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Versions: (draft-bhandari-dhc-access-network-identifier) 00 01 02 03 04 05 06 07 08 09 10 11 12 13 RFC 7839

Network Working Group                                        S. Bhandari
Internet-Draft                                             S. Gundavelli
Intended status: Standards Track                           Cisco Systems
Expires: August 17, 2014                                     J. Korhonen
                                                          Renesas Mobile
                                                              M. Grayson
                                                           Cisco Systems
                                                       February 13, 2014


                Access-Network-Identifier Option in DHCP
              draft-ietf-dhc-access-network-identifier-02

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.

Requirements Language

   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 [RFC2119].

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 17, 2014.

Copyright Notice

   Copyright (c) 2014 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



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   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.  Motivation . . . . . . . . . . . . . . . . . . . . . . . . . .  3
   3.  Terminology  . . . . . . . . . . . . . . . . . . . . . . . . .  4
   4.  DHCPv4 Access-Network-Identifier Option  . . . . . . . . . . .  5
     4.1.  DHCPv4 Access-Network-Identifier Sub-options . . . . . . .  5
   5.  DHCPv6 Access-Network-Identifier options . . . . . . . . . . .  6
   6.  DHCPv4 and DHCPv6 Access-Network-Identifier Options  . . . . .  6
     6.1.  Access-Network-Type option . . . . . . . . . . . . . . . .  6
     6.2.  Network-Identifier options . . . . . . . . . . . . . . . .  8
     6.3.  Operator identifier options  . . . . . . . . . . . . . . . 11
   7.  Client Behavior  . . . . . . . . . . . . . . . . . . . . . . . 13
   8.  Relay Agent Behavior . . . . . . . . . . . . . . . . . . . . . 14
   9.  Server Behavior  . . . . . . . . . . . . . . . . . . . . . . . 14
   10. IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 14
   11. Security Considerations  . . . . . . . . . . . . . . . . . . . 15
   12. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 16
   13. Change log . . . . . . . . . . . . . . . . . . . . . . . . . . 16
   14. Normative References . . . . . . . . . . . . . . . . . . . . . 16
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 17




















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1.  Introduction

   Access network identification of a network device has a range of
   application.  For e.g.  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 v4
   (DHCPv4) [RFC2131] and Dynamic Host Configuration Protocol v6
   (DHCPv6) [RFC3315] options for access network identification that is
   added by Client or Relay agent in the DHCPv4 or DHCPv6 messages
   towards the Server.

   Dynamic Host Configuration Protocol (DHCP) client or 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 type 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
   Access Gateway (MAG) to LMA.  MAG can learn this information from
   DHCP options as inserted by DHCP client or Relay agent before MAG.



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   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) inserts access network identifiers in DHCP
   messages.  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.com
          +--+ DHCP
          |AP|-------.                        {Access Specific Policies)
          +--+       |             _-----_             |
                   +-----+       _(       )_        +-----+
                   | MAG |-=====(   PMIPv6  )======-| LMA |-
                   +-----+       (_ Tunnel_)        +-----+
          +--+ DHCP  |             '-----'
          |AP|-------'
          +--+
          SSID: IETF-2
          Operator-Id: provider2.example.com


                      Access Networks attached to MAG


3.  Terminology

   All the DHCP related terms used in this document to be interpreted as
   defined in the Dynamic Host Configuration Protocol v4 (DHCPv4)
   [RFC2131] and Dynamic Host Configuration Protocol v6 (DHCPv6)
   [RFC3315] specifications.  DHCP refers to both DHCPv4 and DHCPv6
   messages and entities throughout this document.

   All the mobility related terms used in this document are to be
   interpreted as defined in the Proxy Mobile IPv6 specifications
   [RFC5213] and [RFC5844].  Additionally, this document uses the
   following abbreviations:

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




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   Vendor ID The Vendor ID is the SMI Network Management Private
   Enterprise Code of the IANA-maintained Private Enterprise Numbers
   registry [SMI].


4.  DHCPv4 Access-Network-Identifier Option

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

   The format of the DHCPv4 Access-Network-Identifier option is shown
   below.


   Code    Len          ANI Sub-options
  +------+------+------+------+------+--   --+-----+
  | code |  len |  s1  |  s2  |  s2  |  ...  |  sn |
  +------+------+------+------+------+--   --+-----+

   code: 8-bit code carrying Access Network Identifier sub-options,
         If added by relay agent: Relay Agent Information Option (82)
         If added by client: OPTION_ACCESS_NETWORK_ID (TBD1)

   len: 8 bit indicating total length of the included suboptions.

