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Access Network Identifier Option in DHCP
draft-ietf-dhc-access-network-identifier-12

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 7839.
Authors Shwetha Bhandari , Sri Gundavelli , Mark Grayson , Bernie Volz , Jouni Korhonen
Last updated 2016-01-30
Replaces draft-bhandari-dhc-access-network-identifier
RFC stream Internet Engineering Task Force (IETF)
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Stream WG state Submitted to IESG for Publication
Document shepherd Sheng Jiang
Shepherd write-up Show Last changed 2015-09-16
IESG IESG state Became RFC 7839 (Proposed Standard)
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Needs a YES. Needs 10 more YES or NO OBJECTION positions to pass.
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IANA IANA review state Version Changed - Review Needed
draft-ietf-dhc-access-network-identifier-12
Network Working Group                                        S. Bhandari
Internet-Draft                                             S. Gundavelli
Intended status: Standards Track                              M. Grayson
Expires: August 2, 2016                                          B. Volz
                                                           Cisco Systems
                                                             J. Korhonen
                                                 Broadcom Communications
                                                        January 30, 2016

                Access Network Identifier Option in DHCP
              draft-ietf-dhc-access-network-identifier-12

Abstract

   This document specifies the format and mechanism that is to be used
   for encoding access network identifiers in DHCPv4 and DHCPv6 messages
   by defining new access network identifier options and sub-options.

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 August 2, 2016.

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

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   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
   2.  Motivation . . . . . . . . . . . . . . . . . . . . . . . . . .  3
   3.  Terminology  . . . . . . . . . . . . . . . . . . . . . . . . .  4
   4.  DHCPv4 Access-Network-Identifier Option  . . . . . . . . . . .  5
     4.1.  DHCPv4 Access-Network-Identifier Sub-options . . . . . . .  5
     4.2.  DHCPv4 Access-Technology-Type Sub-option . . . . . . . . .  6
     4.3.  DHCPv4 Network-Identifier Sub-options  . . . . . . . . . .  7
       4.3.1.  DHCPv4 Network Name Sub-option . . . . . . . . . . . .  7
       4.3.2.  DHCPv4 Access-Point Name Sub-option  . . . . . . . . .  8
       4.3.3.  DHCPv4 Access-Point BSSID Sub-option . . . . . . . . .  8
     4.4.  DHCPv4 Operator Identifier Sub-options . . . . . . . . . .  9
       4.4.1.  DHCPv4 Operator-Identifier Sub-option  . . . . . . . .  9
       4.4.2.  DHCPv4 Operator-Realm Sub-option . . . . . . . . . . . 10
   5.  DHCPv6 Access-Network-Identifier Options . . . . . . . . . . . 10
     5.1.  DHCPv6 Access-Technology-Type Option . . . . . . . . . . . 11
     5.2.  DHCPv6 Network-Identifier Options  . . . . . . . . . . . . 11
       5.2.1.  DHCPv6 Network Name Option . . . . . . . . . . . . . . 11
       5.2.2.  DHCPv6 Access-Point Name Option  . . . . . . . . . . . 12
       5.2.3.  DHCPv6 Access-Point BSSID Option . . . . . . . . . . . 12
     5.3.  DHCPv6 Operator Identifier Options . . . . . . . . . . . . 13
       5.3.1.  DHCPv6 Operator-Identifier Option  . . . . . . . . . . 13
       5.3.2.  DHCPv6 Operator-Realm Option . . . . . . . . . . . . . 13
   6.  Relay Agent Behavior . . . . . . . . . . . . . . . . . . . . . 14
   7.  Server Behavior  . . . . . . . . . . . . . . . . . . . . . . . 14
   8.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 15
   9.  Security Considerations  . . . . . . . . . . . . . . . . . . . 16
   10. Acknowledgments  . . . . . . . . . . . . . . . . . . . . . . . 17
   11. References . . . . . . . . . . . . . . . . . . . . . . . . . . 17
     11.1. Normative References . . . . . . . . . . . . . . . . . . . 17
     11.2. Informative References . . . . . . . . . . . . . . . . . . 18
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 19

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1.  Introduction

   Access network identification (ANI) of a network device has a range
   of applications.  For example the local mobility anchor in a Proxy
   Mobile IPv6 domain is able to provide access network and access
   operator specific handling or policing of the mobile node traffic
   using information about the access network to which the mobile node
   is attached.

