Internet Engineering Task Force (IETF) S. Krishnan
Request for Comments: 7077 Ericsson
Category: Standards Track S. Gundavelli
ISSN: 2070-1721 Cisco
M. Liebsch
NEC
H. Yokota
KDDI
J. Korhonen
Broadcom
November 2013
Update Notifications for Proxy Mobile IPv6
Abstract
This document specifies protocol enhancements for allowing the local
mobility anchor in a Proxy Mobile IPv6 domain to asynchronously
notify the mobile access gateway about changes related to a mobility
session. These Update Notification messages are exchanged using a
new Mobility Header message type specifically designed for this
purpose.
Status of This Memo
This is an Internet Standards Track document.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 5741.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc7077.
Copyright Notice
Copyright (c) 2013 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Conventions and Terminology . . . . . . . . . . . . . . . . . 3
2.1. Conventions . . . . . . . . . . . . . . . . . . . . . . . 3
2.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4
3. Notification Message - Usage Examples . . . . . . . . . . . . 4
4. Message Formats . . . . . . . . . . . . . . . . . . . . . . . 5
4.1. Update Notification (UPN) . . . . . . . . . . . . . . . . 5
4.2. Update Notification Acknowledgement (UPA) . . . . . . . . 7
5. LMA Considerations . . . . . . . . . . . . . . . . . . . . . 8
5.1. Constructing the Update Notification Message . . . . . . 9
5.2. Receiving the Update Notification Acknowledgement Message 10
6. MAG Considerations . . . . . . . . . . . . . . . . . . . . . 12
6.1. Receiving the Update Notification Message . . . . . . . . 12
6.2. Constructing the Update Notification Acknowledgement
Message . . . . . . . . . . . . . . . . . . . . . . . . . 14
7. Protocol Configuration Variables . . . . . . . . . . . . . . 15
8. Security Considerations . . . . . . . . . . . . . . . . . . . 15
9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 16
10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 16
11. References . . . . . . . . . . . . . . . . . . . . . . . . . 18
11.1. Normative References . . . . . . . . . . . . . . . . . . 18
11.2. Informative References . . . . . . . . . . . . . . . . . 18
1. Introduction
In some situations, there is a need for the local mobility anchor
(LMA) to send asynchronous notification messages to the mobile access
gateway (MAG) in the course of a mobility session. These situations
include changes to mobility session parameters and policy parameters.
In this context, "Asynchronous messages" is used to mean messages
that are not synchronous with the Proxy Binding Update and Proxy
Binding Acknowledgement messages of the base Proxy Mobile IPv6
specification [RFC5213]. The base Proxy Mobile IPv6 specification
does not have a provision for sending unsolicited Update Notification
messages from the local mobility anchor to the mobile access gateway.
Proxy Mobile IPv6 [RFC5213] is a network-based mobility management
protocol. It is designed to provide IP mobility management support
to a mobile node without requiring the participation of the mobile
node in any IP mobility-related signaling. The protocol defines two
mobility management entities: the LMA and the MAG. These entities
are responsible for managing IP mobility management support for a
mobile node in a Proxy Mobile IPv6 domain. The setup of the mobility
session is initiated by the mobile access gateway by sending a Proxy
Binding Update message and acknowledged by the local mobility anchor
in the Proxy Binding Acknowledgement message. Once the mobility
session is set up, currently there is no mechanism for the local
mobility anchor to inform the mobile access gateway about changes to
the mobility session or any parameters related to the mobility
session. However, there are mechanisms in the Proxy Mobile IPv6
protocol that allow a local mobility anchor to send signaling
messages to the mobile access gateway asynchronously, as defined in
the Proxy Mobile IPv6 Heartbeat message [RFC5847] or in the Binding
Revocation message [RFC5846], but these signaling messages are
designed for a very specific purpose and are not sufficient for
supporting a notification framework.