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

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

  ANI Sub-options are defined in following sections.

4.1.  DHCPv4 Access-Network-Identifier Sub-options

   Access network identifier information will be defined in multiple
   sub-options.  The initial assignment of DHCP access network
   identifier Sub-options is as follows:








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           Sub-option Code            Sub-Option Description
          ---------------            ----------------------
               TBD7                   Access-Network-Type Sub-option
               TBD8                   Network-Name Sub-option
               TBD9                   AP-Name Sub-option
               TBD12                  AP-BSSID Sub-option
               TBD10                  Operator-Identifier Sub-option
               TBD11                  Operator-Realm Sub-option



5.  DHCPv6 Access-Network-Identifier options

   The Access Network Identifier option defined here will be added by
   DHCPv6 client in upstream DHCPv6 messages or by the Relay in Relay-
   forward messages.

           Option Code             Descrption
          ---------------   ----------------------
              TBD2           OPTION_ANI_ATT
              TBD3           OPTION_ANI_NETWORK_NAME
              TBD4           OPTION_ANI_AP_NAME
              TBD13          OPTION_ANI_AP_BSSID
              TBD5           OPTION_ANI_OPERATOR_ID
              TBD6           OPTION_ANI_OPERATOR_REALM



6.  DHCPv4 and DHCPv6 Access-Network-Identifier Options

   This section defines DHCPv4 suboption and DHCPv6 options for access
   network identification.

6.1.  Access-Network-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:














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   DHCPv4:
   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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | suboption-code|   Length      |          ATT                  |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

    suboption-code:  8-bit code, it should be set to value of (TBD7),
                      indicating that its a Access-Network-Type sub-option

    Length: 8-bit unsigned integer indicating the length of this suboption
        in octets, excluding the suboption-code and length fields.
        This field MUST be set to 2.

   DHCPv6:
    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 Code (TBD2)      |            OptLen             |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |                       ATT                                     +
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


   option-code:        16-bit code OPTION_ANI_ATT (TBD2)
   option-length:      16-bit unsigned integer indicating length
                       in octets of this option

   Common format applicable to DHCPv4 and DHCPv6:
   Access Technology Type (ATT)

        An 16-bit field that specifies the access technology through
        which the client is connected to the access link.

        The values is as populated from the IANA name space
        Access Technology Type Option type values as requested in [RFC5213]

        0: Reserved         ("Reserved")
        1: Virtual          ("Logical Network Interface")
        2: PPP              ("Point-to-Point Protocol")
        3: IEEE 802.3       ("Ethernet")
        4: IEEE 802.11a/b/g ("Wireless LAN")
        5: IEEE 802.16e     ("WIMAX")








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6.2.  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.



   DHCPv4:

    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |suboption code |   Length      |                               ~
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                     Network Name (e.g., SSID or PLMNID)       ~
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


   suboption code:  8-bit code, it should be set to value of (TBD8),
                    indicating that its a Network-Name sub-option

   Length:  8-bit indicating Total length of this sub option,
           excluding the suboption code and length fields.
           The value can be in the range of 2 to 32 octets.


   DHCPv6:
    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 Code (TBD3)      |            OptLen             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                     Network Name (e.g., SSID or PLMNID)       ~
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


   option-code:        16-bit code OPTION_ANI_NETWORK_NAME (TBD3)
   option-length:      16-bit unsigned integer indicating length
                       in octets of this option.The value can be in the
                       range of 2 to 32 octets.

   Common format applicable to DHCPv4 and DHCPv6:


   Network Name:  The name of the access network to which the mobile



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      node is attached.  The type of the Network Name is dependent on
      the access technology to which the mobile node is attached.  If it
      is 802.11 access, the Network Name MUST be the SSID of the
      network.  If the access network is 3GPP access, the Network Name
      is the PLMN Identifier of the network.  If the access network is
      3GPP2 access, the Network Name is the
      Access Network 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'.  Encoding MUST be UTF-8.







































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   DHCPv4:

    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |suboption code |   Length      |                               ~
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                        Access-Point Name                      ~
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   suboption code: 8-bit code, it should be set to value of (TBD9),
                   indicating that its a Network-AP-Name sub-option

   Length:  8-bit indicating Total length of this sub option,
           excluding the suboption code and length fields.
           The value can be in the range of 2 to 32 octets.