   This document specifies Dynamic Host Configuration Protocol for IPv4
   (DHCPv4) [RFC2131] and Dynamic Host Configuration Protocol for IPv6
   (DHCPv6) [RFC3315] options for access network identification that is
   added by Relay agent in the DHCPv4 or DHCPv6 messages towards the
   Server.  The scope of applicability for this option is between a DHCP
   relay agent and a mobile access gateway where the same operator
   typically operates both these functions

   Dynamic Host Configuration Protocol (DHCP) relay agent aware of the
   access network and access operator add this information in the DHCP
   messages.  This information can be used to provide differentiated
   services and policing of traffic based on the access network to which
   a client is attached.  Examples of how this information can be used
   in mobile networks can be found in [RFC6757].

2.  Motivation

   Proxy mobile IPv6 [RFC5213] can be used for supporting network-based
   mobility management in various types of network deployments.  The
   network architectures, such as Service provider Wi-Fi access
   aggregation or, WLAN integrated mobile packet core are examples where
   Proxy Mobile IPv6 is a component of the overall architecture.  Some
   of these architectures require the ability of the local mobility
   anchor (LMA) [RFC5213] to provide differentiated services and
   policing of traffic to the mobile nodes based on the access network
   to which they are attached.  Policy systems in mobility architectures
   such as PCC [TS23203] and ANDSF [TS23402] in 3GPP system allow
   configuration of policy rules with conditions based on the access
   network information.  For example, the service treatment for the
   mobile node's traffic may be different when they are attached to a
   access network owned by the home operator than when owned by a
   roaming partner.  The service treatment can also be different based
   on the configured Service Set Identifiers (SSID) in case of IEEE
   802.11 based access networks.  Other examples of services include the
   operator's ability to apply tariff based on the location.

   The PMIPv6 extension as specified in [RFC6757] defines PMIPv6 options
   to carry access network identifiers in PMIPv6 signaling from Mobile

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   Access Gateway (MAG) to LMA.  MAG can learn this information from
   DHCP options as inserted by DHCP Relay agent before MAG.  If MAG
   relays DHCP messages to LMA as specified in [RFC5844] this
   information can be inserted by MAG towards LMA in the forwarded DHCP
   messages.

   Figure 1 illustrates an example Proxy Mobile IPv6 deployment where
   Access Points (AP) acting as a DHCP relay agent inserts access
   network identifiers in DHCP messages relayed from the connected
   clients.  The DHCP Server collocated on the mobile access gateway
   learns this information over DHCP and delivers the information
   elements related to the access network to the local mobility anchor
   over Proxy Mobile IPv6 signaling messages.  In this example, the
   additional information could comprise the SSID of the used IEEE
   802.11 network and the identities of the operators running the IEEE
   802.11 access network infrastructure.

          SSID: IETF-1
          Operator-Id: provider1.example
          +--+ DHCP
          |AP|-------.                        {Access Specific Policies)
          +--+       |             _-----_             |
                   +-----+       _(       )_        +-----+
                   | MAG |-=====(   PMIPv6  )======-| LMA |-
                   +-----+       (_ Tunnel_)        +-----+
          +--+ DHCP  |             '-----'
          |AP|-------'
          +--+
          SSID: IETF-2
          Operator-Id: provider2.example

                      Access Networks attached to MAG

3.  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].

