One document matched: draft-ietf-netext-bulk-re-registration-02.xml


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<rfc category="std" docName="draft-ietf-netext-bulk-re-registration-02"
     ipr="trust200902">
  <front>
    <title abbrev="PMIPv6 Bulk Re-registration">Bulk Re-registration for Proxy
    Mobile IPv6</title>
    <author role="editor" fullname="Fuad Abinader" initials="F." surname="Abinader">
	  <organization>Instituto Nokia de Tecnologia</organization>
      <address>
        <postal>
          <street>Av. Torquato Tapajos, 7200 - Km. 12 - Col Terra Nova</street>
          <city>Manaus</city>
          <region>AM</region>
          <code>69048-660</code>
          <country>BRAZIL</country>
        </postal>
        <email>fuad.junior@indt.org.br</email>
      </address>
    </author>

    <author fullname="Sri Gundavelli" initials="S." surname="Gundavelli">
      <organization>Cisco</organization>

      <address>
        <postal>
          <street>170 West Tasman Drive</street>

          <city>San Jose</city>

          <region>CA</region>

          <code>95134</code>

          <country>USA</country>
        </postal>

        <phone></phone>

        <facsimile></facsimile>

        <email>sgundave@cisco.com</email>

        <uri></uri>
      </address>
    </author>

    <author fullname="Kent Leung" initials="K." surname="Leung">
      <organization>Cisco</organization>

      <address>
        <postal>
          <street>170 West Tasman Drive</street>

          <city>San Jose</city>

          <region>CA</region>

          <code>95134</code>

          <country>USA</country>
        </postal>

        <phone></phone>

        <facsimile></facsimile>

        <email>kleung@cisco.com</email>

        <uri></uri>
      </address>
    </author>

    <author fullname="Suresh Krishnan" initials="S." surname="Krishnan">
      <organization>Ericsson</organization>

      <address>
        <postal>
          <street>8400 Decarie Blvd.</street>

          <city>Town of Mount Royal</city>

          <region>QC</region>

          <code></code>

          <country>Canada</country>
        </postal>

        <phone>+1 514 345 7900 x42871</phone>

        <facsimile></facsimile>

        <email>suresh.krishnan@ericsson.com</email>

        <uri></uri>
      </address>
    </author>

    <author fullname="Domagoj Premec" initials="D." surname="Premec">
      <organization>Unaffiliated</organization>

      <address>
        <postal>
          <street></street>

          <city></city>

          <code></code>

          <region></region>

          <country></country>
        </postal>

        <email>domagoj.premec@gmail.com</email>
      </address>
    </author>

    <date year="2010" />

    <area>Internet Area</area>

    <workgroup>Netext Working Group</workgroup>

    <keyword>Proxy Mobile IPv6</keyword>

    <keyword>PMIPv6</keyword>

    <keyword>bulk registrations</keyword>

    <keyword>MN group ID</keyword>

    <abstract>
      <t>Proxy Mobile IPv6 specification requires the Mobile Access Gateway
      (MAG) to send a separate Proxy Binding Update (PBU) message to the Local
      Mobility Agent (LMA) for each mobile node (MN) to renew the MN’s
      mobility binding. This document defines a mechanism by which a MAG can
      update the mobility bindings of multiple MNs attached to it with a
      single PBU message to the serving LMA. This document also specifies a
      new mobility option that can be used by the mobility entities in a Proxy
      Mobile IPv6 domain for carrying the group affiliation of a mobile node
      in any of the mobility signaling messages.</t>
    </abstract>

    <note title="Requirements Language">
      <t>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 <xref
      target="RFC2119">RFC 2119</xref>.</t>
    </note>
  </front>

  <middle>
    <section title="Introduction">
      <t>The Proxy Mobile IPv6 (PMIPv6) base specification <xref target="RFC5213"/> 
	  uses the Mobile Node Identifier (MN-ID) option in the mobility signaling messages,
	  i.e. Proxy Binding Update (PBU) and Proxy Binding Acknowledgement (PBAck)
	  messages, for identifying a single Mobile Node (MN). However, these signaling 
	  messages lack the capability to identify a set of mobile nodes which have 
	  a common characteristic. A group identifier associated with a set of mobile 
	  nodes enables the ability to perform protocol operation on this set of mobile 
	  nodes via a single transaction. The group identifier also provides a more
	  optimal mechanism for protocol operation which would otherwise require
	  multiple atomic transactions on a mobile node basis. Following are some
	  of the use-cases where such identifier can be used.</t>

      <t><list style="symbols">
          <t>In a blade architecture system running the Local Mobility Anchor
          (LMA) service, all the mobile node sessions anchored on a given 
		  card can belong to a single group. When there is a failure on a
		  specific card, the LMA can initiate the revocation signaling to the
		  Mobile Access Gateway (MAG) by sending a single revocation request 
		  carrying the group identifier.</t>

          <t>For periodic re-registrations, the MAG may send a single 
		  re-registration message for all the mobile nodes that belong to 
		  a group by informing just the mobile node group identification that
		  identifies that group.</t>

          <t>The MAG or the LMA in a PMIPv6 domain may choose to revoke the 
		  registration of all mobile nodes associated with a specific realm. In
		  such cases the MAG or the LMA can perform the binding revocation 
		  signaling using the group ID associated with a specific set of mobile
		  nodes.</t>
        </list></t>
		
