One document matched: draft-mdt-softwire-map-dhcp-option-02.xml


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<rfc category="std" docName="draft-mdt-softwire-map-dhcp-option-02"
     ipr="trust200902">
  <front>
    <title abbrev="MAP DHCPv6 Options">DHCPv6 Options for Mapping of Address and Port</title>

    <author fullname="Tomasz Mrugalski" initials="T." surname="Mrugalski" role="editor">
      <organization abbrev="ISC">Internet Systems Consortium, Inc.
      </organization>
      <address>
        <postal>
          <street>950 Charter Street</street>
          <city>Redwood City</city>
          <region>CA</region>
          <code>94063</code>
          <country>USA</country>
        </postal>
        <phone>+1 650 423 1345</phone>
        <email>tomasz.mrugalski@gmail.com</email>
	<uri>http://isc.org/</uri>
      </address>
    </author>

    <author fullname="Mohamed Boucadair" initials="M." surname="Boucadair">
      <organization>France Telecom</organization>
      <address>
        <postal>
	  <street></street>
          <city>Rennes</city>
          <code>35000</code>
          <country>France</country>
        </postal>
        <email>mohamed.boucadair@gmail.com</email>
	<uri>http://www.francetelecom.com/</uri>
      </address>
    </author>

    <author initials="X." surname="Deng" fullname="Xiaohong Deng">
      <organization>France Telecom</organization>
      <address>
        <postal>
          <street>Haidian district</street>
          <code>100190</code>
          <city>Beijing</city>
          <country>China</country>
        </postal>
        <email>xiaohong.deng@orange.com</email>
	<uri>http://www.francetelecom.com/</uri>
      </address>
    </author>

    <author fullname="Ole Troan" initials="O" surname="Troan">
      <organization abbrev="Cisco">Cisco Systems, Inc.</organization>
      <address>
        <postal>
          <street>Telemarksvingen 20</street>
          <city>Oslo</city>
          <code>N-0655</code>
          <country>Norway</country>
        </postal>
        <email>ot@cisco.com</email>
	<uri>http://cisco.com</uri>
      </address>
    </author>


    <author initials="C.X." surname="Bao" fullname="Congxiao Bao">
      <organization abbrev="Tsinghua University">
      CERNET Center/Tsinghua University</organization>
      <address>
        <postal>
          <street>Room 225, Main Building, Tsinghua University</street>
          <city>Beijing</city> <code>100084</code>
          <country>CN</country>
        </postal>
        <phone>+86 10-62785983</phone>
        <email>congxiao@cernet.edu.cn</email>
      </address>
    </author>

    <!-- Qiong Sun requested joining author team as well (22.10.2011 12:10) -->

    <date day="24" month="January" year="2012" />

    <area>Internet</area>
    <workgroup>Softwire WG</workgroup>
    <keyword>MAP</keyword>
    <keyword>DHCPv6</keyword>

    <!--  SECTION 0:  Abstract                      -->

    <abstract>
      <t>Generic mechanism for mapping between an IPv4 prefix, address
      or parts of thereof, and transport layer ports and an
      IPv6 prefix or address is specified in <xref
      target="I-D.mdt-softwire-mapping-address-and-port"/>. This is a companion document that
      specifies provisioning mechanism of MAP rules. It defines DHCPv6
      options which are meant to be used between Customer Edge (CE)
      devices and DHCPv6 server to obtain necessary parameters to
      configure MAP rules. Since specification of MAP
      architecture is still expected to evolve, DHCPv6 options may
      have to evolve too to fit the revised MAP specification.</t>
      <t></t>
    </abstract>
  </front>

  <middle>
    <!--  SECTION 1:  Introduction                  -->

    <section title="Introduction">
      <t>Mapping of Address and Port (MAP) defined in <xref
      target="I-D.mdt-softwire-mapping-address-and-port" /> is a mechanism for providing
      IPv4 connectivity service to end users over a service provider's
      IPv6 network. It defines both MAP Border Relay (BR) router that is located at the edge
    of a MAP domain and MAP Customer Edge (CE) that typically deployed at
    customers' location. In a residential broadband deployment, CE
    is sometimes referred to as a Residential Gateway (RG) or
      Customer Premises Equipment (CPE). A MAP CE may also be referred
      to simply as a "CE" within the context of MAP.</t>

