ECRIT R. Marshall Internet-Draft J. Martin Intended status: Standards Track TCS Expires: January 13, 2012 B. Rosen Neustar July 12, 2011 A LoST extension to support return of complete and similar location info draft-marshall-ecrit-similar-location-01 Marshall, et al. Expires January 13, 2012 [Page 1] Internet-Draft Returned Location Extensions to LoST July 2011 This document may contain material from IETF Documents or IETF Contributions published or made publicly available before November 10, 2008. The person(s) controlling the copyright in some of this material may not have granted the IETF Trust the right to allow modifications of such material outside the IETF Standards Process. Without obtaining an adequate license from the person(s) controlling the copyright in such materials, this document may not be modified outside the IETF Standards Process, and derivative works of it may not be created outside the IETF Standards Process, except to format it for publication as an RFC or to translate it into languages other than English. Marshall, et al. Expires January 13, 2012 [Page 2] Internet-Draft Returned Location Extensions to LoST July 2011 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 a valid or invalid location is 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 location element set for a valid response, and one or more suggested sets of civic location information for invalid LoST responses. These two types of civic addresses are referred to as either "complete" or "similar" locations, and are included as compilation of ca type xml elements within the existing response 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 January 13, 2012. Copyright Notice Copyright (c) 2011 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. Marshall, et al. Expires January 13, 2012 [Page 3] Internet-Draft Returned Location Extensions to LoST July 2011 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 5 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 6 3. Overview of Returned Location Information . . . . . . . . . . 7 4. Returned Location Information . . . . . . . . . . . . . . . . 9 5. Complete Location returned for Valid response . . . . . . . . 10 6. Similar Location returned for Invalid Response . . . . . . . . 12 7. Relax NG schema . . . . . . . . . . . . . . . . . . . . . . . 14 8. Security Considerations . . . . . . . . . . . . . . . . . . . 16 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 17 10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 18 11. References . . . . . . . . . . . . . . . . . . . . . . . . . . 19 11.1. Normative References . . . . . . . . . . . . . . . . . . 19 11.2. Informative References . . . . . . . . . . . . . . . . . 19 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 20 Marshall, et al. Expires January 13, 2012 [Page 4] Internet-Draft Returned Location Extensions to LoST July 2011 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 usefullness of the supported xml elements, "valid", "invalid", and "unchecked", is limited, because while they each provide an indication of validity for any one element as a part of the whole address, the mechanism is insufficient in providing either the complete set of address elements that the LoST server contains, or of providing alternate suggestions (hints) as to which civic address is intended. Whether the input civic location is valid and missing information, or invalid due to missing or wrong information during input, this document provides a mechanism to return full address information for those valid or invalid cases. This enhancement to the validation feature within LoST is required in order to ensure a high level of address matching, to overcome user and system input errors, and to support the usefullness of location- based systems in general. The structure of this document includes terminology, Section 2, followed by a discussion of the basic elements involved in location validation. These 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. Marshall, et al. Expires January 13, 2012 [Page 5] Internet-Draft Returned Location Extensions to LoST July 2011 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], with the important qualification that, unless otherwise stated, these terms apply to the design of the Location Configuration Protocol and the Location Dereferencing Protocol, not its implementation or application. The following terms are defined in this document: Address: The term Address is used interchangeably with the concept of Civic Location. Invalid: The result of the attempt to match an individual input data as part of a larger set of data that has already been successfully matched. Invalid Civic Element: An unmatched result of an individual civic location element as part of a broader set of elements that make up a civic location. Invalid Civic Location: An unmatched result of an input civic location, when taken as a whole, based on one or more individual unmatched civic address elements. Complete Location: An expanded civic location that includes additional address elements in addition to the existing validated civic elements provided. Similar Location: A suggested civic location that is comparatively close to the civic location which was input, but which had one or more invalid element. Returned Location Information: A set of standard civic location elements returned in a LoST response. Marshall, et al. Expires January 13, 2012 [Page 6] Internet-Draft Returned Location Extensions to LoST July 2011 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. Since a LoST server often contains more data than what is often included within a findService request, it is expected that this additional location information could be returned within response messages that may be both valid and invalid. For valid responses, where a LoST server contains additional location information relating to that civic address, the findServiceResponse message can return additional location information along with the original validated elements in order to form a complete civic location. On the other hand, for an invalid LoST response that contains address elements returned with one or more of them marked as invalid, and constituting an invalid location, this document introduces the idea of reusing this same mechanism, but for a different purpose - to supply similar location information - again, information that is contained within the LoST server, but is provided as a complete "similar" civic location put forward as a suggested alternative address that is also a valid location. In valid location responses, this works in the following way: when a LoST server returns a response to a findService request that contains a set of CAtype elements considered valid, the location information in the findServiceResponse is extended to include additional location information specific for that location. As an example, the query may contain a HNO (house number), RD (road name) and A3 (city) but may not contain A1, A2, PC (Postal Code) CAtypes. The RD and PC elements may be sufficient to locate the address specified in the request and thus be considered