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Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 GEOPRIV M. Thomson 3 Internet-Draft Microsoft 4 Intended status: Standards Track J. Winterbottom 5 Expires: January 7, 2013 Commscope 6 July 6, 2012 8 Using Device-provided Location-Related Measurements in Location 9 Configuration Protocols 10 draft-ietf-geopriv-held-measurements-05 12 Abstract 14 A method is described by which a Device is able to provide location- 15 related measurement data to a LIS within a request for location 16 information. Location-related measurement information are 17 observations concerning properties related to the position of a 18 Device, which could be data about network attachment or about the 19 physical environment. When a LIS generates location information for 20 a Device, information from the Device can improve the accuracy of the 21 location estimate. A basic set of location-related measurements are 22 defined, including common modes of network attachment as well as 23 assisted Global Navigation Satellite System (GNSS) parameters. 25 Status of this Memo 27 This Internet-Draft is submitted in full conformance with the 28 provisions of BCP 78 and BCP 79. 30 Internet-Drafts are working documents of the Internet Engineering 31 Task Force (IETF). Note that other groups may also distribute 32 working documents as Internet-Drafts. The list of current Internet- 33 Drafts is at http://datatracker.ietf.org/drafts/current/. 35 Internet-Drafts are draft documents valid for a maximum of six months 36 and may be updated, replaced, or obsoleted by other documents at any 37 time. It is inappropriate to use Internet-Drafts as reference 38 material or to cite them other than as "work in progress." 40 This Internet-Draft will expire on January 7, 2013. 42 Copyright Notice 44 Copyright (c) 2012 IETF Trust and the persons identified as the 45 document authors. All rights reserved. 47 This document is subject to BCP 78 and the IETF Trust's Legal 48 Provisions Relating to IETF Documents 49 (http://trustee.ietf.org/license-info) in effect on the date of 50 publication of this document. Please review these documents 51 carefully, as they describe your rights and restrictions with respect 52 to this document. Code Components extracted from this document must 53 include Simplified BSD License text as described in Section 4.e of 54 the Trust Legal Provisions and are provided without warranty as 55 described in the Simplified BSD License. 57 This document may contain material from IETF Documents or IETF 58 Contributions published or made publicly available before November 59 10, 2008. The person(s) controlling the copyright in some of this 60 material may not have granted the IETF Trust the right to allow 61 modifications of such material outside the IETF Standards Process. 62 Without obtaining an adequate license from the person(s) controlling 63 the copyright in such materials, this document may not be modified 64 outside the IETF Standards Process, and derivative works of it may 65 not be created outside the IETF Standards Process, except to format 66 it for publication as an RFC or to translate it into languages other 67 than English. 69 Table of Contents 71 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 6 72 2. Conventions used in this document . . . . . . . . . . . . . . 6 73 3. Location-Related Measurements in LCPs . . . . . . . . . . . . 7 74 4. Location-Related Measurement Data Types . . . . . . . . . . . 8 75 4.1. Measurement Container . . . . . . . . . . . . . . . . . . 9 76 4.1.1. Time of Measurement . . . . . . . . . . . . . . . . . 9 77 4.1.2. Expiry Time on Location-Related Measurement Data . . . 9 78 4.2. RMS Error and Number of Samples . . . . . . . . . . . . . 10 79 4.2.1. Time RMS Error . . . . . . . . . . . . . . . . . . . . 10 80 4.3. Measurement Request . . . . . . . . . . . . . . . . . . . 11 81 4.4. Identifying Location Provenance . . . . . . . . . . . . . 12 82 5. Location-Related Measurement Data Types . . . . . . . . . . . 15 83 5.1. LLDP Measurements . . . . . . . . . . . . . . . . . . . . 15 84 5.2. DHCP Relay Agent Information Measurements . . . . . . . . 16 85 5.3. 802.11 WLAN Measurements . . . . . . . . . . . . . . . . . 16 86 5.3.1. Wifi Measurement Requests . . . . . . . . . . . . . . 20 87 5.4. Cellular Measurements . . . . . . . . . . . . . . . . . . 20 88 5.4.1. Cellular Measurement Requests . . . . . . . . . . . . 23 89 5.5. GNSS Measurements . . . . . . . . . . . . . . . . . . . . 23 90 5.5.1. GNSS System and Signal . . . . . . . . . . . . . . . . 25 91 5.5.2. Time . . . . . . . . . . . . . . . . . . . . . . . . . 26 92 5.5.3. Per-Satellite Measurement Data . . . . . . . . . . . . 26 93 5.5.4. GNSS Measurement Requests . . . . . . . . . . . . . . 27 94 5.6. DSL Measurements . . . . . . . . . . . . . . . . . . . . . 27 95 5.6.1. L2TP Measurements . . . . . . . . . . . . . . . . . . 28 96 5.6.2. RADIUS Measurements . . . . . . . . . . . . . . . . . 28 97 5.6.3. Ethernet VLAN Tag Measurements . . . . . . . . . . . . 29 98 5.6.4. ATM Virtual Circuit Measurements . . . . . . . . . . . 29 99 6. Privacy Considerations . . . . . . . . . . . . . . . . . . . . 30 100 6.1. Measurement Data Privacy Model . . . . . . . . . . . . . . 30 101 6.2. LIS Privacy Requirements . . . . . . . . . . . . . . . . . 30 102 6.3. Measurement Data and Location URIs . . . . . . . . . . . . 31 103 6.4. Third-Party-Provided Measurement Data . . . . . . . . . . 31 104 7. Security Considerations . . . . . . . . . . . . . . . . . . . 31 105 7.1. Threat Model . . . . . . . . . . . . . . . . . . . . . . . 31 106 7.1.1. Acquiring Location Information Without 107 Authorization . . . . . . . . . . . . . . . . . . . . 32 108 7.1.2. Extracting Network Topology Data . . . . . . . . . . . 33 109 7.1.3. Lying By Proxy . . . . . . . . . . . . . . . . . . . . 33 110 7.1.4. Measurement Replay . . . . . . . . . . . . . . . . . . 34 111 7.1.5. Environment Spoofing . . . . . . . . . . . . . . . . . 35 112 7.2. Mitigation . . . . . . . . . . . . . . . . . . . . . . . . 36 113 7.2.1. Measurement Validation . . . . . . . . . . . . . . . . 37 114 7.2.1.1. Effectiveness . . . . . . . . . . . . . . . . . . 37 115 7.2.1.2. Limitations (Unique Observer) . . . . . . . . . . 38 116 7.2.2. Location Validation . . . . . . . . . . . . . . . . . 38 117 7.2.2.1. Effectiveness . . . . . . . . . . . . . . . . . . 39 118 7.2.2.2. Limitations . . . . . . . . . . . . . . . . . . . 39 119 7.2.3. Supporting Observations . . . . . . . . . . . . . . . 40 120 7.2.3.1. Effectiveness . . . . . . . . . . . . . . . . . . 40 121 7.2.3.2. Limitations . . . . . . . . . . . . . . . . . . . 40 122 7.2.4. Attribution . . . . . . . . . . . . . . . . . . . . . 41 123 7.2.5. Stateful Correlation of Location Requests . . . . . . 42 124 8. Measurement Schemas . . . . . . . . . . . . . . . . . . . . . 42 125 8.1. Measurement Container Schema . . . . . . . . . . . . . . . 43 126 8.2. Measurement Source Schema . . . . . . . . . . . . . . . . 45 127 8.3. Base Type Schema . . . . . . . . . . . . . . . . . . . . . 45 128 8.4. LLDP Measurement Schema . . . . . . . . . . . . . . . . . 48 129 8.5. DHCP Measurement Schema . . . . . . . . . . . . . . . . . 49 130 8.6. WiFi Measurement Schema . . . . . . . . . . . . . . . . . 51 131 8.7. Cellular Measurement Schema . . . . . . . . . . . . . . . 54 132 8.8. GNSS Measurement Schema . . . . . . . . . . . . . . . . . 57 133 8.9. DSL Measurement Schema . . . . . . . . . . . . . . . . . . 58 134 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 60 135 9.1. IANA Registry for GNSS Types . . . . . . . . . . . . . . . 60 136 9.2. URN Sub-Namespace Registration for 137 urn:ietf:params:xml:ns:pidf:geopriv10:lmsrc . . . . . . . 61 138 9.3. URN Sub-Namespace Registration for 139 urn:ietf:params:xml:ns:geopriv:lm . . . . . . . . . . . . 62 140 9.4. URN Sub-Namespace Registration for 141 urn:ietf:params:xml:ns:geopriv:lm:basetypes . . . . . . . 63 142 9.5. URN Sub-Namespace Registration for 143 urn:ietf:params:xml:ns:geopriv:lm:lldp . . . . . . . . . . 64 144 9.6. URN Sub-Namespace Registration for 145 urn:ietf:params:xml:ns:geopriv:lm:dhcp . . . . . . . . . . 64 146 9.7. URN Sub-Namespace Registration for 147 urn:ietf:params:xml:ns:geopriv:lm:wifi . . . . . . . . . . 65 148 9.8. URN Sub-Namespace Registration for 149 urn:ietf:params:xml:ns:geopriv:lm:cell . . . . . . . . . . 66 150 9.9. URN Sub-Namespace Registration for 151 urn:ietf:params:xml:ns:geopriv:lm:gnss . . . . . . . . . . 66 152 9.10. URN Sub-Namespace Registration for 153 urn:ietf:params:xml:ns:geopriv:lm:dsl . . . . . . . . . . 67 154 9.11. XML Schema Registration for Measurement Source Schema . . 68 155 9.12. XML Schema Registration for Measurement Container 156 Schema . . . . . . . . . . . . . . . . . . . . . . . . . . 68 157 9.13. XML Schema Registration for Base Types Schema . . . . . . 68 158 9.14. XML Schema Registration for LLDP Schema . . . . . . . . . 68 159 9.15. XML Schema Registration for DHCP Schema . . . . . . . . . 69 160 9.16. XML Schema Registration for WiFi Schema . . . . . . . . . 69 161 9.17. XML Schema Registration for Cellular Schema . . . . . . . 69 162 9.18. XML Schema Registration for GNSS Schema . . . . . . . . . 70 163 9.19. XML Schema Registration for DSL Schema . . . . . . . . . . 70 164 10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 70 165 11. References . . . . . . . . . . . . . . . . . . . . . . . . . . 71 166 11.1. Normative References . . . . . . . . . . . . . . . . . . . 71 167 11.2. Informative References . . . . . . . . . . . . . . . . . . 72 168 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 73 170 1. Introduction 172 A location configuration protocol (LCP) provides a means for a Device 173 to request information about its physical location from an access 174 network. A location information server (LIS) is the server that 175 provides location information; information that is available due to 176 the knowledge about the network and physical environment that is 177 available to the LIS. 179 As a part of the access network, the LIS is able to acquire 180 measurement results from network Devices within the network that are 181 related to Device location. The LIS also has access to information 182 about the network topology that can be used to turn measurement data 183 into location information. However, this information can be enhanced 184 with information acquired from the Device itself. 186 A Device is able to make observations about its network attachment, 187 or its physical environment. The location-related measurement data 188 might be unavailable to the LIS; alternatively, the LIS might be able 189 to acquire the data, but at a higher cost in time or otherwise. 190 Providing measurement data gives the LIS more options in determining 191 location, which could improve the quality of the service provided by 192 the LIS. Improvements in accuracy are one potential gain, but 193 improved response times and lower error rates are also possible. 195 This document describes a means for a Device to report location- 196 related measurement data to the LIS. Examples based on the HELD 197 [RFC5985] location configuration protocol are provided. 199 2. Conventions used in this document 201 The terms LIS and Device are used in this document in a manner 202 consistent with the usage in [RFC5985]. 204 This document also uses the following definitions: 206 Location Measurement: An observation about the physical properties 207 of a particular Device's network access. The result of a location 208 measurement--"location-related measurement data", or simply 209 "measurement data" given sufficient context--can be used to 210 determine the location of a Device. Location-related measurement 211 data does not identify a Device; measurement data can change with 212 time if the location of the Device also changes. 214 Location-related measurement data does not necessarily contain 215 location information directly, but it can be used in combination 216 with contextual knowledge of the network, or algorithms to derive 217 location information. Examples of location-related measurement 218 data are: radio signal strength or timing measurements, Ethernet 219 switch and port identifiers. 221 Location-related measurement data can be considered sighting 222 information, based on the definition in [RFC3693]. 224 Location Estimate: The result of location determination, a location 225 estimate is an approximation of where the Device is located. 226 Location estimates are subject to uncertainty, which arise from 227 errors in measurement results. 229 GNSS: Global Navigation Satellite System. A satellite-based system 230 that provides positioning and time information. For example, the 231 US Global Positioning System (GPS) or the European Galileo system. 233 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 234 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 235 document are to be interpreted as described in [RFC2119]. 237 3. Location-Related Measurements in LCPs 239 This document defines a standard container for the conveyance of 240 location-related measurement parameters in location configuration 241 protocols. This is an XML container that identifies parameters by 242 type and allows the Device to provide the results of any measurement 243 it is able to perform. A set of measurement schemas are also defined 244 that can be carried in the generic container. 246 The simplest example of measurement data conveyance is illustrated by 247 the example message in Figure 1. This shows a HELD location request 248 message with an Ethernet switch and port measurement taken using LLDP 249 [IEEE.8021AB]. 251 252 civic 253 255 256 0a01003c 257 c2 258 259 260 262 Figure 1: HELD Location Request with Measurement Data 264 Measurement data that the LIS does not support or understand can be 265 ignored. The measurements defined in this document follow this rule; 266 extensions that could result in backward incompatibility MUST be 267 added as new measurement definitions rather than extensions to 268 existing types. 270 Multiple sets of measurement data, either of the same type or from 271 different sources can be included in the "measurements" element. See 272 Section 4.1.1 for details on repetition of this element. 