      <t>A typical CE adopting MAP rules will serve a residential
      site with one WAN side interface and one or more LAN side
      interfaces. To operate properly, it requires one or more MAP
      rules and additional informations. In larger networks it is
      infeasible to configure such parameters manually. Therefore
      provisioning mechanism is required. Such mechanism is defined in
      this document. It leverages existing DHCPv6 <xref
      target="RFC3315"/> protocol to deliver necessary parameters to
      CE.</t>

      <t>This document defines several DHCPv6 options that allow
      delivery of required information to configure CE. Configuration
      of the BR is outside of scope of this document. Definitions of
      used parameters are provided in <xref target="I-D.mdt-softwire-mapping-address-and-port" />.</t>

      <t>Since specification of MAP architecture is still expected to
      evolve, DHCPv6 options may have to evolve too to fit the revised
      MAP specification.
      </t>

      <t>Described proposal is not a dynamic port allocation mechanism.
      </t>

      <t>Reader interested in deployment considerations is encouraged
      to read <xref target="map-d"/>.</t>
    </section>

    <!--  SECTION 2: REQUIREMENTS LANGUAGE                                         -->

    <section anchor="conventions" title="Conventions">
      <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 RFC 2119 <xref
      target="RFC2119"></xref>.</t>
    </section>

    <!-- conventions -->

    <!--  SECTION 3: DESCRIPTION                                                   -->

    <section anchor="description" title="Provisioning mechanism">

      <t>A typical MAP CE usually acts as a DHCPv6 client and requests
      options that are being provided by a DHCPv6 server located
      somewhere in ISP network. This server provides typical
      information to configured nodes: namely IPv6 address (in IA_NA
      option) and delegates a prefix (in IA_PD option). Server also
      provides additional parameters that are MAP specific. In
      particular, it provides the following information:</t>

      <t>
      <list style="symbols">
        <t>One or more MAP rules. MAP mapping rules are defined in Section 4 of <xref
        target="I-D.mdt-softwire-mapping-address-and-port"/>. There are
        several mapping rule types defined: Basic Mapping Rule (BMR), Forwarding 
        Mapping Rule (FMR) and Default Mapping Rule (DMR).

        Depending on rule type, number
        of exact useful parameters may be different. Rule parameters may contain
        Rule IPv6 prefix (including prefix length), Rule IPv4 prefix (including
        prefix length), and additional values that
        define Rule Port Parameters. One MAP CE can receive
        one or more MAP mapping rules from the DHCPv6 server. Exactly one of those
        rules MUST be the default MAP mapping rule for the
        initiated CE of its own, possibly accompanied with additional mapping rules
        within the MAP domain if necessary.</t>
        <t>Transport mode indicates encapsulation or translation mode for MAP
        approach. It should be conducted on interface-by-interface
        basis.</t>
      </list>
      </t>

      <!--
      <t>Discussion: Qiong Sun also proposed to add deployment mode
      here.  Jacni Qin recommends against it. Deployment mode is to
      notify whether CE is in Hub and spoke mode or mesh. In Hub and
      spoke mode, only the first default MAP mapping rule is needed
      in the following MAP procedure. While in mesh mode, all MAP
      mapping rules are included to achieve CE-CE traffic
      optimization. Tomek: I believe that hub and spoke or mesh
      affects number of rules, so server will provision one (hub and
      spoke) or many (mesh) rules. CE does not need to explicitly be
      information about this. It can derive this information in a
      simple manner: if (number of rules>1) then mode=mesh else
      mode=hub_and_spoke.</t> -->
      <!-- Tomek: Discussion resolved: see additional comment in "MAP
           Flags Option" section. Algo for detecting mode: In th hub
           and spoke mode, all traffic should be forwarded using
           DMR. Hub and spoke mode is achieved with a BMR IPv4 rule
           prefix length of 32 and no further FMR. -->
    </section>

