Internet DRAFT - draft-cao-dhc-anqp-option

draft-cao-dhc-anqp-option






Internet Engineering Task Force                                   Z. Cao
Internet-Draft                                                    T. Sun
Intended status: Informational                              China Mobile
Expires: April 25, 2013                                        S. McCann
                                                      Research in Motion
                                                        October 22, 2012


  DHCPv4 and DHCPv6 Options for Access Network Query Protocol Servers
                      draft-cao-dhc-anqp-option-01

Abstract

   This document defines a DHCPv4 option and DHCPv6 option of the Access
   Network Query Protocol (ANQP) server address.  These options are used
   to configure the ANQP server addresses on the Access Point of WLAN
   system.

Status of this Memo

   This Internet-Draft is submitted in full conformance with the
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   This Internet-Draft will expire on April 25, 2013.

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   described in the Simplified BSD License.


Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . . . 3
     1.1.  Requirements Language . . . . . . . . . . . . . . . . . . . 3
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . 3
   3.  DHCPv4 Option of ANQP Server Address  . . . . . . . . . . . . . 4
   4.  DHCPv6 Option of ANQP Server Address  . . . . . . . . . . . . . 5
   5.  Advertisement Server Type . . . . . . . . . . . . . . . . . . . 6
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6
   7.  Security Considerations . . . . . . . . . . . . . . . . . . . . 7
   8.  References  . . . . . . . . . . . . . . . . . . . . . . . . . . 7
     8.1.  Normative References  . . . . . . . . . . . . . . . . . . . 7
     8.2.  Informative References  . . . . . . . . . . . . . . . . . . 7
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . . . 8


































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1.  Introduction

   Access Network Query Protocol (ANQP) was defined by IEEE 802.11u Task
   Group [IEEE-ELEVENU]and is now integrated into the 802.11-2012
   specification suite.  And ANQP has been further extended by the
   Hotspot 2.0 Technical Group of Wi-Fi Alliance (WFA), and it has been
   included in the representative certification program called
   "Passpoint" [PASSPOINT].

   ANQP is an example of the query protocol for access network
   information retrieval, and it is transported by the IEEE 802.11
   defined Generic Advertisement Service (GAS) Public Action frames.
   GAS enables a WLAN client (e.g., a STA) to exchange messages with an
   advertisement server (e.g., an ANQP server) in the pre-association
   state, i.e., prior to association.  With the information retrieved
   via this server, the WLAN client connection manager can make informed
   selection among multiple access networks.  One example of using ANQP
   is that the WLAN client in a roaming environment can select the
   correct visited access network that has roaming relationship with its
   home service provider without user intervention.

   In a scalable deployment environment, the ANQP server will not be
   placed on the Access Point (AP), rather it should be placed on a
   centralized device that serves different APs.  The AP will forward
   the ANQP message on the IP network between AP and ANQP Server.  Then
   the problem of configuring the ANQP server address on the AP arises.

   This document defines a DHCPv4 option and DHCPv6 option of the ANQP
   server addresses.  As introduced above, these options are used to
   configure the ANQP server addresses on the APs.  This document also
   defines the "Advertisement Protocol Type" field in the DHCPv4/v6
   options which can be extended to configure other types of
   advertisement protocols servers.

1.1.  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].


2.  Terminology

   ANQP: Access Network Query Protocol.  ANQP is an example of a query
   protocol for access network information retrieval transported by
   Generic Advertisement Service (GAS) Public Action frames defined in
   IEEE 802.11.  ANQP message exchanges happen before network
   association.  ANQP is defined in the IEEE 802.11 specification and



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   has been further extended by the Wi-Fi Alliance.

   ANQP Server: ANQP Server is the network entity that terminates and
   responds to ANQP enquiries.  In a scalable deployment, the ANQP
   Server is placed in centralized device and administrated by the Wi-Fi
   server provider.

   IEEE 802.11u: IEEE 802.11u-2011 is an amendment to the IEEE 802.11-
   2007 standard that added features that improve interworking with
   external networks.  It is now incorporated within IEEE 802.11-2012.
   A key amendment to IEEE 802.11-2012 is the capability of WLAN client
   network discovery and selection.

   Passpoint: Wi-Fi Alliance Certified Program Name.  The technical
   specification of Passpoint is based on the output of the WFA Hotspot
   2.0 (HS2.0) Technical Task Group.  HS2.0 defines further vendor
   specific ANQP options and has developed a test plan for Passpoint
   certification.

   RLQP: Registered Location Query Protocol.  This is an additional
   advertisement protocol defined by IEEE 802.11af [RLQP] (TV White
   Spaces), which assists with location information, but operates as a
   separate RLQP Server.  The RLQP Server and ANQP Server may be co-
   located.


