PAWS Lei. Zhu Internet-Draft Huawei Technologies Intended status: Informational March 5, 2012 Expires: September 6, 2012 Protocol to Access White Space database: PAWS framework data model draft-lei-paws-framework-datamodel-00.txt Abstract Portions of the radio spectrum that are allocated to a licensed, primary use but are unused or unoccupied at specific locations and times are defined as "white space". In this document the framework of PAWS is introduced, which includes framework of PAWS, protocol stack, definition of interface, parameters and schema running over interface, and security considerations. The realization of database and the calculation of protected contour are not considered in this framework draft. 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 September 6, 2012. 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 to this document. Code Components extracted from this document must Zhu Expires September 6, 2012 [Page 1] Internet-Draft PAWS framework data model March 2012 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. This document may contain material from IETF Documents or IETF Contributions published or made publicly available before November 10, 2008. The person(s) controlling the copyright in some of this material may not have granted the IETF Trust the right to allow modifications of such material outside the IETF Standards Process. Without obtaining an adequate license from the person(s) controlling the copyright in such materials, this document may not be modified outside the IETF Standards Process, and derivative works of it may not be created outside the IETF Standards Process, except to format it for publication as an RFC or to translate it into languages other than English. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology and Abbreviation . . . . . . . . . . . . . . . . . 4 2.1. Conventions Used in This Document . . . . . . . . . . . . 4 2.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4 3. Framework of PAWS . . . . . . . . . . . . . . . . . . . . . . 4 4. Protocol Stack . . . . . . . . . . . . . . . . . . . . . . . . 8 5. Protocl framework and interface of PAWS . . . . . . . . . . . 9 5.1. Database Discovery . . . . . . . . . . . . . . . . . . . . 9 5.2. Device Registration with Trusted Database . . . . . . . . 12 5.3. White Space Channel Query . . . . . . . . . . . . . . . . 15 5.4. White Space Channel Update . . . . . . . . . . . . . . . . 18 6. Message Encoding . . . . . . . . . . . . . . . . . . . . . . . 20 7. Security Considerations . . . . . . . . . . . . . . . . . . . 33 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 33 9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 33 10. Normative Reference . . . . . . . . . . . . . . . . . . . . . 33 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 33 Zhu Expires September 6, 2012 [Page 2] Internet-Draft PAWS framework data model March 2012 1. Introduction "White Space" means the radio spectrum which has been allocated for some primary use, but is not fully occupied by that primary use at a specific location and time. Currently the white space in TV bands which is called TV white space (TVWS) is widely discussed, TVWS has some good characteristics such as propagation ability and low power consumption. The regulatory bodies in some countries have carried out the rules allowing secondary white space access, the secondary user must make sure of not interfering with the primary user when using white space. The purpose of white space study is to design a mechanism that the secondary user can use the white space resource without interfering with the primary user. The widely accepted scheme of utilizing white space is by querying the database and the related protocol "Protocol to Access White Space database (PAWS)" is proposed, the use cases and requirements of PAWS have been discussed in document "draft-ietf-paws-problem-stmt-usecases-rqmts". Spectrum management rules of different spectrum regulatory bodies are different, so the white space spectrum database may be designed to implement different spectrum policies in different countries. In order to satisfy the need of globally applicable feature, the database query protocol MUST be independent of different spectrum management rules. PAWS is a protocol between the Master device and the Database. The Master device could act as a WiFi AP, a cellular base station (e.g.,3GPP LTE eNodeB) in the whitespace spectrum; the PAWS protocol is agnostic to the technology used by the Master device. In this document the framework of PAWS is introduced, which includes framework of PAWS, protocol stack, definition of interface, parameters and schema running over interface, and security considerations. Based on the possible implementations, the common framework fulfilling requirements and major scenarios is introduced with some kind of extensible designs. White space Database (WSDB) is entity operated by government regulatory body which dominates wireless spectrum resource of a large country with different areas which owns sub branches of spectrum management authorizations. Responsibility for a WSDB for a large area with also quite number of population is a burden and likely devided into sub Database of branch spectrum management authorizations. This scenario obviously impacts on Database discovery process and some minor implantations of framework of PAWS. This document is to satisfy this situation with minimum influence. Zhu Expires September 6, 2012 [Page 3] Internet-Draft PAWS framework data model March 2012 2. Terminology and Abbreviation 2.1. Conventions Used in This Document 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 [RFC2119]. 