		<t>The remainder of this document defines a new mobility option,
		named Mobile Node Group Identifier option, that can be used by a local
		mobility anchor and a mobile access gateway for exchanging the mobile
		node's group identifier as well as its application for bulk periodic
		re-registrations.</t>
		
    </section>

    <section title="Terminology">
      <t>General mobility related terminology is defined in <xref
      target="RFC3775"></xref>. Additional PMIPv6 specific terminology can be
      found in <xref target="RFC5213"/>.</t>

      <t><list style="hanging">
          <t hangText="PMIPv6"><vspace blankLines="0" />Proxy Mobile IPv6
          protocol, as specified in <xref target="RFC5213"/>.</t>

          <t hangText="PMIPv6 domain"><vspace blankLines="0" />Network
          providing the network based IP mobility service as defined in <xref
          target="RFC5213"/>.</t>

          <t hangText="Group Identifier"><vspace blankLines="0" />An opaque 
		  identifier (i.e. not containing any information that is at risk of 
		  becoming not valid in the future) that is allocated by the LMA, and
		  which uniquely identifies the bulk set to which the MN was added in 
		  both the LMA and in the MAG. As an example of the meaning of such 
		  opacity, the LMA may decide to use random numbers as the value for 
		  the group identifier. This group identifier shall be used on signaling
		  messages operating over bulk registration sets between the MAG and
		  the LMA.</t>

          <t hangText="Bulk registration"><vspace
          blankLines="0" />Operation involving the exchange of PBU/PBAck messages
		  where the bulk registration flag (B) is set to 1.</t>

          <t hangText="Bulk registration set"><vspace blankLines="0" />A
          set of MNs identified by the Mobile Node Group Identifier option to 
		  which the bulk registration operation applies.</t>
        </list></t>
    </section>

    <section anchor="overview" title="Bulk Registration Overview">
      <section title="Motivation for bulk re-registration">
        <t>In a PMIPv6 domain a single LMA serves multiple MAGs and the
        capacity of the LMA in terms of the number of attached MNs can be
        quite large. It can be expected that LMA capacity in managed networks
        may easily exceed hundreds of thousands (or even more) of attached 
		MNs. However, as the number of managed MNs grows, it also grows the
		demand for bandwidth for signaling messages to refresh the mobility 
		bindings of such MNs. The following simple formula gives an estimate 
		of the average number of re-registration transactions per second as a
		function of the number of registered MNs and the binding lifetime
		period:</t>

        <t>transactions/sec = (number of registered MNs) / (binding
        lifetime*4)</t>

        <t>For a scenario of 50.000 MNs and the binding lifetime of half an 
		hour this gives: 50000 MNs / 1800 sec = 27,7 transactions/sec</t>

        <t>Based on the above formula and example scenario it is apparent that 
		the default PMIPv6 re-registration process where the MAG sends a separate
		message for each MN is inefficient or suboptimal. These re-registration 
		messages consume significant network resources, both in terms of processing
        power at the LMA and MAG and in terms of network bandwidth.</t>

        <t>This document proposes an optimization of the PMIPv6 re-registration
        process by which the signaling load for re-registration can be reduced
        to a single transaction per MAG, irrespective of the number of
        attached MNs. According to this proposal, a MAG adds a MN to a set of MNs
        re-registered in a bulk mode by setting the bulk registration flag
        (B) in the PBU message. The PBAck message sent in response contains the
        Mobile Node Group Identifier mobility option which is defined later in
        this document. In the context of bulk re-registrations the Mobile Node
        Group Identifier is an opaque identifier that is allocated by the LMA
        and which uniquely identifies the bulk set to which the MN was added.</t>

        <t>A MAG requests a bulk re-registration for a set of MNs by sending a
        single PBU message which includes a Mobile Node Group Identifier option, 
		and the LMA then extends the binding lifetime of all the MNs that 
        belong to that group. By using this method, the MAG and LMA may
        accomplish the re-registration of MNs attached to a MAG in a single
        transaction. The number of re-registration transactions at the LMA
        becomes independent of the number of attached MNs; instead it is
        dependent only on the number of MAGs (i.e. bulk registration 
		sets).</t>

        <t>In addition to minimizing the signaling overhead associated with
        the lifetime extension of the mobility bindings, the MAG and LMA may
        use a single timer per bulk registration set to monitor the binding
        lifetime of all the member MNs instead of an individual timer per
        MN.</t>
      </section>

      <section title="Bulk re-registration operation">
        <t>The bulk re-registration mechanism allows the MAG and the LMA to
        extend the binding lifetime for a number of MNs with a single
        transaction. The MAG and LMA maintain a set of MNs that can be
        re-registered in bulk mode. Such set is called a bulk registration
        set, and is a subset of the MNs attached to a MAG. There can be
        multiple bulk registration sets for a given MAG-LMA pair; however, 
		there can be only one MAG and one LMA associated with a given bulk
		registration set at any moment.</t>
		
		<t>There are two basic operations related to bulk registration sets
		which may be requested by the MAG for any given MN, namely the addition 
		(BULK_ADD_MN) of a MN to some bulk registration set (to be determined
		by the LMA) and the removal (BULK_REMOVE_MN) of a MN from some bulk 
		re-registration set. In the case of the removal of a single MN from a 
		bulk registration set (BULK_REMOVE_MN), the LMA may also take a 
		unilateral decision to remove the MN, as specified later in this 
		specification.</t>
		
