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RADIUS Attribute for MAP
draft-ietf-softwire-map-radius-06

The information below is for an old version of the document.
Document Type
This is an older version of an Internet-Draft that was ultimately published as RFC 8658.
Authors Sheng Jiang , Yu Fu , Bing Liu , Peter Deacon , Chongfeng Xie , Tianxiang Li
Last updated 2016-07-06 (Latest revision 2016-06-17)
Replaces draft-jiang-softwire-map-radius
RFC stream Internet Engineering Task Force (IETF)
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Additional resources Mailing list discussion
Stream WG state WG Document
Document shepherd Yong Cui
IESG IESG state Became RFC 8658 (Proposed Standard)
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Send notices to "Yong Cui" <cuiyong@tsinghua.edu.cn>
draft-ietf-softwire-map-radius-06
Softwire                                                   S. Jiang, Ed.
Internet-Draft                              Huawei Technologies Co., Ltd
Intended status: Standards Track                              Y. Fu, Ed.
Expires: December 19, 2016                                         CNNIC
                                                                  B. Liu
                                            Huawei Technologies Co., Ltd
                                                               P. Deacon
                                                      IEA Software, Inc.
                                                                  C. Xie
                                                           China Telecom
                                                                   T. Li
                                                     Tsinghua University
                                                           June 17, 2016

                        RADIUS Attribute for MAP
                   draft-ietf-softwire-map-radius-06

Abstract

   IPv4-over-IPv6 transition mechanisms provide both IPv4 and IPv6
   connectivity services simultaneously during the IPv4/IPv6 co-existing
   period.  The Dynamic Host Configuration Protocol for IPv6 (DHCPv6)
   options have been defined to configure Customer Edge (CE) in MAP-E,
   MAP-T, and Lightweight 4over6.  However, in many networks, the
   configuration information may be stored in Authentication
   Authorization and Accounting (AAA) servers while user configuration
   is mainly from Broadband Network Gateway (BNG) through DHCPv6
   protocol.  This document defines a Remote Authentication Dial In User
   Service (RADIUS) attribute that carries CE configuration information
   from AAA server to BNG.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at http://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on December 19, 2016.

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Copyright Notice

   Copyright (c) 2016 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  Configuration process with RADIUS . . . . . . . . . . . . . .   3
   4.  Attributes  . . . . . . . . . . . . . . . . . . . . . . . . .   6
     4.1.  MAP-Configuration Attribute . . . . . . . . . . . . . . .   6
     4.2.  S46 Container Options . . . . . . . . . . . . . . . . . .   7
     4.3.  Sub Options for S46 Container Option  . . . . . . . . . .   7
       4.3.1.  S46-Rule Sub Option . . . . . . . . . . . . . . . . .   8
       4.3.2.  S46-BR Sub Option . . . . . . . . . . . . . . . . . .   8
       4.3.3.  S46-DMR Sub Option  . . . . . . . . . . . . . . . . .   9
       4.3.4.  S46-V4V6Bind Sub Option . . . . . . . . . . . . . . .  10
       4.3.5.  S46-PORTPARAMS Sub Option . . . . . . . . . . . . . .  10
     4.4.  Sub Options for S46-RULE Sub Option . . . . . . . . . . .  11
       4.4.1.  Rule-IPv6-Prefix Sub Option . . . . . . . . . . . . .  11
       4.4.2.  Rule-IPv4-Prefix Sub Option . . . . . . . . . . . . .  12
       4.4.3.  EA Length Sub Option  . . . . . . . . . . . . . . . .  13
     4.5.  Table of attributes . . . . . . . . . . . . . . . . . . .  13
   5.  Diameter Considerations . . . . . . . . . . . . . . . . . . .  13
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  14
   7.  Security Considerations . . . . . . . . . . . . . . . . . . .  14
   8.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  14
   9.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  15
     9.1.  Normative References  . . . . . . . . . . . . . . . . . .  15
     9.2.  Informative References  . . . . . . . . . . . . . . . . .  15
   Additional Authors  . . . . . . . . . . . . . . . . . . . . . . .  17
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  18