2.2. Terminology The Terminology Section of the latest version of [I-D.ietf-paws- problem-stmt-usecases-rqmts] shall be included by reference. Coordinating Database Coordinating Database is an entity implemented between Master Device and Database in framework, having function to retrieve available channel list from Database on behaviors of Master device (fulfilled by function of white space device) and can response proper available channel list when receiving query request from Master Device. The concepts in PAWS framework is described in section 3. WS interface The interface between white space device and Database specifies data model and process of PAWS in this document. AddrDatabase A kind of database that provides the Internet addresses of regulatory authorized Database in the relevant regulatory domain to the white space device, the AddrDatabase is provisioned to Master device and used in the Database discovery procedure. The AddrDatabase is either hosted by or under control of the national regulator. 3. Framework of PAWS The first stage of PAWS would have defined entities of Master Device and Database, and common interface between these two entities. In this section, author(s) specified an extendable framework of PAWS which would support fulfill early stage protocol perspective purpose and be extensible to satisfy more requirement if it is utilized in further stages. Figure 1 shows a common system model consisting of Master Device and Database merely. The Master Device connects to the database directly using WS interface. Zhu Expires September 6, 2012 [Page 4] Internet-Draft PAWS framework data model March 2012 WS interface is the interface between white space device and database which specifies data model and process of PAWS in this document. The messages of WS are encoded in XML, considering of transportation reliable and security the TCP and HTTPS are used to load the message. More details about the protocol of WS see section "protocol stack". +-------+ +--------+ |Master +-------------+Database| |Device | +--------+ +-------+ Figure 1: Frame of PAWS Master device in Figure 1 is a kind of white space device which querying available channel list from database providing radio access to user equipments. Due to PAWS principle of access technology agnostic, it can be access point of WiFi, NodeB of 3GPP WCDMA or eNodeB of 3GPP LTE etc. Database in Figure 1 is in charge of storing and maintaining white space channel information for certain area(s), it may be operated by regulatory. When the database receives request of white space spectrum querying from the master device, it will respond a list of available white space channel list to the master device if there are available spectrums. The master device can connect to the database by any means other than using the white space radio. There is an optional system model can be implemented based on common PAWS framework, shown in Figure 2, an entity named Coordinating Database is implemented between master device and database. Coordinating Database is logical function which is a combination of master device and Database (which stores a part or all of the white space spectrum information in certain area), the Coordinating Database gets white space spectrum from database acting as Master Device, the logical function of Coordinating Database is depicted in Figure 3. Master device can get white space from the Coordinating Database just like getting white space from database; the Coordinating Database can be maintained and operated by organizations and / or regulatory body (e.g. FCC). Zhu Expires September 6, 2012 [Page 5] Internet-Draft PAWS framework data model March 2012 +-------------+ +-------------+ |Coordinating | +-----------+ |Master Device+--+----+Database +----+---+Database | +-------------+ WS +-------------+ WS +-----------+ Figure 2: Alternative implementation framework of PAWS The concept of database in this document is the same as the one in "I-D.ietf-paws-problem-stmt-usecases-rqmts", which contains current information about available spectrum at any given location and other types of information. Database is in charge of storing and providing white space channels of a large area, for example there are only several databases operated by different operators in America. Here the coordinating database is defined to provide white space channels information for a relatively smaller area (e.g. a state, a region or even campus and a building which contains a huge number users). The coordinating database can get white space channels from database, receive the white space querying message from master device and provide the available white space channels for master devices with some degree decision making process. These decision making process might provide functionality of white space access protocol power to response available channels according to received device parameters (e.g. power, RF parameter), location information(e.g. altitude, position and direction of antenna ) and some particular white space spectrum decision making