   DHCPv6:

    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 Code (TBD3)      |          OptLen               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                        Access-Point Name                      ~
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   option-code:        16-bit code OPTION_ANI_AP_NAME (TBD4)
   option-length:      16-bit unsigned integer indicating length
                       in octets of this option.The value can be in the
                       range of 2 to 32 octets.

   Common format applicable to DHCPv4 and DHCPv6:

   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 Media Access
      Control (MAC) address 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 string is carried in UTF-8
      representation.






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   DHCPv4:

    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |suboption code |   Length(6)      |                            ~
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   ~                        Access-Point BSSID                     |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   suboption code: 8-bit code, it should be set to value of (TBD12),
                   indicating that its a AP-BSSID sub-option

   Length:  8-bit indicating Total length of this sub option,
           excluding the suboption code and length fields.
           The value is set to 6.

   DHCPv6:

    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 Code (TBD3)      |          OptLen(6)            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                        Access-Point BSSID                     ~
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   ~                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   option-code:        16-bit code OPTION_ANI_AP_BSSID (TBD13)
   option-length:      16-bit unsigned integer indicating length
                       in octets of this option.The value is set to 6.

   Common format applicable to DHCPv4 and DHCPv6:

   Access-Point BSSID:   The 48-bit Basic service set identification(BSSID)
      of the access point to which the mobile node is attached.

6.3.  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.









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 DHCPv4:

    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | suboptioncode |     Length    |                               ~
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   ~      Operator Enterprise ID   |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   suboption code:  8 bit code, It should be set to value of (TBD10),
                  indicating that it is Operator-Identifier sub-option

   Length:  Total length of this sub option, excluding the suboption code
      and length fields.


 DHCPv6:
    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 Code (TBD4)      |            OptLen             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                Operator Enterprise ID                         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


   option-code:        16-bit code OPTION_ANI_OPERATOR_ID (TBD5)
   option-length:      16-bit unsigned integer indicating length
                       in octets of this option.

 Common format applicable to DHCPv4 and DHCPv6:

   Operator Enterprise ID: Vendor ID as a four octet
                           Private Enterprise Number [SMI].
















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  DHCPv4:

     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
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    | suboptioncode |     Length    |                               ~
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    ~                        Operator Realm                         ~
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

    suboption code:  8 bit code, It should be set to value of (TBD11),
                   indicating that it is Operator-Realm sub-option

    Length:  Total length of this sub option, excluding the suboption
       code and length fields.


  DHCPv6:
     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 Code (TBD4)      |              OptLen           |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    ~                       Operator Realm                          ~
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


    option-code:        16-bit code OPTION_ANI_OPERATOR_REALM (TBD6)
    option-length:      16-bit unsigned integer indicating length
                        in octets of this option.

  Common format applicable to DHCPv4 and DHCPv6:

  Operator Realm:  Realm of the operator. Realm names are required to be
          unique, and are piggybacked on the administration of the DNS
          namespace.  Realms are encoded using a domain name encoding
          defined in [RFC1035].Up to 253 octets of the operator realm.



7.  Client Behavior

   All hosts or clients MAY include access network identifier options in
   all the upstream DHCP messages to inform the receiver about the
   access network it is attached to.






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8.  Relay Agent Behavior

   DHCP Relay Agents MAY include these options before forwarding the
   DHCP message to provide information about the access network over
   which DHCP messages from the client is received.

   If the DHCPv4 relay agent receives DHCPv4 message already containing
   access network identifier sub-options within option 82 based on its
   configured policy it MAY overwrite the options.


9.  Server Behavior

   If DHCP Server is unable to understand these options it MUST be
   ignored.  There is no requirement that a server return these options
   and its data in a downstream DHCP message.  If DHCP Server is able to
   process these options it MAY use it for address pool selection policy
   decisions if configured.  It MAY store this information along with
   the lease for logging and audit purpose.

   If the DHCPv6 server is configured to store or use, it SHOULD look
   for the access network identifier options in the Relay-Forward DHCP
   message of the DHCPv6 relay agent(s) or from the DHCPv6 client based
   on its configured policy.  Similarly DHCPv4 server can use the
   options inserted by the DHCPv4 client or DHCPv4 relay agent based on
   its configured policy.


10.  IANA Considerations

   This document defines DHCPv4 Access Network Identifier option which
   requires assignment of DHCPv4 option code TBD1 assigned from "Bootp
   and DHCP options" registry (http://www.iana.org/assignments/
   bootp-dhcp-parameters/bootp-dhcp-parameters.xml), as specified in
   [RFC2939].