One such scenario where such a mechanism is needed is when the local
mobility anchor wants to inform the mobile access gateway that it
needs to re-register the mobility session for a mobile node. It is
possible to achieve a similar effect by using a short lifetime for
the mobility sessions, but in several networks this results in an
unacceptable, and mostly unnecessary, increase in the signaling load
and overhead. A more suitable scenario would be to enable demand-
based signaling from the local mobility anchor to one or more mobile
access gateways. Another example is when there is a change in a QoS
policy [PMIPv6-QoS], an IP flow mobility policy [PMIPv6-FLOW-MOB], or
an IPv4 traffic offload policy [RFC6909] for a mobility session. In
this case, the local mobility anchor wants to request that the mobile
access gateway perform re-registration of the mobility session in
order to update the policies associated with the mobility session of
a mobile node.
This document defines a new Mobility Header message for allowing the
local mobility anchor to send notification messages to the mobile
access gateway and a corresponding Mobility Header message for the
mobile access gateway to acknowledge the notification message. The
purpose of the notification message is twofold: (1) to enable the
local mobility anchor to notify the mobile access gateway about the
updated session parameters and (2) to enable the local mobility
anchor to request that the mobile access gateway renegotiate the
session parameters.
2. Conventions and Terminology
2.1. Conventions
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].
2.2. Terminology
All the mobility-related terms used in this document are to be
interpreted as defined in the base Proxy Mobile IPv6 specifications
[RFC5213] and [RFC5844].
3. Notification Message - Usage Examples
Use Case 1: Consider a use case where the local mobility anchor wants
the mobile access gateway to re-register a specific mobility session.
MN MAG LMA
|------>| | 1. Mobile Node Attach
| |------->| 2. Proxy Binding Update
| |<-------| 3. Proxy Binding Acknowledgement
| |========| 4. Tunnel/Route Setup
| | |
| |<-------| 5. Update Notification (FORCE-REREGISTRATION)
| |------->| 6. Update Notification Acknowledgement
| | |
| |------->| 7. Proxy Binding Update
| |<-------| 8. Proxy Binding Acknowledgement
| | |
Figure 1: Update Notification: FORCE-REREGISTRATION
Use Case 2: Consider a use case where the local mobility anchor wants
to notify the mobile access gateway of the updated session
parameters, for example, an updated QoS profile or an updated IPv4
offload policy.
MN MAG LMA
|------>| | 1. Mobile Node Attach
| |------->| 2. Proxy Binding Update
| |<-------| 3. Proxy Binding Acknowledgement
| |========| 4. Tunnel/Route Setup
| | |
| |<-------| 5. Update Notification
| | | (UPDATE-SESSION-PARAMETERS)
| |------->| 6. Update Notification Acknowledgement
| + | 7. MAG applies the new policy option
| | |
Figure 2: Update Notification: Session Parameters UPDATE-SESSION-PARAMETERS
4. Message Formats
4.1. Update Notification (UPN)
The Update Notification is a Mobility Header message that has an MH
Type value of 19. It is used by the local mobility anchor to notify
the mobile access gateway that some parameters related to the
mobility session have changed.
The format of the Update Notification message 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 # |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Notification Reason |A|D| Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
. .
. Mobility options .
. .
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 3: Update Notification Message
Sequence Number
This 16-bit unsigned integer is used by the local mobility anchor
to match the received Update Notification Acknowledgement message
with this Update Notification message. This Sequence Number could
be a random number and can be managed under the same variable used
in Proxy Mobile IPv6 signaling messages [RFC5213].
Implementations MUST ensure that there is no collision between the
Sequence Numbers of all outstanding Update Notification messages
at any time.
Notification Reason
This 16-bit unsigned integer indicates the Notification Reason
code. This code corresponds to the reason that the local mobility
anchor sent the Update Notification to the mobile access gateway.
This field does not contain any structure and MUST be treated as
an enumeration. The reason code can indicate a vendor-specific
reason if the semantics of the Update Notification message are to
be based on the attached vendor-specific options, not solely from
the reason code. These attached options can be deployment
specific and are not specified in this document. The following
Notification Reason values are currently defined:
(0) - Reserved
This value is currently reserved and cannot be used.
(1) - FORCE-REREGISTRATION
Request to re-register the session by sending a Proxy
Binding Update for the mobility session.
(2) - UPDATE-SESSION-PARAMETERS
Request to apply the updated session parameters obtained
from the message on the mobility session.