3.  DHCPv4 Option of ANQP Server Address

   This section describes the ANQP Server Address Option for DHCPv4.
   The option layout is depicted below Figure 1:

       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   |   Length_1    |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |      Type     |    Length_2   |        IPv4 Address (0-15)    |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       | IPv4 Address (16-31)          |                               |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       .                               |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


              Figure 1: ANQP Server Address Option for DHCPv4







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   Option Code:  OPTION-IPv4_Address-Adv-Server

   Length_1  Length (in bytes) of the option excluding the 'Option Code'
      and the 'Length_1' fields;

   Type (Advertisement Server Type):  Indicates the type of the
      advertisement server.  There are different advertisement servers
      defined in 802.11, including ANQP and RLQP.  The values of those
      server types are discussed in Section 5.

   Length_2:  Length (in bytes) of the IPv4 addresses of the
      advertisement server; its value equals four times of the number of
      IPv4 addresses (4*N);

   IP Address:  IPv4 address(es) of ANQP server(s)

   Note: Length_2 is necessary because there are multiple types of
   advertisement servers and each has different number of IPv4 addresses
   configured.


4.  DHCPv6 Option of ANQP Server Address

   This section describes the ANQP Server Address Option for DHCPv6.
   The option layout is depicted below Figure 2:

       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              |            Length_1           |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |      Type     |    Length_2   |        IPv6 Address (0-15)    |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                                                               |
       |                    IPv6 Address(16-127)                       |
       |                                _______________________________|
       |                               |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

              Figure 2: ANQP Server Address Option for DHCPv6

   Option Code:  OPTION-IPv6_Address-Adv-Server

   Length_1:  Length (in bytes) of the option excluding the 'Option
      Code' and the 'Length_1' fields;







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   Type (Advertisement Server Type):  Indicates the type of the
      advertisement server.  There are different advertisement servers
      defined in 802.11, including ANQP and RLQP.  The values of those
      server types are discussed in Section 5.

   Length_2:  Length (in bytes) of the IPv6 addresses of the
      advertisement server; its value equals 16 times of the number of
      IPv6 addresses (16*N);

   IP address:  IPv6 address(es) of ANQP server(s)

   Note: Length_2 is necessary because there are multiple types of
   advertisement servers and each has different number of IPv6 addresses
   configured.


5.  Advertisement Server Type

   There are different types of advertisement servers defined in 802.11,
   including ANQP Server and RLQP Server.  IEEE may define other
   advertisement servers in future.  To make options defined in this
   document scalable to further extensions, and also avoid the need of
   an individual option code for each of such advertisement servers,
   this document defines the Avertisement Server Type field in both the
   DHCPv4 and DHCPv6 options.

   The Advertisement Server Type value of ANQP is suggested in this
   document as below.
   +-----------+---------------+
   |    Type   |      Value    |
   +-----------+---------------+
   |  Reserved |       0       |
   +-----------+---------------+
   |    ANQP   |       1       |
   +-----------+---------------+
   |  Reserved |     2-255     |
   +-----------+---------------+

   In addition to ANQP, other advertisement protocols have been defined
   within IEEE 802.11 (e.g.  RLQP).  These operate in a similar manner
   to ANQP, but allow information exchange with different servers than
   that of the ANQP Server.  The Advertisement Server Type value of
   other protocols including RLQP will be extended by future work.


6.  IANA Considerations

   This document has the following requests to the IANA.



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   Option Code for OPTION-IPv4_Address-Adv-Server in DHCPv4, as defined
   in Section. 3 of this document.

   Option Code for OPTION-IPv6_Address-Adv-Server in DHCPv6, as defined
   in Section. 4 of this document.

   Advertisement Server Type for ANQP, as defined in Section. 5 or this
   document.


7.  Security Considerations

   If adversaries are able forge rogue ANQP Server options, the ANQP
   messages will be directed to wrong servers and bogus information
   about the queried access network would be injected.  The DHCP
   authentication option described in [RFC3315] and [RFC3118] MAY be
   used to mitigate the above attacks.  Lower layer security such as L2
   traffic filtering and firewall SHOULD be configured prevent such
   attacks.


8.  References

8.1.  Normative References

   [IEEE-ELEVENU]
              IEEE, "IEEE 802.11u Specification", 2011, <http://
              standards.ieee.org/findstds/standard/802.11-2012.html>.

   [PASSPOINT]
              Wi-Fi Alliance, "Wi-Fi CERTIFIED Passpoint", 2012, <http:/
              /www.wi-fi.org/discover-and-learn/
              wi-fi-certified-passpoint>.

   [RLQP]     "Wireless LAN in the TV White Space", 2012,
              <http://www.ieee802.org/11/Reports/tgaf_update.htm>.

8.2.  Informative References

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

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



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Authors' Addresses

   Zhen Cao
   China Mobile
   Xuanwumenxi Ave. No. 32
   Beijing,   100871
   China

   Phone: +86-10-52686688
   Email: zehn.cao@gmail.com, caozhen@chinamobile.com


   Tao Sun
   China Mobile
   Xuanwumenxi Ave. No. 32
   Beijing,   100871
   China

   Phone: +86-10-52686688
   Email: suntao@chinamobile.com


   Stephen McCann
   Research in Motion
   200 Bath Road
   Slough, SL1 3XE,
   United Kingdom

   Phone: +44 1754 66700
   Fax:
   Email: smccann@rim.com
   URI:



















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