    <section title="DHCPv6 Options Format">
      <t>DHCPv6 protocol is used for CE provisioning. Several new
      options are defined for conveying MAP-specific parameters. Their
      format and usage is defined in the following sections.</t>

      <t>Discussion: As the exact parameters required to configure MAP
      rules and MAP in general are expected to change, this section
      is expected to be updated or even rewritten completely.</t>

      <t>Discussion: Proposed layout assumes that several simple
      options are used. Such approach simplifies implementation as it
      is much easier for implementors to reuse existing code handling
      such options. This design choice comes at a cost,
      however. Clients must perform checks if provided set of options
      is complete. Alternatively, it would be possible to define one
      complex option that contains all mandatory
      parameters. </t>

      <t>Discussion: It should be noted that initial concept of 4rd
      provisioning was presented in DHC working group meeting. It used
      one complex option to convey all required parameters. Strong
      suggestion from DHC WG was to use several simpler
      options. Options (possibly nested) are preferred over
      conditional option formatting. See DHCP option guidelines
      document <xref target="I-D.ietf-dhc-option-guidelines"/>).</t>

      <section title="Options Cardinality">
        <t>MAP rule is defined in <xref target="I-D.mdt-softwire-mapping-address-and-port"/>, Section 4.</t>

        <t>Discussion: If you want additional parameter added to the
        OPTION_MAP_RULE option (or any other option), please update <xref
        target="I-D.mdt-softwire-mapping-address-and-port"/> first.</t>

        <t>Server that supports MAP configuration and is configured to
        provision requesting CE MUST include exactly one OPTION_MAP
        option in a REPLY message for each MAP domain. It is envisaged
        that in typical network, there will be only one MAP domain deployed.</t>

        <t>OPTION_MAP option MUST include one or more OPTION_MAP_RULE options.</t>
      </section>

      <section anchor="option-flags" title="MAP Flags Option">
        <t>This option specifies MAP flags and is used to group all rules for
	specified MAP domain. Currently the only
        defined flag is T that describes transport mode. Other flags that affect
        all mapping rules or the whole MAP domain may be specified
        here at a later date.</t>
        
        <t>Each OPTION_MAP option MUST contain one or more MAP Rule
        Options.</t>
        <figure align="center" anchor="img-option-flags" title="MAP Flags Option">
          <preamble></preamble>
          <artwork align="center"><![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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|        OPTION_MAP             |         option-length         |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|   reserved  |T|                                               .
+-+-+-+-+-+-+-+-+                                               .
.                     sub-options (variable length)             .
+---------------------------------------------------------------+]]>
          </artwork>
        </figure>
        <t>
          <list style="symbols">
            <t>option-code: OPTION_MAP (TBD1)</t>

            <t>option-length: 1</t>

            <t>reserved: This 7-bits long reserved field is not used
            and MUST be set to 0 by server. Its value MUST be ignored
            by clients.</t>
            <t>T: 1 bit field that specifies transport mode:
            translation (0) or encapsulation (1).</t>
            <t>suboptions: sub-options specific to this MAP
            domain. MUST contain one or more MAP_RULE options.</t>
          </list>
        </t>

        <t>It was suggested to also provision information whether MAP
        network is working in hub and spoke or full mesh mode. That is
        not necessary, as this information can be derived from
        provisioned MAP rules. In the hub and spoke mode, all traffic
        should be forwarded using DMR. Hub and spoke mode is achieved
        with a BMR IPv4 rule prefix length of 32 and no further FMR.
        </t>
      </section>

      <section title="MAP Rule Option">
        <t>MAP Rule Option option represents a single MAP
        Rule. Depending on deployment mode, each CE may require one or
        more MAP Rules to operate properly.</t>