(3) - VENDOR-SPECIFIC-REASON
This Notification Reason is for vendor-specific use.
The processing rules are to be based on the Vendor-
Specific Mobility option(s) [RFC5094] present in the
message.
(4) - ANI-PARAMS-REQUESTED
Request to send currently known Access Network
Identifier (ANI) [RFC6757] parameters for the mobility
session.
(255) - Reserved
This value is currently reserved and cannot be used.
Acknowledgement Requested Flag ((A) Flag)
When this flag is set to a value of (1), it is an indication that
the local mobility anchor is requesting that the mobile access
gateway send an Update Notification Acknowledgement message. When
this flag is set to a value of (0), it is an indication that the
local mobility anchor is not requesting any Update Notification
Acknowledgement messages.
Retransmit Flag ((D) Flag)
When this flag is set to a value of (1), it is an indication that
the message is a retransmitted message and has the same Sequence
Number and other message contents as in the previously sent
message. The (D) flag is set for retransmitted request messages,
to aid the reliable detection of duplicate requests at the
receiver of the request message. It is set when originating
requests that have not yet been acknowledged, as an indication of
a possible duplicate due to a retransmission. This flag MUST be
cleared when sending a request for the first time for a given
Sequence Number; otherwise, the sender MUST set this flag.
Reserved
This field is unused for now. The value MUST be initialized to 0
by the sender and MUST be ignored by the receiver.
Mobility Options
This variable-length field is of such length that the complete
Mobility Header is an integer multiple of 8 octets long; the Pad1
and PadN options [RFC6275] can be used for padding. This field
contains zero or more TLV-encoded mobility options. Any of the
Mobility Header options, including Vendor-Specific Mobility
options [RFC5094], can be included here. The receiver MUST ignore
and skip any options that it does not understand. These mobility
options are used by the mobile access gateway to identify the
specific binding for which the Update Notification message is
sent.
4.2. Update Notification Acknowledgement (UPA)
The Update Notification Acknowledgement is a Mobility Header message
that has an MH Type value of 20. The mobile access gateway sends
this message in order to acknowledge that it has received an Update
Notification message with the (A) flag set and to indicate the status
after processing the message.
The format of the Update Notification Acknowledgement message 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 # |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Status Code | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
. .
. Mobility options .
. .
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 4: Update Notification Acknowledgement Message
Sequence Number
This 16-bit unsigned integer is copied from the Update
Notification message and is used for matching the Update
Notification Acknowledgement message with the Update Notification
message.
Status Code
This 8-bit unsigned integer indicates the status code and
specifies the result of the processing of the Update Notification
message. Status codes between 0 and 127 signify successful
processing of the Update Notification message, and codes between
128 and 255 signify that an error occurred during processing of
the Update Notification message. The following status code values
are currently defined:
(0) - SUCCESS
The mobile access gateway successfully processed the
received Update Notification message.
(128) - FAILED-TO-UPDATE-SESSION-PARAMETERS
The mobile access gateway was not able to apply the
session parameters sent by the local mobility anchor in
the Update Notification message.
(129) - MISSING-VENDOR-SPECIFIC-OPTION
The received Update Notification message does not have
the required Vendor-Specific Mobility option(s) needed
for handling the message.
Reserved
This field is unused for now. The value MUST be initialized to 0
by the sender and MUST be ignored by the receiver.
Mobility Options
This variable-length field is of such length that the complete
Mobility Header is an integer multiple of 8 octets long; the Pad1
and PadN options [RFC6275] can be used for padding. This field
contains zero or more TLV-encoded mobility options. Any of the
Mobility Header options, including Vendor-Specific Mobility
options [RFC5094], can be included here. The receiver MUST ignore
and skip any options that it does not understand. These mobility
options are used by the mobile access gateway to identify the
specific binding for which the Update Notification Acknowledgement
message is sent.
5. LMA Considerations
o The local mobility anchor sends the Update Notification message in
response to a condition that is specified in the Notification
Reason field. The Notification Reason field in the Update
Notification message MUST be set to a specific value that
identifies the reason for which the Update Notification message is
being sent. The Notification Reason, based on the chosen value,
may require a specific action that the mobile access gateway needs
to perform (for example, requiring re-registration of a mobility
session).
o The Update Notification message MUST include either the Mobile
Node Identifier option [RFC4283] or the Mobile Node Group
Identifier option [RFC6602].