		<t>In addition to these MN operations, the MAG may also request two
		additional operations for any given bulk registration set. The first
		operation is the collective re-registration (BULK_REREG_SET) of a set 
		of MNs within a given bulk registration set with a single atomic 
		operation. The other operation is the the removal of all MNs previously 
		contained in a given bulk registration set (BULK_TERMINATE_SET), which 
		means that all MNs previously in that bulk registration set must be 
		individually registered again by the MAG on the	LMA. The LMA may also
		decide to terminate the mobility binding of all MNs previously 
		contained in a given bulk registration set (BULK_TERMINATE_SET), in 
		which case it must use the proper mechanism described further in this
		document.</t>
		
		<t>Note that this specification  does not define any new PMIPv6 signaling, but 
		solely defines new mobility options for the existing PMIPv6 signaling 
		messages, whose are defined  in	details on <xref target="mnid_option"/>.</t>
		
		<t>In the following sections are provided further details both on the two operations 
		over the MNs in a bulk registration set (BULK_ADD_MN and BULK_REMOVE_MN) as
		well as on the two operations over the bulk registration sets themselves
		(BULK_REREG_SET and BULK_TERMINATE_SET) are provided.</t>
		
		<section title="BULK_ADD_MN operation" anchor="BULK_ADD_MN">
			<t>Initially the bulk registration set is empty. MAG requests to add 
			individual MNs to the bulk registration set (while at the same time 
			refreshing the MN binding itself) by sending a regular PBU message that 
			(a) identifies an individual MN with its MN-ID and (b) sets the bulk 
			re-registration flag in the message to 1. Based on the received bulk 
			re-registration flag on the PBU message, the LMA takes the decision 
			whether to add the MN to a bulk registration set or not. If the LMA 
			decides for including the MN on a bulk registration set, it responds 
			to the MAG with a PBAck message where (a) the bulk registration flag (B) 
			set to 1 and (b) the bulk registration set to which the MN was added 
			is represented by the Mobile Node Group ID option. If, instead, the LMA 
			decides for reject the addition of the MN on a bulk registration set, 
			the LMA processes the PBU message as if the bulk registration flag 
			was not set, and responds with PBAck message where the bulk 
			re-registration flag is set to 0.</t>
			
	        <t>There may be different aspects involved in the LMA decision process
			whether to include or not a MN on a bulk registration set upon a 
			request by the MAG via a PBU message with the the bulk registration 
			flag (B) in the message set to 1. However, they may be implementation or
	        domain specific, and therefore are outside the scope of this 
			specification.</t>
		</section>
		
		<section title="BULK_REMOVE_MN operation" anchor="BULK_REMOVE_MN">
	        <t>A MAG may remove a single MN from the bulk registration set in 
			which it is currently included by sending a regular PBU message to the
			LMA identifying the MN to be removed (i.e. MN-ID) and with the bulk 
			re-registration flag set to 0. This PBU message not only informs the
			LMA to remove the MN from its current bulk registration set, but also
			requests to refresh the binding of that MN as well, just as a regular
			PBU message would do. The LMA then responds with a regular PBAck message
			where the bulk registration flag set to 0 and the MN-ID that identifies
			that MN, therefore indicating to the MAG that the binding of such MN was
			refreshed.</t>
			
			<t>The LMA itself may also decide (for some implementation or domain specific 
			reason not covered on this specification) to remove a single MN from its
			current bulk registration set, in which case it sends a non-solicited 
			regular PBAck message to the MAG, with the the bulk registration flag 
			set to 0 and with the MN identification field (i.e. MN-ID). This message
			not only informs that a given MN previously contained in a bulk 
			re-registration set was removed, but also that the binding of such MN was
			also refreshed. If the lifetime value in the non-solicited PBAck message
			is set to a value different than 0, this must indicate to the MAG that the
			MN is no longer on a bulk registration set but the binding of the MN in
			the LMA is indeed refreshed and valid, and therefore this MN refreshing 
			timer must be controlled separately in a proper way, just as a regular MN
			as per the <xref target="RFC5213"/>. If however the the lifetime value 
			indicated in the non-solicited PBAck message is set to 0, it not only 
			indicates that the MN was removed from the bulk registration set, but also
			that the binding of that MN on the LMA itself has expired, and therefore is
			no longer valid.</t>		
		</section>
		
		<section title="BULK_REREG_SET operation" anchor="BULK_REREG_SET">
	        <t>Once there is a non-empty bulk registration set registered at the
			LMA (with one or more MNs), the MAG can request to extend the binding 
			lifetime for all MNs belonging to such bulk registration set by 
			sending a PBU message with the bulk registration (B) flag set and by 
			including the Mobile Node Group ID identifying the bulk registration 
			set itself, which value was previously received from the LMA. Such PBU 
			message lacks any options that identify an individual MN. In particular,
			the MAG omits both the MN-ID (Mobile Node Identifier) and the HNP (Home 
			Network Prefix) options.</t>

