Internet DRAFT - draft-probasco-paws-discovery

draft-probasco-paws-discovery






Working Group Draft                                     S. Probasco, Ed.
Internet-Draft                                                  B. Patil
Intended status: Informational                                     Nokia
Expires: January 17, 2013                                  July 16, 2012


           Protocol to Access White Space database: Discovery
                    draft-probasco-paws-discovery-01

Abstract

   A white space master device needs to query a white space database and
   obtain information about available spectrum/channels prior to
   operation.  White space databases which contain information about
   available spectrum/channels are associated with a regulatory domain
   and hence specific to a country or region.  A white space master
   device needs to discover the relevant white space database(s) given
   its current location and the regulatory domain that it is operating
   in.  The white space database discovery is the preliminary step that
   a white space master device has to perform.

Status of this Memo

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   This Internet-Draft will expire on January 17, 2013.

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   Copyright (c) 2012 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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   (http://trustee.ietf.org/license-info) in effect on the date of
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   carefully, as they describe your rights and restrictions with respect



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   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 . . . . . . . . . . . . . . . . . . . . . . . . . . 4
   3.  Overview  . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
   4.  Specification . . . . . . . . . . . . . . . . . . . . . . . . . 6
     4.1.  Protocol Description  . . . . . . . . . . . . . . . . . . . 6
     4.2.  Protocol Messages . . . . . . . . . . . . . . . . . . . . . 7
     4.3.  Data Model  . . . . . . . . . . . . . . . . . . . . . . . . 7
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 7
   6.  Security Considerations . . . . . . . . . . . . . . . . . . . . 7
   7.  Summary and Conclusion  . . . . . . . . . . . . . . . . . . . . 8
   8.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . 8
   9.  References  . . . . . . . . . . . . . . . . . . . . . . . . . . 8
     9.1.  Normative References  . . . . . . . . . . . . . . . . . . . 8
     9.2.  Informative References  . . . . . . . . . . . . . . . . . . 8
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . . . 8




























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1.  Introduction

   White space database discovery is preliminary to creating a radio
   network using white space.  The radio network is created by a master
   device that must contact a trusted database to learn if any radio
   frequencies or channels are available for use before the master
   device transmits in white space spectrum.  Discovery is a necessary
   service for PAWS protocol, see PAWS: problem statement, use cases and
   requirements [PAWS RQMTS].


                                 +-----------------------+
                                 | collect addresses of  |
                                 | white space databases |
                                 |                       |
                                 +-----------------------+
                                             |
                                             |
                                 +-----------------------+
                                 |     sort multiple     |
                                 | addresses in priority |
                                 |         order         |
                                 +-----------------------+
                                             |
                            repeat as needed |
                            ---------------->|
                            |                |
                            |    +-----------------------+
                            |    | contact top priority  |
                            ---- | database to determine |
                                 |    suitability for    |
                                 |       service         |
                                 +-----------------------+
                                             |
                                             |
                                            end


        Figure 1: High level view of white space database discovery

   Figure 1 shows at a high level how white space master devices
   discover a suitable trusted white space database.  In this document
   we describe how the master device may collect the addresses of one or
   more white space database.  Steps and criteria to sort multiple
   addresses into a priority order is left to implementation and not
   specified.  Procedures to contact a white space database are
   specified in (ED NOTE: insert reference to PAWS standard, when
   available).  Steps and criteria to determine the suitability of a



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   particular white space database are left to implementation.


2.  Terminology

   The terminology from PAWS: problem statement, use cases and
   requirements [PAWS RQMTS] is applicable to this document.

   White Space Database (WSDB)

      In the context of white space and cognitive radio technologies,
      the database is an entity which contains, but is not limited to,
      current information as required by by the regulatory policies
      about available spectrum at any given location and time, and other
      types of related (to the white space spectrum) or relevant
      information.

   White Space Database Discovery Server (WSDB DS)

      A server function provided to a white space device, the client.
      The white space device contacts a white space database discovery
      server to receive the service of discovering or identifying one or
      more white space databases.  The white space database discovery
      server is a known entity to the white space device, which knows at
      least a useable internet address for the white space database
      discovery server.  The white space database discovery server takes
      as input positioning information from the white space device and
      returns both address information which allows the white space
      device to contact a trusted, regulatory-authorized white space
      database, suitable for service at the white space device's current
      location and indication of the regulatory domain governing at the
      white space device's current location.  A single white space
      database discovery server may have global scope, serving clients
      located globally.


3.  Overview

   Before the WSD can query a trusted WSDB for a list of available
   frequencies or channels for use in the white space spectrum, the WSD
   must first discover the available databases and addresses serving the
   regulatory domain in which the device is currently located.  At
   power-up the WSD does not reliably know the regulatory domain
   corresponding to its current location, and therefore does not
   reliably know with which white space database(s) it can communicate.
   Furthermore it is essential that the WSD connect with a trusted WSDB
   for proper operation and indeed regulatory compliance.  By including
   contact information of a trusted WSDB DS in the WSD's programmed



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   instructions or firmware, the WSD can reliably determine the address
   of a trusted database or database listing server, as appropriate for
   its current physical location.

