ECRIT R. Marshall Internet-Draft J. Martin Intended status: Standards Track TCS Expires: April 21, 2016 B. Rosen Neustar October 19, 2015 A LoST extension to return complete and similar location info draft-ietf-ecrit-similar-location-01 Abstract This document introduces a new way to provide returned location information in LoST responses that is either of a completed or similar form to the original input civic location, based on whether valid or invalid civic address elements are returned within the findServiceResponse message. This document defines a new extension to the findServiceResponse message within the LoST protocol [RFC5222] that enables the LoST protocol to return a completed civic address element set for a valid location response, and one or more suggested sets of similar location information for invalid LoST responses. These two types of civic addresses are referred to as either "complete location" or "similar location", and are included as compilation of ca type xml elements within the existing LoST findServiceResponse message structure. Status of This Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." This Internet-Draft will expire on April 21, 2016. Marshall, et al. Expires April 21, 2016 [Page 1] Internet-Draft Returned Location Extensions to LoST October 2015 Copyright Notice Copyright (c) 2015 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. Overview of Returned Location Information . . . . . . . . . . 4 4. Returned Location Information . . . . . . . . . . . . . . . . 7 5. Complete Location returned for Valid Location response . . . 7 6. Similar Location returned for Invalid Location response . . . 9 7. Relax NG schema . . . . . . . . . . . . . . . . . . . . . . . 11 8. Security Considerations . . . . . . . . . . . . . . . . . . . 13 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 14 9.1. Relax NG Schema Registration . . . . . . . . . . . . . . 14 9.2. LoST Namespace Registration . . . . . . . . . . . . . . . 14 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 15 10.1. Normative References . . . . . . . . . . . . . . . . . . 15 10.2. Informative References . . . . . . . . . . . . . . . . . 15 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 16 1. Introduction The LoST protcol [RFC5222] supports the validation of civic location information as input, by providing a set of validation result status indicators. The current usefulness of the supported xml elements, "valid", "invalid", and "unchecked", is limited, because while they each provide an indication of validity for any one location element as a part of the whole civic address, the mechanism is insufficient in providing either the complete set of civic address elements that the LoST server contains, or of providing alternate suggestions (hints) as to which civic address is intended for use. Whether the input civic location is valid and missing information, or invalid due to missing or wrong information during input, this Marshall, et al. Expires April 21, 2016 [Page 2] Internet-Draft Returned Location Extensions to LoST October 2015 document provides a mechanism to return a complete set of civic address elements for those valid or invalid cases. This enhancement to the validation feature within LoST is required by systems that rely on accurate location for processing in order to increase the likelihood that the correct and/or complete form of a civic location becomes known in those cases where it is incomplete or just plain wrong. One such use case is that of location based emergency calling. The use of this protocol extension will reduce user and system input errors, and will result in a higher level of civic address matching, reducing the number of mismatch errors, where a civic address that appears to be valid gets wrongly associated with the physical location of the caller. The structure of this document includes terminology, Section 2, followed by a discussion of the basic elements involved in location validation. The use of these elements, by way of example, is discussed in an overview section, Section 3, with accompanying rationale, and a brief discussion of the impacts to LoST, and its current schema. 2. Terminology The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119 [RFC2119]. The following terms are defined in this document: Location: The term Location can be used to refer to either a civic location or a geodetic location. Geodetic Location: a geographic coordinate set of values that describes a point within a defined geographic datum. For example, a WGS84 referenced lattitude, longitude coordinate pair (2D), or lattitude, longitude, and altitude (3D). Note: geodetic location is defined here for context, but is not used elsewhere within this document. Civic Location: The term civic location applies to a set of one or more civic address elements that are used in conjunction with each other, and in accordance with a known ruleset to designates a place within a defined grid or basemap, The example used within this document is a street address as defined in [RFC5139] Civic Address: The term Civic Address is used interchangeably with the term Civic Location within this document. Marshall, et al. Expires April 21, 2016 [Page 3] Internet-Draft Returned Location Extensions to LoST October 2015 Street Address: The term Street Address is used to represent a place, or location on a defined grid or map. While generally equated to both terms, Civic Location and Civic Address, it is not used within this document. Civic Address Element: The term Civic Address Element