* If the Mobile Node Identifier option is present, it indicates
that the Update Notification message is sent for that specific
mobility session.
* If the Mobile Node Group Identifier option is present, it
indicates that the Update Notification message is sent for the
set of mobility sessions identified by the Group Identifier.
The Group Identifier is negotiated as part of the initial Proxy
Mobile IPv6 signaling. If the Group Identifier is not
negotiated in the initial Proxy Mobile IPv6 signaling, a value
of (1) for the Group Identifier can always be used. The Group
Identifier value of (1) identifies all the mobility sessions
established between that local mobility anchor and the mobile
access gateway.
o The Update Notification message MAY contain a modified session
parameter in the form of a mobility option (e.g., an IPv4 traffic
offload option or a QoS option), so the mobile access gateway can
apply them on the identified mobility session.
5.1. Constructing the Update Notification Message
The local mobility anchor, when sending the Update Notification
message to the mobile access gateway, has to construct the message as
specified below:
o For requesting an Acknowledgement message and an indication about
the result of processing the message from the mobile access
gateway for the Update Notification message, the (A) flag in the
Update Notification message MUST be set to a value of (1);
otherwise, it MUST be set to a value of (0). However, if the
Notification Reason is set to a value of (1)
"FORCE-REREGISTRATION" or (4) "ANI-PARAMS-REQUESTED", then it is
RECOMMENDED that the (A) flag be set to a value of (0). For
certain general notifications that are informational in nature,
the local mobility anchor may choose not to request
acknowledgement for the Update Notification message.
o The Sequence Number field of the message MUST be initialized to a
random number and increased monotonically for subsequent messages.
Once the Sequence Number hits the maximum value, it should be
wrapped around to 0. Furthermore, if the message is a
retransmission of a previously sent message, then the Sequence
Number value is not changed.
o When using IPv4 transport, the source address in the IPv4 header
MUST be set to the local mobility anchor's IPv4 address
(IPv4-LMAA), and the destination address in the IPv4 header MUST
be set to the IPv4-Proxy-CoA (Care-of Address) of the mobile
access gateway. The Mobility Header (without the IPv6 header)
containing the Update Notification message is encapsulated in a
UDP header with the destination port of 5436 [RFC5844]. If IPsec
Encapsulating Security Payload (ESP) [RFC4303] is used to protect
signaling, the packet is processed using transport mode ESP.
o The format of the Update Notification message sent over IPv4 and
protected using ESP is shown below:
IPv4 header (src=IPv4-LMAA, dst=IPv4-Proxy-CoA)
ESP header (in transport mode)
UDP header (sport=5436, dport=5436)
Mobility Header (Update Notification)
(one or more Mobility Header options)
o When using IPv6 transport, the source address in the IPv6 header
MUST be set to the local mobility anchor's IPv6 address (LMAA).
The destination address in the IPv6 header MUST be set to the
Proxy-CoA of the mobile access gateway. The Mobility Header is
part of the IPv6 headers.
o The format of the Update Notification message sent over IPv6 and
protected using ESP is shown below:
IPv6 header (src=LMAA, dst=Proxy-CoA)
Mobility Header (Update Notification)
ESP header (in transport mode)
(one or more Mobility Header options)
5.2. Receiving the Update Notification Acknowledgement Message
o If the local mobility anchor does not receive an Update
Notification Acknowledgement message from the mobile access
gateway for the Update Notification message with the (A) flag set,
then the local mobility anchor MUST retransmit the message. The
related considerations are as follows:
* When retransmitting an Update Notification message, the
Sequence Number value and other message contents MUST be the
same as in the original message. The (D) flag in the message
MUST be set to a value of (1).
* There MUST be a minimum delay of
MIN_DELAY_BETWEEN_UPDATE_NOTIFICATION_REPLAY (Section 7), with
a default value of 1000 milliseconds, between two retransmit
messages.