			<t>MAG may also include multiple instances of the Mobile Node Group 
			Identifier option in a single PBU message only if the intent is to request
			lifetime refreshment for several bulk registration sets at the same time.
			Even further, the MAG may even request to re-register all bulk 
			re-registration sets previously established with the LMA by sending
			a single PBU message where there is a single Mobile Node Group Identifier 
			option with the value of all bits set to 1 (see <xref target="mnid_option"/>
			for more information). However, PBU messages that try to extend binding 
			time to some bulk registration sets while at the same time terminating 
			bindings with other bulk registration sets (e.g. by setting zero 
			lifetime) in the same PBU message are not possible, as this PBU message 
			would be ambiguous in determining which bulk registration sets would 
			be refreshed and which bulk registration sets would be terminated. As
			a consequence, if for some reason those two classes of operations need to
			be performed concurrently, they must be done with the use of separate PBU
			messages.</t>
			
	        <t>Upon the receive of the PBU message with the bulk registration (B)
			bit set and by including the Mobile Node Group ID instance(s) identifying 
			the bulk registration set(s) to re-register (i.e. refresh the binding
			of each MN belonging to each bulk registration set informed), the LMA 
			extends the mobility binding of all MNs that are members of the indicated 
			bulk registration set(s) and responds with the PBAck message echoing 
			the received Mobile Node Group Identifier mobility options, in special with
			the bulk registration (B) flag set and including the Mobile Node Group ID 
			instance(s) identifying the bulk registration set(s) re-registered.</t>
		</section>		
		
		<section title="BULK_TERMINATE_SET operation" anchor="BULK_TERMINATE_SET">
			<t>A MAG may request to terminate any given bulk registration set at any 
			moment with a single atomic operation, which implicates (a) in the expiration 
			of the mobility bindings of all the MNs belonging to that bulk registration 
			set on the LMA at the same time and (b) on the termination of the bulk 
			registration set itself on both the MAG and the LMA. For that, the MAG sends 
			a PBU message with the bulk registration flag (B) set to 1, sets the lifetime 
			value to zero and informs the bulk registration set to the LMA by including 
			the Group I-D option in the message. Here, the MAG may also perform the 
			termination of more than one bulk registration sets with a single atomic 
			operation, in which case the PBU message contains the multiple mobile node
			Group I-D options representing these multiple bulk registration sets. Finally,
			the MAG may also request to terminate all bulk registration sets, in which case
			it should send the Group I-D option with the value of all bits set to 1 (see 
			<xref target="mnid_option"/> for more information).</t>

			<t>Upon receive of such PBU message indicating a bulk registration termination 
			request, the LMA expires the mobility bindings of all the MNs belonging to all the
			bulk registration sets specified in the PBU message and extinguish the 
			representations of the bulk registration sets themselves. Then, the LMA sends
			back a PBAck message to the MAG, reproducing all the mobility options informed on 
			the original PBU message, including the bulk registration flag (B) set to 1,
			the lifetime value set to zero and the Group I-Ds originally mentioned.</t>
			
			<t>The LMA itself may also decide unilaterally that one or more bulk registration
			sets are terminated, in which case it shall expires the mobility bindings of all the
			MNs belonging to these bulk registration sets, extinguish the representations of 
			these bulk registration sets and send a PBAck message to the MAG where the bulk 
			re-registration flag (B) is set to 1, the lifetime value is set to zero and the 
			Group I-Ds identifying bulk registration sets. The MAG, upon the receive of such
			PBAck message, then proceeds with the expiration of the mobility bindings of the MNs
			belonging to the specified bulk registration sets as per <xref target="RFC5213"/>,
			and then extinguish the management of the bulk registration sets themselves.
			The reasons for both the MAG or LMA deciding to extinguish bulk registration sets
			may be implementation or domain specific, and therefore are outside the scope of this 
			specification.</t>
		</section>
      </section>
    </section>

    <section title="Message formats">
      <t>This section introduces extensions to PBU and PBAck messages used in
      this specification.</t>

      <section title="Proxy Binding Update message" anchor="pbu_message">
        <figure anchor="PBU-format">
            <artwork><![CDATA[ 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|B|   Reserved    |            Lifetime           |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|                                                               |
.                                                               .
.                        Mobility options                       .
.                                                               .
|                                                               |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
]]></artwork>
          </figure>

        <t>A Proxy Binding Update message is defined in the <xref target="RFC5213"/>.
		A new flag (B) is defined for the Binding Update message, as seen on 
		<xref target="PBU-format"/>, while the other remaining fields (i.e. 
		Sequence #, flags and Lifetime) keep their definition as per defined
		in the <xref target="RFC5213"/>.</t>

        <t>Bulk Registration Flag (B)</t>

        <t>If the bulk registration flag (B) is set to 1, then the PBU message
        is a request to add the MN to the bulk registration set. If the
        bulk registration flag (B) is set to 0 and if the MN is found to be a
        member of the bulk registration set, then the MN is removed from
        the bulk registration set.</t>

        <t>Mobility Options</t>

        <t>For descriptions of the mobility options, refer to <xref
        target="RFC5213"></xref>. When the PBU message is sent to refresh
        bindings in a bulk mode, the message MUST contain at least one Mobile
        Node Group Identifier mobility option and does not contain the MN-ID
        and the HNP mobility options.</t>
      </section>

      <section title="Proxy Binding Acknowledgment message" anchor="pback_message">
        <figure anchor="PBAck-message"
            title="Proxy Binding Acknowledgment message">
            <artwork><![CDATA[ 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|B|  Res. |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|         Sequence #            |           Lifetime            |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|                                                               |
.                                                               .
.                        Mobility options                       .
.                                                               .
|                                                               |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
]]></artwork>
          </figure>