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1.  Introduction

   Recently providers start to deploy IPv6 and consider how to transit
   to IPv6.  Many transition mechanisms have been proposed for running
   IPv4 over IPv6-only infrastructure, including MAP-E, MAP-T, and
   Lightweight 4over6.  Mapping of Address and Port with
   Encapsulation(MAP-E)[RFC7597], Mapping of Address and Port with using
   Translation(MAP-T)[RFC7599] are stateless mechanisms for running IPv4
   over IPv6-only infrastructure.  Lightweight 4over6[RFC7596] is a hub-
   and-spoke IPv4-over-IPv6 tunneling mechanism, with complete
   independence of IPv4 and IPv6 addressing.  They provide both IPv4 and
   IPv6 connectivity services simultaneously during the IPv4/IPv6 co-
   existing period.  MAP-E, MAP-T and Lightweight 4over6 have adopted
   Dynamic Host Configuration Protocol for IPv6 (DHCPv6) [RFC3315] as
   auto-configuring protocol.  The Customer Edge (CE) uses DHCPv6
   options to discover the Border Relay (BR) and get MAP configurations.

   In many networks, user configuration information may be stored by AAA
   (Authentication, Authorization, and Accounting) servers.  Current AAA
   servers communicate using the Remote Authentication Dial In User
   Service (RADIUS) [RFC2865] protocol.  In a fixed line broadband
   network, the Broadband Network Gateways (BNGs) act as the access
   gateway of users.  The BNGs are assumed to embed a DHCPv6 server
   function that allows them to locally handle any DHCPv6 requests
   initiated by hosts.

   Since the MAP configuration information is stored in AAA servers and
   user configuration is mainly transmitted through DHCPv6 protocol
   between BNGs and hosts/CEs, new RADIUS attributes are needed to
   propagate the information from AAA servers to BNGs.  The RADIUS
   attributes designed in this document are especially for the MAP-
   E[RFC7597], MAP-T[RFC7599] and Lightweight 4over6[RFC7596], providing
   enough information to form the correspondent DHCPv6 configuration
   options[RFC7598].

2.  Terminology

   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 [RFC2119].

3.  Configuration process with RADIUS

   The below Figure 1 illustrates how the RADIUS protocol and DHCPv6
   cooperate to provide CE with MAP configuration information.

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        CE                         BNG                       AAA Server
         |                          |                             |
         |------DHCPv6 Solicit----->|                             |
         | (Option Request w/container option)                    |
         |                          |-------Access-Request------->|
         |                          |       (Map attriubte)       |
         |                          |                             |
         |                          |<-------Access-Accept--------|
         |<---DHCPv6 Advertisement--|       (MAP attriubte)       |
         |                          |                             |
         |------DHCPv6  Request---->|                             |
         |   (container Option)     |                             |
         |<---- -DHCPv6 Reply-------|                             |
         |   (cointainer option)    |                             |
         |                          |                             |
                   DHCPv6                        RADIUS

    Figure 1: the cooperation between DHCPv6 and RADIUS combining with
                           RADIUS authentication

   The BNG acts as a RADIUS client and as a DHCPv6 server.  First, CE
   MAY initiate a DHCPv6 Solicit message that includes an Option Request
   option (6) [RFC3315] with the Container options as defined
   in[RFC7598].  OPTION_S46_CONT_MAPE should be included for MAP-
   E[RFC7597], OPTION_S46_CONT_MAPT for MAP-T[RFC7599], and
   OPTION_S46_CONT_LW for Lightweight 4over6[RFC7596].  But note that
   the ORO (Option Request option) with the MAP option could be optional
   if the network was planned as MAP-enabled as default.  When BNG
   receives the SOLICIT, it SHOULD initiates radius Access-Request
   message, in which the User-Name attribute (1) SHOULD be filled by the
   CE MAC address or interface-id or both, to the RADIUS server and the
   User-password attribute (2) SHOULD be filled by the shared password
   that has been preconfigured on the DHCPv6 server, requesting
   authentication as defined in [RFC2865] with the corresponding MAP-
   Configuration Attribute, which will be defined in the next Section.

   If the authentication request is approved by the AAA server, an
   Access-Accept message MUST be acknowledged with the corresponding
   MAP-Configuration Attribute.  After receiving the Access-Accept
   message with the corresponding Attribute, the BNG SHOULD respond the
   user an Advertisement message.  Then the user can requests for the
   corresponding Container option, and the BNG SHOULD reply the user
   with the message containing the Container option.  The recommended
   format of the MAC address is defined as Calling-Station-Id
   (Section 3.20 in [RFC3580] without the SSID (Service Set Identifier)
   portion.