* The message MUST be retransmitted up to the number of times
defined by the configuration variable
MAX_UPDATE_NOTIFICATION_RETRANSMIT_COUNT (Section 7), with a
default value of (1). If there is no Update Notification
Acknowledgement message after the retransmission count reaches
the value defined by the configuration variable
MAX_UPDATE_NOTIFICATION_RETRANSMIT_COUNT, then the message MUST
be discarded, and the event SHOULD be logged.
o If the local mobility anchor receives a Binding Error message with
the Status field set to 2 as described in [RFC6275], this
indicates that the mobile access gateway does not support the
Update Notification message, and hence the local mobility anchor
MUST NOT send any further Update Notification messages to that
mobile access gateway unless an administrative action is taken.
o When receiving an Update Notification Acknowledgement message, the
local mobility anchor MUST verify the Mobility Header as described
in Section 9.2 of [RFC6275]. If the packet is dropped due to
failure of any of the Mobility Header test checks, the local
mobility anchor MUST follow the processing rules as described in
Section 9.2 of [RFC6275].
o Upon receiving the Update Notification Acknowledgement message,
the local mobility anchor MUST verify that the received message is
protected by the security association that is being used to
protect the other signaling messages between those two peers. For
example, if the Proxy Binding Update and Proxy Binding
Acknowledgement messages are protected using an IPsec security
association [RFC4301], then the Update Notification
Acknowledgement message MUST have the IPsec protection with the
currently established IPsec security association that is being
used for protecting the other Proxy Mobile IPv6 signaling
messages.
o If the local mobility anchor receives an Update Notification
Acknowledgement message with a failure status and a value of 128
or greater, then it SHOULD log an error.
o If the Sequence Number in the received Update Notification
Acknowledgement message does not match any of the Update
Notification messages that the local mobility anchor sent, then
the message MUST be discarded, and the message should be logged.
o If the local mobility anchor receives an Update Notification
Acknowledgement message from the mobile access gateway for an
Update Notification message that did not have the (A) flag set,
the local mobility anchor MUST process the received message in the
same way as a response to an Update Notification message with the
(A) flag set.
6. MAG Considerations
6.1. Receiving the Update Notification Message
o When receiving an Update Notification message, the mobile access
gateway MUST verify the Mobility Header as described in
Section 9.2. of [RFC6275]. If the packet is dropped due to
failure of any of the Mobility Header test checks, the mobile
access gateway MUST follow the processing rules as described in
Section 9.2 of [RFC6275].
o Upon receiving the Update Notification message, the mobile access
gateway MUST verify that the received packet is protected by the
security association that is being used to protect the other
signaling messages between those two peers. For example, if the
Proxy Binding Update and Proxy Binding Acknowledgement messages
are protected using an IPsec security association, then the Update
Notification message MUST have the IPsec protection with the
currently established IPsec security association that is being
used for protecting the other Proxy Mobile IPv6 signaling
messages.
o If the received Update Notification message is a retransmission of
a previously received message, as identified by the Sequence
Number, then the mobile access gateway MUST NOT handle the message
as a new request. The (D) flag is used as an indication of a
retransmitted request, e.g., due to lost messages or the local
mobility anchor not seeing the requested update actions. If the
mobile access gateway has not seen the (potentially lost) initial
request message, it MUST treat the received Update Notification
message (with the (D) flag set) as an initial request and continue
processing based on that. If the mobile access gateway detects
that the request is a retransmission based on the (D) flag and the
Sequence Number, then it SHOULD redo the requested update action,
e.g., when the Acknowledgement Requested ((A)) flag is not set.
The mobile access gateway MUST always respond to the retransmitted
request if the (A) flag is set.
o Upon accepting the Update Notification message, the mobile access
gateway MUST process the message and perform the actions based on
the Notification Reason.
* If the (A) flag in the message is set to a value of (1), the
mobile access gateway MUST send an Update Notification
Acknowledgement message with the status code field set based on
the result of processing the Update Notification message.
* If the Notification Reason is set to a value of (1)
"FORCE-REREGISTRATION", then the mobile access gateway MUST
send a Proxy Binding Update message to the local mobility
anchor and obtain the updated session parameters for that
mobility session.