        <t>A Proxy Binding Acknowledgment message is defined in the <xref
        target="RFC5213"/>. A new flag (B) is defined for the Binding
        Acknowledgment message, as seen on <xref target="PBAck-message"/>.</t>

        <t>Bulk Registration Flag (B)</t>

        <t>A new flag (B) is included in the Binding Acknowledgment message to
        indicate to the MAG that the MN was successfully added to the bulk
        re-registration set. The flag MUST NOT be set to the value of 1 if it
        was not set to 1 in the corresponding PBU message.</t>

        <t>Mobility Options</t>

        <t>These are the original PMIPv6 mobility options as defined in 
		<xref target="RFC5213"/>. Additionally, at least one instance of the Mobile Node 
		Group Identifier mobility option (see <xref target="mnid_option"/>) MUST
		be included on the PBAck message if the bulk registration flag is set to 1
        in the PBU message. When the Mobile Node Group Identifier mobility option(s) 
		were included in the PBU message, the PBAck message echoes back the Mobile 
		Node Group Identifier options from the PBU message.<xref target="RFC5213"/>.</t>
      </section>

      <section title="Mobile Node Group Identifier Option " anchor="mnid_option">
        <t>A new option, Mobile Node Group Identifier option is defined for
        using it in Proxy Binding Update and Proxy Binding Acknowledgement
        messages exchanged between a local mobility anchor and mobile access
        gateway. This option is used for carrying the mobile node's group
        identifier.</t>

        <t>The alignment requirement for this option is 4n.</t>

        <figure anchor="GID_option"
                title="Mobile Node Group Identifier Option">
          <artwork><![CDATA[
      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      |           Sub-type            |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                 Mobile Node Group Identifier                  |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

]]></artwork>
        </figure>

        <t><list style="hanging">
            <t hangText="Type"><vspace blankLines="0" /><IANA></t>

            <t hangText="Length"><vspace blankLines="0" />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 6 in the case where the PBU message is requesting the binding
            refresh, both for the situation where the Mobile Node Group 
			Identifier specifies a single bulk registration set and for
			the situation where this field specifies all the MNs attached to 
			the MAG that are members of any bulk set.</t>

            <t hangText="Sub-type"><vspace blankLines="0" />Identifies the
            specific group type. This number space will be managed by the
            IANA.</t>

            <t hangText="Mobile Node Group Identifier ">A 32-bit field
            containing the mobile node's group identifier. This field may 
			identify either a single bulk registration set or all the 
			MNs attached to the MAG that are members of any bulk set, 
			depending on the value. Specifically in the case where the field 
			is representing all the MNs attached to the MAG that are members 
			of any bulk set, then all the bits of that field should be set to 
			1.</t>
          </list>

		  <t>The Mobile Node's Group Identifier option reflects the group
		  affiliation that is local to the specific LMA-MAG pair. The specific
		  value for the Mobile Node group Identifier is always determined by the
		  LMA on the PBAck message, and must be used by the MAG on all future
		  bulk re-registration procedures for that bulk registration set.</t>
		</t>
      </section>
    </section>

    <section title="MAG Operation">
      <t>The conceptual Binding Update List entry data structure maintained by
      the MAG, described in Section 6.1 of <xref target="RFC5213"/>, MUST be 
	  extended to store the mobile node's group identifier. The MAG SHALL maintain
	  separate bulk registration sets for each LMA.</t>

      <t>Bulk re-registration operations are optional to PMIPv6 <xref 
	  target="RFC5213"/>, so the Mobile Node Group Identifier option MAY be used 
	  in the PBU message sent by the MAG to the LMA only when a bulk registration 
	  operation (i.e. BULK_REREG_SET and BULK_TERMINATE_SET) is intended. When 
	  this option is included, the identifier value in the option MUST be set to 
	  the mobile node's group identifier that was assigned previously by the LMA.</t>

      <t>When a new MN attaches to a MAG, the MAG registers the MN with the
      LMA by sending the PBU message formatted as described in <xref target="RFC5213"/>. 
	  Additionally, the MAG MAY set the bulk registration flag (B) in the 
	  PBU message to 1 to request the LMA to add the MN to the bulk registration set.</t>

	  <t>The decision to request the bulk registration mode for a MN is a 
	  matter of local policy at the MAG and is outside the scope of this 
	  specification.</t>

      <t>The MAG SHALL add the MN to its bulk registration set when it
      receives a PBAck message with the bulk registration flag (B) set to 1 and if
      the corresponding PBU message was previously requesting the LMA to add 
	  the MN to a bulk registration set. The MAG SHALL associate the MN being
      registered with the Mobile Node Group Identifier received in the PBAck
      message. If instead the MAG sets the bulk registration flag to 1 in a PBU 
	  message but the bulk registration flag (B) is set to 0 in a PBAck message, 
	  the MAG SHALL process the PBAck message as per <xref target="RFC5213"/>.
	  In addition, the MAG MAY infer that the LMA does not support bulk 
	  re-registration procedure. The MAG MAY switch to regular, per-MN 
	  re-registration mode as described in <xref target="RFC5213"/>, and 
	  MAY NOT retry bulk registration set additions to that LMA unless
	  an administrative action is taken.</t>
	  