policies. The coordinating database gets available white space channel list from WS database acting as master device and provides white space channels to the master device that connects to it. Master device can get white space from the Coordinating Database just like getting white space from database. When provides white space channels to the master device, the coordinating database may be used to implements private spectrum using policies. The coordinating database can updates white space channels from database. The function diagram of coordinating database is shown in Figure 3. Coordinating database includes three main functions: (1) The function of master device. It can retrieve available channel list from Database on behaviors of master device (fulfilled by function of white space device). Zhu Expires September 6, 2012 [Page 6] Internet-Draft PAWS framework data model March 2012 (2) The function of database. To master device the coordinating database acts just like a database, it can receive the registration information from master device, response with proper available channel list when receiving query request from master device etc. (3) The function of implementing spectrum management policies. For example, the white space coordination control between different master devices. Some deployment scenarios based on coordinating database are introduced below: (1) In a private network, master devices are deployed to provide wireless access, but the master device cannot connect to Internet directly, the Coordinating database run by private network's manager can be added between Master devices and WS database, so the master devices can get white space channels from coordinating database. (2) A private network or ISP which serves a lot of master devices and it establishes wireless network using these master device, it can set a Coordinating database which gets white space in its area from WS database and all of its master devices query available white space channels from the Coordinating database, because private network owner who dominates the Coordinating database so it can implement its policy of spectrum utilizing. It makes the implementation of private white space utilizing policy possible. +-----------------------------------------------------------+ | | | | | +--------------------+ +-------------------------+ | | |Function of database| |Function of master device| | | +--------------------+ +-------------------------+ | | | | +-------------------------+ | | |Function of implementing | | | |spectrum management | | | |policy | | | | | | | +-------------------------+ | | | | | | Coordinating Database | | | +-----------------------------------------------------------+ Figure 3: Logical Function of Coordinating Database Zhu Expires September 6, 2012 [Page 7] Internet-Draft PAWS framework data model March 2012 By adding the Coordinating database the burden of database will be reduced, when the master device is connected to Coordinating database, it will query available white space channels from Coordinating database instead of WS database. The interface between master device and Coordinating Database is WS, the interface between Coordinating Database and database is WS. In order to provide database discover mechanism another local entity called AddrDatabase is added to the system, the AddrDatabase MAY be independent or be integrated in other entity (such as database), Shown in Figure 4. The function of AddrDatabase is to provide the Internet addresses of trusted database in the relevant regulatory domain to the master device. The AddrDatabase is either hosted by or under control of the national regulator. +-------+ +------------+ |Master +-------------+AddrDatabase| |Device | +------------+ +-------+ Figure 4: Framework of PAWS database discovery When the master device is going to provide radio access service, it MUST discover one database that can provide white space spectrum information for it, and it needs to register some necessary information to the database, and then the master device can query white space channel from the database. There SHOULD be some authentication procedures and some security related procedures between database and master device. 4. Protocol Stack The database querying message should be sent on reliable transport protocol, and the database querying procedure is of request/response model, besides the message MUST be transported securely. In order to utilize the existing Internet protocol, a protocol stack model is proposed here, shown in Figure 5, the transport layer is TCP and the application layer is HTTPS. There may be some other protocol models, for example using the Diameter as the application layer protocol. Zhu Expires September 6, 2012 [Page 8] Internet-Draft PAWS framework data model March 2012 +------------+ +------------+ |WS.App +-------------+ WS.App | +------------+ +------------+ |HTTPS +-------------+HTTPS | +------------+ +------------+ |TCP +-------------+TCP | +------------+ +------------+ |IP +-------------+IP | +------------+ +------------+ Master Device Database Figure 5: Protocol stack of PAWS protocol WS.App is the white space spectrum application protocol. This protocol stack is used by WS interface. 