarts. MinDelayBeforeBCEDelete This variable specifies the amount of time in milliseconds the local mobility anchor MUST wait before it deletes a Binding Cache entry of a mobile node, upon receiving a Proxy Binding Update message from a mobile access gateway with a lifetime value of 0. During this wait time, if the local mobility anchor receives a Proxy Binding Update for the same mobility binding, with a lifetime value greater than 0, then it must update the binding cache entry with the accepted binding values. By the end of this wait-time, if the local mobility anchor did not receive any valid Proxy Binding Update message for that mobility binding, it MUST delete the Binding Cache entry. This delay essentially ensures a mobile node's Binding Cache entry is not deleted too quickly and allows some time for the new mobile access gateway to complete the signaling for the mobile node. The default value for this variable is 10000 milliseconds.
MaxDelayBeforeNewBCEAssign
This variable specifies the amount of time in milliseconds the
local mobility anchor MUST wait for the de-registration message
for an existing mobility session before it decides to create a new
mobility session.
The default value for this variable is 1500 milliseconds.
Note that there is a dependency between this value and the values
used in the retransmission algorithm for Proxy Binding Updates.
The retransmissions need to happen before
MaxDelayBeforeNewBCEAssign runs out, as otherwise there are
situations where a de-registration from a previous mobile access
gateway may be lost, and the local mobility anchor creates,
needlessly, a new mobility session and new prefixes for the mobile
node. However, this affects situations where there is no
information from the lower layers about the type of a handoff or
other parameters that can be used for identifying the mobility
session.
TimestampValidityWindow
This variable specifies the maximum amount of time difference in
milliseconds between the timestamp in the received Proxy Binding
Update message and the current time of day on the local mobility
anchor, that is allowed by the local mobility anchor for the
received message to be considered valid.
The default value for this variable is 300 milliseconds. This
variable must be adjusted to suit the deployments.
9.2. Mobile Access Gateway - Configuration Variables
The mobile access gateway MUST allow the following variables to be
configured by the system management. The configured values for these
protocol variables MUST survive server reboots and service restarts.
EnableMAGLocalRouting
This flag indicates whether or not the mobile access gateway is
allowed to enable local routing of the traffic exchanged between a
visiting mobile node and a correspondent node that is locally
connected to one of the interfaces of the mobile access gateway.
The correspondent node can be another visiting mobile node as
well, or a local fixed node.
The default value for this flag is set to a value of 0, indicating
that the mobile access gateway MUST reverse tunnel all the traffic
to the mobile node's local mobility anchor.
When the value of this flag is set to a value of 1, the mobile
access gateway MUST route the traffic locally.
This aspect of local routing MAY be defined as policy on a per
mobile basis and when present will take precedence over this flag.
9.3. Proxy Mobile IPv6 Domain - Configuration Variables
All the mobile entities (local mobility anchors and mobile access
gateways) in a Proxy Mobile IPv6 domain MUST allow the following
variables to be configured by the system management. The configured
values for these protocol variables MUST survive server reboots and
service restarts. These variables MUST be globally fixed for a given
Proxy Mobile IPv6 domain resulting in the same values being enforced
on all the mobility entities in that domain.
TimestampBasedApproachInUse
This flag indicates whether or not the timestamp-based approach
for message ordering is in use in that Proxy Mobile IPv6 domain.
When the value for this flag is set to 1, all the mobile access
gateways in that Proxy Mobile IPv6 domain MUST apply the
timestamp-based considerations listed in Section 5.5. When the
value of this flag is set to 0, sequence-number-based
considerations listed in Section 5.5 MUST be applied. The default
value for this flag is set to value of 1, indicating that the
timestamp-based mechanism is in use in that Proxy Mobile IPv6
domain.
MobileNodeGeneratedTimestampInUse
This flag indicates whether or not the mobile-node-generated
timestamp approach is in use in that Proxy Mobile IPv6 domain.
When the value for this flag is set to 1, the local mobility
anchors and mobile access gateways in that Proxy Mobile IPv6
domain MUST apply the mobile node generated timestamp
considerations as specified in Section 5.5.
This flag is relevant only when timestamp-based approach is in
use. The value for this flag MUST NOT be set to value of 1, if
the value of the TimestampBasedApproachInUse flag is set to 0.
The default value for this flag is set to value of 0, indicating
that the mobile node generated timestamp mechanism is not in use
in that Proxy Mobile IPv6 domain.
FixedMAGLinkLocalAddressOnAllAccessLinks
This variable indicates the link-local address value that all the
mobile access gateways SHOULD use on any of the access links
shared with any of the mobile nodes in that Proxy Mobile IPv6
domain. If this variable is initialized to ALL_ZERO value, it
implies the use of fixed link-local address mode is not enabled
for that Proxy Mobile IPv6 domain.