   All the DHCP related terms used in this document are to be
   interpreted as defined in the Dynamic Host Configuration Protocol
   (DHCPv4) [RFC2131] and Dynamic Host Configuration Protocol for IPv6
   (DHCPv6) [RFC3315] specifications.  DHCP message refers to both
   DHCPv4 and DHCPv6 messages throughout this document.

   All the mobility related terms used in this document are to be

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   interpreted as defined in the Proxy Mobile IPv6 specifications
   [RFC5213] and [RFC5844].  Additionally, this document uses the
   following abbreviations:

   Service Set Identifier (SSID)

      Service Set Identifier (SSID) identifies the name of the IEEE
      802.11 network.  SSID differentiates from one network to the
      other.

   Operator-Identifier

      The Operator-Identifier is the Structure of Management Information
      (SMI) Network Management Private Enterprise Code of the IANA-
      maintained "Private Enterprise Numbers" registry [SMI].

4.  DHCPv4 Access-Network-Identifier Option

   The Access Network Identifier carries information to identify the
   access network to which the client is attached.  This information
   includes access technology type, network identifier, and access-
   network operator identifiers.

   Relay agents that include Access Network Identifier information
   include one or more sub-options (see Section 4.1) in the Relay Agent
   Information option [RFC3046].

4.1.  DHCPv4 Access-Network-Identifier Sub-options

   The access network identifier information will be defined in multiple
   sub-options, allocated from the DHCP Relay Agent Sub-Option Codes.

   ANI Sub-options: The ANI Sub-options consists of a sequence of Sub-
   Option Code, Length, and Value tuples for each sub-option, encoded in
   the following manner:

       SubOpt  Len     Sub-option Data
      +------+------+------+------+------+------+--...-+------+
      | code |   N  |  s1  |  s2  |  s3  |  s4  |      |  sN  |
      +------+------+------+------+------+------+--...-+------+

   Subopt code
      The 1-octet code for the sub-options defined in the following
      sections.

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   Len
      An unsigned 8-bit integer giving the length of the Sub-option Data
      field in this sub-option in octets.

   Sub-option Data (s1 to sN)
      The data area for the sub-option.

   The initial assignment of DHCP access network identifier sub-options
   is as follows:

      +=================+=======================================+
      | SUB-OPTION CODE |      SUB-OPTION DESCRIPTION           |
      +=================+=======================================+
      |    <IANA-1>     | Access Technology Type Sub-option     |
      +=========================================================+
      |    <IANA-2>     | Access Network Name Sub-option        |
      +=========================================================+
      |    <IANA-3>     | Access Point Name Sub-option          |
      +=========================================================+
      |    <IANA-4>     | Access Point BSSID Sub-option         |
      +=========================================================+
      |    <IANA-5>     | Operator-Identifier Sub-option        |
      +=========================================================+
      |    <IANA-6>     | Operator-Realm Sub-option             |
      +=========================================================+

4.2.  DHCPv4 Access-Technology-Type Sub-option

   This sub-option is used for exchanging the type of the access
   technology of the network to which the client is attached.  Its
   format is as follows:

       0                   1                   2                   3
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |  Subopt Code  |     Length    |   Reserved    |      ATT      |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Subopt Code
      <IANA-1>.

   Length
      2.

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   Reserved
      An 8-bit field that is unused for now.  The value MUST be
      initialized to 0 by the sender and MUST be ignored by the
      receiver.

   Access-Technology-Type (ATT)
      An 8-bit field that specifies the access technology through which
      the client is connected to the access link from the IANA name
      space Access Technology Type Option type value registry defined in
      [RFC5213].

4.3.  DHCPv4 Network-Identifier Sub-options

   These sub-options are used for carrying the name of the access
   network (e.g., a SSID in case of IEEE 802.11 Access Network, or PLMN
   Identifier [TS23003] in case of 3GPP access) and Access Point name to
   which the client is attached.  The format of these sub-options is
   defined the following sections.  The Network-Identifier sub-options
   are only for the currently known access technology types.