* If the Notification Reason is set to a value of (2)
"UPDATE-SESSION-PARAMETERS", then the mobile access gateway
MUST apply the session parameters that are obtained from the
Update Notification message in the form of mobility options.
However, if the mobile access gateway is unable to apply the
received session parameters, then the mobile access gateway
MUST apply the following considerations:
+ If the received Update Notification message has the (A) flag
in the message set to a value of (0), then the mobile access
gateway MUST drop the received Update Notification message
and log the error.
+ If the received Update Notification message has the (A) flag
in the message set to a value of (1), then the mobile access
gateway MUST send an Update Notification Acknowledgement
message with a status code value of 128
(FAILED-TO-UPDATE-SESSION-PARAMETERS).
* If the Notification Reason is set to a value of (3)
"VENDOR-SPECIFIC-REASON", then the mobile access gateway MUST
apply the considerations related to handling of the
Vendor-Specific Mobility option [RFC5094] that is carried in
the Update Notification message. However, if there is no
Vendor-Specific Mobility option present in the message, the
mobile access gateway MUST apply the following considerations:
+ If the received Update Notification message has the (A) flag
in the message set to a value of (0), then the mobile access
gateway MUST drop the received Update Notification message
and log the error.
+ If the received Update Notification message has the (A) flag
in the message set to a value of (1), then the mobile access
gateway MUST send an Update Notification Acknowledgement
message with a status code value of 129
(MISSING-VENDOR-SPECIFIC-OPTION).
* If the Notification Reason is set to a value of (4)
"ANI-PARAMS-REQUESTED", then the mobile access gateway MUST
send a Proxy Binding Update message to the local mobility
anchor with the Access Network Identifier option [RFC6757].
The Access Network Identifier option MUST reflect the current
access network parameters for that mobility session as known to
the mobile access gateway at the time of sending the Proxy
Binding Update message.
* For other Notification Reason values not reserved by this
document, the processing required on the mobile access gateway
is out of scope for this document and will be specified for
each Notification Reason defined by other documents.
6.2. Constructing the Update Notification Acknowledgement Message
The mobile access gateway, when sending the Update Notification
Acknowledgement message to the local mobility anchor, has to
construct the message as specified below:
o The Sequence Number MUST be the same as the Sequence Number from
the received Update Notification message.
o The Status field of the Update Notification message MUST be set to
a value that reflects the status of the processing of the Update
Notification request. A value of 0 (SUCCESS) indicates that the
handling of the Update Notification message was successful.
o The Update Notification Acknowledgement message MUST contain
either the Mobile Node Identifier option or the Mobile Node Group
Identifier option, copied from the Update Notification message.
Furthermore, the mobile access gateway MAY include other Mobility
Header options.
o The source address in the IP header of the Update Notification
Acknowledgement message MUST be set to the destination IP address
of the received Update Notification message.
o The destination address in the IP header of the Update
Notification Acknowledgement message MUST be set to the source
address of the received Update Notification message.
o If IPsec ESP is used to protect signaling, the packet is processed
using transport mode ESP.
o The format of the Update Notification Acknowledgement message sent
over IPv4 and protected using ESP is shown below:
IPv4 header (src=IPv4-Proxy-CoA, dst=IPv4-LMAA)
ESP header (in transport mode)
UDP header (sport=5436, dport=5436)
Mobility Header (Update Notification Acknowledgement)
(one or more Mobility Header options)
o The format of the Update Notification Acknowledgement message sent
over IPv6 and protected using ESP is shown below:
IPv6 header (src=Proxy-CoA, dst=LMAA)
Mobility Header (Update Notification Acknowledgement)
ESP header (in transport mode)
(one or more Mobility Header options)
7. Protocol Configuration Variables
This specification defines the following configuration variables that
control the Update Notification feature.
The mobility entities, the local mobility anchor, and the mobile
access gateway have to allow these variables to be configured by the
system management. The configured values for these protocol
variables have to survive server reboots and service restarts.
MAX_UPDATE_NOTIFICATION_RETRANSMIT_COUNT
This variable specifies the maximum number of times a local
mobility anchor can retransmit an Update Notification message
before it receives an Update Notification Acknowledgement message.
The default value for this parameter is 1. The suggested range of
configured values for this variable is between 0 and 5.