is used within this document to apply to an individual CAtype data descriptor, for example, as is described in [RFC4776], [RFC5774], and [RFC6848] Invalid: The status result of the unsuccessful attempt to match an individual input data as part of a larger set of data that has already been successfully matched and as shown by the [RFC5222] defined xml named element Valid: The status result of the successful attempt to match an individual input data as part of a larger set of data that has already also been successfully matched and shown by the [RFC5222] defined xml named element Invalid Location: A Civic Location that was included in a LoST request and subsequently returned with one or more civic address elements marked as invalid. Valid Location: A Civic Location that was included in a LoST request and subsequently returned with all civic address elements marked as valid. Complete Location: An expanded civic location that includes other civic address elements in addition to the existing validated civic address elements provided as input to a LoST server. Similar Location: A suggested civic location that is comparatively close to the civic location which was input, but which had one or more invalid civic address elements returned by the LoST server. Returned Location Information: A set of standard civic address elements returned in a LoST response. 3. Overview of Returned Location Information This document describes an extension to LoST [RFC5222] to allow additional location information to be returned in a findServiceResponse for two different use cases. When a LoST server is asked to validate a civic location, its goal is to take the set of civic address elements provided as the location information in the LoST request, and find a unique location in its Marshall, et al. Expires April 21, 2016 [Page 4] Internet-Draft Returned Location Extensions to LoST October 2015 database that matches the information in the request. Uniqueness might not require values for all possible elements in the civic address that the database might hold. Further, the input location information might not represent the form of location the users of the LoST service prefer to have. As an example, there are LoST civic address elements that could be used to define a postal location, suitable for delivery mail as well as a municipal location suitable for responding to an emergency call. While the LoST server might be able to determine the location from the postal elements provided, the emergency services would prefer that the municipal location be used for any subsequent emergency call. Since validation is often performed well in advance of an end-user placing an emergency call, if the LoST server could return the preferred form of location (or more properly in this example, the municipal elements in addition to the postal elements), those elements could be stored in a LIS and used in a later emergency call. Since a LoST server often contains more data than what is included within a findService request, it is expected that this additional location information, if present, SHOULD only be returned within response messages that contain only valid civic address elements in the corresponding request, and where the set of valid civic address elements in the request identify a unique location. Where a LoST server contains additional location information relating to that civic address, the findServiceResponse message MAY return additional location information along with the original validated civic address elements in order to form a complete location based on local implementation policy. In addition, this document describes the reuse of the same mechanism, but for a different purpose: to supply similar location information in the case where a LoST server response includes one or more civic address elements marked as invalid, constituting an invalid location response. In this case, the response contains one or more suggested alternative, but valid locations. Clients MAY ignore the location information this extension defines in the response. The information is optional to send, and optional to use. In the case where the location information in the request was valid, this extension does not change the validity. In the case where the location information in the request is invalid, but alternate location information is returned, the original location remains invalid, and the LoST server does not change the mapping response other than optionally including the information defined by this extension. In a valid location response, a LoST server returns a response to a findService request that contains a set of civic address elements Marshall, et al. Expires April 21, 2016 [Page 5] Internet-Draft Returned Location Extensions to LoST October 2015 marked valid, the location information in the findServiceResponse message MAY be extended to include additional location information specific for that location. As an example, the query might contain a HNO (house number), RD (road name) and A3 (city) and a few more caType elements, but might not contain A1 (state) or PC (Postal Code) CAtypes. The HNO, RD, STS, POD, and A3 civic address elements might be sufficient enough to the LoST server to uniquely locate the address specified in the request and thus be considered valid. Yet, downstream entities might find it helpful to have the additional country, A1 (state), and PC, (Postal Code), civic address elements that are present within the LoST server, be included as part of a complete location response. Since [RFC5222] currently