RFC7077

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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.

  5.2. Receiving the Update Notification Acknowledgement
  6.2. Constructing the Update Notification Acknowledgement

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.

Conventions and Terminology

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.

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.

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: UPDATE-SESSION-PARAMETERS

Message Formats

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.

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.

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.

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)

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.

MAG Considerations

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.

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)

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.

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.

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, November 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: [email protected]

Sri Gundavelli Cisco 170 West Tasman Drive San Jose, CA 95134 USA

EMail: [email protected]

Marco Liebsch NEC Kurfuersten-Anlage 36 D-69115 Heidelberg Germany

EMail: [email protected]

Hidetoshi Yokota KDDI

EMail: [email protected]

Jouni Korhonen Broadcom Porkkalankatu 24 Helsinki FIN-00180 Finland

EMail: [email protected]