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   For Lightweight 4over6 [RFC7596], the subscriber's binding state
   should be synchronized between AAA server and the lwAFTR.  If the
   bindings are pre-configured statically in both AAA server and lwAFTR,
   the AAA server does not need to configure lwAFTR anymore.  Otherwise,
   if the bindings are locally creately in AAA server on-demand, it
   should inform the lwAFTR with the subscriber's binding state, to
   synchronise the binding information of the lwB4 with the lwAFTR.  In
   the Lightweight 4over6 scenario, the lwB4 could also be configured
   through DHCPv4-over-DHCPv6 [RFC7341] as well as PCP [RFC6887], in
   which the lwB4 act a PCP client and the BNG act as both a Radius
   client and a PCP server.

   Figure 2 describes another scenario, in which the authorization
   operation is not coupled with authentication.  Authorization is done
   independently after the authentication process.  As similar to above
   scenario, the ORO with the corresponding MAP option in the initial
   DHCPv6 request could be optional if the network was planned as MAP-
   enabled as default.

      CE                           BNG                       AAA Server
         |                          |                             |
         |------DHCPv6  Request---->|                             |
         |(Option Request w/container option)                     |
         |                          |-------Access-Request------->|
         |                          |       (MAP attribute)       |
         |                          |                             |
         |                          |<-------Access-Accept--------|
         |                          |       (MAP attribute)       |
         |<-----DHCPv6 Reply--------|                             |
         |   (container option)     |                             |
         |                          |                             |
                  DHCPv6                         RADIUS

    Figure 2: the cooperation between DHCPv6 and RADIUS decoupled with
                           RADIUS authentication

   In the above mentioned scenario, the Access-Request packet SHOULD
   contain a Service-Type attribute (6) with the value Authorize Only
   (17); thus, according to [RFC5080], the Access-Request packet MUST
   contain a State attribute that obtained from the previous
   authentication process.

   In both above-mentioned scenarios, Message-authenticator (type 80)
   [RFC2869] SHOULD be used to protect both Access-Request and Access-
   Accept messages.

   After receiving the corresponding MAP-Configuration Attribute in the
   initial Access-Accept, the BNG SHOULD store the received MAP

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   configuration parameters locally.  When the CE sends a DHCPv6 Request
   message to request an extension of the lifetimes for the assigned
   address, the BNG does not have to initiate a new Access-Request
   towards the AAA server to request the MAP configuration parameters.
   The BNG could retrieve the previously stored MAP configuration
   parameters and use them in its reply.

   If the BNG does not receive the corresponding MAP-Configuration
   Attribute in the Access-Accept it MAY fallback to a pre-configured
   default MAP configuration, if any.  If the BNG does not have any pre-
   configured default MAP configuration or if the BNG receives an
   Access-Reject, the MAP cannot be established.

   As specified in [RFC3315], section 18.1.4, "Creation and Transmission
   of Rebind Messages ", if the DHCPv6 server to which the DHCPv6 Renew
   message was sent at time T1 has not responded by time T2, the CE
   (DHCPv6 client) SHOULD enter the Rebind state and attempt to contact
   any available server.  In this situation, the secondary BNG receiving
   the DHCPv6 message MUST initiate a new Access-Request towards the AAA
   server.  The secondary BNG MAY include the MAP-Configuration
   Attribute in its Access-Request.

4.  Attributes

   This section defines S46 Attributes which are used in the MAP
   scenario.  The attribute design follows [RFC6158] and refers
   to[RFC6929].

   The S46 attributes are designed following the simplify principle.
   Different sub options are required for each type of S46 Container
   option.

4.1.  MAP-Configuration Attribute

   The MAP-Configuration Attribute is structured 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     |                               |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+                               +
|                                                               |
+                    S46 Container Option(s)                    +
|                                                               |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  Type
    TBD
  Length
    2 + the length of the S46 Container option(s)
  S46 Container Option (s)
    A variable field that may contains one or more S46 Container option(s),
   defined in Section 4.2

4.2.  S46 Container Options

   Depending on the deployment scenario, a client might request for more
   than one transition mechanism at a time, at least one S46 Container
   option MUST be included in one MAP-Configuration Attribute.