274 Use of location-related measurement data is at the discretion of the 275 LIS, but the "method" parameter in the PIDF-LO SHOULD be adjusted to 276 reflect the method used. 278 Location-related measurement data need not be provided exclusively by 279 Devices. A third party location requester can request location 280 information using measurement data, if they are able and authorized. 281 There are privacy considerations relating to the use of measurements 282 by third parties, which are discussed in Section 6.4. 284 Location-related measurement data and its use presents a number of 285 security challenges. These are described in more detail in 286 Section 7. 288 4. Location-Related Measurement Data Types 290 A common container is defined for the expression of location 291 measurement data, as well as a simple means of identifying specific 292 types of measurement data for the purposes of requesting them. 294 The following example shows a measurement container with measurement 295 time and expiration time included. A WiFi measurement is enclosed. 297 300 301 302 00-12-F0-A0-80-EF 303 wlan-home 304 305 306 308 Figure 2: Measurement Example 310 4.1. Measurement Container 312 The "measurement" element is used to encapsulate measurement data 313 that is collected at a certain point in time. It contains time-based 314 attributes that are common to all forms of measurement data, and 315 permits the inclusion of arbitrary measurement data. 317 This container can be added to any request for location information, 318 such as a HELD location request [RFC5985]. 320 4.1.1. Time of Measurement 322 The "time" attribute records the time that the measurement or 323 observation was made. This time can be different to the time that 324 the measurement information was reported. Time information can be 325 used to populate a timestamp on the location result, or to determine 326 if the measurement information is used. 328 The "time" attribute is optional to avoid forcing an arbitrary choice 329 of timestamp for relatively static types of measurement (for 330 instance, the DSL measurements in Section 5.6) and for legacy Devices 331 that don't record time information (such as the Home Location 332 Register/Home Subscriber Server for cellular). However, time SHOULD 333 be provided whenever possible. 335 The "time" attribute is attached to the root "measurement" element. 336 If it is necessary to provide multiple sets of measurement data with 337 different times, multiple "measurement" elements SHOULD be provided. 339 4.1.2. Expiry Time on Location-Related Measurement Data 341 A Device is able to indicate an expiry time in the location 342 measurement using the "expires" attribute. Nominally, this attribute 343 indicates how long information is expected to be valid for, but it 344 can also indicate a time limit on the retention and use of the 345 measurement data. A Device can use this attribute to prevent the LIS 346 from retaining measurement data or limit the time that a LIS retains 347 this information. 349 Note: Movement of a Device might result in the measurement data 350 being invalidated before the expiry time. 352 The LIS MUST NOT keep location-related measurement data beyond the 353 time indicated in the "expires" attribute. 355 4.2. RMS Error and Number of Samples 357 Often a measurement is taken more than once over a period of time. 358 Reporting the average of a number of measurement results mitigates 359 the effects of random errors that occur in the measurement process. 361 Reporting each measurement individually can be the most effective 362 method of reporting multiple measurements. This is achieved by 363 providing multiple "measurement" elements for different times. 365 The alternative is to aggregate multiple measurements and report a 366 mean value across the set of measurements. Additional information 367 about the distribution of the results can be useful in determining 368 location uncertainty. 370 Two optional attributes are provided for certain measurement values: 372 rmsError: The root-mean-squared (RMS) error of the set of 373 measurement values used in calculating the result. RMS error is 374 expressed in the same units as the measurement, unless otherwise 375 stated. If an accurate value for RMS error is not known, this 376 value can be used to indicate an upper bound or estimate for the 377 RMS error. 379 samples: The number of samples that were taken in determining the 380 measurement value. If omitted, this value can be assumed to be a 381 very large value, so that the RMS error is an indication of the 382 standard deviation of the sample set. 384 For some measurement techniques, measurement error is largely 385 dependent on the measurement technique employed. In these cases, 386 measurement error is largely a product of the measurement technique 387 and not the specific circumstances, so RMS error does not need to be 388 actively measured. A fixed value MAY be provided for RMS error where 389 appropriate. 391 The "rmsError" and "samples" elements are added as attributes of 392 specific measurement data types. 394 4.2.1. Time RMS Error 396 Measurement of time can be significant in certain circumstances. The 397 GNSS measurements included in this document are one such case where a 398 small error in time can result in a large error in location. Factors 399 such as clock drift and errors in time sychronization can result in 400 small, but significant, time errors. Including an indication of the 401 quality of the time can be helpful. 403 An optional "timeError" attribute can be added to the "measurement" 404 element to indicate the RMS error in time. "timeError" indicates an 405 upper bound on the time RMS error in seconds. 407 The "timeError" attribute does not apply where multiple samples of a 408 measurement is taken over time. If multiple samples are taken, each 409 SHOULD be included in a different "measurement" element. 411 4.3. Measurement Request 413 A measurement request is used by a protocol peer to describe a set of 414 measurement data that it desires. A "measurementRequest" element is 415 defined that can be included in a protocol exchange. 417 For instance, a LIS can use a measurement request in HELD responses. 418 If the LIS is unable to provide location information, but it believes 419 that a particular measurement type would enable it to provide a 420 location, it can include a measurement request in an error response. 422 The "measurement" element of the measurement request identifies the 423 type of measurement that is requested. The "type" attribute of this 424 element indicates the type of measurement, as identified by an XML 425 qualified name. An optional "samples" attribute indicates how many 426 samples of the identified measurement are requested. 428 The "measurement" element can be repeated to request multiple (or 429 alternative) measurement types. 431 Additional XML content might be defined for a particular measurement 432 type that is used to further refine a request. These elements either 433 constrain what is requested or specify optional components of the 434 measurement data that are needed. These are defined along with the 435 specific measurement type. 437 In the HELD protocol, the inclusion of a measurement request in a 438 error response with a code of "locationUnknown" indicates that the 439 LIS believes that providing the indicated measurements would increase 440 the likelihood of a subsequent request being successful. 442 The following example shows a HELD error response that indicates that 443 WiFi measurement data would be useful if a later request were made. 444 Additional elements indicate that received signal strength for an 445 802.11n access point is requested. 447 449 Insufficient measurement data 450 453 454 n 455 wifi:rcpi 456 457 458 460 Figure 3: HELD Error Requesting Measurement Data 462 A measurement request that is included in other HELD messages has 463 undefined semantics and can be safely ignored. Other specifications 464 might define semantics for measurement requests under other 465 conditions. 467 4.4. Identifying Location Provenance 469 An extension is made to the PIDF-LO [RFC4119] that allows a location 470 recipient to identify the source (or sources) of location information 471 and the measurement data that was used to determine that location 472 information. 474 The "source" element is added to the "geopriv" element of the 475 PIDF-LO. This element does not identify specific entities. Instead, 476 it identifies the type of source. 478 The following types of measurement source are identified: 480 lis: Location information is based on measurement data that the LIS 481 or sources that it trusts have acquired. This label might be used 482 if measurement data provided by the Device has been completely 483 validated by the LIS. 485 device: Location information is based on measurement data that the 486 Device has provided to the LIS. 488 other: Location information is based on measurement data that a 489 third party has provided. This might be an authorized third party 490 that uses identity parameters 491 [I-D.ietf-geopriv-held-identity-extensions] or any other entity. 493 No assertion is made about the veracity of the measurement data from 494 sources other than the LIS. A combination of tags MAY be included to 495 indicate that measurement data from both sources was used. 497 For example, the first tuple of the following PIDF-LO indicates that 498 measurement data from a LIS and a device was combined to produce the 499 result, the second tuple was produced by the LIS alone. 501 507 508 509 510 511 512 7.34324 134.47162 513 514 850.24 515 516 517 518 519 OTDOA 520 lis device 521 522 523 524 525 526 527 528 529 7.34379 134.46484 530 531 9000 532 533 534 535 536 Cell 537 lis 538 539 540 541 543 5. Location-Related Measurement Data Types 545 This document defines location-related measurement data types for a 546 range of common network types. 548 All included measurement data definitions allow for arbitrary 549 extension in the corresponding schema. As new parameters that are 550 applicable to location determination are added, these can be added as 551 new XML elements in a unique namespace. Though many of the 552 underlying protocols support extension, creation of specific XML- 553 based extensions to the measurement format is favored over 554 accomodating protocol-specific extensions in generic containers. 556 5.1. LLDP Measurements 558 Link-Layer Discovery Protocol (LLDP) [IEEE.8021AB] messages are sent 559 between adjacent nodes in an IEEE 802 network (e.g. wired Ethernet, 560 WiFi, 802.16). These messages all contain identification information 561 for the sending node, which can be used to determine location 562 information. A Device that receives LLDP messages can report this 563 information as a location-related measurement to the LIS, which is 564 then able to use the measurement data in determining the location of 565 the Device. 567 Note: The LLDP extensions defined in LLDP Media Endpoint Discovery 568 (LLDP-MED) [ANSI-TIA-1057] provide the ability to acquire location 569 information directly from an LLDP endpoint. Where this 570 information is available, it might be unnecessary to use any other 571 form of location configuration. 573 Values are provided as hexadecimal sequences. The Device MUST report 574 the values directly as they were provided by the adjacent node. 575 Attempting to adjust or translate the type of identifier is likely to 576 cause the measurement data to be useless. 578 Where a Device has received LLDP messages from multiple adjacent 579 nodes, it should provide information extracted from those messages by 580 repeating the "lldp" element. 582 An example of an LLDP measurement is shown in Figure 4. This shows 583 an adjacent node (chassis) that is identified by the IP address 584 192.0.2.45 (hexadecimal c000022d) and the port on that node is 585 numbered using an agent circuit ID [RFC3046] of 162 (hexadecimal a2). 587 589 590 c000022d 591 a2 592 593 595 Figure 4: LLDP Measurement Example 597 IEEE 802 Devices that are able to obtain information about adjacent 598 network switches and their attachment to them by other means MAY use 599 this data type to convey this information. 601 5.2. DHCP Relay Agent Information Measurements 603 The DHCP Relay Agent Information option [RFC3046] provides 604 measurement data about the network attachment of a Device. This 605 measurement data can be included in the "dhcp-rai" element. 607 The elements in the DHCP relay agent information options are opaque 608 data types assigned by the DHCP relay agent. The three items are all 609 optional: circuit identifier ("circuit", [RFC3046]), remote 610 identifier ("remote", [RFC3046], [RFC4649]) and subscriber identifier 611 ("subscriber", [RFC3993], [RFC4580]). The DHCPv6 remote identifier 612 has an associated enterprise number [IANA.enterprise] as an XML 613 attribute. 615 617 618 ::ffff:192.0.2.158 619 108b 620 621 623 Figure 5: DHCP Relay Agent Information Measurement Example 625 The "giaddr" is specified as a dotted quad IPv4 address or an RFC 626 4291 [RFC4291] IPv6 address, using the forms defined in [RFC3986]. 627 The enterprise number is specified as a decimal integer. All other 628 information is included verbatim from the DHCP request in hexadecimal 629 format. 631 5.3. 802.11 WLAN Measurements 633 In WiFi, or 802.11 [IEEE.80211], networks a Device might be able to 634 provide information about the access point (AP) that it is attached 635 to, or other WiFi points it is able to see. This is provided using 636 the "wifi" element, as shown in Figure 6, which shows a single 637 complete measurement for a single access point. 639 641 642 Intel(r)PRO/Wireless 2200BG 643 644 AB-CD-EF-AB-CD-EF 645 example 646 5 647 648 649 -34.4 150.8 650 651 652 a 653 5 654 2 655 2 656 2.56e-9 657 658 23 659 5 660 -59 661 23 662 663 664 10 665 9 666 -98.5 667 7.5 668 669 670 671 673 Figure 6: 802.11 WLAN Measurement Example 675 A wifi element is made up of one or more access points, and an 676 optional "nicType" element. Each access point is described using the 677 "ap" element, which is comprised of the following fields: 679 bssid: The basic service set identifier. In an Infrastructure BSS 680 network, the bssid is the 48 bit MAC address of the access point. 