4.3.1.  DHCPv4 Network Name 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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |  Subopt Code  |     Length    |                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+                               |
      .                                                               .
      .                     Network Name (e.g., SSID or PLMNID)       .
      .                                                               .
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Subopt Code
      <IANA-2>.

   Length
      The length of the Network Name field.

   Network Name
      The name of the access network to which the mobile node is
      attached.  The encoding MUST be UTF-8 as described in [RFC3629].

      The type of the Network Name is dependent on the access technology
      to which the mobile node is attached.  For IEEE 802.11 based
      networks, the network name will be the SSID of the network.  For
      3GPP access based it is the PLMN Identifier of the access network
      and for 3GPP2 access, the Network Name is the Access Network

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      Identifier[ANI].

      When encoding the PLMN Identifier, both the Mobile Network Code
      (MNC) [TS23003] and Mobile Country Code (MCC) [TS23003] MUST be 3
      digits.  If the MNC in use only has 2 digits, then it MUST be
      preceded with a '0'.

4.3.2.  DHCPv4 Access-Point Name 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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |  Subopt Code  |     Length    |                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+                               |
      .                                                               .
      .                        Access-Point Name                      .
      .                                                               .
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Subopt Code
      <IANA-3>.

   Length
      The length of the Access-Point Name field.

   Access-Point Name
      The name of the access point (physical device name) to which the
      mobile node is attached.  This is the identifier that uniquely
      identifies the access point.  While Network Name (e.g., SSID)
      identifies the operator's access network, Access-Point Name
      identifies a specific network device in the network to which the
      mobile node is attached.  In some deployments, the Access-Point
      Name can be set to the string representation of the Media Access
      Control (MAC) address as specified in [RFC6991] mac-address string
      type of the device or some unique identifier that can be used by
      the policy systems in the operator network to unambiguously
      identify the device.  The encoding MUST be UTF-8 as described in
      [RFC3629].

4.3.3.  DHCPv4 Access-Point BSSID Sub-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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |  Subopt Code  |     Length    |                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+                               |
      |                        Access-Point BSSID                     |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Subopt Code
      <IANA-4>.

   Length
      6.

   Access-Point BSSID
      The 48-bit Basic Service Set Identification (BSSID) of the access
      point to which the mobile node is attached.

4.4.  DHCPv4 Operator Identifier Sub-options

   The Operator identifier sub-options can be used for carrying the
   operator identifiers of the access network to which the client is
   attached.  The format of these sub-options is defined below.

4.4.1.  DHCPv4 Operator-Identifier 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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |  Subopt Code  |     Length    |                               .
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      .      Operator-Identifier      |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Subopt Code  <IANA-5>.

   Length
      4.

   Operator-Identifier  Operator-Identifier as a variable-length Private
      Enterprise Number (PEN) [SMI] encoded in a network-byte order.
      Please refer to (section 3.1.3 of [RFC6757]) for additional
      details.

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4.4.2.  DHCPv4 Operator-Realm 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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |  Subopt Code  |     Length    |                               |
      |-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+                               |
      .                                                               .
      .                        Operator-Realm                         .
      .                                                               .
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Subopt Code
      <IANA-6>.

   Length
      The length of the Operator Realm field.

   Operator-Realm
      Realm of the operator (e.g., EXAMPLE.COM).  Please refer to
      (section 3.1.3 of [RFC6757]) for additional details.

5.  DHCPv6 Access-Network-Identifier Options

   The Access Network Identifier options defined here may be added by
   the DHCPv6 Relay agent in Relay-forward messages.