FixedMAGLinkLayerAddressOnAllAccessLinks
This variable indicates the link-layer address value that all the
mobile access gateways SHOULD use on any of the access links
shared with any of the mobile nodes in that Proxy Mobile IPv6
domain. For access technologies where there is no link-layer
address, this variable MUST be initialized to ALL_ZERO value.
10. IANA Considerations
This document defines six new Mobility Header options, the Home
Network Prefix Option, Handoff Indicator Option, Access Technology
Type Option, Mobile Node Link-layer Identifier Option, Link-local
Address Option, and Timestamp Option. These options are described in
Section 8. The Type value for these options has been assigned from
the same numbering space as allocated for the other mobility options,
as defined in [RFC3775].
The Handoff Indicator Option, defined in Section 8.4 of this
document, introduces a new Handoff Indicator (HI) numbering space,
where the values from 0 to 5 have been reserved by this document.
Approval of new Handoff Indicator type values are to be made through
IANA Expert Review.
The Access Technology Type Option, defined in Section 8.5 of this
document, introduces a new Access Technology type (ATT) numbering
space, where the values from 0 to 5 have been reserved by this
document. Approval of new Access Technology type values are to be
made through IANA Expert Review.
This document also defines new Binding Acknowledgement status values,
as described in Section 8.9. The status values MUST be assigned from
the same number space used for Binding Acknowledgement status values,
as defined in [RFC3775]. The allocated values for each of these
status values must be greater than 128.
This document creates a new registry for the flags in the Binding
Update message called the "Binding Update Flags".
The following flags are reserved:
(A) 0x8000 [RFC3775]
(H) 0x4000 [RFC3775]
(L) 0x2000 [RFC3775]
(K) 0x1000 [RFC3775]
(M) 0x0800 [RFC4140]
(R) 0x0400 [RFC3963]
This document reserves a new flag (P) as follows:
(P) 0x0200
The rest of the values in the 16-bit field are reserved. New values
can be assigned by Standards Action or IESG approval.
This document also creates a new registry for the flags in the
Binding Acknowledgment message called the "Binding Acknowledgment
Flags". The following values are reserved.
(K) 0x80 [RFC3775]
(R) 0x40 [RFC3963]
This document reserves a new flag (P) as follows:
(P) 0x20
The rest of the values in the 8-bit field are reserved. New values
can be assigned by Standards Action or IESG approval.
11. Security Considerations
The potential security threats against any network-based mobility
management protocol are described in [RFC4832]. This section
explains how Proxy Mobile IPv6 protocol defends itself against those
threats.
Proxy Mobile IPv6 protocol recommends the signaling messages, Proxy Binding Update and Proxy Binding Acknowledgement, exchanged between the mobile access gateway and the local mobility anchor to be protected using IPsec using the established security association between them. This essentially eliminates the threats related to the impersonation of the mobile access gateway or the local mobility anchor. This specification allows a mobile access gateway to send binding registration messages on behalf of a mobile node. If proper authorization checks are not in place, a malicious node may be able to hijack a mobile node's mobility session or may carry out a denial- of-service attack. To prevent this attack, this specification requires the local mobility anchor to allow only authorized mobile access gateways that are part of that Proxy Mobile IPv6 domain to send Proxy Binding Update messages on behalf of a mobile node. To eliminate the threats on the interface between the mobile access gateway and the mobile node, this specification requires an established trust between the mobile access gateway and the mobile node and to authenticate and authorize the mobile node before it is allowed to access the network. Further, the established authentication mechanisms enabled on that access link will ensure that there is a secure binding between the mobile node's identity and its link-layer address. The mobile access gateway will definitively identify the mobile node from the packets that it receives on that access link. To address the threat related to a compromised mobile access gateway, the local mobility anchor, before accepting a Proxy Binding Update message for a given mobile node, may ensure that the mobile node is attached to the mobile access gateway that sent the Proxy Binding Update message. This may be accomplished by contacting a trusted entity, which is able to track the mobile node's current point of attachment. However, the specific details of the actual mechanisms for achieving this is outside the scope of this document.12. Acknowledgements