        <t>Server includes one or more MAP Rule Options in MAP Flags option.</t>

        <t>Server MAY send more than one MAP Rule Option, if it is
        configured to do so. Clients MUST NOT send MAP Rule
        Option.</t>

        <figure align="center" anchor="img-option-rule" title="MAP Rule Option">
          <preamble></preamble>
          <artwork align="center"><![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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|        OPTION_MAP_RULE        |         option-length         |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|  prefix4-len  |     ea-len    |  prefix6-len  |               |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+               |
|                        rule-ipv6-prefix                       |
|                       (variable length)                       |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|                       rule-ipv4-prefix                        |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

|                                                               |
.                rule sub-options (variable length)             .
.                                                               .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

]]>
</artwork>
        </figure>

        <t>Explicit parameters are:
          <list style="symbols">
            <t>option-code: OPTION_MAP_RULE (TBD2)</t>

            <t>option-length: length of the option, excluding
            option-code and option-length fields, including length of
            all sub-options.</t>

            <t>prefix4-len: 8 bits long field expressing length of the
            IPv4 prefix, specified in the rule-ipv4-prefix field,
            expressed in bits.</t>

	    <t>ea-len: 8-bits long field that specifies
	    Embedded-Address (EA) - length, expressed in bits. This
	    field is meaningful only for FMR. For other rules types,
	    it MUST be set to zero by the server and its content MUST
	    be ignored by the clients.</t>

            <t>prefix6-len: 8 bits long length of the IPv6 prefix,
            specified in the rule-ipv6-prefix field, expressed in
            bits.</t>

            <t>rule-ipv6-prefix: a variable size field that specifies
            Rule IPv6 prefix. Length of the
            field is defined by prefix6-len field and is rounded up to
            the nearest octet boundary (if case when prefix6-len is
            not divisible by 8). In such case additional padding bits
            must be zeroed.</t>

            <t>rule-ipv4-prefix: a 32-bits long field that specifies
            an IPv4 prefix that appears in a MAP rule.</t>

            <t>rule sub-options: a variable field that may contains
            zero or more options that specify additional parameters
            for this rule. Those options follow standard DHCPv6 option
            format, as defined in <xref target="RFC3315"/>, Section
            22.1. Currently there is only one option defined that may
            appear in rule sub-options field. This option is
            OPTION_MAP_PORTPARAMS, defined in section <xref
            target="option-portparams"/>. Other options may be defined
            at a later date.</t>
          </list>
        </t>

        <t>There are also number of implicit parameters that may be
        derived from content of MAP and other options. In particular,
        End-User IPv6 Prefix (or Delegated prefix, specified in IA_PD
        option, see <xref target="RFC3633"/>) and assigned IPv6
        address (specified in IA_NA option, see <xref
        target="RFC3315"/>) are needed. Even though these values are
        not provided explicitely, they are required for proper MAP
        rule configuration. Following implicit parameters may be
        calculated:
        <list style="symbols">
          <t>rule type: Depending on rule content, it can be Basic
          Mapping Rule (BMR), Forwarding Mapping Rule (FMR) or
          Default Mapping Rule (DMR). See Sections 4.2, 4.3 and 4.4
          in <xref
          target="I-D.mdt-softwire-mapping-address-and-port"/> for
          detailed description of those rules. A CE node can
          determine, which received rule is the basic rule based on
          the longest match between End-User IPv6 prefix (received
          in IAPREFIX option in IA_PD) and the Rule IPv6 prefix
          (received in Map Rule Option). A Default rule can be
          determined by the fact that it has Rule IPv4 prefix of
          0.0.0.0/0.</t>
	  <!--
          <t>L parameter. It is equal to a length of a prefix
          delegated to CE, conveyed in OPTION_IA_PD and IAPREFIX, as
          defined in <xref target="RFC3633"/>.</t> -->
          <t>Embedded Address bits (EA-bits) length can be derived
          as a length of the delegated prefix (specified in
          prefix-length field in IAPREFIX option) decreased by MAP
          Domain IPv6 prefix length (specified in prefix6-len of the
          DMR).</t>
        </list>
        </t>