    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 Options                           +
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      Type
        1 MAP-E Container Option
        2 MAP-T Container Option
        3 Lightweight 4over6 Container Option
      Length
        2 + the length of the sub options
      Sub Option
        A variable field that contains necessary sub options defined in
        Section 4.3 and zero or several optional sub options, defined
        in Section 4.4

4.3.  Sub Options for S46 Container Option

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4.3.1.  S46-Rule Sub Option

   Depending on deployment scenario, one Basic Mapping Rule and zero or
   more Forwarding Mapping Rules MUST be included in one MAP-E or MAP-T
   Container Option.

    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |     SubType   |    SubLen     |                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+                               +
   |                                                               |
   +                         Sub Options                           +
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      SubType
        1 Basic Mapping Rule (Not Forwarding Mapping Rule)
        2 Forwarding Mapping Rule (Not Basic Mapping Rule)
        3 Basic & Forwarding Mapping Rule
      SubLen
        2 + the length of the sub options
      Sub Option
        A variable field that contains sub options defined in
        Section 4.4

4.3.2.  S46-BR Sub Option

   There MUST be atleast one S46-BR Sub Option included in one S46
   Container Option.

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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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |    SubType    |    SubLen     |         BR-ipv6-address       |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+                               +
   |                           BR-ipv6-address                     |
   +                                                               +
   |                           BR-ipv6-address                     |
   +                                                               +
   |                           BR-ipv6-address                     |
   +                               +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |       BR-ipv6-address         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      SubType
         4 (SubType number, for the S46-BR sub option)
      SubLen
         18 (the length of the S46-BR sub option)
      BR-ipv6-address
         a 128-bits field that specifies the IPv6 address for the BR.

4.3.3.  S46-DMR Sub Option

   There MUST be exactly one S46-DMR Sub Option included in one MAP-T
   Container Option.

    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |    SubType    |    SubLen     |dmr-prefix6-len|dmr-ipv6-prefix|
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+               +
   |                        dmr-ipv6-prefix                        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

      SubType
         5 (SubType number, for the S46-DMR sub option)
      SubLen
         8 (the length of the Rule-IPv4-Prefix6 sub option)
      dmr-prefix6-len
         length of the IPv6 prefix, specified in the dmr-ipv6-prefix
         field, expressed in bits
      dmr-ipv6-prefix
         a 32-bits field that specifies an IPv6 prefix that appears in
         the Default Mapping Rule

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4.3.4.  S46-V4V6Bind Sub Option

   There MUST be atmost one S46-RULE Sub Option included in each
   Lightweight 4over6 Container Option.

    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |    SubType    |    SubLen     |         ipv4-address          |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |          (Continued)          |bindprefix6-len|               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+               +
   |                         bind-ipv6-prefix                      |
   +                                                               +
   |                         bind-ipv6-prefix                      |
   +                                                               +
   |                         bind-ipv6-prefix                      |
   +                                               +-+-+-+-+-+-+-+-+
   |             bind-ipv6-prefix                  |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

      SubType
         6 (SubType number, for the S46-V4V6Bind sub option)
      SubLen
         23 (the length of the S46-V4V6Bind sub option)
      Prefix4-len
         length of the IPv4 prefix, specified in the rule-ipv4-prefix
         field, expressed in bits
      ipv4-address
         a 32-bits field that specifies an IPv4 address that appears in
         the V4V6Bind Option
      bindprefix6-len
         length of the IPv6 prefix, specified in the bind-ipv6-prefix
         field, expressed in bits
      rule-ipv6-prefix
         a 128-bits field that specifies an IPv6 prefix that appears in
         the V4V6Bind Option

4.3.5.  S46-PORTPARAMS Sub Option

   The S46-PORTPARAMS sub option specifies optional port set information
   that MAY be provided to CEs.  The S46-PORTPARAMS sub option canbe
   included optionally by each type of S46 Container Option.

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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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|    SubType    |    SubLen     |  PSID-Offset  |   PSID-len    |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|              PSID             |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   SubType
      7 (SubType number, for the S46-PORTPARAMS Sub Option sub option)
   SubLen
      6 (the length of the S46-PORTPARAMS Sub Option sub option)
   PSID Offset
      8 bits long field that specifies the numeric value for the S46 algorithm's excluded
      port range/ offset bits (a bits), as per Section 5.1 of RFC 7597.
      Allowed values are between 0 and 15. Default values for this field are specific to the
      Softwire mechanism being implemented and are defined in the relevant specification document.
   PSID-len
      Bit length value of the number of significant bits in the PSID
      field. (also known as 'k'). When set to 0, the PSID field is to
      be ignored. After the first 'a' bits, there are k bits in the
      port number representing valid of PSID. Subsequently, the
      address sharing ratio would be 2 ^k.
   PSID (Port-set ID)
      Explicit 16-bit (unsigned word) PSID value.  The PSID value
      algorithmically identifies a set of ports assigned to a CE. The
      first k-bits on the left of this 2-octets field is the PSID
      value. The remaining (16-k) bits on the right are padding zeros.