MIN_DELAY_BETWEEN_UPDATE_NOTIFICATION_REPLAY
This variable specifies the minimum delay in seconds before an
Update Notification message is retransmitted. The default value
for this parameter is 1000 milliseconds. The suggested range of
configured values for this variable is between 500 and
5000 milliseconds.
8. Security Considerations
The Update Notification protocol described in this specification is
for use between a local mobility anchor and a mobile access gateway.
This specification defines two new Mobility Header messages: Update
Notification messages and Update Notification Acknowledgement
messages. These Mobility Header messages are to be protected using
the same security mechanism that is used for protecting the Proxy
Mobile IPv6 signaling messages exchanged between a given local
mobility anchor and mobile access gateway.
If IPsec is used, the IPsec security association that is used for
protecting the Proxy Binding Update and Proxy Binding Acknowledgement
also needs to be used for protecting Update Notification and Update
Notification Acknowledgement messages. A Proxy Mobile IPv6
implementation and the IPsec layer are typically able to communicate
with each other through an implementation-specific interface, for
example, to exchange configuration and notification information.
The traffic selectors associated with the Security Policy Database
(SPD) entry for protecting Proxy Binding Update and Proxy Binding
Acknowledgement messages (Section 4.2 of [RFC5213]) have to be
extended to include the Mobility Header Type values 19 and 20, which
have been allocated for Update Notification and Update Notification
Acknowledgement messages, respectively. Furthermore, any time there
is rekeying of the IPsec security association between the mobile
access gateway and the local mobility anchor, the newly established
IPsec security association will be used for protecting the Update
Notification and Update Notification Acknowledgement messages.
9. Acknowledgements
The authors would like to thank Basavaraj Patil, Rajeev Koodli,
Lionel Morand, Itsuma Tanaka, Rajesh Pazhyannur, Carlos Jesus
Bernardos Cano, John Kaippallimalil, Brian Haberman, and other
members of the NETEXT working group for all the comments and
discussions on the document.
The authors would like to thank Barry Leiba, Robert Sparks, Carlos
Pignataro, Benoit Claise, Stephen Farrell, and Jari Arkko for their
inputs to the document as part of the IESG review process.
10. IANA Considerations
IANA has taken the following actions.
o This specification defines a new Mobility Header Type message,
Update Notification. This Mobility Header message is described in
Section 4.1. The type value 19 for this message has been
allocated from the "Mobility Header Types - for the MH Type field
in the Mobility Header" registry at <http://www.iana.org/
assignments/mobility-parameters>.
o This specification defines a new Mobility Header Type message,
Update Notification Acknowledgement. This Mobility Header message
is described in Section 4.2. The type value 20 for this message
has been allocated from the "Mobility Header Types - for the MH
Type field in the Mobility Header" registry at <http://
www.iana.org/assignments/mobility-parameters>.
o This specification defines a new registry for Notification
Reasons. It is called the "Update Notification Reasons Registry".
This registry has been created under the "Mobile IPv6 Parameters"
registry at <http://www.iana.org/assignments/mobility-parameters>.
The Notification Reason is a field in the Update Notification
message (Section 4.1). The number space for the Notification
Reason field needs to be managed by IANA, under the "Update
Notification Reason Registry". This specification reserves the
following type values. The allocation policy for this field is
"Specification Required" [RFC5226].
+=====+===========================+====================+
|Value| Description | Reference |
+=====+===========================+====================+
| 0 | Reserved | [RFC7077] |
+=====+================================================+
| 1 | FORCE-REREGISTRATION | [RFC7077] |
+=====+================================================+
| 2 | UPDATE-SESSION-PARAMETERS | [RFC7077] |
+=====+================================================+
| 3 | VENDOR-SPECIFIC-REASON | [RFC7077] |
+=====+================================================+
| 4 | ANI-PARAMS-REQUESTED | [RFC7077] |
+=====+================================================+
|255 | Reserved | [RFC7077] |
+=====+================================================+
o This specification defines a new registry for Status. It is
called the "Update Notification Acknowledgement Status Registry".
This registry has been created under the "Mobile IPv6 Parameters"
registry at <http://www.iana.org/assignments/mobility-parameters>.