valid. Yet, downstream entities may find it helpful to have the additional A1, A2, and PC location elements that exist, and so the mechanism described here supports their inclusion. Since [RFC5222] currently does not have a way for this additional location information to be returned in the findServiceResponse, this document extends RFC5222 so that it can include a completeLocation element within the findServiceResponse message, representing a "complete" civic location. input address: 6000 15th Ave NW Seattle completed address: 6000 15th Ave NW Seattle, WA 98105 US When invalid location responses are received, the same mechanism works as follows: when a LoST server returns a response to a findService request that contains a set of CAtype elements with one Marshall, et al. Expires January 13, 2012 [Page 7] Internet-Draft Returned Location Extensions to LoST July 2011 or more that are tagged as invalid, the location information in the findServiceResponse is extended to include additional location information specific for that location. Differing results in the same data used in the above example, where the RD and PC elements are not sufficient to locate a unique address leads to an "invalid" result. This is the case, despite the fact that the LoST server typically contains additional location elements which could have resulted in a uniquely identifiable location if additional data had been supplied in the query. Since [RFC5222] currently does not have a way for this additional location information to be returned in the findServiceResponse, this document extends RFC5222 so that it can include one or more similarLocation elements within the findServiceResponse message representing "similar" civic locations. To show this, suppose that a similar address as above is inserted within a Lost findService request: input address: 6000 15th Ave Seattle, WA. Different from the above case, this time we make the assumption that the address is deemed "invalid" by the LoST server because there is no plain "15th Ave" in the city of Seattle with a house number that matches 6000. However 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 document proposes 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: Marshall, et al. Expires January 13, 2012 [Page 8] Internet-Draft Returned Location Extensions to LoST July 2011 4. Returned Location Information The LoST server knows the data that is available internally, and can determine which additional elements can be provided either as part of a complete civic location (CCL) or a similar civic location (SCL). The inclusion of either CCL or SCL is not triggered by any message parameter, but is triggered based on whether the returned location information is valid or invalid. It is not turned on or off, but is implementation specific. Marshall, et al. Expires January 13, 2012 [Page 9] Internet-Draft Returned Location Extensions to LoST July 2011 5. Complete Location returned for Valid 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. Seattle 15th Ave NW 6000 urn:service:sos Seattle 911 urn:service:sos sip:seattle-911@example.com 911 Marshall, et al. Expires January 13, 2012 [Page 10] Internet-Draft Returned Location Extensions to LoST July 2011 ca:A3 ca:A6 ca:STS ca:POD ca:HNO US WA SEATTLE 15TH AVE NW 6000 98106 SEATTLE Marshall, et al. Expires January 13, 2012 [Page 11] Internet-Draft Returned Location Extensions to LoST July 2011 6. Similar Location returned for Invalid Response The following example shows returned location information provided in a findServiceResponse message when the original input address is considered invalid, because (in this case) of missing data that the LoST server needs to provide a unique mapping. US WA Seattle 15th Ave 6000 urn:service:sos Seattle 911 urn:service:sos sip:seattle-911@example.com 911 Marshall, et al. Expires January 13, 2012 [Page 12] Internet-Draft Returned Location Extensions to LoST July 2011 ca:country ca:A1 ca:A3 ca:A6 ca:HNO US WA SEATTLE 15TH AVE NW 6000 98106 SEATTLE US WA SEATTLE 15TH AVE NE 6000 98105 SEATTLE Marshall, et al. Expires January 13, 2012 [Page 13] Internet-Draft Returned Location Extensions to LoST July 2011 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 [TBA]. namespace a = "http://relaxng.org/ns/compatibility/annotations/1.0" default namespace ns1 = "urn:ietf:params:xml:ns:lost-ext2" ## ## Extensions to the Location-to-Service Translation (LoST) ## Protocol ## ## LoST Extensions define two new elements: completeLocation and ## similarLocation. ## start = completeLocation | similarLocation ## ## complete Location ## div { completeLocation= element completeLocation } ## ## similar Location ## div { similarLocation= element completeLocation } ## ## Patterns for inclusion of elements from schemas in ## other namespaces. ## div { ## ## Any element not in the LoST Extensions ## namespace. Marshall, et al. Expires January 13, 2012 [Page 14] Internet-Draft Returned Location Extensions to LoST July 2011 ## notLostExt = 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 = notLostExt* } [Editor's note: above needs refinement] Marshall, et al. Expires January 13, 2012 [Page 15] Internet-Draft Returned Location Extensions to LoST July 2011 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. In the case where the input location is valid, the requester still may not actually understand where that locaiton is. For valid location use cases, this extension returns more location information than the requester may have had which, in turn, may reveal more about the location. While this may be very desirable when, for example, supporing an emergency call, it may not be as desirable for other services. The LoST server implementation should consider the risk of releasing more detail verses the value in doing so. Generally, we do not believe this is 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. Marshall, et al. Expires January 13, 2012 [Page 16] Internet-Draft Returned Location Extensions to LoST July 2011 9. IANA Considerations Marshall, et al. Expires January 13, 2012 [Page 17] Internet-Draft Returned Location Extensions to LoST July 2011 10. Acknowledgements Marshall, et al. Expires January 13, 2012 [Page 18] Internet-Draft Returned Location Extensions to LoST July 2011 11. References 11.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. 11.2. Informative References [RFC5222] Hardie, T., Newton, A., Schulzrinne, H., and H. Tschofenig, "LoST: A Location-to-Service Translation Protocol", RFC 5222, August 2008. Marshall, et al. Expires January 13, 2012 [Page 19] Internet-Draft Returned Location Extensions to LoST July 2011 Authors' Addresses Roger Marshall TeleCommunication Systems, Inc. 2401 Elliott Avenue 2nd Floor Seattle, WA 98121 US Phone: +1 206 792 2424 Email: rmarshall@telecomsys.com URI: http://www.telecomsys.com Jeff Martin TeleCommunication Systems, Inc. 2401 Elliott Avenue 2nd Floor Seattle, WA 98121 US Phone: +1 206 792 2584 Email: jmartin@telecomsys.com URI: http://www.telecomsys.com Brian Rosen Neustar 470 Conrad Dr Mars, PA 16046 US Phone: Email: br@brianrosen.net URI: Marshall, et al. Expires January 13, 2012 [Page 20]