5. Protocl framework and interface of PAWS The protocol message interface defines the message contents and message format of WS and WS'. The message interface should satisfy the following requirements: 1. The message sent in the message interface should be independent of the specific radio interface technology( e.g. 802.11af, IEEE 802.16, IEEE 802.22, LTE ); 2. The message interface should be spectrum agnostic. The message interface should not only be used for TV white space but also be used for other spectrum; 3. The message interface should be satisfied to different scenarios using white space. In different scenarios the white space device's coverage area and the bandwidth may be different; 4. The message should address different regulations by different regulatory bodies; 5. Security requirement, such as ciphering and integrity protection. 5.1. Database Discovery The database discovery procedure is the process for white space device to find the database from which it can query white space. In this sub-clause the term database means the database entity from which the white space device can query white space channel. Database discovery is the prerequisite of the other procedures, Zhu Expires September 6, 2012 [Page 9] Internet-Draft PAWS framework data model March 2012 before the white space device can transmit in white space spectrum, it MUST contact a trusted database where the device can learn if any channels are available for it to use. The white space device gets the list of databases providing white space spectrum querying service in the relevant regulatory domain, and then the device will select one of the databases to connecting to. Optionally the white space device MAY be pre-programmed with the Internet address of at least one trusted database manually. The device can establish contact with a trusted database using one of the pre-provisioned IP addresses. Optionally the white space device can discover a list of databases from AddrDatabase on the Internet which maintains a list of TVWS databases and their Internet addresses. The procedure is shown in Figure 6. +------------------+ +------------+ |white space device| |AddrDatabase| +------------------+ +------------+ | | | | | | | | | DISCOVERY REQ | |----------------------------------------->| | | | | | DISCOVERY RESP | |< ----------------------------------------| | | | | Figure 6: Discovery procedure The discovery procedures shown in Figure 6 are as follows: (1)The white space device is connected to the Internet by any means other than using the white space radio. (2)The white space device sends Database Discover request message to AddrDatabase, when AddrDatabase receives the request message, it finds out whether there are available trusted database for the device to access to. (3)The white space device waits a limited time for Database Discover Zhu Expires September 6, 2012 [Page 10] Internet-Draft PAWS framework data model March 2012 response message, If there is no available database or no acceptable response is received within the limited time, the white space device concludes that no trusted database is available, otherwise the device will select a trusted database to connect to. DISCOVERY_REQ is Database Discover request message and DISCOVERY_RESP is Database Discover response message. DISCOVERY_REQ: White space device sends its geo-location and coverage area information to AddrDatabase, depending on the information the AddrDatabase finds out databases which the white space device can access to. Parameters included in DISCOVERY_REQ message: |------------------------------------------------------------------| | parameters | comments | |------------------------------------------------------------------| | version | version of the protocol | |------------------------------------------------------------------| | message type | indicates the type of this message | | | DISCOVERY_REQ here. | |------------------------------------------------------------------| | device id | device id of white space device | |------------------------------------------------------------------| | manufacture Series | the Series number of manufacture | | number | of device | |------------------------------------------------------------------| | geo-location | geo-location of the white space device| | | in the form of (latitude,longitude) | |------------------------------------------------------------------| | coverage range |coverage range of the white space device| | | unit: m. | |------------------------------------------------------------------| DISCOVERY_RESP: AddrDatabase sends the list of databases' information to white space device by this message. The parameter "result" indicates whether there are available databases or not. Parameters included in DISCOVERY_ RESP message: Zhu Expires September 6, 2012 [Page 11] Internet-Draft PAWS framework data model March 2012 |------------------------------------------------------------------| | parameters | comments | |------------------------------------------------------------------| | version | version of the protocol | |------------------------------------------------------------------| | message type | indicates the type of this message | | | DISCOVERY_RESP here. | |------------------------------------------------------------------| | result | Indicating whether there are | | | available databases or not. | |------------------------------------------------------------------| | list of databases | A list of available databases to | | | which the white space device can | | | access to. | |------------------------------------------------------------------| 5.2. Device Registration with Trusted Database The registration procedure is used to register the information that will not change very frequently to the trusted database which the white space device will connects to, before the device can transmit in white space, it must contact a trusted database where the device can learn if any channels are available for it to use. The registration procedure occurs when one of these conditions happens : (1) The master device will operate in white space for the first time after power up. (2) The location of master device changes by a predetermined distance. (3) After a certain regular time interval. (4) When the registered information before changed, and the master device need update its registration information. In this sub-clause the term database means the database entity from which the white space device can query white space channel. The registration procedure also includes the authentication procedure and the establishment of security-related information which may be used in subsequent messages. The registration procedure is shown in Figure 7. Zhu Expires September 6, 2012 [Page 12] Internet-Draft PAWS framework data model March 2012 +------------------+ +------------+ |white space device| | Database| +------------------+ +------------+ | | | | | | | | | REGISTRATION_REQ | |----------------------------------------->| | | | | | REGISTRATION_RESP | |< ----------------------------------------| | | | | Figure 7: The registration procedure The registration procedure using the following steps: (1)The white space device connects to the selected trusted database. (2)The white space device sends registration request message to the trusted database. In this message the parameters to be registered and the security-related information are included. (3)The database sends the registration response message to the white space device indicating whether the registration is success or not, the database also sends security-related information, that will be used in the subsequent procedures. REGISTRATION_REQ is the registration request message and REGISTRATION_RESP is the registration response message. REGISTRATION_REQ: Zhu Expires September 6, 2012 [Page 13] Internet-Draft PAWS framework data model March 2012 |------------------------------------------------------------------| | parameters | comments | |------------------------------------------------------------------| | version | version of the protocol | |------------------------------------------------------------------| | message type | indicates the type of this message | | | REGISTRATION_REQ here. | |------------------------------------------------------------------| | device id | device id of white space device | |------------------------------------------------------------------| | device type | the device type of the | | | white space device| | |------------------------------------------------------------------| | manufacture Series | the Series number of manufacture | | number | of device | |------------------------------------------------------------------| | | Antenna characteristic of the white | | | space device.Includes:Antenna height | | antenna characteristic |above the ground, direction, gain, | | | maximum output power, spectrum mask | | | | |------------------------------------------------------------------| | |includes:name of the individual or | | |business that owns the device, name of a| | |contact person responsible for the | | Device owner's | device's operation, address for the | | information | contact person, email address for the | | | contact person and phone number of the| | | contact person | |------------------------------------------------------------------| |authentication |the information for authentication | | information |between white space device and database | |------------------------------------------------------------------| REGISTRATION_RESP: Zhu Expires September 6, 2012 [Page 14] Internet-Draft PAWS framework data model March 2012 |------------------------------------------------------------------| | parameters | comments | |------------------------------------------------------------------| | version | version of the protocol | |------------------------------------------------------------------| | message type | indicates the type of this message | | | REGISTRATION_RESP here. | |------------------------------------------------------------------| | result | indicates whether the connection | | |establishment is success or fail | |------------------------------------------------------------------| | | the identification that the database | | entity id | assigns for white space device. the | | | Entity ID is unique in the scope of | | | the database | |------------------------------------------------------------------| | authentication |the information for authentication | | information |between white space device and database | |------------------------------------------------------------------| 5.3. White Space Channel Query In this sub-clause the term database means the database entity from which the white space device can query white space spectrum. The query procedure is used for white space device to query the white space channel from