      +=================+=======================================+
      |    OPTION CODE  |      OPTION DESCRIPTION               |
      +=================+=======================================+
      |    <IANA-7>     | OPTION_ANI_ATT                        |
      +=========================================================+
      |    <IANA-8>     | OPTION_ANI_NETWORK_NAME               |
      +=========================================================+
      |    <IANA-9>     | OPTION_ANI_AP_NAME                    |
      +=========================================================+
      |    <IANA-10>    | OPTION_ANI_AP_BSSID                   |
      +=========================================================+
      |    <IANA-11>    | OPTION_ANI_OPERATOR_ID                |
      +=========================================================+
      |    <IANA-12>    | OPTION_ANI_OPERATOR_REALM             |
      +=========================================================+

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5.1.  DHCPv6 Access-Technology-Type Option

   This option is used for exchanging the type of the access technology
   the client is attached to the network.  Its format is as follows:

        0                   1                   2                   3
        0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |         OPTION_ANI_ATT        |           Option-Len          |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |   Reserved    |       ATT     |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Option-Code
      OPTION_ANI_ATT (<IANA-7>).

   Option-Len
      2.

   Reserved
      An 8-bit field that is unused for now.  The value MUST be
      initialized to 0 by the sender and MUST be ignored by the
      receiver.

   Access Technology Type (ATT):
      The contents of this field is the same as the ATT field described
      in Section 4.2.

5.2.  DHCPv6 Network-Identifier Options

   These options can be used for carrying the name of the access network
   (e.g., a SSID in case of IEEE 802.11 Access Network, or PLMN
   Identifier [TS23003] in case of 3GPP access) and Access Point name to
   which the client is attached.  The format of these options is defined
   below.

5.2.1.  DHCPv6 Network Name 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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |    OPTION_ANI_NETWORK_NAME    |           Option-Len          |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      .                                                               .
      .                     Network Name (e.g., SSID or PLMNID)       .
      .                                                               .

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      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Option-Code
      OPTION_ANI_NETWORK_NAME (<IANA-8>).

   Option-Len
      The length of the Network Name field.

   Network Name
      The contents of this field is the same as the Network Name field
      described in Section 4.3.1.

5.2.2.  DHCPv6 Access-Point Name 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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |       OPTION_ANI_AP_NAME      |           Option-Len          |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      .                                                               .
      .                        Access-Point Name                      .
      .                                                               .
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Option-Code
      OPTION_ANI_AP_NAME (<IANA-9>).

   Option-Len
      The length of the Access-Point Name field.

   Access-Point Name
      The contents of this field is the same as the Access-Point Name
      field described in Section 4.3.2.

5.2.3.  DHCPv6 Access-Point BSSID 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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |       OPTION_ANI_AP_BSSID     |           Option-Len          |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                        Access-Point BSSID                     |
      +                               +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

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   Option-Code
      OPTION_ANI_AP_BSSID (<IANA-10>).

   Option-Len
      6.

   Access-Point BSSID
      The contents of this field is the same as the Access-Point BSSID
      field described in Section 4.3.3.

5.3.  DHCPv6 Operator Identifier Options

   The Operator Identifier options can be used for carrying the operator
   identifier of the access network to which the client is attached.
   The format of these options is defined below.

5.3.1.  DHCPv6 Operator-Identifier 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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |     OPTION_ANI_OPERATOR_ID    |           Option-Len          |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                      Operator-Identifier                      |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Option-Code
      OPTION_ANI_OPERATOR_ID (<IANA-11>).

   Option-Len
      4.

   Operator Enterprise ID
      The contents of this field is the same as the DHCPv4 Operator-
      Identifier Sub-option field described in Section 4.4.1.

5.3.2.  DHCPv6 Operator-Realm 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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |   OPTION_ANI_OPERATOR_REALM   |           Option-Len          |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      .                                                               .
      .                        Operator-Realm                         .
      .                                                               .

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      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Option-Code
      OPTION_ANI_OPERATOR_REALM (<IANA-12>).

   Option-Len
      The length of the Operator Realm field.

   Operator-Realm
      The contents of this field is the same as the Operator-Realm field
      described in Section 4.4.2.