682 The "verified" attribute of this element describes whether the 683 device has verified the MAC address or it authenticated the access 684 point or the network operating the access point (for example, a 685 captive portal accessed through the access point has been 686 authenticated). This attributes defaults to a value of "false" 687 when omitted. 689 ssid: The service set identifier (SSID) for the wireless network 690 served by the access point. 692 The SSID is a 32-octet identifier that is commonly represented as 693 a ASCII [RFC0020] or UTF-8 [RFC3629] encoded string. To represent 694 octets that cannot be directly included in an XML element, 695 escaping is used. Sequences of octets that do not represent a 696 valid UTF-8 encoding can be escaped using a backslash ('\') 697 followed by two case-insensitive hexadecimal digits representing 698 the value of a single octet. 700 The canonical or value-space form of an SSID is a sequence of up 701 to 32 octets that is produced from the concatenation of UTF-8 702 encoded sequences of unescaped characters and octets derived from 703 escaped components. 705 channel: The channel number (frequency) that the access point 706 operates on. 708 location: The location of the access point, as reported by the 709 access point. This element contains any valid location, using the 710 rules for a "location-info" element, as described in [RFC5491]. 712 type: The network type for the network access. This element 713 includes the alphabetic suffix of the 802.11 specification that 714 introducted the radio interface, or PHY; e.g. "a", "b", "g", or 715 "n". 717 band: The frequency band for the radio, in gigahertz (GHz). 802.11 718 [IEEE.80211] specifies PHY layers that use 2.4, 3.7 and 5 719 gigahertz frequency bands. 721 regclass: The regulatory domain and class. The "country" attribute 722 optionally includes the applicable two character country 723 identifier (dot11CountryString), which can be followed by an 'O', 724 'I' or 'X'. The element text content includes the value of the 725 regulatory class: an 8-bit integer in decimal form. 727 antenna: The antenna identifier for the antenna that the access 728 point is using to transmit the measured signals. 730 flightTime: Flight time is the difference between the time of 731 departure (TOD) of signal from a transmitting station and time of 732 arrival (TOA) of signal at a receiving station, as defined in 733 [IEEE.80211V]. Measurement of this value requires that stations 734 synchronize their clocks. This value can be measured by access 735 point or Device; because the flight time is assumed to be the same 736 in either direction - aside from measurement errors - only a 737 single element is provided. This element includes optional 738 "rmsError" and "samples" attributes. RMS error might be derived 739 from the reported RMS error in TOD and TOA. 741 apSignal: Measurement information for the signal transmitted by the 742 access point, as observed by the Device. Some of these values are 743 derived from 802.11v [IEEE.80211V] messages exchanged between 744 Device and access point. The contents of this element include: 746 transmit: The transmit power reported by the access point, in 747 dBm. 749 gain: The gain of the access point antenna reported by the access 750 point, in dB. 752 rcpi: The received channel power indicator for the access point 753 signal, as measured by the Device. This value SHOULD be in 754 units of dBm (with RMS error in dB). If power is measured in a 755 different fashion, the "dBm" attribute MUST be set to "false". 756 Signal strength reporting on current hardware uses a range of 757 different mechanisms; therefore, the value of the "nicType" 758 element SHOULD be included if the units are not known to be in 759 dBm and the value reported by the hardware should be included 760 without modification. This element includes optional 761 "rmsError" and "samples" attributes. 763 rsni: The received signal to noise indicator in dB. This element 764 includes optional "rmsError" and "samples" attributes. 766 deviceSignal: Measurement information for the signal transmitted by 767 the device, as reported by the access point. This element 768 contains the same child elements as the "ap" element, with the 769 access point and Device roles reversed. 771 All elements are optional except for "bssid". 773 The "nicType" element is used to specify the make and model of the 774 wireless network interface in the Device. Different 802.11 chipsets 775 report measurements in different ways, so knowing the network 776 interface type aids the LIS in determining how to use the provided 777 measurement data. The content of this field is unconstrained and no 778 mechanisms are specified to ensure uniqueness. 780 5.3.1. Wifi Measurement Requests 782 Two elements are defined for requesting WiFi measurements in a 783 measurement request: 785 type: The "type" element identifies the desired type (or types that 786 are requested. 788 parameter: The "parameter" element identifies an optional 789 measurements are requested for each measured access point. An 790 element is identified by its qualified name. The optional 791 "context" parameter can be used to specify if an element is 792 included as a child of the "ap" or "device" elements; omission 793 indicates that it applies to both. 795 Multiple types or parameters can be requested by repeating either 796 element. 798 5.4. Cellular Measurements 800 Cellular Devices are common throughout the world and base station 801 identifiers can provide a good source of coarse location information. 802 This information can be provided to a LIS run by the cellar operator, 803 or may be provided to an alternative LIS operator that has access to 804 one of several global cell-id to location mapping databases. 806 A number of advanced location determination methods have been 807 developed for cellular networks. For these methods a range of 808 measurement parameters can be collected by the network, Device, or 809 both in cooperation. This document includes a basic identifier for 810 the wireless transmitter only; future efforts might define additional 811 parameters that enable more accurate methods of location 812 determination. 814 The cellular measurement set allows a Device to report to a LIS any 815 LTE (Figure 7), UMTS (Figure 8), GSM (Figure 9) or CDMA (Figure 10) 816 cells that it is able to observe. Cells are reported using their 817 global identifiers. All 3GPP cells are identified by public land 818 mobile network (PLMN), which is formed of mobile country code (MCC) 819 and mobile network code (MNC); specific fields are added for each 820 network type. 822 Formats for 3GPP cell identifiers are described in [TS.3GPP.23.003]. 823 Bit-level formats for CDMA cell identifiers are described in 824 [TIA-2000.5]; decimal representations are used. 826 MCC and MNC are provided as digit sequences; a leading zero in an MCC 827 or MNC is significant. All other values are decimal integers. 829 831 832 833 4652080936424 834 835 836 4650610736789 837 838 839 841 Long term evolution (LTE) cells are identified by a 28-bit cell 842 identifier (eucid). 844 Figure 7: Example LTE Cellular Measurement 846 848 849 850 46520 851 200065000 852 853 854 46506 855 1638332767 856 857 858 860 Universal mobile telephony service (UMTS) cells are identified by 12- 861 or 16-bit radio network controller (rnc) id and a 16-bit cell id 862 (cid). 864 Figure 8: Example UMTS Cellular Measurement 866 868 869 870 46506 871 1638332767 872 873 874 876 Global System for Mobile communication (GSM) cells are identified by 877 a 16-bit location area code (lac) and 16-bit cell id (cid). 879 Figure 9: Example GSM Cellular Measurement 881 883 884 885 15892472312 886 887 888 15892472313 889 890 891 893 Code division multiple access (CDMA) cells are not identified by 894 PLMN, instead these usea 15-bit system id (sid), a 16-bit network id 895 (nid) and a 16-bit base station id (baseid). 897 Figure 10: Example CDMA Cellular Measurement 899 In general a cellular Device will be attached to the cellular network 900 and so the notion of a serving cell exists. Cellular network also 901 provide overlap between neighbouring sites, so a mobile Device can 902 hear more than one cell. The measurement schema supports sending 903 both the serving cell and any other cells that the mobile might be 904 able to hear. In some cases, the Device may simply be listening to 905 cell information without actually attaching to the network, mobiles 906 without a SIM are an example of this. In this case the Device may 907 simply report cells it can hear without flagging one as a serving 908 cell. An example of this is shown in Figure 11. 910 912 913 914 46520 915 200065000 916 917 918 46506 919 1638332767 920 921 922 924 Figure 11: Example Observed Cellular Measurement 926 5.4.1. Cellular Measurement Requests 928 Two elements can be used in measurement requests for cellular 929 measurements: 931 type: A label indicating the type of identifier to provide: one of 932 "gsm", "umts", "lte", or "cdma". 934 network: The network portion of the cell identifier. For 3GPP 935 networks, this is the combination of MCC and MNC; for CDMA, this 936 is the network identifier. 938 Multiple identifier types or networks can be identified by repeating 939 either element. 941 5.5. GNSS Measurements 943 GNSS use orbiting satellites to transmit signals. A Device with a 944 GNSS receiver is able to take measurements from the satellite 945 signals. The results of these measurements can be used to determine 946 time and the location of the Device. 948 Determining location and time in autonomous GNSS receivers follows 949 three steps: 951 Signal acquisition: During the signal acquisition stage, the 952 receiver searches for the repeating code that is sent by each GNSS 953 satellite. Successful operation typically requires measurement 954 data for a minimum of 5 satellites. At this stage, measurement 955 data is available to the Device. 957 Navigation message decode: Once the signal has been acquired, the 958 receiver then receives information about the configuration of the 959 satellite constellation. This information is broadcast by each 960 satellite and is modulated with the base signal at a low rate; for 961 instance, GPS sends this information at about 50 bits per second. 963 Calculation: The measurement data is combined with the data on the 964 satellite constellation to determine the location of the receiver 965 and the current time. 967 A Device that uses a GNSS receiver is able to report measurements 968 after the first stage of this process. A LIS can use the results of 969 these measurements to determine a location. In the case where there 970 are fewer results available than the optimal minimum, the LIS might 971 be able to use other sources of measurement information and combine 972 these with the available measurement data to determine a position. 974 Note: The use of different sets of GNSS _assistance data_ can 975 reduce the amount of time required for the signal acquisition 976 stage and obviate the need for the receiver to extract data on the 977 satellite constellation. Provision of assistance data is outside 978 the scope of this document. 980 Figure 12 shows an example of GNSS measurement data. The measurement 981 shown is for the GPS system and includes measurement data for three 982 satellites only. 984 986 988 989 499.9395 990 0.87595747 991 45 992 993 994 378.2657 995 0.56639479 996 52 997 998 999 -633.0309 1000 0.57016835 1001 48 1002 1003 1004 1006 Figure 12: Example GNSS Measurement 1008 Each "gnss" element represents a single set of GNSS measurement data, 1009 taken at a single point in time. Measurements taken at different 1010 times can be included in different "gnss" elements to enable 1011 iterative refinement of results. 1013 GNSS measurement parameters are described in more detail in the 1014 following sections. 1016 5.5.1. GNSS System and Signal 1018 The GNSS measurement structure is designed to be generic and to apply 1019 to different GNSS types. Different signals within those systems are 1020 also accounted for and can be measured separately. 1022 The GNSS type determines the time system that is used. An indication 1023 of the type of system and signal can ensure that the LIS is able to 1024 correctly use measurements. 1026 Measurements for multiple GNSS types and signals can be included by 1027 repeating the "gnss" element. 1029 This document creates an IANA registry for GNSS types. Two satellite 1030 systems are registered by this document: GPS [GPS.ICD] and Galileo 1031 [Galileo.ICD]. Details for the registry are included in Section 9.1. 1033 5.5.2. Time 1035 Each set of GNSS measurements is taken at a specific point in time. 1036 The "time" attribute is used to indicate the time that the 1037 measurement was acquired, if the receiver knows how the time system 1038 used by the GNSS relates to UTC time. 1040 Alternative to (or in addition to) the measurement time, the 1041 "gnssTime" element MAY be included. The "gnssTime" element includes 1042 a relative time in milliseconds using the time system native to the 1043 satellite system. For the GPS satellite system, the "gnssTime" 1044 element includes the time of week in milliseconds. For the Galileo 1045 system, the "gnssTime" element includes the time of day in 1046 milliseconds. 1048 The accuracy of the time measurement provided is critical in 1049 determining the accuracy of the location information derived from 1050 GNSS measurements. The receiver SHOULD indicate an estimated time 1051 error for any time that is provided. An RMS error can be included 1052 for the "gnssTime" element, with a value in milliseconds. 1054 5.5.3. Per-Satellite Measurement Data 1056 Multiple satellites are included in each set of GNSS measurements 1057 using the "sat" element. Each satellite is identified by a number in 1058 the "num" attribute. The satellite number is consistent with the 1059 identifier used in the given GNSS. 1061 Both the GPS and Galileo systems use satellite numbers between 1 and 1062 64. 