	  <t>The MAG SHALL decide to remove a single MN from the bulk registration 
	  set in which it is currently included at any time, and in order to proceed 
	  with such operation the MAG SHALL send a standard PMIPv6 PBU message (as
	  per the <xref target="RFC5213"/>) identifying the MN and with the bulk 
	  registration flag (B) set to 0. This PBU message not only informs the LMA
	  to remove the MN from its current bulk registration set, but also requests
	  to refresh the mobility binding of that MN as well, as a regular PMIPv6 message
	  would do.</t>
	  
	  <t>Upon receive of a standard PBAck message in response for the PBU message
	  just sent, the MAG SHALL process the message as per the remove the <xref 
	  target="RFC5213"/>, and then remove the MN from the bulk registration set. If
	  the lifetime of the PBAck message is larger than zero, it SHALL mean that the
	  MN only was removed from the bulk registration set but the mobility binding
	  of such MN is still valid, and therefore the mobility binding should be renewed
	  as specified in <xref target="RFC5213"/>; if however the lifetime is equal to
	  zero, it SHALL mean for the MAg that not only the MN was removed from the bulk
	  registration set but also that the mobility binding of such MN is no longer 
	  valid, and SHALL proceed as specified in <xref target="RFC5213"/>.<t>
	  
	  </t>The MAG may also receive a non-solicited standard PBAck message for a 
	  MN which is currently on a bulk registration set, which SHALL mean for the
	  MAG that the LMA decided unilaterally to remove the MN from the bulk 
	  registration set. The MAG SHALL proceed processing this PBAck message as
	  defined in the previous paragraph, as if this PBAck message was sent in 
	  response to a request by the MAG to remove the MN from the bulk registration
	  set it is currently in.</t>
	  
      <t>The binding lifetime of MNs which belong to a given bulk registration 
      set becomes the binding lifetime of the bulk registration set itself. 
      Therefore, both the MAG and the LMA MAY not keep separate binding 
      lifetimes for all MNs in a given bulk registration set, and instead
      SHALL keep a common binding lifetime for the whole bulk registration set.	  
      If later on a given MN leaves the bulk registration set, then both the 
      MAG and the LMA SHALL keep separate binding lifetimes for this MN.</t>
	  
      <t>When the binding lifetime of a bulk registration set is about to expire, 
      the MAG SHALL request the bulk re-registration by sending the PBU message 
      containing  the Mobile Node Group Identifier mobility option. 
      Alternatively, the MAG MAY include one or more Mobile Node Group 
      Identifier options containing the values that were indicated by the LMA 
      in the PBAck messages when the MN was added to the bulk set. In this case 
      the MAG asks for refreshment of specific bulk sets indicated by the Mobile 
      Node Group Identifier options. The MAG MAY even request the refreshment of
	  all the MNs attached to the MAG that are members of any bulk set with a 
	  single atomic operation, in which case there will be a single Mobile Node 
	  Group Identifier option on the PBU message with all the field bits set to 1
	  as specified in <xref target="mnid_option"/>. In any case, the MAG SHALL NOT
	  include the MN ID and the HNP options in the PBU message requesting bulk 
	  refreshment.</t>

      <t>The MAG MAY trigger a bulk re-registration at any time. The policy
      and exact conditions for these additional triggers are outside of scope
      of this specification.</t>

      <t>When the MAG receives a PBAck message indicating success and which
      echoes the Mobile Node Group Identifier options that were included in
      the corresponding PBU message, the MAG SHALL update the binding lifetime
      of all MNs belonging to the indicated groups to the lifetime value
      contained in the PBAck message. If in the case of bulk registration the
	  PBAck message repeatedly indicate an error, the MAG SHALL fall back to 
	  individual re-registration mode.</t>
	  
	  <t>A MAG MAY decide to terminate any given bulk registration set at any 
	  moment, for reasons not covered at this specification. In order to proceed
	  with such operation, the MAG SHALL request the termination of such bulk 
	  registration set in a single atomic operation by sending a PBU message with
	  the bulk registration flag (B) set to 1, sets the lifetime 
	  value to zero and informs the bulk registration set to the LMA by including 
	  the Group I-D option in the message. Here, the MAG may also perform the 
	  termination of more than one bulk registration sets with a single atomic 
	  operation, in which case the PBU message contains the multiple mobile node
	  Group I-D options representing these multiple bulk registration sets. Finally,
	  the MAG may even request to terminate all bulk registration sets, in which case
	  it should send the Group I-D option with the value of all bits set to 1 (see 
	  <xref target="mnid_option"/> for more information).</t>
	  
	  <t>Upon receive the PBAck message echoing the PBU message requesting bulk 
	  registration set(s) termination(s), the MAG SHALL expire the mobility 
	  bindings of all the MNs belonging to that bulk registration sets and also 
	  terminate the bulk registration set itself.</t>
	  
	  <t>The reasons for the MAG deciding to terminate the bulk registration sets 
	  may be implementation or domain specific, and therefore are outside the 
	  scope of this specification.</t>
	  
	  <t>The MAG may also receive a non-solicited PBAck message where the bulk
	  registration flag (B) is set to 1 and with one or more mobile node group 
	  identifier option instances, just as if this message was sent in reply to
	  a PBU message sent by the MAG when requiring the terminaiton of bulk
	  registration sets. In this case, the MAG SHALL interpret this as a 
	  unilateral decision by the LMA to terminate the mobility bindings of the
	  MNs previously belonging to these bulk registration sets, and therefore
	  it should expire the mobility bindings of all the MNs belonging to the 
	  bulk registration sets at the same time and also terminate the bulk 
	  registration set(s) specified in the PBAck message.</t>
    </section>

