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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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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