1064 The GNSS receiver measures the following parameters for each 1065 satellite: 1067 doppler: The observed Doppler shift of the satellite signal, 1068 measured in meters per second. This is converted from a value in 1069 Hertz by the receiver to allow the measurement to be used without 1070 knowledge of the carrier frequency of the satellite system. This 1071 value includes an optional RMS error attribute, also measured in 1072 meters per second. 1074 codephase: The observed code phase for the satellite signal, 1075 measured in milliseconds. This is converted the system-specific 1076 value of chips or wavelengths into a system independent value. 1077 Larger values indicate larger distances from satellite to 1078 receiver. This value includes an optional RMS error attribute, 1079 also measured in milliseconds. 1081 cn0: The signal to noise ratio for the satellite signal, measured in 1082 decibel-Hertz (dB-Hz). The expected range is between 20 and 50 1083 dB-Hz. 1085 mp: An estimation of the amount of error that multipath signals 1086 contribute in metres. This parameter is optional. 1088 cq: An indication of the carrier quality. Two attributes are 1089 included: "continuous" may be either "true" or "false"; direct may 1090 be either "direct" or "inverted". This parameter is optional. 1092 adr: The accumulated Doppler range, measured in metres. This 1093 parameter is optional and is not useful unless multiple sets of 1094 GNSS measurements are provided or differential positioning is 1095 being performed. 1097 All values are converted from measures native to the satellite system 1098 to generic measures to ensure consistency of interpretation. Unless 1099 necessary, the schema does not constrain these values. 1101 5.5.4. GNSS Measurement Requests 1103 Measurement requests can include a "gnss" element, which includes the 1104 "system" and "signal" attributes. Multiple elements can be included 1105 to indicate a requests for GNSS measurements from multiple systems or 1106 signals. 1108 5.6. DSL Measurements 1110 Digital Subscriber Line (DSL) networks rely on a range of network 1111 technologies. DSL deployments regularly require cooperation between 1112 multiple organizations. These fall into two broad categories: 1113 infrastructure providers and Internet service providers (ISPs). For 1114 the same end user, an infrastructure and Internet service can be 1115 provided by different entities. Infrastructure providers manage the 1116 bulk of the physical infrastructure including cabling. End users 1117 obtain their service from an ISP, which manages all aspects visible 1118 to the end user including IP address allocation and operation of a 1119 LIS. See [DSL.TR025] and [DSL.TR101] for further information on DSL 1120 network deployments and the parameters that are available. 1122 Exchange of measurement information between these organizations is 1123 necessary for location information to be correctly generated. The 1124 ISP LIS needs to acquire location information from the infrastructure 1125 provider. However, since the infrastructure provider could have no 1126 knowledge of Device identifiers, it can only identify a stream of 1127 data that is sent to the ISP. This is resolved by passing 1128 measurement data relating to the Device to a LIS operated by the 1129 infrastructure provider. 1131 5.6.1. L2TP Measurements 1133 Layer 2 Tunneling Protocol (L2TP) is a common means of linking the 1134 infrastructure provider and the ISP. The infrastructure provider LIS 1135 requires measurement data that identifies a single L2TP tunnel, from 1136 which it can generate location information. Figure 13 shows an 1137 example L2TP measurement. 1139 1141 1142 1143 192.0.2.10 1144 192.0.2.61 1145 528 1146 1147 1148 1150 Figure 13: Example DSL L2TP Measurement 1152 5.6.2. RADIUS Measurements 1154 When authenticating network access, the infrastructure provider might 1155 employ a RADIUS [RFC2865] proxy at the DSL Access Module (DSLAM) or 1156 Access Node (AN). These messages provide the ISP RADIUS server with 1157 an identifier for the DSLAM or AN, plus the slot and port that the 1158 Device is attached on. These data can be provided as a measurement, 1159 which allows the infrastructure provider LIS to generate location 1160 information. 1162 The format of the AN, slot and port identifiers are not defined in 1163 the RADIUS protocol. Slot and port together identify a circuit on 1164 the AN, analogous to the circuit identifier in [RFC3046]. These 1165 items are provided directly, as they were in the RADIUS message. An 1166 example is shown in Figure 14. 1168 1170 1171 AN-7692 1172 3 1173 06 1174 1175 1176 Figure 14: Example DSL RADIUS Measurement 1178 5.6.3. Ethernet VLAN Tag Measurements 1180 For Ethernet-based DSL access networks, the DSL Access Module (DSLAM) 1181 or Access Node (AN) provide two VLAN tags on packets. A C-TAG is 1182 used to identify the incoming residential circuit, while the S-TAG is 1183 used to identify the DSLAM or AN. The C-TAG and S-TAG together can 1184 be used to identify a single point of network attachment. An example 1185 is shown in Figure 15. 1187 1189 1190 613 1191 1097 1192 1193 1195 Figure 15: Example DSL VLAN Tag Measurement 1197 Alternatively, the C-TAG can be replaced by data on the slot and port 1198 that the Device is attached to. This information might be included 1199 in RADIUS requests that are proxied from the infrastructure provider 1200 to the ISP RADIUS server. 1202 5.6.4. ATM Virtual Circuit Measurements 1204 An ATM virtual circuit can be employed between the ISP and 1205 infrastructure provider. Providing the virtual port ID (VPI) and 1206 virtual circuit ID (VCI) for the virtual circuit gives the 1207 infrastructure provider LIS the ability to identify a single data 1208 stream. A sample measurement is shown in Figure 16. 1210 1212 1213 55 1214 6323 1215 1216 1218 Figure 16: Example DSL ATM Measurement 1220 6. Privacy Considerations 1222 Location-related measurement data can be as privacy sensitive as 1223 location information. 1225 Measurement data is effectively equivalent to location information if 1226 the contextual knowledge necessary to generate one from the other is 1227 readily accessible. Even where contextual knowledge is difficult to 1228 acquire, there can be no assurance that an authorized recipient of 1229 the contextual knowledge is also authorized to receive location 1230 information. 1232 In order to protect the privacy of the subject of location-related 1233 measurement data, this implies that measurement data is protected 1234 with the same degree of protection as location information. 1236 6.1. Measurement Data Privacy Model 1238 It is less desirable to distribute measurement data in the same 1239 fashion as location information. Measurement data is less useful to 1240 location recipients than location information. Therefore, a simple 1241 distribution model is desirable. 1243 In this simple model, the Device is the only entity that is able to 1244 distribute measurement data. To use an analogy from the GEOPRIV 1245 architecture, the Device - as the Location Generator (or the 1246 Measurement Data Generator) - is the sole entity that can assume the 1247 roles of Rule Maker and Location Server. 1249 No entity is permitted to redistribute measurement data. The Device 1250 directs other entities in how measurement data is used and retained. 1252 6.2. LIS Privacy Requirements 1254 A LIS MUST NOT reveal location-related measurement data or location 1255 information based on measurement data to any other entity unless 1256 directed to do so by the Device. 1258 By adding measurement data to a request for location information, the 1259 Device implicitly grants permission for the LIS to generate the 1260 requested location information using the measurement data. 1261 Permission to use this data for any other purpose is not implied. 1263 As long as measurement data is only used in serving the request that 1264 contains it, rules regarding data retention are not necessary. A LIS 1265 MUST discard location-related measurement data after servicing a 1266 request, unless the Device grants permission to use that information 1267 for other purposes. 1269 6.3. Measurement Data and Location URIs 1271 A LIS MAY use measurement data provided by the Device to serve 1272 requests to location URIs, if the Device permits it. A Device 1273 permits this by including measurement data in a request that 1274 explcitly requests a location URI. By requesting a location URI, the 1275 Device grants permission for the LIS to use the measurement data in 1276 serving requests to that URI. 1278 Note: In HELD, the "any" type is not an explicit request for a 1279 location URI, though a location URI might be provided. 1281 The usefulness of measurement data that is provided in this fashion 1282 is limited. The measurement data is only valid at the time that it 1283 was acquired by the Device. At the time that a request is made to a 1284 location URI, the Device might have moved, rendering the measurement 1285 data incorrect. 1287 A Device is able to explicitly limit the time that a LIS retains 1288 measurement data by adding an expiry time to the measurement data, 1289 see Section 4.1.2. 1291 6.4. Third-Party-Provided Measurement Data 1293 An authorized third-party request for the location of a Device (see 1294 [I-D.ietf-geopriv-held-identity-extensions]) can include location- 1295 related measurement data. This is possible where the third-party is 1296 able to make observations about the Device. 1298 A third-party that provides measurement data MUST be authorized to 1299 provide the specific measurement for the identified device. A third- 1300 party MUST either be trusted by the LIS for the purposes of providing 1301 measurement data of the provided type, or the measurement data MUST 1302 be validated (see Section 7.2.1) before being used. 1304 How a third-party authenticates its identity or gains authorization 1305 to use measurement data is not covered by this document. 1307 7. Security Considerations 1309 Use of location-related measurement data has privacy considerations 1310 that are discussed in Section 6. 1312 7.1. Threat Model 1314 The threat model for location-related measurement data concentrates 1315 on the Device providing falsified, stolen or incorrect measurement 1316 data. 1318 A Device that provides location location-related measurement data 1319 might use data to: 1321 o acquire the location of another Device, without authorization; 1323 o extract information about network topology; or 1325 o coerce the LIS into providing falsified location information based 1326 on the measurement data. 1328 Location-related measurement data describes the physical environment 1329 or network attachment of a Device. A third party adversary in the 1330 proximity of the Device might be able to alter the physical 1331 environment such that the Device provides measurement data that is 1332 controlled by the third party. This might be used to indirectly 1333 control the location information that is derived from measurement 1334 data. 1336 7.1.1. Acquiring Location Information Without Authorization 1338 Requiring authorization for location requests is an important part of 1339 privacy protections of a location protocol. A location configuration 1340 protocol usually operates under a restricted policy that allows a 1341 requester to obtain their own location. HELD identity extensions 1342 [I-D.ietf-geopriv-held-identity-extensions] allows other entities to 1343 be authorized, conditional on a Rule Maker providing sufficient 1344 authorization. 1346 The intent of these protections is to ensure that a location 1347 recipient is authorized to acquire location information. Location- 1348 related measurement data could be used by an attacker to circumvent 1349 such authorization checks if the association between measurement data 1350 and Target Device is not validated by a LIS. 1352 A LIS can be coerced into providing location information for a Device 1353 that a location recipient is not authorized to receive. A request 1354 identifies one Device (implicitly or explicitly), but measurement 1355 data is provided for another Device. If the LIS does not check that 1356 the measurement data is for the identified Device, it could 1357 incorrectly authorize the request. 1359 By using unvalidated measurement data to generate a response, the LIS 1360 provides information about a Device without appropriate 1361 authorization. 1363 The feasibility of this attack depends on the availability of 1364 information that links a Device with measurement data. In some 1365 cases, measurement data that is correlated with a target is readily 1366 available. For instance, LLDP measurements (Section 5.1) are 1367 broadcast to all nodes on the same network segment. An attacker on 1368 that network segment can easily gain measurement data that relates a 1369 Device with measurements. 1371 For some types of measurement data, it's necessary for an attacker to 1372 know the location of the target in order to determine what 1373 measurements to use. This attack is meaningless for types of 1374 measurement data that require that the attacker first know the 1375 location of the target before measurement data can be acquired or 1376 fabricated. GNSS measurements (Section 5.5) share this trait with 1377 many wireless location determination methods. 1379 7.1.2. Extracting Network Topology Data 1381 Allowing requests with measurements might be used to collect 1382 information about a network topology. This is possible if requests 1383 containing measurements are permitted. 1385 Network topology can be considered sensitive information by a network 1386 operator for commercial or security reasons. While it is impossible 1387 to completely prevent a Device from acquiring some knowledge of 1388 network topology if a location service is provided, a network 1389 operator might desire to limit how much of this information is made 1390 available. 1392 Mapping a network topology does not require that an attacker be able 1393 to associate measurement data with a particular Device. If a 1394 requester is able to try a number of measurements, it is possible to 1395 acquire information about network topology. 1397 It is not even necessary that the measurements are valid; random 1398 guesses are sufficient, provided that there is no penalty or cost 1399 associated with attempting to use the measurements. 