The authors would like to specially thank Jari Arkko, Julien Laganier, Christian Vogt, Dave Thaler, Pasi Eronen, Pete McCann, Brian Haley, Ahmad Muhanna, JinHyeock Choi, and Elwyn Davies for their thorough reviews of this document. The authors would also like to thank Alex Petrescu, Alice Qinxia, Alper Yegin, Ashutosh Dutta, Behcet Sarikaya, Charles Perkins, Domagoj Premec, Fred Templin, Genadi Velev, George Tsirtsis, Gerardo Giaretta, Henrik Levkowetz, Hesham Soliman, James Kempf, Jean-Michel
Combes, John Jason Brzozowski, Jun Awano, John Zhao, Jong-Hyouk Lee, Jonne Soininen, Jouni Korhonen, Kalin Getov, Kilian Weniger, Lars Eggert, Magnus Westerlund, Marco Liebsch, Mohamed Khalil, Nishida Katsutoshi, Pierrick Seite, Phil Roberts, Ralph Droms, Ryuji Wakikawa, Sangjin Jeong, Suresh Krishnan, Tero Kauppinen, Uri Blumenthal, Ved Kafle, Vidya Narayanan, Youn-Hee Han, and many others for their passionate discussions in the working group mailing list on the topic of localized mobility management solutions. These discussions stimulated much of the thinking and shaped the document to the current form and we acknowledge that! The authors would also like to thank Ole Troan, Akiko Hattori, Parviz Yegani, Mark Grayson, Michael Hammer, Vojislav Vucetic, Jay Iyer, Tim Stammers, Bernie Volz, and Josh Littlefield for their input on this document.13. References
13.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC2473] Conta, A. and S. Deering, "Generic Packet Tunneling in IPv6 Specification", RFC 2473, December 1998. [RFC3168] Ramakrishnan, K., Floyd, S., and D. Black, "The Addition of Explicit Congestion Notification (ECN) to IP", RFC 3168, September 2001. [RFC3315] Droms, R., Bound, J., Volz, B., Lemon, T., Perkins, C., and M. Carney, "Dynamic Host Configuration Protocol for IPv6 (DHCPv6)", RFC 3315, July 2003. [RFC3775] Johnson, D., Perkins, C., and J. Arkko, "Mobility Support in IPv6", RFC 3775, June 2004. [RFC4282] Aboba, B., Beadles, M., Arkko, J., and P. Eronen, "The Network Access Identifier", RFC 4282, December 2005. [RFC4283] Patel, A., Leung, K., Khalil, M., Akhtar, H., and K. Chowdhury, "Mobile Node Identifier Option for Mobile IPv6 (MIPv6)", RFC 4283, November 2005. [RFC4291] Hinden, R. and S. Deering, "IP Version 6 Addressing Architecture", RFC 4291, February 2006.
[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. [RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman, "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861, September 2007.13.2. Informative References
[RFC1981] McCann, J., Deering, S., and J. Mogul, "Path MTU Discovery for IP version 6", RFC 1981, August 1996. [RFC2865] Rigney, C., Willens, S., Rubens, A., and W. Simpson, "Remote Authentication Dial In User Service (RADIUS)", RFC 2865, June 2000. [RFC3588] Calhoun, P., Loughney, J., Guttman, E., Zorn, G., and J. Arkko, "Diameter Base Protocol", RFC 3588, September 2003. [RFC3963] Devarapalli, V., Wakikawa, R., Petrescu, A., and P. Thubert, "Network Mobility (NEMO) Basic Support Protocol", RFC 3963, January 2005. [RFC3971] Arkko, J., Kempf, J., Zill, B., and P. Nikander, "SEcure Neighbor Discovery (SEND)", RFC 3971, March 2005. [RFC4140] Soliman, H., Castelluccia, C., El Malki, K., and L. Bellier, "Hierarchical Mobile IPv6 Mobility Management (HMIPv6)", RFC 4140, August 2005. [RFC4306] Kaufman, C., "Internet Key Exchange (IKEv2) Protocol", RFC 4306, December 2005. [RFC4330] Mills, D., "Simple Network Time Protocol (SNTP) Version 4 for IPv4, IPv6 and OSI", RFC 4330, January 2006. [RFC4372] Adrangi, F., Lior, A., Korhonen, J., and J. Loughney, "Chargeable User Identity", RFC 4372, January 2006. [RFC4821] Mathis, M. and J. Heffner, "Packetization Layer Path MTU Discovery", RFC 4821, March 2007.
[RFC4830] Kempf, J., "Problem Statement for Network-Based Localized Mobility Management (NETLMM)", RFC 4830, April 2007. [RFC4831] Kempf, J., "Goals for Network-Based Localized Mobility Management (NETLMM)", RFC 4831, April 2007. [RFC4832] Vogt, C. and J. Kempf, "Security Threats to Network- Based Localized Mobility Management (NETLMM)", RFC 4832, April 2007. [RFC4862] Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless Address Autoconfiguration", RFC 4862, September 2007. [RFC4941] Narten, T., Draves, R., and S. Krishnan, "Privacy Extensions for Stateless Address Autoconfiguration in IPv6", RFC 4941, September 2007. [RFC5094] Devarapalli, V., Patel, A., and K. Leung, "Mobile IPv6 Vendor Specific Option", RFC 5094, December 2007. [IPV4-PMIP6] Wakikawa, R. and S. Gundavelli, "IPv4 Support for Proxy Mobile IPv6", Work in Progress, May 2008. [DNAV6] Narayanan, S., Ed., "Detecting Network Attachment in IPv6 Networks (DNAv6)", Work in Progress, February 2008.