6.  Relay Agent Behavior

   DHCPv4 Relay Agents MAY include sub-options defined in section 4.2
   through 4.4 in the Relay Agent Information option as defined in
   [RFC3046] for providing information about the access network over
   which DHCP messages from the client is received.

   The DHCPv4 Relay Agent when including any of these sub-options in the
   DHCP message, DHCPv4 Network Name Sub-option (Section 4.3.1), DHCPv4
   Access-Point Name Sub-option (Section 4.3.2), DHCPv4 Access-Point
   BSSID Sub-option (Section 4.3.3), MUST include the DHCPv4 Access-
   Technology-Type Sub-option (Section 4.2)

   DHCPv6 Relay Agents MAY include options defined in Section 5 in
   Relay-forward message when forwarding any DHCPv6 message type from
   clients to the servers to provide information about the access
   network over which DHCPv6 messages from the client is received.

   The DHCPv6 Relay Agent when including any of these options in the
   DHCP message, DHCPv6 Network Name Option (Section 5.2.1), DHCPv6
   Access-Point Name Option (Section 5.2.2), DHCPv6 Access-Point BSSID
   Option (Section 5.2.3), MUST include the DHCPv6 Access-Technology-
   Type Option (Section 5.1)

7.  Server Behavior

   DHCPv4 base specification [RFC2131] requires that the DHCPv4 server
   ignore the DHCPv4 Access Network Identifier option if it does not
   understand the option.

   If the DHCPv4 server does not understand the received sub-option
   defined in sections 4.1 through 4.4 in the DHCPv4 Relay Agent
   Information option (82) it MUST ignore those sub-options only.  If
   DHCPv4 Server is able to process the DHCPv4 Access Network Identifier

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   sub-options defined in sections 4.1 through 4.4 received in DHCPv4
   Relay Agent Information option, it MAY use this information obtained
   from the sub-option for address pool selection, or for policy
   decisions as per its configured policy.  This information obtained
   from the sub-option SHOULD NOT be stored unless it is absolutely
   needed, However, if it is stored, the information MUST be deleted as
   quickly as possible to eliminate any possibility of the information
   getting exposed to an intruder.

   If the received DHCPv4 message does not include DHCPv4 Access-
   Technology-Type Sub-option (Section 4.2), but if it includes any one
   of these other options, DHCPv4 Network Name Sub-option
   (Section 4.3.1), DHCPv4 Access-Point Name Sub-option (Section 4.3.2),
   or DHCPv4 Access-Point BSSID Sub-option (Section 4.3.3), then the
   DHCPv4 server MUST ignore the received DHCPv4 Access-Network-
   Identifier option and process the rest of the message as per the base
   DHCPv4 specifications

   DHCPv6 base specification [RFC3315] requires that the DHCPv6 server
   ignore the DHCPv6 Access-Network-Identifier option if it does not
   understand the option.

   If the DHCPv6 server receives the options defined in Section 5 and is
   configured to use the options defined in Section 5, it SHOULD look
   for the DHCPv6 Access Network identifier options in the Relay-forward
   message of the DHCPv6 relay agent(s) based on its configured policy.
   The server MAY use received ANI options for its address pool
   selection policy decisions as per its configured policy.  This
   information obtained from the options SHOULD NOT be stored unless it
   is absolutely needed, However, if it is stored, the information MUST
   be deleted as quickly as possible to eliminate any possibility of the
   information getting exposed to an intruder.

   If the received DHCPv6 message does not include DHCPv6 Access-
   Technology-Type Option (Section 5.1), but it includes any one of
   these other options, DHCPv6 Network Name Option (Section 5.2.1),
   DHCPv6 Access-Point Name Option (Section 5.2.2), or DHCPv6 Access-
   Point BSSID Option (Section 5.2.3), then the DHCPv6 server MUST
   ignore the received DHCPv6 Access-Network-Identifier option and
   process the rest of the message as per the base DHCPv6
   specifications.

