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RFC 5213

 
 
 

Proxy Mobile IPv6

Part 4 of 4, p. 67 to 92
Prev RFC Part

 


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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

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   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.

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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.

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   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].

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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

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      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:

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       0                   1                   2                   3
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |      Type     |   Length      |   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.

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   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.

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   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")

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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.

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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:

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     0                   1                   2                   3
     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
                                     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                                     |      Type     |   Length      |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                                                               |
     +                          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

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   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

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   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 resources

9.  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.

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   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.

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      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.

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      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.

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   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.

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   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

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   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.

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   [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.

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   [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.

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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.

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   +==================================================================+
   |  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

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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

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