The status is a field in the Update Notification Acknowledgement
message (Section 4.2). The number space for the Status field
needs to be managed by IANA, under the "Update Notification
Acknowledgement Status Registry". This specification reserves the
following type values. The allocation policy for this field is
"Specification Required". Status codes between 0 and 127 signify
successful processing of the Update Notification message, and
codes between 128 and 255 signify that an error occurred during
processing of the Update Notification message.
+=====+=====================================+=============+
|Value| Description | Reference |
+=====+=====================================+=============+
| 0 | SUCCESS | [RFC7077] |
+=====+=====================================+=============+
|128 | FAILED-TO-UPDATE-SESSION-PARAMETERS | [RFC7077] |
+=====+=====================================+=============+
|129 | MISSING-VENDOR-SPECIFIC-OPTION | [RFC7077] |
+=====+=====================================+=============+
11. References
11.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC4283] Patel, A., Leung, K., Khalil, M., Akhtar, H., and K.
Chowdhury, "Mobile Node Identifier Option for Mobile IPv6
(MIPv6)", RFC 4283, November 2005.
[RFC5094] Devarapalli, V., Patel, A., and K. Leung, "Mobile IPv6
Vendor Specific Option", RFC 5094, December 2007.
[RFC5213] Gundavelli, S., Leung, K., Devarapalli, V., Chowdhury, K.,
and B. Patil, "Proxy Mobile IPv6", RFC 5213, August 2008.
[RFC5844] Wakikawa, R. and S. Gundavelli, "IPv4 Support for Proxy
Mobile IPv6", RFC 5844, May 2010.
[RFC6275] Perkins, C., Johnson, D., and J. Arkko, "Mobility Support
in IPv6", RFC 6275, July 2011.
[RFC6602] Abinader, F., Gundavelli, S., Leung, K., Krishnan, S., and
D. Premec, "Bulk Binding Update Support for Proxy Mobile
IPv6", RFC 6602, May 2012.
11.2. Informative References
[PMIPv6-FLOW-MOB]
Bernardos, CJ., Ed., "Proxy Mobile IPv6 Extensions to
Support Flow Mobility", Work in Progress, October 2013.
[PMIPv6-QoS]
Liebsch, M., Seite, P., Yokota, H., Korhonen, J., and S.
Gundavelli, "Quality of Service Option for Proxy Mobile
IPv6", Work in Progress, October 2013.
[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.
[RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", BCP 26, RFC 5226,
May 2008.
[RFC5846] Muhanna, A., Khalil, M., Gundavelli, S., Chowdhury, K.,
and P. Yegani, "Binding Revocation for IPv6 Mobility", RFC
5846, June 2010.
[RFC5847] Devarapalli, V., Koodli, R., Lim, H., Kant, N., Krishnan,
S., and J. Laganier, "Heartbeat Mechanism for Proxy Mobile
IPv6", RFC 5847, June 2010.
[RFC6757] Gundavelli, S., Korhonen, J., Grayson, M., Leung, K., and
R. Pazhyannur, "Access Network Identifier (ANI) Option for
Proxy Mobile IPv6", RFC 6757, October 2012.
[RFC6909] Gundavelli, S., Zhou, X., Korhonen, J., Feige, G., and R.
Koodli, "IPv4 Traffic Offload Selector Option for Proxy
Mobile IPv6", RFC 6909, April 2013.
Authors' Addresses
Suresh Krishnan
Ericsson
8400 Blvd Decarie
Town of Mount Royal, Quebec
Canada
Phone: +1 514 345 7900 x42871
EMail: suresh.krishnan@ericsson.com
Sri Gundavelli
Cisco
170 West Tasman Drive
San Jose, CA 95134
USA
EMail: sgundave@cisco.com
Marco Liebsch
NEC
Kurfuersten-Anlage 36
D-69115 Heidelberg
Germany
EMail: marco.liebsch@neclab.eu
Hidetoshi Yokota
KDDI
EMail: yokota@kddilabs.jp
Jouni Korhonen
Broadcom
Porkkalankatu 24
Helsinki FIN-00180
Finland
EMail: jouni.nospam@gmail.com