        <t>It is expected that in a typical simple scenarios, there
        will be a single BMR with a single DMR (that will also work as
        FMR). For detailed discussion about MAP deployment
        considerations, see <xref target="map-d"/>.</t>

        <t>Note that the DMR is a simplified version of BMR. While it
        reuses the same DHCPv6 option format, DMR uses only Rule IPv6
        prefix, Rule IPv6 Prefix Length and IPv4 address that denotes
        BR IPv4 address. All other parameters are ignored for Default
        Mapping Rule. Client MUST ignore those parameters for DMR and
        server MUST set those parameters to zero.</t>

        <!--
        <t>Discussion: Remi Despres pointed out that not all of
        prefix4len + prefix6-len + ea-len + excluded ports + off are
        needed. Only 4 of these are independent, so one of them will be removed.</t>-->
        <!-- tomek: the one that had to go is ea-len -->
      </section>

      <section anchor="option-portparams" title="Port Parameters Option">
        <t>Port Parameters Option specifies optional Rule Port
        Paramters that MAY be provided as part of the Mapping Rule. It
        MAY appear as sub-option in OPTION_MAP_RULE option. It MUST
        NOT appear directly in a message.</t>
        <t>See <xref target="I-D.mdt-softwire-mapping-address-and-port"/>, Section 4.1
        for detailed description of Port mapping algorithm.</t>

        <figure align="center" anchor="img-option-portparams" title="MAP Port Parameters Option">
          <preamble></preamble>
          <artwork align="center"><![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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|     OPTION_MAP_PORTPARAMS     |         option-length         |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|         excluded-ports        |   rsv   | off |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+]]>
</artwork>
        </figure>

        <t>
          <list style="symbols">
            <t>option-code: OPTION_MAP_PORTPARAMS (TBD3)</t>

            <t>option-length: 3</t>

            <t>excluded-ports: defines upper bound for range of
            excluded ports.  The lower range is 0. For example a
            value 1023 means that excluded range is 0-1023 ports. Value of 0
            (range 0-0) means that no ports are excluded.</t>
            <t>rsvd: This 5-bits long field is currently not used and
            MUST be set to 0 by server. Its value MUST be ingored
            by clients.</t>
            <t>off: 3 bits long field that specifies offset bits. It
            is referred to as 'a' value and specifies length of a A
            field, as presented in Fig. 1 in <xref
            target="I-D.mdt-softwire-mapping-address-and-port"/>,
            Section 4.1.1.</t>
          </list>
        </t>

	<t>TODO: Ole pointed out that excluded-ports are related to the offset.
	with a = 6, j > 0 you exclude 0-1023;
	with a = 4, j > 0 you exclude 0-4095;
	with a = 0, no ports excluded and number of systems ports per user given by PSID/PSID length
	the flag would allow j = 0.</t>

        <t>Map Port Parameters Option is optional. If it is not present,
        the following default values are assumed:
        <list style="numbers">
          <t>Excluded ports: 0-4095 (excluded-ports field value is 4095)</t>
          <t>Offset bits: 4 (off field value is 4)</t>
        </list>
        If administrator wants to provision only one of those
        parameters, remaining fields SHOULD be set to their default
        value.
        </t>
      </section>

      <section anchor="example" title="MAP Options Examples">
        <t>DHCPv6 server provisioning a single MAP Rule to a CE
        (DHCPv6 client) will convey the following MAP options in its
        messages:</t>

        <section title="BMR Option Example">
          <figure align="center" anchor="img-bmr-example" title="BMR Option Example">
            <preamble></preamble>
            <artwork align="center"><![CDATA[
            TODO: Reflect example in section 4.2 of MAP draft
            ]]></artwork>
          </figure>
        </section>
        
        <section title="FMR Option Example">
          <figure align="center" anchor="img-fmr-example" title="FMR Option Example">
            <preamble></preamble>
            <artwork align="center"><![CDATA[
            TODO: Reflect example in section 4.3 of MAP draft
            ]]></artwork>
          </figure>
        </section>