1401 7.1.3. Lying By Proxy 1403 Location information is a function of its inputs, which includes 1404 measurement data. Thus, falsified measurement data can be used to 1405 alter the location information that is provided by a LIS. 1407 Some types of measurement data are relatively easy to falsify in a 1408 way that the resulting location information to be selected with 1409 little or no error. For instance, GNSS measurements are easy to use 1410 for this purpose because all the contextual information necessary to 1411 calculate a position using measurements is broadcast by the 1412 satellites [HARPER]. 1414 An attacker that falsifies measurement data gains little if they are 1415 the only recipients of the result. The attacker knows that the 1416 location information is bad. The attacker only gains if the 1417 information can somehow be attributed to the LIS by another location 1418 recipient. 1420 A recipient might evaluate the trustworthiness of the location 1421 information based on the credibility of its source. By coercing the 1422 LIS into providing falsified location information, any credibility 1423 that the LIS might have - that the attacker does not - is gained by 1424 the attacker. 1426 A third-party that is reliant on the integrity of the location 1427 information might base an evaluation of the credibility of the 1428 information on the source of the information. If that third party is 1429 able to attribute location information to the LIS, then an attacker 1430 might gain. 1432 Location information that is provided to the Device without any means 1433 to identify the LIS as its source is not subject to this attack. The 1434 Device is identified as the source of the data when it distributes 1435 the location information to location recipients. 1437 An attacker gains if they are able to coerce the LIS into providing 1438 location information based on falsified measurement data and that 1439 information can be attributed to the LIS. 1441 Location information is attributed to the LIS either through the use 1442 of digital signatures or by having the location recipient directly 1443 interact with the LIS. A LIS that digitally signs location 1444 information becomes identifiable as the source of the data. 1445 Similarly, the LIS is identified as a source of data if a location 1446 recipient acquires information directly from a LIS using a location 1447 URI. 1449 7.1.4. Measurement Replay 1451 The value of some measured properties do not change over time for a 1452 single location. This allows for simple replay attacks, where an 1453 attacker acquires measurements that can later be used without being 1454 detected as being invalid. 1456 Measurement data is frequently an observation of an time-invariant 1457 property of the environment at the subject location. For 1458 measurements of this nature, nothing in the measurement itself is 1459 sufficient proof that the Device is present at the resulting 1460 location. Measurement data might have been previously acquired and 1461 reused. 1463 For instance, the identity of a radio transmitter, if broadcast by 1464 that transmitter, can be collected and stored. An attacker that 1465 wishes it known that they exist at a particular location, can claim 1466 to observe this transmitter at any time. Nothing inherent in the 1467 claim reveals it to be false. 1469 For properties of a network, time-invariance is often directly as a 1470 result of the practicalities of operating the network. Limiting the 1471 changes to a network ensures greater consistency of service. A 1472 largely static network also greatly simplifies the data management 1473 tasks involved with providing a location service. 1475 7.1.5. Environment Spoofing 1477 Some types of measurement data can be altered or influenced by a 1478 third party so that a Device. If it is possible for a third party to 1479 alter the measured phenomenon, then any location information that is 1480 derived from this data can be indirectly influenced. 1482 Altering the environment in this fashion might not require 1483 involvement with either Device or LIS. Measurement that is passive - 1484 where the Device observes a signal or other phenomenon without direct 1485 interaction - are most susceptible to alteration by third parties. 1487 Measurement of radio signal characteristics is especially vulnerable 1488 since an adversary need only be in the general vicinity of the Device 1489 and be able to transmit a signal. For instance, a GNSS spoofer is 1490 able to produce fake signals that claim to be transmitted by any 1491 satellite or set of satellites (see [GPS.SPOOF]). 1493 Measurements that require direct interaction increases the complexity 1494 of the attack. For measurements relating to the communication 1495 medium, a third party cannot avoid direct interaction, they need only 1496 be on the comminications path (that is, man in the middle). 1498 Even if the entity that is interacted with is authenticated, this 1499 does not provide any assurance about the integrity of measurement 1500 data. For instance, the Device might authenticate the identity of a 1501 radio transmitter through the use of cryptographic means and obtain 1502 signal strength measurements for that transmitter. Radio signal 1503 strength is trivial for an attacker to increase simply by receiving 1504 and amplifying the raw signal; it is not necessary for the attacker 1505 to be able to understand the signal content. 1507 Note: This particular "attack" is more often completely legitimate. 1508 Radio repeaters are commonplace mechanism used to increase radio 1509 coverage. 1511 Attacks that rely on altering the observed environment of a Device 1512 require countermeasures that affect the measurement process. For 1513 radio signals, countermeasures could include the use of authenticated 1514 signals, altered receiver design. In general, countermeasures are 1515 highly specific to the individual measurement process. An exhaustive 1516 discussion of these issues is left to the relevant literature for 1517 each measurement technology. 1519 A Device that provides measurement data is assumed to be responsible 1520 for applying appropriate countermeasures against this type of attack. 1522 For a Device that is the ultimate recipient of location information 1523 derived from measurement data, a LIS might choose to provide location 1524 information without any validation. The responsibility for ensuring 1525 the veracity of the measurement data lies with the Device. 1527 Measurement data that is susceptible to this sort of influence MUST 1528 be treated as though it were produced by an untrusted Device for 1529 those cases where a location recipient might attribute the location 1530 information to the LIS. Such measurement data MUST be subjected to 1531 the same validation as for other types of attacks that rely on 1532 measurement falsification. 1534 Note: Altered measurement data might be provided by a Device that 1535 has no knowledge of the alteration. Thus, an otherwise trusted 1536 Device might still be an unreliable source of measurement data. 1538 7.2. Mitigation 1540 The following measures can be applied to limit or prevent attacks. 1541 The effectiveness of each depends on the type of measurement data and 1542 how that measurement data is acquired. 1544 Two general approaches are identified for dealing with untrusted 1545 measurement data: 1547 1. Require independent validation of measurement data or the 1548 location information that is produced. 1550 2. Identify the types of sources that provided the measurement data 1551 that location information was derived from. 1553 This section goes into more detail on the different forms of 1554 validation in Section 7.2.1, Section 7.2.2, and Section 7.2.3. The 1555 impact of attributing location information to sources is discussed in 1556 more detail in Section 7.2.4. 1558 7.2.1. Measurement Validation 1560 Detecting that measurement data has been falsified is difficult in 1561 the absence of integrity mechanisms. 1563 Independent confirmation of the veracity of measurement data ensures 1564 that the measurement is accurate and that it applies to the correct 1565 Device. By gathering the same measurement data from a trusted and 1566 independent source, the LIS is able to check that the measurement 1567 data is correct. 1569 Measurement information might contain no inherent indication that it 1570 is falsified. On the contrary, it can be difficult to obtain 1571 information that would provide any degree of assurance that the 1572 measurement device is physically at any particular location. 1573 Measurements that are difficult to verify require other forms of 1574 assurance before they can be used. 1576 7.2.1.1. Effectiveness 1578 Measurement validation MUST be used if measurement data for a 1579 particular Device can be easily acquired by unauthorized location 1580 recipients, as described in Section 7.1.1. This prevents 1581 unauthorized access to location information using measurement data. 1583 Validation of measurement data can be significantly more effective 1584 than independent acquisition of the same. For instance, a Device in 1585 a large Ethernet network could provide a measurement indicating its 1586 point of attachment using LLDP measurements. For a LIS, acquiring 1587 the same measurement data might require a request to all switches in 1588 that network. With the measurement data, validation can target the 1589 identified switch with a specific query. 1591 Validation is effective in identifying falsified measurement data 1592 (Section 7.1.3), including attacks involving replay of measurement 1593 data (Section 7.1.4). Validation also limits the amount of network 1594 topology information (Section 7.1.2) made available to Devices to 1595 that portion of the network topology that they are directly attached. 1597 Measurement validation has no effect if the underlying effect is 1598 being spoofed (Section 7.1.5). 1600 7.2.1.2. Limitations (Unique Observer) 1602 A Device is often in a unique position to make a measurement. It 1603 alone occupies the point in space-time that the location 1604 determination process seeks to determine. The Device becomes a 1605 unique observer for a particular property. 1607 The ability of the Device to become a unique observer makes the 1608 Device invaluable to the location determination process. As a unique 1609 observer, it also makes the claims of a Device difficult to validate 1610 and easily to spoof. 1612 As long as no other entity is capable of making the same 1613 measurements, there is also no other entity that can independently 1614 check that the measurements are correct and applicable to the Device. 1615 A LIS might be unable to validate all or part of the measurement data 1616 it receives from a unique observer. For instance, a signal strength 1617 measurement of the signal from a radio tower cannot be validated 1618 directly. 1620 Some portion of the measurement data might still be independently 1621 verified, even if all information cannot. In the previous example, 1622 the radio tower might be able to provide verification that the Device 1623 is present if it is able to observe a radio signal sent by the 1624 Device. 1626 If measurement data can only be partially validated, the extent to 1627 which it can be validated determines the effectiveness of validation 1628 against these attacks. 1630 The advantage of having the Device as a unique observer is that it 1631 makes it difficult for an attacker to acquire measurements without 1632 the assistance of the Device. Attempts to use measurements to gain 1633 unauthorized access to measurement data (Section 7.1.1) are largely 1634 ineffectual against a unique observer. 1636 7.2.2. Location Validation 1638 Location information that is derived from location-related 1639 measurement data can also be verified against trusted location 1640 information. Rather than validating inputs to the location 1641 determination process, suspect locations are identified at the output 1642 of the process. 1644 Trusted location information is acquired using sources of measurement 1645 data that are trusted. Untrusted location information is acquired 1646 using measurement data provided from untrusted sources, which might 1647 include the Device. These two locations are compared. If the 1648 untrusted location agrees with the trusted location, the untrusted 1649 location information is used. 1651 Algorithms for the comparison of location information are not 1652 included in this document. However, a simple comparison for 1653 agreement might require that the untrusted location be entirely 1654 contained within the uncertainty region of the trusted location. 1656 There is little point in using a less accurate, less trusted 1657 location. Untrusted location information that has worse accuracy 1658 than trusted information can be immediately discarded. There are 1659 multiple factors that affect accuracy, uncertainty and currency being 1660 the most important. How location information is compared for 1661 accuracy is not defined in this document. 1663 7.2.2.1. Effectiveness 1665 Location validation limits the extent to which falsified - or 1666 erroneous - measurement data can cause an incorrect location to be 1667 reported. 1669 Location validation can be more efficient than validation of inputs, 1670 particularly for a unique observer (Section 7.2.1.2). 1672 Validating location ensures that the Device is at or near the 1673 resulting location. Location validation can be used to limit or 1674 prevent all of the attacks identified in this document. 1676 7.2.2.2. Limitations 1678 The trusted location that is used for validation is always less 1679 accurate than the location that is being checked. The amount by 1680 which the untrusted location is more accurate, is the same amount 1681 that an attacker can exploit. 1683 For example, a trusted location might indicate a five kilometer 1684 radius uncertainty region. An untrusted location that describes a 1685 100 meter uncertainty within the larger region might be accepted as 1686 more accurate. An attacker might still falsify measurement data to 1687 select any location within the larger uncertainty region. While the 1688 100 meter uncertainty that is reported seems more accurate, a 1689 falsified location could be anywhere in the five kilometer region. 