database, the procedure is depicted in Figure 8. +------------------+ +------------+ |white space device| | Database| +------------------+ +------------+ | | | | | | | | | AVAIL_WS_REQ | |----------------------------------------->| | | | | | AVAIL_WS_RESP | |< ----------------------------------------| | | | | | | Figure 8: The available channel query procedure The query procedure using the following steps: Zhu Expires September 6, 2012 [Page 15] Internet-Draft PAWS framework data model March 2012 (1) The white space device sends the white space query request message to database and waits a limited period of time for white space query response message from database. (2) On receiving the white space query request message, database will find out the available white space channels and send the available white space channel list to the white space device. (3) If there is no available channel or no acceptable response is received within the limited time, the white space device concludes that no channel is available. AVAIL_WS_REQ is the available white space query request message; AVAIL_WS_RESP is the available white space query response message. AVAIL_WS_REQ: Zhu Expires September 6, 2012 [Page 16] Internet-Draft PAWS framework data model March 2012 |------------------------------------------------------------------| | parameters | comments | |------------------------------------------------------------------| | version | version of the protocol | |------------------------------------------------------------------| | message type | indicates the type of this message | | | AVAIL_WS_REQ here. | |------------------------------------------------------------------| | device id | device id of white space device | |------------------------------------------------------------------| | device type | the device type of the | | | white space device | |------------------------------------------------------------------| | List of coverage area(s)| a list of coverage area(s) where the | | information | master device may provide white space | | | access service.incudes:geo-location ( | | | latitude ,longitude), uncertainty of | | | geo-location(in meters),and confidence(| | | in percentage ) for the location | | | determination,coverage range. | |------------------------------------------------------------------| | | Antenna characteristic of the white | | | space device.Includes:Antenna height | | antenna characteristic |above the ground, direction, gain, | | | maximum output power, spectrum mask | | |( optional in this message) | |------------------------------------------------------------------| | |The bandwidth the device needs to form | | Bandwidth |the wireless network. | | | | |------------------------------------------------------------------| | Entity ID |the identification that the database | | |assigns for device. the Entity ID | | | is unique in the scope of database | |------------------------------------------------------------------| AVAIL_WS_RESP: Zhu Expires September 6, 2012 [Page 17] Internet-Draft PAWS framework data model March 2012 |------------------------------------------------------------------| | parameters | comments | |------------------------------------------------------------------| | version | version of the protocol | |------------------------------------------------------------------| | message type | indicates the type of this message | | | AVAIL_WS_RESP here. | |------------------------------------------------------------------| | device id | device id of white space device | |------------------------------------------------------------------| | device type | the device type of the | | | white space device| | |------------------------------------------------------------------| | result | indicates whether the query procedure | | | is success or fail | |------------------------------------------------------------------| | |includes:frequency information,available| | | bandwidth, available time duration, | | White Space channel |coverage area, maximum transmission | | lists | power | | | | |------------------------------------------------------------------| | Entity ID |the identification that the database | | |assigns for device. the Entity ID | | | is unique in the scope of database | |------------------------------------------------------------------| 5.4. White Space Channel Update In order to avoid interfering with the primary user or other secondary user, the white space updating mechanism is provided in this draft. There are two methods for white space updating: Method 1: The white space device MUST access the database to obtain and update the list of available channels that could be utilized by the device. According to some regulatory rules the white space device SHOULD update the white space channel periodically, and the period may be different due to different regulatory rules. Method 2: Database push updates in channel availability changes to the master device, when the availability of channel changes database SHOULD inform the master device and after receiving the notification the master device SHOULD begin the white space channel query procedure to get the updated white space channel. The update procedure of method 1 is shown in Figure 9. Zhu Expires September 6, 2012 [Page 18] Internet-Draft PAWS framework data model March 2012 +------------------+ +------------+ |white space device| | Database| +------------------+ +------------+ | | +--------------------+ | |Update timer expires| | +--------------------+ | | | | | | | | | | white space channel query procedure | |< --------------------------------------->| | | | | Figure 9: White space channel update procedure for method 1 In white space channel update procedure of method 1, an update timer is set, after the white space device query the database for first time, the timer start to run, when the timer expires the device will implement the white space channel query procedure and update the channel list, and then clear the update timer. The update procedure of method 2 is shown in Figure 10. +------------------+ +-------------+ |Database | |Master device| +------------------+ +-------------+ | | +-------------------------+ | |The availability of some | | | channel changes | | +-------------------------+ | | | | | | send channel updates message | |----------------------------------------->| | | | | | white space channel query procedure | |< --------------------------------------->| | | | | Figure 10: White space channel update procedure for method 2 As shown in Figure 10, when the availability of some white space Zhu Expires September 6, 2012 [Page 19] Internet-Draft PAWS framework data model March 2012 channels change, database will send channel updates message to the white space device, and after receiving the message white space device MUST start white space channel query procedure, discussed in section 5.3. Here the white space device can be a coordinating database as well as a master device. The parameters included in this channel updates message are shown below: CHANNEL_UPDATE_NOTIFICATION: |------------------------------------------------------------------| | parameters | comments | |------------------------------------------------------------------| | version | version of the protocol | |------------------------------------------------------------------| | message type | indicates the type of this message | | | CHANNEL_UPDATE_NOTIFICATION here. | |------------------------------------------------------------------| | |Includes owner's name, or other of the | |Owner information of the |information for identify the owner | | database | database | |------------------------------------------------------------------| | Address information | URL or IP address of database | |------------------------------------------------------------------| 6. Message Encoding In this framework XML is used to encode the message. HTTPS is used to carry the XML, there is an example of how XML formatted message is embedded in HTTP: (1) For the request message: GET destination_url HTTP/1.0 Accept: */* Proxy-Connection: Keep-Alive User-Agent: Mozilla/4.0 Host: host name Content-Type: text/xml xml message. (2) For the response message: Zhu Expires September 6, 2012 [Page 20] Internet-Draft PAWS framework data model March 2012 HTTP/1.1 200 OK Proxy-Connection: Keep-Alive Connection: Keep-Alive Content-Length: 59042 Date: Thu, 09 Sep 2010 03:31:54 GMT Content-Type: text/xml Server: server name Cache-Control: max-age=7200 xml message. The details of XML schema is shown below, the details of parameters in the message are included in the XML schema: Zhu Expires September 6, 2012 [Page 22] Internet-Draft PAWS framework data model March 2012 Zhu Expires September 6, 2012 [Page 23] Internet-Draft PAWS framework data model March 2012 Zhu Expires September 6, 2012 [Page 24] Internet-Draft PAWS framework data model March 2012 Zhu Expires September 6, 2012 [Page 27] Internet-Draft PAWS framework data model March 2012 Zhu Expires September 6, 2012 [Page 28] Internet-Draft PAWS framework data model March 2012 Zhu Expires September 6, 2012 [Page 29] Internet-Draft PAWS framework data model March 2012 Zhu Expires September 6, 2012 [Page 30] Internet-Draft PAWS framework data model March 2012 Zhu Expires September 6, 2012 [Page 31] Internet-Draft PAWS framework data model March 2012 Zhu Expires September 6, 2012 [Page 32] Internet-Draft PAWS framework data model March 2012 7. Security Considerations There are some security consideration about PAWS: o Mutual authentication between master device and database, master device and coordination database, coordination database and database is needed. o In order to protect the message from being changed by attacker, all the messages need integrity protection. o Because there are some private information included in the messages, so a ciphering mechanism SHOULD be used to encrypt the messages. 8. IANA Considerations There have been no IANA considerations so far in this document. 9. Acknowledgments Thanks to my colleagues for their sincerely help and comments when drafting this document. 10. Normative Reference [I-D.ietf-paws-problem-stmt-usecases-rqmts] Probasco, S. and B. Patil, "Protocol to Access White Space database: PS, use cases and rqmts", draft-ietf-paws-problem-stmt-usecases-rqmts-03 (work in progress), February 2012. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. Zhu Expires September 6, 2012 [Page 33] Internet-Draft PAWS framework data model March 2012 Author's Address Lei Zhu Huawei Technologies Huawei Building, Q20 No.156 Beiqing Rd.Z-park Haidian District, Beijing 100095 P. R. China Phone: +86-10-60612078 Email: lei.zhu@huawei.com Zhu Expires September 6, 2012 [Page 34]