does not have a way for this additional location information to be returned in the findServiceResponse, this document extends the LoST protocol so that it can include a completeLocation element within the findServiceResponse message, allowing for the representation of complete location information. An example showing complete location information supplied: input address: 6000 15th Ave NW Seattle complete location: 6000 15th Ave NW Seattle, WA 98105 US By contrast, when invalid location is received from the LoST server, with this extension, the same mechanism works as follows: if a LoST server returns a response to a findService request that contains a set of civic address elements with one or more labeled as invalid, the location information in the findServiceResponse is extended to include additional location information that it suspects might be the location desired. In the example cited above, policy at the LoST server might deem a missing A3 element as invalid, even if the location information in the request was sufficient to identify a unique address. In that case, the missing element would be listed in the invalid list, and similarLocation could be returned in the response showing the missing elements including A3, the same as the above example. As another example of the use of similarLocation, consider the results based on a similar data set as used above, where the HNO, RD, STS, A1, and A3 civic address elements are not sufficient to locate a unique address, which leads to an invalid location result. This is the case, despite the fact that the LoST server typically contains additional civic address elements which could have resulted in a uniquely identifiable location if additional data had been supplied with the query. Since [RFC5222] currently does not have a way for this additional location information to be returned in the Marshall, et al. Expires April 21, 2016 [Page 6] Internet-Draft Returned Location Extensions to LoST October 2015 findServiceResponse, this document extends [RFC5222] so that the LoST findServiceResponse message can include one or more similarLocation elements within the findServiceResponse message representing similar civic locations. To show this, suppose that a slightly modified address as above is inserted within a Lost findService request: input address: 6000 15th Ave N Seattle, WA. This time we make the assumption that the address is deemed "invalid" by the LoST server because there is no such thing as "15th Ave N" within the LoST server's data for the city of Seattle. However, we also happen to know for this example that there are two addresses within the address dataset that are "similar", when all parts of the address are taken as a whole. These similar addresses that could be suggested to the user are as follows: similar address #1: 6000 15th Ave NW Seattle, WA 98107 similar address #2: 6000 15th Ave NE Seattle, WA 98105 This extension would allow the LoST server to include the above similar addresses as civicAddress elements in the response to locationValidation. The next section shows examples of the LoST request and response xml message fragments for the above valid and invalid scenarios, returning the complete or similar addresses, respectively: 4. Returned Location Information The LoST server implementing this extension MAY include completeLocation or similarLocation in the findService response. completeLocation and similarLocation contain a list of civic address elements identical to the elements used in the location element with the "civic profile". 5. Complete Location returned for Valid Location response Based on the example input request, returned location information is provided in a findServiceResponse message when the original input address is considered valid, but is missing some additional data that the LoST server has. Marshall, et al. Expires April 21, 2016 [Page 7] Internet-Draft Returned Location Extensions to LoST October 2015 WA Seattle 15th Ave NW 6000 urn:service:sos xmlns="urn:ietf:params:xml:ns:lost1" xmlns:rli="urn:ietf:params:xml:ns:lost-rli1"> xmlns:ca="urn:ietf:params:xml:ns:pidf:geopriv10:civicAddr"> Seattle 911 urn:service:sos sip:seattle-911@example.com 911 ca:A3 ca:RD ca:STS ca:POD ca:HNO Marshall, et al. Expires April 21, 2016 [Page 8] Internet-Draft Returned Location Extensions to LoST October 2015 US WA SEATTLE 15TH AVE NW 6000 98106 SEATTLE 6. Similar Location returned for Invalid Location response The following example shows returned location information provided in a findServiceResponse message when the original input address is considered invalid, because of the unmatchable POD data (in this example) that the LoST server needs to provide a unique mapping. Marshall, et al. Expires April 21, 2016 [Page 9] Internet-Draft Returned Location Extensions to LoST October 2015 US WA Seattle 15th Ave N 6000 urn:service:sos xmlns="urn:ietf:params:xml:ns:lost1" xmlns:rli="urn:ietf:params:xml:ns:lost-rli1"> xmlns:ca="urn:ietf:params:xml:ns:pidf:geopriv10:civicAddr"> Seattle 911 urn:service:sos sip:seattle-911@example.com 911 ca:country ca:A1 ca:A3 ca:STS ca:RD ca:POD ca:HNO US WA SEATTLE 15TH Marshall, et al. Expires April 21, 2016 [Page 10] Internet-Draft Returned Location Extensions to LoST October 2015 AVE NW 6000 98106 SEATTLE US WA SEATTLE 15TH AVE NE 6000 98105 SEATTLE 7. Relax NG schema This section provides the Relax NG schema of LoST extensions in the compact form. The verbose form is included in a later section [to be supplied in a later version of this draft]. namespace a = "http://relaxng.org/ns/compatibility/annotations/1.0" default namespace ns1 = "urn:ietf:params:xml:ns:lost-rli1" ## ## Extension to LoST to support returned location information ## Marshall, et al. Expires April 21, 2016 [Page 11] Internet-Draft Returned Location Extensions to LoST October 2015 start = returnedLocation div { returnedLocationResponse = element returnedLocationResponse { completeLocation, similarLocation, extensionPoint } } ## ## completeLocation ## div { completeLocation = element location { attribute id { xsd:token }, locationInformation }+ } ## ## similarLocation ## div { similarLocation = element location { attribute id { xsd:token }, locationInformation }+ } ## ## Location Information ## div { locationInformation = extensionPoint+, attribute profile { xsd:NMTOKEN }? } ## ## Patterns for inclusion of elements from schemas in ## other namespaces. ## div { ## ## Any element not in the LoST namespace. Marshall, et al. Expires April 21, 2016 [Page 12] Internet-Draft Returned Location Extensions to LoST October 2015 ## notLost = element * - (ns1:* | ns1:*) { anyElement } ## ## A wildcard pattern for including any element ## from any other namespace. ## anyElement = (element * { anyElement } | attribute * { text } | text)* ## ## A point where future extensions ## (elements from other namespaces) ## can be added. ## extensionPoint = notRLI* } 8. Security Considerations Whether the input to the LoST server is valid or invalid, the LoST server ultimately determines what it considers to be valid. Even in the case where the input location is valid, the requester still might not actually understand where that location is. For this kind of valid location use case, this described extension would typically return more location information than the requester started with, which might reveal more about the location. While this might be very desirable in some scenarios including, for example, supporting an emergency call, it might not be as desirable for other services. Individual LoST server implementations SHOULD consider the risk of releasing more detail verses the value in doing so. Generally, it is not expected that this would be a significant problem as the requester must have enough location information to be considered valid, which in most cases is enough to uniquely locate the address. Providing more CAtypes generally doesn't actually reveal anything more. For invalid locations that are submitted, this extension would allow the LoST response to include location information which is similar to what was input, again resulting in more information provided in the response than was known during input. LoST server implementations SHOULD evaluate the particular use cases where this extension is supported, and weigh the risks around its use. Many similar database services available today via the Internet offer Marshall, et al. Expires April 21, 2016 [Page 13] Internet-Draft Returned Location Extensions to LoST October 2015 similar features, such as "did you mean", and address completion, so this capability is not introducing any fundamentally new threat. 9. IANA Considerations 9.1. Relax NG Schema Registration URI: urn:ietf:params:xml:schema:lost-rli1 Registrant Contact: IETF ECRIT Working Group, Brian Rosen (br@brianrosen.net). Relax NG Schema: The Relax NG schema to be registered is contained in Section 7. Its first line is default namespace = "urn:ietf:params:xml:ns:lost-rli1 and its last line is } 9.2. LoST Namespace Registration Marshall, et al. Expires April 21, 2016 [Page 14] Internet-Draft Returned Location Extensions to LoST October 2015 URI: urn:ietf:params:xml:ns:lost-rli1 Registrant Contact: IETF ECRIT Working Group, Brian Rosen (br@brianrosen.net). XML: BEGIN LoST Planned Change Namespace

Namespace for LoST Returned Location Information extension

urn:ietf:params:xml:ns:lost-rli1

See RFC????.

END 10. References 10.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [RFC5222] Hardie, T., Newton, A., Schulzrinne, H., and H. Tschofenig, "LoST: A Location-to-Service Translation Protocol", RFC 5222, DOI 10.17487/RFC5222, August 2008, . 10.2. Informative References [RFC4776] Schulzrinne, H., "Dynamic Host Configuration Protocol (DHCPv4 and DHCPv6) Option for Civic Addresses Configuration Information", RFC 4776, DOI 10.17487/RFC4776, November 2006, . Marshall, et al. Expires April 21, 2016 [Page 15] Internet-Draft Returned Location Extensions to LoST October 2015 [RFC5139] Thomson, M. and J. Winterbottom, "Revised Civic Location Format for Presence Information Data Format Location Object (PIDF-LO)", RFC 5139, DOI 10.17487/RFC5139, February 2008, . [RFC5774] Wolf, K. and A. Mayrhofer, "Considerations for Civic Addresses in the Presence Information Data Format Location Object (PIDF-LO): Guidelines and IANA Registry Definition", BCP 154, RFC 5774, DOI 10.17487/RFC5774, March 2010, . [RFC6848] Winterbottom, J., Thomson, M., Barnes, R., Rosen, B., and R. George, "Specifying Civic Address Extensions in the Presence Information Data Format Location Object (PIDF- LO)", RFC 6848, DOI 10.17487/RFC6848, January 2013, . Authors' Addresses Roger Marshall TeleCommunication Systems, Inc. 2401 Elliott Avenue 2nd Floor Seattle, WA 98121 US Email: rmarshall@telecomsys.com URI: http://www.telecomsys.com Jeff Martin TeleCommunication Systems, Inc. 2401 Elliott Avenue 2nd Floor Seattle, WA 98121 US Email: jmartin@telecomsys.com URI: http://www.telecomsys.com Brian Rosen Neustar 470 Conrad Dr Mars, PA 16046 US Email: br@brianrosen.net Marshall, et al. Expires April 21, 2016 [Page 16]