1691 Where measurement data might have been falsified, the actual 1692 uncertainty is effectively much higher. Local policy might allow 1693 differing degrees of trust to location information derived from 1694 untrusted measurement data. This might not be a boolean operation 1695 with only two possible outcomes: untrusted location information might 1696 be used entirely or not at all, or it could be combined with trusted 1697 location information with the degree to which each contributes based 1698 on a value set in local policy. 1700 7.2.3. Supporting Observations 1702 Replay attacks using previously acquired measurement data are 1703 particularly hard to detect without independent validation. Rather 1704 than validate the measurement data directly, supplementary data might 1705 be used to validate measurements or the location information derived 1706 from those measurements. 1708 These supporting observations could be used to convey information 1709 that provides additional assurance that the Device was acquired at a 1710 specific time and place. In effect, the Device is requested to 1711 provide proof of its presence at the resulting location. 1713 For instance, a Device that measures attributes of a radio signal 1714 could also be asked to provide a sample of the measured radio signal. 1715 If the LIS is able to observe the same signal, the two observations 1716 could be compared. Providing that the signal cannot be predicted in 1717 advance by the Device, this could be used to support the claim that 1718 the Device is able to receive the signal. Thus, the Device is likely 1719 to be within the range that the signal is transmitted. A LIS could 1720 use this to attribute a higher level of trust in the associated 1721 measurement data or resulting location. 1723 7.2.3.1. Effectiveness 1725 The use of supporting observations is limited by the ability of the 1726 LIS to acquire and validate these observations. The advantage of 1727 selecting observations independent of measurement data is that 1728 observations can be selected based on how readily available the data 1729 is for both LIS and Device. The amount and quality of the data can 1730 be selected based on the degree of assurance that is desired. 1732 Use of supporting observations is similar to both measurement 1733 validation and location validation. All three methods rely on 1734 independent validation of one or more properties. Applicability of 1735 each method is similar. 1737 Use of supporting observations can be used to limit or prevent all of 1738 the attacks identified in this document. 1740 7.2.3.2. Limitations 1742 The effectiveness of the validation method depends on the quality of 1743 the supporting observation: how hard it is to obtain at a different 1744 time or place, how difficult it is to guess and what other costs 1745 might be involved in acquiring this data. 1747 In the example of an observed radio signal, requesting a sample of 1748 the signal only provides an assurance that the Device is able to 1749 receive the signal transmitted by the measured radio transmitter. 1750 This only provides some assurance that the Device is within range of 1751 the transmitter. 1753 As with location validation, a Device might still be able to provide 1754 falsified measurements that could alter the value of the location 1755 information as long as the result is within this region. 1757 Requesting additional supporting observations can reduce the size of 1758 the region over which location information can be altered by an 1759 attacker, or increase trust in the result, but each additional has a 1760 cost. Supporting observations contribute little or nothing toward 1761 the primary goal of determining the location of the Device. Any 1762 costs in acquiring supporting observations are balanced against the 1763 degree of integrity desired of the resulting location information. 1765 7.2.4. Attribution 1767 Lying by proxy (Section 7.1.3) relies on the location recipient being 1768 able to attribute location information to a LIS. The effectiveness 1769 of this attack is negated if location information is explicitly 1770 attributed to a particular source. 1772 This requires an extension to the location object that explicitly 1773 identifies the source (or sources) of each item of location 1774 information. 1776 Rather than relying on a process that seeks to ensure that location 1777 information is accurate, this approach instead provides a location 1778 recipient with the information necessary to reach their own 1779 conclusion about the trustworthiness of the location information. 1781 Including an authenticated identity for all sources of measurement 1782 data is presents a number of technical and operational challenges. 1783 It is possible that the LIS has a transient relationship with a 1784 Device. A Device is not expected to share authentication information 1785 with a LIS. There is no assurance that Device identification is 1786 usable by a potential location recipient. Privacy concerns might 1787 also prevent the sharing identification information, even if it were 1788 available and usable. 1790 Identifying the type of measurement source allows a location 1791 recipient to make a decision about the trustworthiness of location 1792 information without depending on having authenticated identity 1793 information for each source. An element for this purpose is defined 1794 in Section 4.4. 1796 When including location information that is based on measurement data 1797 from sources that might be untrusted, a LIS SHOULD include 1798 alternative location information that is derived from trusted sources 1799 of measurement data. Each item of location information can then be 1800 labelled with the source of that data. 1802 A location recipient that is able to identify a specific source of 1803 measurement data (whether it be LIS or Device) can use this 1804 information to attribute location information to either or both 1805 entity. The location recipient is then better able to make decisions 1806 about trustworthiness based on the source of the data. 1808 A location recipient that does not understand the "source" element is 1809 unable to make this distinction. When constructing a PIDF-LO 1810 document, trusted location information MUST be placed in the PIDF-LO 1811 so that it is given higher priority to any untrusted location 1812 information according to Rule #8 of [RFC5491]. 1814 Attribution of information does nothing to address attacks that alter 1815 the observed parameters that are used in location determination 1816 (Section 7.1.5). 1818 7.2.5. Stateful Correlation of Location Requests 1820 Stateful examination of requests can be used to prevent a Device from 1821 attempting to map network topology using requests for location 1822 information (Section 7.1.2). 1824 Simply limiting the rate of requests from a single Device reduces the 1825 amount of data that a Device can acquire about network topology. 1827 8. Measurement Schemas 1829 The schema are broken up into their respective functions. There is a 1830 base container schema into which all measurements are placed, plus 1831 definitions for a measurement request (Section 8.1). A PIDF-LO 1832 extension is defined in a separate schema (Section 8.2). There is a 1833 basic types schema, that contains various base type definitions for 1834 things such as the "rmsError" and "samples" attributes IPv4, IPv6 and 1835 MAC addresses (Section 8.3). Then each of the specific measurement 1836 types is defined in its own schema. 1838 8.1. Measurement Container Schema 1839 1840 1848 1849 1851 1852 1853 1855 This schema defines a framework for location measurements. 1856 1857 1859 1861 1862 1863 1864 1865 1866 1868 1869 1870 1871 1872 1873 1874 1875 1876 1878 1880 1881 1882 1883 1884 1886 1888 1889 1890 1891 1893 1894 1895 1896 1897 1898 1900 1901 1902 1903 1904 1905 1907 1908 1909 1910 1911 1912 1913 1914 1915 1916 1917 1918 1919 1920 1922 Measurement Container Schema 1924 8.2. Measurement Source Schema 1926 1927 1934 1935 1937 1938 1939 1941 This schema defines an extension to PIDF-LO that indicates the 1942 type of source that produced the measurement data used in 1943 generating the associated location information. 1944 1945 1947 1948 1949 1950 1951 1952 1953 1954 1955 1956 1957 1958 1959 1961 Measurement Source PIDF-LO Extension Schema 1963 8.3. Base Type Schema 1965 Note that the pattern rules in the following schema wrap due to 1966 length constraints. None of the patterns contain whitespace. 1968 1969 1976 1977 1979 1980 1981 1983 This schema defines a set of base type elements. 1984 1985 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2027 2028 2029 2031 2032 2033 2034 2035 An IP version 6 address, based on RFC 4291. 2036 2037 2038 2039 2040 2041 2042 2043 2044 2046 2048 2050 2052 2054 2056 2057 2058 2059 2067 2068 2069 2070 2072 2073 2074 2075 2079 2080 2082 2083 2084 2085 2087 2088 2090 2092 Base Type Schema 2094 8.4. LLDP Measurement Schema 2096 2097 2105 2106 2108 2109 2110 2112 This schema defines a set of LLDP location measurements. 2113 2114 2115 2117 2118 2119 2120 2121 2122 2123 2124 2126 2127 2128 2129 2130 2132 2133 2134 2135 2137 2138 2139 2141 2142 2143 2144 2145 2146 2148 2150 LLDP measurement schema 2152 8.5. DHCP Measurement Schema 2154 2155 2163 2164 2166 2167 2168 2170 This schema defines a set of DHCP location measurements. 2171 2172 2174 2176 2177 2178 2179 2180 2181 2182 2183 2185 2187 2189 2191 2192 2193 2194 2195 2197 2198 2199 2200 2202 2203 2204 2206 2208 DHCP measurement schema 2210 8.6. WiFi Measurement Schema 2211 2212 2221 2222 2224 802.11 location measurements 2225 2226 2227 2229 This schema defines a basic set of 802.11 location measurements. 2230 2231 2233 2234 2236 2238 2239 2240 2241 2242 2244 2246 2247 2248 2249 2250 2252 2253 2254 2255 2256 2257 2260 2262 2264 2266 2268 2270 2272 2274 2276 2278 2279 2281 2282 2283 2284 2286 2287 2288 2289 2291 2292 2293 2295 2297 2298 2299 2300 2301 2303 2304 2305 2306 2307 2308 2309 2310 2311 2312 2313 2314 2315 2316 2317 2318 2319 2320 2322 2323 2324 2325 2326 2328 2329 2330 2331 2332 2334 2335 2337 2339 2341 2342 2343 2344 2346 2347 2348 2349 2350 2351 2352 2354 2355 2356 2358 2359 2360 2361 2362 2363 2364 2365 2366 2367 2368 2369 2370 2371 2373 2375 WiFi measurement schema 2377 8.7. Cellular Measurement Schema 2379 2380 2387 2388 2390 2391 2392 2394 This schema defines a set of cellular location measurements. 2395 2396 2398 2400 2401 2402 2403 2404 2405 2406 2407 2408 2410 2411 2412 2413 2414 2416 2417 2418 2419 2420 2421 2422 2423 2424 2425 2426 2427 2428 2429 2430 2431 2432 2433 2435 2436 2437 2438 2439 2440 2442 2443 2445 2446 2447 2448 2450 2451 2452 2453 2454 2456 2457 2458 2459 2460 2462 2463 2464 2465 2466 2468 2470 2471 2472 2473 2474 2475 2476 2477 2478 2480 2481 2482 2483 2484 2485 2486 2487 2488 2489 2490 2491 2492 2493 2495 2497 Cellular measurement schema 2499 8.8. GNSS Measurement Schema 2500 2501 2509 2510 2512 2513 2514 2516 This schema defines a set of GNSS location measurements 2517 2518 2520 2522 2523 2524 2525 2526 2527 2528 2530 2531 2532 2533 2534 2536 2538 2540 2541 2542 2543 2544 2545 2546 2547 2548 2549 2550 2551 2552 2554 2555 2557 2559 2560 2561 2563 2564 2565 2567 2568 2569 2570 2572 2573 2574 2575 2576 2577 2578 2579 2580 2581 2582 2583 2585 GNSS measurement Schema 2587 8.9. DSL Measurement Schema 2589 2590 2598 2599 2601 DSL measurement definitions 2602 2603 2604 2606 This schema defines a basic set of DSL location measurements. 2607 2608 2610 2612 2613 2614 2615 2616 2617 2618 2619 2620 2621 2622 2623 2624 2626 2627 2628 2629 2630 2631 2632 2633 2634 2635 2636 2637 2638 2639 2640 2641 2642 2644 2645 2646 2647 2648 2649 2650 2652 2653 2654 2655 2656 2657 2658 2659 2660 2661 2662 2663 2664 2665 2666 2667 2669 2671 DSL measurement schema 2673 9. IANA Considerations 2675 This section creates a registry for GNSS types (Section 5.5) and 2676 registers the namespaces and schema defined in Section 8. 2678 9.1. IANA Registry for GNSS Types 2680 This document establishes a new IANA registry for Global Navigation 2681 Satellite System (GNSS) types. The registry includes tokens for the 2682 GNSS type and for each of the signals within that type. Referring to 2683 [RFC5226], this registry operates under "Specification Required" 2684 rules. The IESG will appoint an Expert Reviewer who will advise IANA 2685 promptly on each request for a new or updated GNSS type. 2687 Each entry in the registry requires the following information: 2689 GNSS name: the name and a brief description of the GNSS 2691 Brief description: the name and a brief description of the GNSS 2693 GNSS token: a token that can be used to identify the GNSS 2695 Signals: a set of tokens that represent each of the signals that the 2696 system provides 2698 Documentation reference: a reference to one or more stable, public 2699 specifications that outline usage of the GNSS, including (but not 2700 limited to) signal specifications and time systems 2702 The registry initially includes two registrations: 2704 GNSS name: Global Positioning System (GPS) 2706 Brief description: a system of satellites that use spread-spectrum 2707 transmission, operated by the US military for commercial and 2708 military applications 2710 GNSS token: gps 2712 Signals: L1, L2, L1C, L2C, L5 2714 Documentation reference: Navstar GPS Space Segment/Navigation User 2715 Interface [GPS.ICD] 2717 GNSS name: Galileo 2719 Brief description: a system of satellites that operate in the same 2720 spectrum as GPS, operated by the European Union for commercial 2721 applications 2723 GNSS Token: galileo 2725 Signals: L1, E5A, E5B, E5A+B, E6 2727 Documentation Reference: Galileo Open Service Signal In Space 2728 Interface Control Document (SIS ICD) [Galileo.ICD] 2730 9.2. URN Sub-Namespace Registration for 2731 urn:ietf:params:xml:ns:pidf:geopriv10:lmsrc 2733 This section registers a new XML namespace, 2734 "urn:ietf:params:xml:ns:pidf:geopriv10:lmsrc", as per the guidelines 2735 in [RFC3688]. 2737 URI: urn:ietf:params:xml:ns:pidf:geopriv10:lmsrc 2739 Registrant Contact: IETF, GEOPRIV working group, 2740 (geopriv@ietf.org), Martin Thomson (martin.thomson@commscope.com). 2742 XML: 2744 BEGIN 2745 2746 2748 2749 2750 Measurement Source for PIDF-LO 2751 2752 2753