        <section title="DMR Option Example">
          <figure align="center" anchor="img-dmr-example" title="DMR Option Examples">
            <preamble></preamble>
            <artwork align="center"><![CDATA[
            TODO: Reflect example in section 4.4 of MAP draft
            ]]></artwork>
          </figure>
        </section>

      </section>

    </section>

    <section title="DHCPv6 Server Behavior">
      <t><xref target="RFC3315">RFC 3315 Section 17.2.2</xref>
      describes how a DHCPv6 client and server negotiate configuration
      values using the ORO.  As a convenience to the reader, we
      mention here that a server will not reply with a MAP Rule Option
      if the client has not explicitly enumerated it on its Option
      Request Option.</t>
      <t>Server conformant to this specification MUST allow
      configuration of one or more MAP Rule Options.</t>
      <t>Server MUST transmit all configured instances of the Mapping
      Rule Options with all sub-options, if client requested it using
      OPTION_MAP_RULE in its Option Request Option (ORO). Server MUST
      transmit MAP Flags Option if client requested OPTION_MAP
      in its ORO.</t>

      <t>Rules assignment is a stateless process from the server's
      perspective. Server does not need to maintain a state of rules
      provisioned to clients, track lifetimes, expire outdated rules
      etc. Server SHOULDs assign the same set of rules to all CEs in
      one MAP Domain, unless there are several classes of CEs defined,
      e.g. regular and premium users. In such case, each class of CEs
      is expected to get the same set of rules. Server is not expected
      to track MAP rules on a per CE basis. Exact assignment of
      specific rules to a specific CEs is outside of scope of this
      document.</t>

    </section>

    <section title="DHCPv6 Client Behavior">
      <t>Although other use cases are allowed, in a typical use case CE
      will act as DHCPv6 client and will request MAP configuration to
      be assigned by the DHCPv6 server located in the ISP network. A
      client that supports MAP CE functionality and conforms to this
      specfication MUST include OPTION_MAP_RULE and OPTION_MAP
      in its ORO.</t>

      <t>For proper operation, MAP CE client MUST also request IPv6
      address (OPTION_IA_NA, defined in <xref target="RFC3315"/>) and
      prefix delegation (OPTION_IA_PD, defined in <xref
      target="RFC3633"/>). MAP CE client SHOULD NOT initiate DHCPv4
      configuration for the purpose of MAP configuration as all
      parameters are delivered over DHCPv6.</t>

      <t>Client supporting MAP functionality SHOULD request
      OPTION_MAP_RULE and OPTION_MAP options in SOLICIT,
      REQUEST, RENEW, REBIND and INFORMATION-REQUEST messages.</t>

      <t>If client receives more than one OPTION_MAP_RULE option, it
      MUST use all received instances. It MUST NOT use only the first
      one, while discarding remaining ones.</t>

      <t>Note that system implementing MAP CE functionality may have
      multiple network interfaces, and these interfaces may be
      configured differently; some may be connected to networks that
      call for MAP, and some may be connected to networks that are
      using normal dual stack or other means.  The MAP CE system
      should approach this specification on an interface-by-interface
      basis.  For example, if the CE system is attached to multiple
      networks that provide the MAP Mapping Rule Option, then the CE
      system MUST configure a MAP connection (i.e. a translation or
      encapsulation) for each interface separately as each MAP
      provides IPv4 connectivity for each distinct interface. Means to
      bind a MAP configuration to a given interface in a multiple
      interfaces device are out of scope of this document.</t>
    </section>


    <section title="IANA Considerations">
      <t>IANA is kindly requested to allocate DHCPv6 option code TBD1 to the
      OPTION_MAP,TBD2 to OPTION_MAP_RULE and TBD3 to
      OPTION_MAP_PORTPARAMS. All three values should be added to the
      DHCPv6 option code space defined in Section 24.3 of <xref
      target="RFC3315"/>.</t>
    </section>