4.4.  Sub Options for S46-RULE Sub Option

4.4.1.  Rule-IPv6-Prefix Sub Option

   The Rule-IPv6-Prefix Sub Option is necessary for every S46-RULE sub
   option.  It should appear for once and only once.

   The IPv6 Prefix sub option is followed the framed IPv6 prefix
   designed in [RFC3162].

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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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |    SubType    |    SubLen     |   Reserved    |  prefix6-len  |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   |                        rule-ipv6-prefix                       |
   |                                                               |
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      SubType
         8 (SubType number, for the Rule-IPv6-Prefix6 sub option)
      SubLen
         20 (the length of the Rule-IPv6-Prefix6 sub option)
      Reserved
         Reserved for future usage. It should be set to all zero
      prefix6-len
         length of the IPv6 prefix, specified in the rule-ipv6-prefix
         field, expressed in bits
      rule-ipv6-prefix
         a 128-bits field that specifies an IPv6 prefix that appears in
         a MAP rule

4.4.2.  Rule-IPv4-Prefix Sub Option

    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |    SubType    |    SubLen     |   Reserved    |  prefix4-len  |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                       rule-ipv4-prefix                        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

      SubType
         9 (SubType number, for the Rule-IPv4-Prefix6 sub option)
      SubLen
         8 (the length of the Rule-IPv4-Prefix6 sub option)
      Reserved
         Reserved for future usage. It should be set to all zero
      Prefix4-len
         length of the IPv6 prefix, specified in the rule-ipv6-prefix
         field, expressed in bits
      rule-ipv4-prefix
         a 32-bits field that specifies an IPv4 prefix that appears in
         a MAP rule

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4.4.3.  EA Length Sub Option

    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |    SubType    |    SubLen     |             EA-len            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

      SubType
         10 (SubType number, for the EA Length sub option)
      SubLen
         4 (the length of the EA Length sub option)
      EA-len
         16 bits long field that specifies the Embedded-Address (EA)
         bit length.  Allowed values range from 0 to 48

4.5.  Table of attributes

   The following table provides a guide to which attributes may be found
   in which kinds of packets, and in what quantity.

   Request Accept Reject Challenge Accounting  #  Attribute
                                    Request
    0-1     0-1     0      0         0-1      TBD1 MAP-
                                                   Configuration
    0-1     0-1     0      0         0-1      1    User-Name
    0-1     0       0      0         0        2    User-Password
    0-1     0-1     0      0         0-1      6    Service-Type
    0-1     0-1     0-1    0-1       0-1      80   Message-Authenticator

   The following table defines the meaning of the above table entries.

   0     This attribute MUST NOT be present in packet.
   0+    Zero or more instances of this attribute MAY be present in
         packet.
   0-1   Zero or one instance of this attribute MAY be present in
         packet.
   1     Exactly one instance of this attribute MUST be present in
         packet.

5.  Diameter Considerations

   This attribute is usable within either RADIUS or Diameter [RFC6733].
   Since the Attributes defined in this document will be allocated from
   the standard RADIUS type space, no special handling is required by
   Diameter entities.

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6.  IANA Considerations

   This document requires the assignment of two new RADIUS Attributes
   Types in the "Radius Types" registry (currently located at
   http://www.iana.org/assignments/radius-types for the following
   attributes:

   o  MAP-Configuration TBD1

   IANA should allocate the numbers from the standard RADIUS Attributes
   space using the "IETF Review" policy [RFC5226].

7.  Security Considerations

   In softwire scenarios, both CE and BNG are within a provider network,
   which can be considered as a closed network and a lower security
   threat environment.  A similar consideration can be applied to the
   RADIUS message exchange between BNG and the AAA server.

   Known security vulnerabilities of the RADIUS protocol are discussed
   in [RFC2607], [RFC2865], and[RFC2869].  Use of IPsec [RFC4301] for
   providing security when RADIUS is carried in IPv6 is discussed in
   [RFC3162].

   A malicious user may use MAC address proofing and/or dictionary
   attack on the shared password that has been preconfigured on the
   DHCPv6 server to get unauthorized configuration information.

