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 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 January 17, 2013. Copyright Notice 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 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 Probasco & Patil Expires January 17, 2013 [Page 1] Internet-Draft PAWS: Discovery July 2012 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 Probasco & Patil Expires January 17, 2013 [Page 2] Internet-Draft PAWS: Discovery July 2012 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 Probasco & Patil Expires January 17, 2013 [Page 3] Internet-Draft PAWS: Discovery July 2012 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 Probasco & Patil Expires January 17, 2013 [Page 4] Internet-Draft PAWS: Discovery July 2012 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. Probasco & Patil Expires January 17, 2013 [Page 5] Internet-Draft PAWS: Discovery July 2012 +-----------+ +-----------+ +----------+ | | | 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 Probasco & Patil Expires January 17, 2013 [Page 6] Internet-Draft PAWS: Discovery July 2012 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 Probasco & Patil Expires January 17, 2013 [Page 7] Internet-Draft PAWS: Discovery July 2012 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 Probasco & Patil Expires January 17, 2013 [Page 8] Internet-Draft PAWS: Discovery July 2012 Basavaraj Patil Nokia 6021 Connection drive Irving, TX 75039 USA Email: basavaraj.patil@nokia.com Probasco & Patil Expires January 17, 2013 [Page 9]