    <section title="LMA operation">
      <t>The conceptual Binding Cache entry data structure maintained by the
      LMA, described in Section 5.1 of <xref target="RFC5213"></xref>, MUST be
      extended to store the mobile node's group identifier. The LMA SHALL
      maintain distinct bulk registration sets for each MAG and there could
      be several such sets per single MAG.</t>

      <t>The Mobile Node Group Identifier option MAY be used in the PBAck
      message sent by the LMA to the MAG. When this option is included, the
      identifier value in the option MUST be set to the MN's group identifier, 
	  local to the LMA.</t>

      <t>When the LMA receives a PBU message with a bulk registration flag (B)
      set to 1, the LMA SHALL first process the PBU message as per <xref
      target="RFC5213"/>. Upon successful processing of the message, the
      LMA SHALL perform additional processing of the PBU message as described
      further below for bulk mode re-registrations.</t>

      <t>If the bulk registration flag in the PBU message is set to 1, the
      LMA MAY add the MN(s) indicated in the PBU to the set of MNs
      re-registered in a bulk mode, subject to the local policy. The decision
      whether to enable bulk re-registration mode is a matter of local policy
      at the LMA and is outside the scope of this specification.</t>

      <t>If the LMA decides to accept the bulk re-registration mode for the
      MN, it SHALL add the MN to a bulk registration set. Upon adding the MN 
	  to the bulk registration set, the LMA SHALL respond with the PBAck message 
	  containing the bulk registration flag set to 1. The LMA SHALL include the 
	  Mobile Node Group Identifier option in the PBAck message. The Mobile Node 
	  Group Identifier is allocated by the LMA and identifies the particular bulk 
	  set to which the MN is assigned. If however the LMA decides to reject the 
	  bulk re-registration mode for the MN, it SHALL proceed with regular 
	  registration as per the <xref target="RFC5213"/>, and return a regular 
	  PBAck message with the bulk registration set flag (B) set to 0.</t>

      <t>The PBU message without the MN ID and HNP options but including the
      Mobile Node Group Identifier mobility option is a valid message and
      indicates a request for bulk mode re-registration of all MNs that are
      members of the indicated bulk registration set. There MAY be several
      Mobile Node Group Identifier options in the PBU message, in which case
      the MAG requests the bulk refreshment of all MNs that are members of the
      indicated bulk sets. If there is a single Mobile Node Group Identifier 
	  option on the PBU message with all the field bits set to 1, as specified in
	  <xref target="mnid_option"/>, the MAG is requesting a lifetime refreshment
	  of all the MNs attached to the MAG that are members of any bulk set. Therefore, 
	  LMA SHALL extend the binding lifetime of all affected MNs attached to the 
	  MAG that sent the bulk PBU.</t>
	  
      <t>The LMA SHALL set the binding lifetime of all MNs re-registered in a
      bulk mode to expire at the same point in time.</t>

      <t>Upon successful processing of bulk mode re-registration request, the
      LMA MUST respond with a PBAck message indicating success and echoing the
      mobility options received from the PBU. The lifetime in the PBAck
      message indicates the time when binding cache entries of affected MNs
      will expire. After successfully processing the bulk PBU message, the LMA 
	  SHALL start a single timer to oversee the binding lifetime of all MNs 
	  affected by this bulk re-registration transaction.</t>

      <t>The LMA not supporting this specification ignores the bulk
      re-registration flag (B) in a PBU message and processes the message as per
	  the baseline specification <xref target="RFC5213"></xref>. In this case 
	  the PBAck message sent in response contains the bulk registration flag
	  (B) set to 0.</t>

      <t>The LMA MAY reject the request for bulk re-registration. In this case
      the LMA MUST NOT update binding cache entries of any MNs and SHALL
      respond with PBAck indicating the reason for the rejection in the status
      code.</t>
	
	  <t>The LMA may receive a PBU message with the bulk registration flag (B) 
	  set to 1 and containing one or more mobile node group identifier option
	  instances, but with the lifetime set to 0. In this case, the LMA SHALL 
	  interpret this as a request by the MAG to terminate these bulk registration 
	  sets, and therefore the LMA SHALL expire the mobility bindings of all the 
	  MNs belonging to all the bulk registration sets specified in the PBU message
	  and also extinguish the rbulk registration sets themselves. Then, the LMA 
	  SHALL send a PBAck message to the MAG, reproducing all the mobility options 
	  informed on the original PBU message, including the bulk registration 
	  flag (B) set to 1, the lifetime value set to zero and the Group I-Ds originally 
	  mentioned on the PBU message.</t>
			
	  <t>The LMA itself may also decide unilaterally that one or more bulk registration
	  sets may be terminated, in which case it shall expires the mobility bindings of 
	  all the MNs belonging to these bulk registration sets, extinguish the representations of 
	  these bulk registration sets and send a PBAck message to the MAG where the bulk 
	  re-registration flag (B) is set to 1, the lifetime value is set to zero and the 
	  Group I-Ds identifying bulk registration sets. The reasons for the LMA deciding 
	  to terminate unilaterally the bulk registration sets may be implementation or 
	  domain specific, and therefore are outside the scope of this specification.</t>
    </section>