8.  IANA Considerations

   IANA is requested to assign Sub-option codes for the following DHCPv4
   Sub-options from the "DHCP Relay Agent Sub-Option Codes" registry,
   <http://www.iana.org/assignments/bootp-dhcp-parameters>:

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      +=================+=======================================+
      | SUB-OPTION CODE |     SUB-OPTION DESCRIPTION            |
      +=================+=======================================+
      |    <IANA-1>     | Access Technology Type Sub-option     |
      +=========================================================+
      |    <IANA-2>     | Access Network Name Sub-option        |
      +=========================================================+
      |    <IANA-3>     | Access Point Name Sub-option          |
      +=========================================================+
      |    <IANA-4>     | Access Point BSSID Sub-option         |
      +=========================================================+
      |    <IANA-5>     | Operator Identifier Sub-option        |
      +=========================================================+
      |    <IANA-6>     | Operator Realm Sub-option             |
      +=========================================================+

   IANA is requested to assign option codes for the following DHCPv6
   options from the "Option Codes registry for DHCPv6" registry
   <http://www.iana.org/assignments/dhcpv6-parameters>, as specified in
   [RFC3315]:

      +=================+=======================================+
      |   OPTION CODE   |      OPTION DESCRIPTION               |
      +=================+=======================================+
      |    <IANA-7>     | OPTION_ANI_ATT                        |
      +=========================================================+
      |    <IANA-8>     | OPTION_ANI_NETWORK_NAME               |
      +=========================================================+
      |    <IANA-9>     | OPTION_ANI_AP_NAME                    |
      +=========================================================+
      |    <IANA-10>    | OPTION_ANI_AP_BSSID                   |
      +=========================================================+
      |    <IANA-11>    | OPTION_ANI_OPERATOR_ID                |
      +=========================================================+
      |    <IANA-12>    | OPTION_ANI_OPERATOR_REALM             |
      +=========================================================+

9.  Security Considerations

   Since there is no privacy protection for DHCP messages, an
   eavesdropper who can monitor the link between the DHCP server and
   relay agent can discover access network information.

   [RFC3118] and [RFC3315] describe many of the threats in using DHCP.
   [RFC3118] and [RFC3315] each provide a solution, the Authentication
   Option for DHCPv4 and DHCPv6 (respectively).  However, neither of

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   these options are in active use and therefore are not a viable
   mitigation option.  DHCP itself is inherently insecure and thus link-
   layer confidentiality and integrity protection SHOULD be employed to
   reduce the risk of disclosure and tampering.

   It is possible for a rogue DHCP relay agent to insert or overwrite
   with incorrect access network identifier options for malicious
   purposes.  A DHCP client can also pose as a rogue DHCP relay agent by
   sending incorrect access network identifier options.  While the
   introduction of fraudulent DHCP relay agent information options can
   be prevented by a perimeter defense that blocks these options unless
   the DHCP relay agent is trusted, a deeper defense using the
   authentication sub-option for DHCPv4 relay agent information option
   [RFC4030] SHOULD be deployed as well.  Administrators SHOULD
   configure DHCP servers that use this option to communicate with their
   relay agents using IPsec, as described in Section 21.1 of [RFC3315].

   The information elements that this draft is exposing is the client's
   access-network information.  These pertain to the access network to
   which the client is attached, such as Access Technology Type (Ex:
   WLAN, Ethernet...etc), Access Point Identity (Name, BSSID), Operator
   Id/Realm.  In deployments where this information cannot be secured
   using IPsec [RFC4301] or other security protocols, administrators
   SHOULD disable the capability specified in this document on the DHCP
   entities.

10.  Acknowledgments

   The authors would like to thank Kim Kinnear, Ted Lemon, Gaurav
   Halwasia, Hidetoshi Yokota, Sheng Jiang and Francis Dupont for their
   valuable inputs.  And, to Tomek Mrugalski for a thorough review of
   the document.

11.  References

11.1.  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>.