Namespace for Location Measurement Source

2754

urn:ietf:params:xml:ns:pidf:geopriv10:lmsrc

2755 [[NOTE TO IANA/RFC-EDITOR: Please update RFC URL and replace XXXX 2756 with the RFC number for this specification.]] 2757

See RFCXXXX.

2758 2759 2760 END 2762 9.3. URN Sub-Namespace Registration for 2763 urn:ietf:params:xml:ns:geopriv:lm 2765 This section registers a new XML namespace, 2766 "urn:ietf:params:xml:ns:geopriv:lm", as per the guidelines in 2767 [RFC3688]. 2769 URI: urn:ietf:params:xml:ns:geopriv:lm 2771 Registrant Contact: IETF, GEOPRIV working group, 2772 (geopriv@ietf.org), Martin Thomson (martin.thomson@commscope.com). 2774 XML: 2776 BEGIN 2777 2778 2780 2781 2782 Measurement Container 2783 2784 2785

Namespace for Location Measurement Container

2786

urn:ietf:params:xml:ns:geopriv:lm

2787 [[NOTE TO IANA/RFC-EDITOR: Please update RFC URL and replace XXXX 2788 with the RFC number for this specification.]] 2789

See RFCXXXX.

2790 2791 2792 END 2794 9.4. URN Sub-Namespace Registration for 2795 urn:ietf:params:xml:ns:geopriv:lm:basetypes 2797 This section registers a new XML namespace, 2798 "urn:ietf:params:xml:ns:geopriv:lm:basetypes", as per the guidelines 2799 in [RFC3688]. 2801 URI: urn:ietf:params:xml:ns:geopriv:lm:basetypes 2803 Registrant Contact: IETF, GEOPRIV working group, 2804 (geopriv@ietf.org), Martin Thomson (martin.thomson@commscope.com). 2806 XML: 2808 BEGIN 2809 2810 2812 2813 2814 Base Device Types 2815 2816 2817

Namespace for Base Types

2818

urn:ietf:params:xml:ns:geopriv:lm:basetypes

2819 [[NOTE TO IANA/RFC-EDITOR: Please update RFC URL and replace XXXX 2820 with the RFC number for this specification.]] 2821

See RFCXXXX.

2822 2823 2825 END 2827 9.5. URN Sub-Namespace Registration for 2828 urn:ietf:params:xml:ns:geopriv:lm:lldp 2830 This section registers a new XML namespace, 2831 "urn:ietf:params:xml:ns:geopriv:lm:lldp", as per the guidelines in 2832 [RFC3688]. 2834 URI: urn:ietf:params:xml:ns:geopriv:lm:lldp 2836 Registrant Contact: IETF, GEOPRIV working group, 2837 (geopriv@ietf.org), Martin Thomson (martin.thomson@commscope.com). 2839 XML: 2841 BEGIN 2842 2843 2845 2846 2847 LLDP Measurement Set 2848 2849 2850

Namespace for LLDP Measurement Set

2851

urn:ietf:params:xml:ns:geopriv:lm:lldp

2852 [[NOTE TO IANA/RFC-EDITOR: Please update RFC URL and replace XXXX 2853 with the RFC number for this specification.]] 2854

See RFCXXXX.

2855 2856 2857 END 2859 9.6. URN Sub-Namespace Registration for 2860 urn:ietf:params:xml:ns:geopriv:lm:dhcp 2862 This section registers a new XML namespace, 2863 "urn:ietf:params:xml:ns:geopriv:lm:dhcp", as per the guidelines in 2864 [RFC3688]. 2866 URI: urn:ietf:params:xml:ns:geopriv:lm:dhcp 2868 Registrant Contact: IETF, GEOPRIV working group, 2869 (geopriv@ietf.org), Martin Thomson (martin.thomson@commscope.com). 2871 XML: 2873 BEGIN 2874 2875 2877 2878 2879 DHCP Measurement Set 2880 2881 2882

Namespace for DHCP Measurement Set

2883

urn:ietf:params:xml:ns:geopriv:lm:dhcp

2884 [[NOTE TO IANA/RFC-EDITOR: Please update RFC URL and replace XXXX 2885 with the RFC number for this specification.]] 2886

See RFCXXXX.

2887 2888 2889 END 2891 9.7. URN Sub-Namespace Registration for 2892 urn:ietf:params:xml:ns:geopriv:lm:wifi 2894 This section registers a new XML namespace, 2895 "urn:ietf:params:xml:ns:geopriv:lm:wifi", as per the guidelines in 2896 [RFC3688]. 2898 URI: urn:ietf:params:xml:ns:geopriv:lm:wifi 2900 Registrant Contact: IETF, GEOPRIV working group, 2901 (geopriv@ietf.org), Martin Thomson (martin.thomson@commscope.com). 2903 XML: 2905 BEGIN 2906 2907 2909 2910 2911 WiFi Measurement Set 2912 2913 2914

Namespace for WiFi Measurement Set

2915

urn:ietf:params:xml:ns:geopriv:lm:wifi

2916 [[NOTE TO IANA/RFC-EDITOR: Please update RFC URL and replace XXXX 2917 with the RFC number for this specification.]] 2918

See RFCXXXX.

2919 2920 2922 END 2924 9.8. URN Sub-Namespace Registration for 2925 urn:ietf:params:xml:ns:geopriv:lm:cell 2927 This section registers a new XML namespace, 2928 "urn:ietf:params:xml:ns:geopriv:lm:cell", as per the guidelines in 2929 [RFC3688]. 2931 URI: urn:ietf:params:xml:ns:geopriv:lm:cell 2933 Registrant Contact: IETF, GEOPRIV working group, 2934 (geopriv@ietf.org), Martin Thomson (martin.thomson@commscope.com). 2936 XML: 2938 BEGIN 2939 2940 2942 2943 2944 Cellular Measurement Set 2945 2946 2947

Namespace for Cellular Measurement Set

2948

urn:ietf:params:xml:ns:geopriv:lm:cell

2949 [[NOTE TO IANA/RFC-EDITOR: Please update RFC URL and replace XXXX 2950 with the RFC number for this specification.]] 2951

See RFCXXXX.

2952 2953 2954 END 2956 9.9. URN Sub-Namespace Registration for 2957 urn:ietf:params:xml:ns:geopriv:lm:gnss 2959 This section registers a new XML namespace, 2960 "urn:ietf:params:xml:ns:geopriv:lm:gnss", as per the guidelines in 2961 [RFC3688]. 2963 URI: urn:ietf:params:xml:ns:geopriv:lm:gnss 2965 Registrant Contact: IETF, GEOPRIV working group, 2966 (geopriv@ietf.org), Martin Thomson (martin.thomson@commscope.com). 2968 XML: 2970 BEGIN 2971 2972 2974 2975 2976 GNSS Measurement Set 2977 2978 2979

Namespace for GNSS Measurement Set

2980

urn:ietf:params:xml:ns:geopriv:lm:gnss

2981 [[NOTE TO IANA/RFC-EDITOR: Please update RFC URL and replace XXXX 2982 with the RFC number for this specification.]] 2983

See RFCXXXX.