    <section anchor="IANA" title="IANA Considerations">
	  <t>This specification specifies a new flag (B) in the Proxy Binding 
	  Update (PBU) and Proxy Binding Acknowledgement (PBAck) messages of 
	  PMIPv6 <xref target="RFC5213"/>. This flag is defined in 
	  <xref target="pbu_message" /> and <xref target="pback_message" />.
	  IANA is requested to allocate the new flag (B) in the Proxy Binding
      Update and Proxy Binging Acknowledgement messages from the <xref 
	  target="RFC5213"/> Proxy Binding Update Flags and the <xref 
	  target="RFC5213"/> proxy Binding Acknowledgment Flags registries.</t>
	
      <t>This specification defines a new Mobility Header option, the Mobile
      Node Group Identifier option. This option is described in <xref target="GID_option"/>.
	  The Type value for this option needs to be assigned from the same numbering 
	  space as allocated for the other mobility options (as defined in <xref target="RFC3775"/>).
	  Also, the Sub-type field of the Mobile Node Group Identifier option (as defined 
	  in <xref target="mnid_option"/>) must have its own brand-new, unique number 
	  pace allocated and managed by IANA.</t>

      <t>Note to RFC Editor: this section may be removed on publication as an
      RFC.</t>
    </section>

    <section anchor="Security" title="Security Considerations">
      <t>As per <xref target="RFC5213"/>, the mobile node's identifier is 
	  always present in the Proxy Mobile IPv6 signaling messages, which exposes 
	  the identification of the user and may result in compromising the privacy 
	  of the user. By additionally carrying the group identity of the mobile node 
	  on the PBU messages that perform bulk registration set addition 
	  operations, similar vulnerabilities are introduced. Specifically, it exposes 
	  the group affiliation of the user and may result in compromising the privacy 
	  of the user or the location information.</t>

      <t>The Mobile Node Group Identifier option defined in this specification
      is for use in Proxy Binding Update and Proxy Binding Acknowledgement
      messages. This option is carried like any other mobility header option
      as specified in <xref target="RFC3775"></xref> and does not require any
      special security considerations.</t>

      <t>The bulk re-registration mechanism does not introduce any new
      security threat or vulnerability to the PMIPv6 specification.</t>
    </section>

    <section anchor="Acknowledgements" title="Acknowledgements">
      <t>Thanks to Jouni Korhonen and Basavaraj Patil for their review and input.</t>

      <t>The authors would like to acknowledge the prior discussions on this
      topic in netlmm mailing list.</t>

    </section>
  </middle>

  <back>
    <references title="Normative References">
      <reference anchor="RFC2119">
        <front>
          <title abbrev="RFC Key Words">Key words for use in RFCs to Indicate
          Requirement Levels</title>

          <author fullname="Scott Bradner" initials="S." surname="Bradner">
            <organization>Harvard University</organization>

            <address>
              <postal>
                <street>1350 Mass. Ave.</street>

                <street>Cambridge</street>

                <street>MA 02138</street>
              </postal>

              <phone>- +1 617 495 3864</phone>

              <email>sob@harvard.edu</email>
            </address>
          </author>

          <date month="March" year="1997" />

          <area>General</area>

          <keyword>keyword</keyword>
        </front>

        <seriesInfo name="BCP" value="14" />

        <seriesInfo name="RFC" value="2119" />

        <format octets="4723" target="ftp://ftp.isi.edu/in-notes/rfc2119.txt"
                type="TXT" />

        <format octets="17491"
                target="http://xml.resource.org/public/rfc/html/rfc2119.html"
                type="HTML" />

        <format octets="5777"
                target="http://xml.resource.org/public/rfc/xml/rfc2119.xml"
                type="XML" />
      </reference>

      <reference anchor="RFC3775">
        <front>
          <title>Mobility Support in IPv6</title>

          <author fullname="D. Johnson" initials="D." surname="Johnson">
            <organization></organization>
          </author>

          <author fullname="C. Perkins" initials="C." surname="Perkins">
            <organization></organization>
          </author>

          <author fullname="J. Arkko" initials="J." surname="Arkko">
            <organization></organization>
          </author>

          <date month="June" year="2004" />
        </front>

        <seriesInfo name="RFC" value="3775" />

        <format octets="393514"
                target="ftp://ftp.isi.edu/in-notes/rfc3775.txt" type="TXT" />
      </reference>

      <reference anchor="RFC5213">
        <front>
          <title>Proxy Mobile IPv6</title>

          <author fullname="S. Gundavelli" initials="S." surname="Gundavelli">
            <organization></organization>
          </author>

          <author fullname="K. Leung" initials="K." surname="Leung">
            <organization></organization>
          </author>

          <author fullname="V. Devarapalli" initials="V."
                  surname="Devarapalli">
            <organization></organization>
          </author>

          <author fullname="K. Chowdhury" initials="K." surname="Chowdhury">
            <organization></organization>
          </author>

          <author fullname="B. Patil" initials="B." surname="Patil">
            <organization></organization>
          </author>

          <date month="August" year="2008" />
        </front>

        <seriesInfo name="RFC" value="5213" />

        <format octets="226902"
                target="ftp://ftp.isi.edu/in-notes/rfc5213.txt" type="TXT" />
      </reference>
    </references>

  </back>
</rfc>

PAFTECH AB 2003-20262026-04-24 12:59:05