   Security considerations for MAP specific between MAP CE and BNG are
   discussed in [RFC7597].  Security considerations for Lightweight
   4over6 are discussed in [RFC7596].  Furthermore, generic DHCPv6
   security mechanisms can be applied DHCPv6 intercommunication between
   CE and BNG.

   Security considerations for the Diameter protocol are discussed in
   [RFC6733].

8.  Acknowledgements

   The authors would like to thank the valuable comments made by Peter
   Lothberg, Wojciech Dec, and Suresh Krishnan for this document.  This
   document was merged with draft-sun-softwire-lw4over6-radext-01,
   thanks to everyone who contributed to this draft.

   This document was produced using the xml2rfc tool [RFC7749].

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9.  References

9.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <http://www.rfc-editor.org/info/rfc2119>.

   [RFC2865]  Rigney, C., Willens, S., Rubens, A., and W. Simpson,
              "Remote Authentication Dial In User Service (RADIUS)",
              RFC 2865, DOI 10.17487/RFC2865, June 2000,
              <http://www.rfc-editor.org/info/rfc2865>.

   [RFC3162]  Aboba, B., Zorn, G., and D. Mitton, "RADIUS and IPv6",
              RFC 3162, DOI 10.17487/RFC3162, August 2001,
              <http://www.rfc-editor.org/info/rfc3162>.

   [RFC3315]  Droms, R., Ed., Bound, J., Volz, B., Lemon, T., Perkins,
              C., and M. Carney, "Dynamic Host Configuration Protocol
              for IPv6 (DHCPv6)", RFC 3315, DOI 10.17487/RFC3315, July
              2003, <http://www.rfc-editor.org/info/rfc3315>.

   [RFC3580]  Congdon, P., Aboba, B., Smith, A., Zorn, G., and J. Roese,
              "IEEE 802.1X Remote Authentication Dial In User Service
              (RADIUS) Usage Guidelines", RFC 3580,
              DOI 10.17487/RFC3580, September 2003,
              <http://www.rfc-editor.org/info/rfc3580>.

   [RFC5080]  Nelson, D. and A. DeKok, "Common Remote Authentication
              Dial In User Service (RADIUS) Implementation Issues and
              Suggested Fixes", RFC 5080, DOI 10.17487/RFC5080, December
              2007, <http://www.rfc-editor.org/info/rfc5080>.

   [RFC6158]  DeKok, A., Ed. and G. Weber, "RADIUS Design Guidelines",
              BCP 158, RFC 6158, DOI 10.17487/RFC6158, March 2011,
              <http://www.rfc-editor.org/info/rfc6158>.

   [RFC6929]  DeKok, A. and A. Lior, "Remote Authentication Dial In User
              Service (RADIUS) Protocol Extensions", RFC 6929,
              DOI 10.17487/RFC6929, April 2013,
              <http://www.rfc-editor.org/info/rfc6929>.

9.2.  Informative References

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   [RFC2607]  Aboba, B. and J. Vollbrecht, "Proxy Chaining and Policy
              Implementation in Roaming", RFC 2607,
              DOI 10.17487/RFC2607, June 1999,
              <http://www.rfc-editor.org/info/rfc2607>.

   [RFC2869]  Rigney, C., Willats, W., and P. Calhoun, "RADIUS
              Extensions", RFC 2869, DOI 10.17487/RFC2869, June 2000,
              <http://www.rfc-editor.org/info/rfc2869>.

   [RFC4301]  Kent, S. and K. Seo, "Security Architecture for the
              Internet Protocol", RFC 4301, DOI 10.17487/RFC4301,
              December 2005, <http://www.rfc-editor.org/info/rfc4301>.

   [RFC5226]  Narten, T. and H. Alvestrand, "Guidelines for Writing an
              IANA Considerations Section in RFCs", BCP 26, RFC 5226,
              DOI 10.17487/RFC5226, May 2008,
              <http://www.rfc-editor.org/info/rfc5226>.

   [RFC6733]  Fajardo, V., Ed., Arkko, J., Loughney, J., and G. Zorn,
              Ed., "Diameter Base Protocol", RFC 6733,
              DOI 10.17487/RFC6733, October 2012,
              <http://www.rfc-editor.org/info/rfc6733>.