2984 2985 2986 END 2988 9.10. URN Sub-Namespace Registration for 2989 urn:ietf:params:xml:ns:geopriv:lm:dsl 2991 This section registers a new XML namespace, 2992 "urn:ietf:params:xml:ns:geopriv:lm:dsl", as per the guidelines in 2993 [RFC3688]. 2995 URI: urn:ietf:params:xml:ns:geopriv:lm:dsl 2997 Registrant Contact: IETF, GEOPRIV working group, 2998 (geopriv@ietf.org), Martin Thomson (martin.thomson@commscope.com). 3000 XML: 3002 BEGIN 3003 3004 3006 3007 3008 DSL Measurement Set 3009 3010 3011

Namespace for DSL Measurement Set

3012

urn:ietf:params:xml:ns:geopriv:lm:dsl

3013 [[NOTE TO IANA/RFC-EDITOR: Please update RFC URL and replace XXXX 3014 with the RFC number for this specification.]] 3015

See RFCXXXX.

3016 3017 3019 END 3021 9.11. XML Schema Registration for Measurement Source Schema 3023 This section registers an XML schema as per the guidelines in 3024 [RFC3688]. 3026 URI: urn:ietf:params:xml:schema:pidf:geopriv10:lmsrc 3028 Registrant Contact: IETF, GEOPRIV working group, (geopriv@ietf.org), 3029 Martin Thomson (martin.thomson@commscope.com). 3031 Schema: The XML for this schema can be found in Section 8.2 of this 3032 document. 3034 9.12. XML Schema Registration for Measurement Container Schema 3036 This section registers an XML schema as per the guidelines in 3037 [RFC3688]. 3039 URI: urn:ietf:params:xml:schema:lm 3041 Registrant Contact: IETF, GEOPRIV working group, (geopriv@ietf.org), 3042 Martin Thomson (martin.thomson@commscope.com). 3044 Schema: The XML for this schema can be found in Section 8.1 of this 3045 document. 3047 9.13. XML Schema Registration for Base Types Schema 3049 This section registers an XML schema as per the guidelines in 3050 [RFC3688]. 3052 URI: urn:ietf:params:xml:schema:lm:basetypes 3054 Registrant Contact: IETF, GEOPRIV working group, (geopriv@ietf.org), 3055 Martin Thomson (martin.thomson@commscope.com). 3057 Schema: The XML for this schema can be found in Section 8.3 of this 3058 document. 3060 9.14. XML Schema Registration for LLDP Schema 3062 This section registers an XML schema as per the guidelines in 3063 [RFC3688]. 3065 URI: urn:ietf:params:xml:schema:lm:lldp 3067 Registrant Contact: IETF, GEOPRIV working group, (geopriv@ietf.org), 3068 Martin Thomson (martin.thomson@commscope.com). 3070 Schema: The XML for this schema can be found in Section 8.4 of this 3071 document. 3073 9.15. XML Schema Registration for DHCP Schema 3075 This section registers an XML schema as per the guidelines in 3076 [RFC3688]. 3078 URI: urn:ietf:params:xml:schema:lm:dhcp 3080 Registrant Contact: IETF, GEOPRIV working group, (geopriv@ietf.org), 3081 Martin Thomson (martin.thomson@commscope.com). 3083 Schema: The XML for this schema can be found in Section 8.5 of this 3084 document. 3086 9.16. XML Schema Registration for WiFi Schema 3088 This section registers an XML schema as per the guidelines in 3089 [RFC3688]. 3091 URI: urn:ietf:params:xml:schema:lm:wifi 3093 Registrant Contact: IETF, GEOPRIV working group, (geopriv@ietf.org), 3094 Martin Thomson (martin.thomson@commscope.com). 3096 Schema: The XML for this schema can be found in Section 8.6 of this 3097 document. 3099 9.17. XML Schema Registration for Cellular Schema 3101 This section registers an XML schema as per the guidelines in 3102 [RFC3688]. 3104 URI: urn:ietf:params:xml:schema:lm:cellular 3106 Registrant Contact: IETF, GEOPRIV working group, (geopriv@ietf.org), 3107 Martin Thomson (martin.thomson@commscope.com). 3109 Schema: The XML for this schema can be found in Section 8.7 of this 3110 document. 3112 9.18. XML Schema Registration for GNSS Schema 3114 This section registers an XML schema as per the guidelines in 3115 [RFC3688]. 3117 URI: urn:ietf:params:xml:schema:lm:gnss 3119 Registrant Contact: IETF, GEOPRIV working group, (geopriv@ietf.org), 3120 Martin Thomson (martin.thomson@commscope.com). 3122 Schema: The XML for this schema can be found in Section 8.8 of this 3123 document. 3125 9.19. XML Schema Registration for DSL Schema 3127 This section registers an XML schema as per the guidelines in 3128 [RFC3688]. 3130 URI: urn:ietf:params:xml:schema:lm:dsl 3132 Registrant Contact: IETF, GEOPRIV working group, (geopriv@ietf.org), 3133 Martin Thomson (martin.thomson@commscope.com). 3135 Schema: The XML for this schema can be found in Section 8.9 of this 3136 document. 3138 10. Acknowledgements 3140 Thanks go to Simon Cox for his comments relating to terminology that 3141 have helped ensure that this document is aligns with ongoing work in 3142 the Open Geospatial Consortium (OGC). Thanks to Neil Harper for his 3143 review and comments on the GNSS sections of this document. Thanks to 3144 Noor-E-Gagan Singh, Gabor Bajko, Russell Priebe, and Khalid Al-Mufti 3145 for their significant input to and suggestions for improving the 3146 802.11 measurements. Thanks to Cullen Jennings for feedback and 3147 suggestions. Bernard Aboba provided review and feedback on a range 3148 of measurement data definitions. Mary Barnes and Geoff Thompson 3149 provided a review and corrections. David Waitzman and John Bressler 3150 both noted shortcomings with 802.11 measurements. Keith Drage, 3151 Darren Pawson provided expert LTE knowledge. 3153 11. References 3154 11.1. Normative References 3156 [DSL.TR025] 3157 Wang, R., "Core Network Architecture Recommendations for 3158 Access to Legacy Data Networks over ADSL", September 1999. 3160 [DSL.TR101] 3161 Cohen, A. and E. Shrum, "Migration to Ethernet-Based DSL 3162 Aggregation", April 2006. 3164 [GPS.ICD] "Navstar GPS Space Segment/Navigation User Interface", 3165 ICD GPS-200, Apr 2000. 3167 [Galileo.ICD] 3168 GJU, "Galileo Open Service Signal In Space Interface 3169 Control Document (SIS ICD)", May 2006. 3171 [RFC0020] Cerf, V., "ASCII format for network interchange", RFC 20, 3172 October 1969. 3174 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 3175 Requirement Levels", BCP 14, RFC 2119, March 1997. 3177 [RFC3629] Yergeau, F., "UTF-8, a transformation format of ISO 3178 10646", STD 63, RFC 3629, November 2003. 3180 [RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform 3181 Resource Identifier (URI): Generic Syntax", STD 66, 3182 RFC 3986, January 2005. 3184 [RFC4119] Peterson, J., "A Presence-based GEOPRIV Location Object 3185 Format", RFC 4119, December 2005. 3187 [RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an 3188 IANA Considerations Section in RFCs", BCP 26, RFC 5226, 3189 May 2008. 3191 [RFC5491] Winterbottom, J., Thomson, M., and H. Tschofenig, "GEOPRIV 3192 Presence Information Data Format Location Object (PIDF-LO) 3193 Usage Clarification, Considerations, and Recommendations", 3194 RFC 5491, March 2009. 3196 [RFC5985] Barnes, M., "HTTP-Enabled Location Delivery (HELD)", 3197 RFC 5985, September 2010. 3199 [TIA-2000.5] 3200 TIA/EIA, "Upper Layer (Layer 3) Signaling Standard for 3201 cdma2000(R) Spread Spectrum Systems", TIA-2000.5-D, 3202 March 2004. 3204 [TS.3GPP.23.003] 3205 3GPP, "Numbering, addressing and identification", 3GPP 3206 TS 23.003 9.4.0, September 2010. 3208 11.2. Informative References 3210 [ANSI-TIA-1057] 3211 ANSI/TIA, "Link Layer Discovery Protocol for Media 3212 Endpoint Devices", TIA 1057, April 2006. 3214 [GPS.SPOOF] 3215 Scott, L., "Anti-Spoofing and Authenticated Signal 3216 Architectures for Civil Navigation Signals", ION- 3217 GNSS Portland, Oregon, 2003. 3219 [HARPER] Harper, N., Dawson, M., and D. Evans, "Server-side 3220 spoofing and detection for Assisted-GPS", Proceedings of 3221 International Global Navigation Satellite Systems Society 3222 (IGNSS) Symposium 2009 16, December 2009, 3223 . 3225 [I-D.ietf-geopriv-held-identity-extensions] 3226 Winterbottom, J., Thomson, M., Tschofenig, H., and R. 3227 Barnes, "Use of Device Identity in HTTP-Enabled Location 3228 Delivery (HELD)", 3229 draft-ietf-geopriv-held-identity-extensions-06 (work in 3230 progress), November 2010. 3232 [I-D.thomson-geopriv-uncertainty] 3233 Thomson, M. and J. Winterbottom, "Representation of 3234 Uncertainty and Confidence in PIDF-LO", 3235 draft-thomson-geopriv-uncertainty-07 (work in progress), 3236 March 2012. 3238 [IANA.enterprise] 3239 IANA, "Private Enterprise Numbers", 2011, 3240 . 3242 [IEEE.80211] 3243 IEEE, "Wireless LAN Medium Access Control (MAC) and 3244 Physical Layer (PHY) specifications - IEEE 802.11 Wireless 3245 Network Management", IEEE Std 802.11-2007, June 2007. 3247 [IEEE.80211V] 3248 IEEE, "Wireless LAN Medium Access Control (MAC) and 3249 Physical Layer (PHY) specifications - IEEE 802.11 Wireless 3250 Network Management (Draft)", P802.11v D12.0, June 2010. 3252 [IEEE.8021AB] 3253 IEEE, "IEEE Standard for Local and Metropolitan area 3254 networks, Station and Media Access Control Connectivity 3255 Discovery", IEEE Std 802.1AB-2009, September 2009. 3257 [RFC2865] Rigney, C., Willens, S., Rubens, A., and W. Simpson, 3258 "Remote Authentication Dial In User Service (RADIUS)", 3259 RFC 2865, June 2000. 3261 [RFC3046] Patrick, M., "DHCP Relay Agent Information Option", 3262 RFC 3046, January 2001. 3264 [RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688, 3265 January 2004. 3267 [RFC3693] Cuellar, J., Morris, J., Mulligan, D., Peterson, J., and 3268 J. Polk, "Geopriv Requirements", RFC 3693, February 2004. 3270 [RFC3993] Johnson, R., Palaniappan, T., and M. Stapp, "Subscriber-ID 3271 Suboption for the Dynamic Host Configuration Protocol 3272 (DHCP) Relay Agent Option", RFC 3993, March 2005. 3274 [RFC4291] Hinden, R. and S. Deering, "IP Version 6 Addressing 3275 Architecture", RFC 4291, February 2006. 3277 [RFC4580] Volz, B., "Dynamic Host Configuration Protocol for IPv6 3278 (DHCPv6) Relay Agent Subscriber-ID Option", RFC 4580, 3279 June 2006. 3281 [RFC4649] Volz, B., "Dynamic Host Configuration Protocol for IPv6 3282 (DHCPv6) Relay Agent Remote-ID Option", RFC 4649, 3283 August 2006. 3285 [RFC5808] Marshall, R., "Requirements for a Location-by-Reference 3286 Mechanism", RFC 5808, May 2010. 3288 Authors' Addresses 3290 Martin Thomson 3291 Microsoft 3292 3210 Porter Drive 3293 Palo Alto, CA 94304 3294 US 3296 Phone: +1 650-353-1925 3297 Email: martin.thomson@gmail.com 3299 James Winterbottom 3300 Commscope 3301 Andrew Building (39) 3302 University of Wollongong 3303 Northfields Avenue 3304 NSW 2522 3305 AU 3307 Phone: +61 2 4221 2938 3308 Email: james.winterbottom@commscope.com