   IANA is requested to assign Sub-option codes for the following DHCPv4
   Sub-options from the "DHCP Relay Agent Sub-Option Codes"













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          Sub-option Code            Sub-Option Description
          ---------------            ----------------------
               TBD7                   Access-Network-Type Sub-option
               TBD8                   Network-Name Sub-option
               TBD9                   AP-Name Sub-option
               TBD10                  Operator-Identifier Sub-option
               TBD11                  Operator-Realm Sub-option
               TBD12                  AP-BSSID Sub-option

   IANA is requested to assign option codes for the following DHCPv6
   options from the "DHCPv6 and DHCPv6 options" registry (http://
   www.iana.org/assignments/dhcpv6-parameters/dhcpv6-parameters.xml).

          Option Code             Descrption
          ---------------   ----------------------
              TBD2           OPTION_ANI_ATT
              TBD3           OPTION_ANI_NETWORK_NAME
              TBD4           OPTION_ANI_AP_NAME
              TBD5           OPTION_ANI_OPERATOR_ID
              TBD6           OPTION_ANI_OPERATOR_REALM
              TBD13         OPTION_ANI_AP_BSSID


11.  Security Considerations

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

   To minimize the unintended exposure of this information, this option
   SHOULD be included by DHCP entities only when it is configured.
   Where critical decisions might be based on the value of this option,
   DHCP authentication as defined in "Authentication for DHCP Messages"
   [RFC3118] and "Dynamic Host Configuration Protocol for IPv6 (DHCPv6)"
   [RFC3315] SHOULD be used to protect the integrity of the DHCP
   options.  Link-layer confidentiality and integrity protection may
   also be employed to reduce the risk of disclosure and tampering.

   Security issues related DHCPv6 are described in section 23 of
   [RFC3315].

   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



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   authentication suboption for DHCPv4 relay agent information option
   [RFC4030] SHOULD be deployed as well.  DHCP server administrators are
   strongly advised to configure DHCP servers that use this option to
   communicate with their relay agents using IPsec, as described in
   Section 21.1 of [RFC3315].


12.  Acknowledgements

   The authors would like to thank Kim Kinnear, Ted Lemon, Gaurav
   Halwasia, Bernie Volz for their valuable inputs.


13.  Change log

   Changes from 00 - 01

   o  Added AP BSSID information

   Changes from 00 - 01

   o  Edited security consideration to handle multiple relay agents
      adding access network identifier options, server and relay agent
      behavior.


14.  Normative 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.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC2131]  Droms, R., "Dynamic Host Configuration Protocol",
              RFC 2131, March 1997.

   [RFC2434]  Narten, T. and H. Alvestrand, "Guidelines for Writing an
              IANA Considerations Section in RFCs", BCP 26, RFC 2434,
              October 1998.

   [RFC2939]  Droms, R., "Procedures and IANA Guidelines for Definition
              of New DHCP Options and Message Types", BCP 43, RFC 2939,
              September 2000.

   [RFC3118]  Droms, R. and W. Arbaugh, "Authentication for DHCP



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              Messages", RFC 3118, June 2001.

   [RFC3315]  Droms, R., Bound, J., Volz, B., Lemon, T., Perkins, C.,
              and M. Carney, "Dynamic Host Configuration Protocol for
              IPv6 (DHCPv6)", RFC 3315, July 2003.

   [RFC4030]  Stapp, M. and T. Lemon, "The Authentication Suboption for
              the Dynamic Host Configuration Protocol (DHCP) Relay Agent
              Option", RFC 4030, March 2005.

   [RFC5213]  Gundavelli, S., Leung, K., Devarapalli, V., Chowdhury, K.,
              and B. Patil, "Proxy Mobile IPv6", RFC 5213, August 2008.

   [RFC5844]  Wakikawa, R. and S. Gundavelli, "IPv4 Support for Proxy
              Mobile IPv6", RFC 5844, May 2010.

   [RFC6757]  Gundavelli, S., Korhonen, J., Grayson, M., Leung, K., and
              R. Pazhyannur, "Access Network Identifier (ANI) Option for
              Proxy Mobile IPv6", RFC 6757, October 2012.

   [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











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

   Email: sgundave@cisco.com


   Jouni Korhonen
   Renesas Mobile
   Linnoitustie 6
   FIN-02600 Espoo,
   Finland

   Phone:
   Email: jouni.nospam@gmail.com


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

   Email: mgrayson@cisco.com

























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