   [RFC6887]  Wing, D., Ed., Cheshire, S., Boucadair, M., Penno, R., and
              P. Selkirk, "Port Control Protocol (PCP)", RFC 6887,
              DOI 10.17487/RFC6887, April 2013,
              <http://www.rfc-editor.org/info/rfc6887>.

   [RFC7341]  Sun, Q., Cui, Y., Siodelski, M., Krishnan, S., and I.
              Farrer, "DHCPv4-over-DHCPv6 (DHCP 4o6) Transport",
              RFC 7341, DOI 10.17487/RFC7341, August 2014,
              <http://www.rfc-editor.org/info/rfc7341>.

   [RFC7596]  Cui, Y., Sun, Q., Boucadair, M., Tsou, T., Lee, Y., and I.
              Farrer, "Lightweight 4over6: An Extension to the Dual-
              Stack Lite Architecture", RFC 7596, DOI 10.17487/RFC7596,
              July 2015, <http://www.rfc-editor.org/info/rfc7596>.

   [RFC7597]  Troan, O., Ed., Dec, W., Li, X., Bao, C., Matsushima, S.,
              Murakami, T., and T. Taylor, Ed., "Mapping of Address and
              Port with Encapsulation (MAP-E)", RFC 7597,
              DOI 10.17487/RFC7597, July 2015,
              <http://www.rfc-editor.org/info/rfc7597>.

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   [RFC7598]  Mrugalski, T., Troan, O., Farrer, I., Perreault, S., Dec,
              W., Bao, C., Yeh, L., and X. Deng, "DHCPv6 Options for
              Configuration of Softwire Address and Port-Mapped
              Clients", RFC 7598, DOI 10.17487/RFC7598, July 2015,
              <http://www.rfc-editor.org/info/rfc7598>.

   [RFC7599]  Li, X., Bao, C., Dec, W., Ed., Troan, O., Matsushima, S.,
              and T. Murakami, "Mapping of Address and Port using
              Translation (MAP-T)", RFC 7599, DOI 10.17487/RFC7599, July
              2015, <http://www.rfc-editor.org/info/rfc7599>.

   [RFC7749]  Reschke, J., "The "xml2rfc" Version 2 Vocabulary",
              RFC 7749, DOI 10.17487/RFC7749, February 2016,
              <http://www.rfc-editor.org/info/rfc7749>.

Additional Authors

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   Qiong Sun
   China Telecom
   Beijing  China
   Email: sunqiong@ctbri.com.cn

   Qi Sun
   Tsinghua University
   Department of Computer Science, Tsinghua University
   Beijing 100084
   P.R.China
   Phone: +86-10-6278-5822
   Email: sunqibupt@gmail.com

   Cathy Zhou
   Huawei Technologies
   Bantian, Longgang District
   Shenzhen 518129
   Email: cathy.zhou@huawei.com

   Tina Tsou
   Huawei Technologies(USA)
   2330 Central Expressway
   Santa Clara, CA 95050
   USA
   Email: Tina.Tsou.Zouting@huawei.com

   ZiLong Liu
   Tsinghua University
   Beijing 100084
   P.R.China
   Phone: +86-10-6278-5822
   Email: liuzilong8266@126.com

   Yong Cui
   Tsinghua University
   Beijing 100084
   P.R.China
   Phone: +86-10-62603059
   Email: yong@csnet1.cs.tsinghua.edu.cn

Authors' Addresses

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   Sheng Jiang
   Huawei Technologies Co., Ltd
   Q14, Huawei Campus, No.156 Beiqing Road
   Hai-Dian District, Beijing, 100095
   P.R. China

   Email: jiangsheng@huawei.com

   Yu Fu
   CNNIC
   No.4 South 4th Street, Zhongguancun
   Hai-Dian District, Beijing, 100190
   P.R. China

   Email: fuyu@cnnic.cn

   Bing Liu
   Huawei Technologies Co., Ltd
   Q14, Huawei Campus, No.156 Beiqing Road
   Hai-Dian District, Beijing, 100095
   P.R. China

   Email: leo.liubing@huawei.com

   Peter Deacon
   IEA Software, Inc.
   P.O. Box 1170
   Veradale, WA  99037
   USA

   Email: peterd@iea-software.com

   Chongfeng Xie
   China Telecom
   Beijing
   P.R. China

   Email: xiechf@ctbri.com.cn

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   Tianxiang Li
   Tsinghua University
   Beijing  100084
   P.R.China

   Email: peter416733@gmail.com

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