    <section title="Security Considerations">
      <t>Implementation of this document does not present any new
      security issues, but as with all DHCPv6-derived configuration
      state, it is completely possible that the configuration is being
      delivered by a third party (Man In The Middle).  As such, there
      is no basis to trust that the access over the MAP can be
      trusted, and it should not therefore bypass any security
      mechanisms such as IP firewalls.</t>

      <t>Readers concerned with security of MAP provisioning over
      DHCPv6 are encouraged to familiarize with <xref
      target="I-D.ietf-dhc-secure-dhcpv6"/>.</t>

      <t>Section XX of <xref target="I-D.mdt-softwire-mapping-address-and-port"/> discusses
      security issues of the MAP mechanism.</t>

      <t>Section 23 of <xref target="RFC3315"/> discusses
      DHCPv6-related security issues.</t>

      <t>Section 6 of <xref target="I-D.murakami-softwire-4rd"/> discusses 4rd
      related security issues that are partially applicable to MAP mechanism.</t>
    </section>

    <section title="Contributors">
      <t>The current members of the MAP design team are:
      Congxiao Bao, Mohamed Boucadair, Gang Chen, Maoke Chen,
      Wojciech Dec, Xiaohong Deng, Jouni Korhonen,
      Xing Li, Satoru Matsushima, Tomasz Mrugalski, Tetsuya
      Murakami, Jacni Qin, Necj Scoberne, Qiong Sun, Tina Tsou, Dan
      Wing, Leaf Yeh and Jan Zorz.</t>
      <t>Former MAP design team members are: Remi Despres.</t>
    </section>

    <section title="Acknowledgements">
      <t>Authors would like to thank Jacni Qin, Qiong Sun and Remi
      Despres for their comments and suggestions.</t>
    </section>
  </middle>

  <back>
    <!--  SECTION 8.1:  Normative References		-->

    <references title="Normative References">
      &rfc2119;
      <?rfc include="http://xml.resource.org/public/rfc/bibxml3/reference.I-D.mdt-softwire-mapping-address-and-port.xml" ?>
      <?rfc include="http://xml.resource.org/public/rfc/bibxml/reference.RFC.3315"?>
      <?rfc include="http://xml.resource.org/public/rfc/bibxml/reference.RFC.3633"?>

    </references>
  <references title="Informative References">
    <reference anchor="map-d" target="">
        <front>
          <title>Mapping of Address and Port (MAP) - Deployment Considerations</title>
          <author fullname="Maoke Chen" initials="M" surname="Chen">
            <organization abbrev="FreeBit">FreeBit Co., Ltd.</organization>
          </author>
          <author fullname="Qiong Sun" initials="Q" surname="Sun">
            <organization>China Telecom</organization>
          </author>
          <author fullname="Gang Chen" initials="G" surname="Chen">
            <organization abbrev="">China Mobile</organization>
          </author>
          <date day="23" month="12" year="2012" />
        </front>
        <seriesInfo name="draft-mdt-softwire-map-deployment" value="00" />
      </reference>
    <?rfc include="http://xml.resource.org/public/rfc/bibxml3/reference.I-D.ietf-dhc-option-guidelines.xml" ?>
    <?rfc include="http://xml.resource.org/public/rfc/bibxml3/reference.I-D.mrugalski-dhc-dhcpv6-4rd.xml" ?>
    <?rfc include="http://xml.resource.org/public/rfc/bibxml3/reference.I-D.boucadair-dhcpv6-shared-address-option.xml" ?>
    <?rfc include="http://xml.resource.org/public/rfc/bibxml3/reference.I-D.ietf-dhc-secure-dhcpv6.xml" ?>
    <?rfc include="http://xml.resource.org/public/rfc/bibxml3/reference.I-D.murakami-softwire-4rd.xml" ?>
    <?rfc include="http://xml.resource.org/public/rfc/bibxml/reference.RFC.5226" ?>
  </references>

    <!--  SECTION 8.2:  Informative References		-->

  </back>
</rfc>

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