   [RFC2131]  Droms, R., "Dynamic Host Configuration Protocol",
              RFC 2131, DOI 10.17487/RFC2131, March 1997,
              <http://www.rfc-editor.org/info/rfc2131>.

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   [RFC3046]  Patrick, M., "DHCP Relay Agent Information Option",
              RFC 3046, DOI 10.17487/RFC3046, January 2001,
              <http://www.rfc-editor.org/info/rfc3046>.

   [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>.

11.2.  Informative References

   [ANI]      "Interoperability Specification (IOS) for High Rate Packet
              Data (HRPD) Radio Access Network Interfaces with Session
              Control in the Access Network, A.S0008-A v3.0",
              October 2008.

   [RFC3118]  Droms, R. and W. Arbaugh., Ed., "Authentication for DHCP
              Messages", RFC 3118, DOI 10.17487/RFC3118, June 2001,
              <http://www.rfc-editor.org/info/rfc3118>.

   [RFC3629]  Yergeau, F., "UTF-8, a transformation format of ISO
              10646", STD 63, RFC 3629, DOI 10.17487/RFC3629,
              November 2003, <http://www.rfc-editor.org/info/rfc3629>.

   [RFC4030]  Stapp, M. and T. Lemon, "The Authentication Suboption for
              the Dynamic Host Configuration Protocol (DHCP) Relay Agent
              Option", RFC 4030, DOI 10.17487/RFC4030, March 2005,
              <http://www.rfc-editor.org/info/rfc4030>.

   [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>.

   [RFC5213]  Gundavelli, S., Ed., Leung, K., Devarapalli, V.,
              Chowdhury, K., and B. Patil, "Proxy Mobile IPv6",
              RFC 5213, DOI 10.17487/RFC5213, August 2008,
              <http://www.rfc-editor.org/info/rfc5213>.

   [RFC5844]  Wakikawa, R. and S. Gundavelli, "IPv4 Support for Proxy
              Mobile IPv6", RFC 5844, DOI 10.17487/RFC5844, May 2010,
              <http://www.rfc-editor.org/info/rfc5844>.

   [RFC6757]  Gundavelli, S., Ed., Korhonen, J., Ed., Grayson, M.,
              Leung, K., and R. Pazhyannur, "Access Network Identifier
              (ANI) Option for Proxy Mobile IPv6", RFC 6757,
              DOI 10.17487/RFC6757, October 2012,
              <http://www.rfc-editor.org/info/rfc6757>.

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   [RFC6991]  Schoenwaelder, J., Ed., "Common YANG Data Types",
              RFC 6991, DOI 10.17487/RFC6991, July 2013,
              <http://www.rfc-editor.org/info/rfc6991>.

   [SMI]      "PRIVATE ENTERPRISE NUMBERS, SMI Network Management
              Private Enterprise Codes", February  2011.

   [TS23003]  "Numbering, addressing and identification", 2011.

   [TS23203]  "Policy and Charging Control Architecture", 2012.

   [TS23402]  "Architecture enhancements for non-3GPP accesses", 2012.

Authors' Addresses

   Shwetha Bhandari
   Cisco Systems
   Cessna Business Park, Sarjapura Marathalli Outer Ring Road
   Bangalore, KARNATAKA  560 087
   India

   Phone: +91 80 4426 0474
   Email: shwethab@cisco.com

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

   Email: sgundave@cisco.com

   Mark Grayson
   Cisco Systems
   11 New Square Park
   Bedfont Lakes, FELTHAM  TW14 8HA
   England

   Email: mgrayson@cisco.com

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   Bernie Volz
   Cisco Systems
   1414 Massachusetts Ave
   Boxborough,, MA  01719
   USA

   Email: volz@cisco.com

   Jouni Korhonen
   Broadcom Communications
   Porkkalankatu 24
   FIN-00180 Helsinki,
   Finland

   Phone:
   Email: jouni.nospam@gmail.com

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