Appendix A. Proxy Mobile IPv6 Interactions with AAA Infrastructure
Every mobile node that roams in a proxy Mobile IPv6 domain would typically be identified by an identifier, MN-Identifier, and that identifier will have an associated policy profile that identifies the mobile node's home network prefix(es) on a per-interface basis, permitted address configuration modes, roaming policy, and other parameters that are essential for providing network-based mobility management service. This information is typically configured in AAA. In some cases, the home network prefix(es) may be dynamically assigned to the mobile node's interface, after its initial attachment to the Proxy Mobile IPv6 domain over that interface and may not be configured in the mobile node's policy profile. The network entities in the proxy Mobile IPv6 domain, while serving a mobile node, will have access to the mobile node's policy profile and these entities can query this information using RADIUS [RFC2865] or DIAMETER [RFC3588] protocols.Appendix B. Routing State
The following section explains the routing state created for a mobile node on the mobile access gateway. This routing state reflects only one specific way of implementation, and one MAY choose to implement it in other ways. The policy based route defined below acts as a traffic selection rule for routing a mobile node's traffic through a specific tunnel created between the mobile access gateway and that mobile node's local mobility anchor and with the specific encapsulation mode, as negotiated. The below example identifies the routing state for two visiting mobile nodes, MN1 and MN2, with their respective local mobility anchors, LMA1 and LMA2. For all traffic from the mobile node, identified by the mobile node's MAC address, ingress interface or source prefix (MN-HNP) to _ANY_DESTINATION_ route via interface tunnel0, next-hop LMAA.
+==================================================================+
| Packet Source | Destination Address | Destination Interface |
+==================================================================+
| MAC_Address_MN1, | _ANY_DESTINATION_ | Tunnel0 |
| (IPv6 Prefix or |----------------------------------------------|
| Input Interface) | Locally Connected | Tunnel0 |
+------------------------------------------------------------------+
| MAC_Address_MN2, | _ANY_DESTINATION_ | Tunnel1 |
+ (IPv6 Prefix or -----------------------------------------------|
| Input Interface | Locally Connected | direct |
+------------------------------------------------------------------+
Example - Policy-Based Route Table
+==================================================================+
| Interface | Source Address | Destination Address | Encapsulation |
+==================================================================+
| Tunnel0 | Proxy-CoA | LMAA1 | IPv6-in-IPv6 |
+------------------------------------------------------------------+
| Tunnel1 | Proxy-CoA | LMAA2 | IPv6-in-IPv6 |
+------------------------------------------------------------------+
Example - Tunnel Interface Table
Authors' Addresses
Sri Gundavelli (editor) Cisco 170 West Tasman Drive San Jose, CA 95134 USA EMail: sgundave@cisco.com Kent Leung Cisco 170 West Tasman Drive San Jose, CA 95134 USA EMail: kleung@cisco.com Vijay Devarapalli Wichorus 3590 North First Street San Jose, CA 95134 USA EMail: vijay@wichorus.com Kuntal Chowdhury Starent Networks 30 International Place Tewksbury, MA EMail: kchowdhury@starentnetworks.com Basavaraj Patil Nokia 6000 Connection Drive Irving, TX 75039 USA EMail: basavaraj.patil@nokia.com
Full Copyright Statement Copyright (C) The IETF Trust (2008). This document is subject to the rights, licenses and restrictions contained in BCP 78, and except as set forth therein, the authors retain all their rights. This document and the information contained herein are provided on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Intellectual Property The IETF takes no position regarding the validity or scope of any Intellectual Property Rights or other rights that might be claimed to pertain to the implementation or use of the technology described in this document or the extent to which any license under such rights might or might not be available; nor does it represent that it has made any independent effort to identify any such rights. Information on the procedures with respect to rights in RFC documents can be found in BCP 78 and BCP 79. Copies of IPR disclosures made to the IETF Secretariat and any assurances of licenses to be made available, or the result of an attempt made to obtain a general license or permission for the use of such proprietary rights by implementers or users of this specification can be obtained from the IETF on-line IPR repository at http://www.ietf.org/ipr. The IETF invites any interested party to bring to its attention any copyrights, patents or patent applications, or other proprietary rights that may cover technology that may be required to implement this standard. Please address the information to the IETF at ietf-ipr@ietf.org.