   While it possible that a WSD knows its location, or information which
   may be used to derive its location, it is not reasonable for every
   WSD to be capable to translate this information into the current
   regulatory domain, i.e. the WSD needs assistance to know what is the
   regulatory environment with jurisdiction at its current location.  A
   WSDB Discovery Server (DS) takes as input location information from
   the WSD and returns to the WSD one or more addresses of WSDBs (or
   WSDB listing servers as appropriate) to the WSD.  If the address or
   addresses of these WSDB DSs are included in the WSD firmware, a
   secure starting point for a trusted relationship is established.
   Because the WSDB DS is selected by the WSD manufacturer, a foundation
   is set to ensure the WSD will be able to discover a trusted WSDB in
   every regulatory domain where the manufacturer expects the WSD to be
   used.

   When the WSD does not have the address of a serviceable WSDB (e.g. at
   power-up), the WSD sends a Discovery Request message to a WSDB DS.
   The address of at least one WSDB DS is included in the WSD operating
   instructions or firmware by the manufacturer for example or
   provisioned using device configuration mechanisms.  The WSD includes
   in the Discovery Request information about its current location.  The
   WSDB DS uses this location information to determine the regulatory
   domain where the WSD is located, and returns a Discovery Response
   message which includes the address of one or more WSDBs (or WSDB
   listing server as appropriate) to the WSD.  See Figure 2.






















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      +-----------+                +-----------+             +----------+
      |           |                |   WSDB    |             |          |
      |    WSD    |                | Discovery |             |   WSDB   |
      |           |                |   Server  |             |          |
      +-----------+                +-----------+             +----------+
            |                            |                         |
            |     Discovery Request      |                         |
            |(location information, etc) |                         |
            |--------------------------->|                         |
            |                            |                         |
            |     Discovery Response     |                         |
            | (address information, etc) |                         |
            |<---------------------------|                         |
            |                            |                         |
            |                            |                         |
            | /--------------------------|-----------------------\ |
            |/       channel request     |                        \|
            |\       channel response    |         (PAWS)         /|
            | \--------------------------|-----------------------/ |
            |                            |                         |
            |                            |                         |

      Figure 2: Example illustration of registration of the discovery
                       process using PAWS: Discovery

   The discovery procedure fulfills requirements P.1, P.2 and P.3 from
   PAWS: problem statement, use cases and requirements [PAWS RQMTS].


4.  Specification

4.1.  Protocol Description

   PAWS: Discovery is an application protocol that uses HTTP/TLS as
   transport.  See Figure 3.

                   +-------------+
                   |  Discovery  |
                   +-------------+
                   |  HTTP/TLS   |
                   +-------------+
                   |    TCP      |
                   +-------------+
                   |    IP       |
                   +-------------+

                         Figure 3: Protocol stack




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4.2.  Protocol Messages

   The WSD sends Discovery-REQ to the WSDB DS and return receive
   Discovery-RSP, see Figure 4.

                Master WSD                WSDB DS
                   |                         |
                   |    Discovery-REQ        |
                   |------------------------>|
                   |                         |
                   |    Discovery-RSP        |
                   |<------------------------|
                   |                         |
                   |                         |

                     Figure 4: Discovery message flow

   1.  The Discovery-REQ message contains information to allow the WSDB
       DS to identify and determine the location of the Master WSD.

   2.  The Discovery-RSP message contains the regulatory domain and
       either the address of a listing server or the address of one or
       more WSDB authorized to provide service where the WSD is
       physically located.  If spectrum access is not authorized at the
       WSD physical location, the response will contain an error code
       and no address information.

4.3.  Data Model


5.  IANA Considerations

   This document has no requests to IANA.


6.  Security Considerations

   The white space database provides a critical service to white space
   master devices in the form of query responses about available
   spectrum/channels for use at a specific location and time.  The white
   space database is specific to a regulatory domain.  A white space
   master device querying a database needs to ensure that it is
   communicating with a valid and authorized entity.  The master device
   performs database discovery prior to establishing a session with a
   white space database for querying spectrum/channel availability.  The
   database discovery process needs to be secured in order to ensure
   that the master device is provided with the address of a valid and
   authorized database for the specific regulatory domain.  There is a



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   trust relationship that needs to be established between the master
   device and the entity which aids it in database discovery.


7.  Summary and Conclusion

   White space database discovery is a preliminary step in the process
   of creating a radio network using white space by devices.  A simple
   and secure means to discover valid and authorized database(s) within
   the scope of a regulatory domain by a WSD is specified in this
   document.  A trust relationship between the WSD and the WSDB
   discovery server ensures security w.r.t the list of databases
   provided to the WSD.


8.  Acknowledgements

   The authors would like to acknowledge Brian Rosen, Peter Stanforth
   and Andy Sago for their comments which have helped improve this
   document.


9.  References

9.1.  Normative References

   [PAWS RQMTS]
              IETF, "Protocol to Access White Space database: PS, use
              cases and rqmts;", December 2012.

9.2.  Informative References


Authors' Addresses

   Scott Probasco (editor)
   Nokia
   6021 Connection drive
   Irving, TX  75039
   USA

   Email: scott.probasco@nokia.com









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   Basavaraj Patil
   Nokia
   6021 Connection drive
   Irving, TX  75039
   USA

   Email: basavaraj.patil@nokia.com












































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