GEOPRIV H. Schulzrinne Internet-Draft Columbia U. Expires: August 8, 2004 February 8, 2004 DHCP Option for Civil Addresses draft-ietf-geopriv-dhcp-civil-01 Status of this Memo This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC2026. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet-Drafts. 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." The list of current Internet-Drafts can be accessed at http:// www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on August 8, 2004. Copyright Notice Copyright (C) The Internet Society (2004). All Rights Reserved. Abstract This document specifies a Dynamic Host Configuration Protocol (DHCP) option for the civil (country, street and community) location of the client. Schulzrinne Expires August 8, 2004 [Page 1] Internet-Draft DHCP Civil February 2004 Table of Contents 1. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 3. Format of the DHCP Civil Location Option . . . . . . . . . . . 5 4. Civil Address Components . . . . . . . . . . . . . . . . . . . 6 5. Security Considerations . . . . . . . . . . . . . . . . . . . 9 Normative References . . . . . . . . . . . . . . . . . . . . . 10 Informative References . . . . . . . . . . . . . . . . . . . . 11 Author's Address . . . . . . . . . . . . . . . . . . . . . . . 11 A. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 12 Intellectual Property and Copyright Statements . . . . . . . . 13 Schulzrinne Expires August 8, 2004 [Page 2] Internet-Draft DHCP Civil February 2004 1. Terminology In this document, the key words "MUST", "MUSTNOT", "REQUIRED", "SHALL", "SHALLNOT", "SHOULD", "SHOULDNOT", "RECOMMENDED", "MAY", and "OPTIONAL" are to be interpreted as described in RFC 2119 [1] and indicate requirement levels for compliant implementations. Schulzrinne Expires August 8, 2004 [Page 3] Internet-Draft DHCP Civil February 2004 2. Introduction Many end system services can benefit by knowing the approximate location of the end device. In particular, IP telephony devices need to know their location to contact the appropriate emergency response agency and to be found by emergency responders. There are two common ways to identify the location of an object, either through geospatial coordinates or by so-called civil coordinates. Geospatial coordinates indicate longitude, latitude and altitude, while civil coordinates indicate a street address. A related draft [6] describes a DHCP [2] option for conveying geospatial information to a device. This draft describes how DHCP can be used to convey the civil location to devices. Both can be used simultaneously, increasing the chance to deliver accurate and timely location information to emergency responders. End systems that obtain location information via the mechanism described here then use other protocol mechanisms to communicate this information to the emergency call center. Civil information is useful since it often provides additional, human-usable information particularly within buildings. Also, compared to geospatial information, it is readily obtained for most occupied structures and can often be interpreted even if incomplete. For example, for many large university or corporate campuses, geocoding information to building and room granularity may not be readily available. Unlike geospatial information, the format for civil information differs from country to country. Thus, this draft establishes an IANA registry for civil location data fields. The initial set of data fields is derived from standards published by the United States National Emergency Numbering Association (NENA) [8]. It is anticipated that other countries can reuse many of the data elements. Schulzrinne Expires August 8, 2004 [Page 4] Internet-Draft DHCP Civil February 2004 3. Format of the DHCP Civil Location Option 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Code TBD | N | Countrycode | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | What | civil address elements ... +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Each civil address element has the following format: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | CAtype | CAlength | CAvalue ... +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Code TBD: The code for this DHCP option is TBD by IANA. N: The length of this option is variable. Countrycode: The two-letter ISO 3166 country code in capital ASCII letters, e.g., DE or US. What: The 'what' element describes which location the DHCP refers to. Currently, three options are defined: the location of the DHCP server (0), the location of the network element believed to be closest to the client (1) or the location of the client (2). Option (2) SHOULD be used, but may not be known. Options (1) and (2) SHOULDNOT be used unless it is known that the DHCP client is in close physical proximity to the server or network element. CAtype: A one-octet descriptor of the data civil address value. CAlength: The length, in octets, of the CAvalue, not including the CAlength field itself. Data SHOULD be encoded in uppercase. CAvalue: The civil address value, encoded as UTF-8, and written in uppercase letters where applicable. Schulzrinne Expires August 8, 2004 [Page 5] Internet-Draft DHCP Civil February 2004 4. Civil Address Components Since each country has different administrative hierarchies, with often the same (English) names, this specification adopts a simple hierarchical notation that is then instantiated for each country. We assume that five levels are sufficient for sub-national divisions above the street level. All elements are OPTIONAL and can appear in any order. Abbreviations do not need a trailing period. +----------------------+----------------------+---------------------+ | CAtype | label | description | +----------------------+----------------------+---------------------+ | 1 | A1 | national | | | | subdivisions | | | | (state, region, | | | | province, | | | | prefecture) | | | | | | 2 | A2 | county, parish, gun | | | | (JP), district (IN) | | | | | | 3 | A3 | city, township, shi | | | | (JP) | | | | | | 4 | A4 | city division, | | | | borough, city | | | | district, ward, | | | | chou (JP) | | | | | | 5 | A5 | neighborhood, block | | | | | | 6 | A6 | street | +----------------------+----------------------+---------------------+ Table 1 For specific countries, the administrative sub-divisions are described below. US (United States): The mapping to NENA designations is shown in parentheses. A1=state (STA), using the the two-letter state and possession abbreviations recommended by the United States Postal Service Publication 28 [7], Appendix B; A2=county (CNA); A3=civil community name (city or town) (MCN); A6=street (STN). A4 and A5 are not used. The civil community name (MCN) reflects the political boundaries. These may differ from postal delivery Schulzrinne Expires August 8, 2004 [Page 6] Internet-Draft DHCP Civil February 2004 assignments for historical or practical reasons. CA (Canada): The mapping to NENA designations is shown in parentheses. A1=province (STA), A2=county (CNA), A3=city or town (MCN). JP (Japan): A1=metropolis (To, Fu) or prefecture (Ken, Do); A2=city (Shi) or rural area (Gun); A3=ward (Ku) or village (Mura); A4=town (Chou or Machi); A5=city district (Choume); A6=block (Banchi or Ban). DE (Germany): A1=state (Bundesstaat); A2=county (Kreis); A3=city (Stadt, Gemeinde); A6=street (Strasse). Additional CA types appear in many countries and are simply omitted where they are not needed: +----------------+----------------+----------------+----------------+ | CAtypej | NENA | Description | Examples | +----------------+----------------+----------------+----------------+ | 16 | PRD | leading street | N | | | | direction | | | | | | | | 17 | POD | trailing | SW | | | | street suffix | | | | | | | | 18 | STS | street suffix | AVE, PLATZ | | | | | | | 19 | HNO | house number | 123 | | | | | | | 20 | HNS | house number | A, 1/2 | | | | suffix | | | | | | | | 21 | LMK | landmark or | SHADELAND | | | | vanity address | CRESCENT APTS | | | | | | | 22 | LOC | additional | APT 17 | | | | location | | | | | information | | | | | | | | 23 | NAM | name | JOE'S | | | | (residence and | BARBERSHOP | | | | office | | | | | occupant) | | | | | | | | 24 | ZIP | postal/zip | 10027-1234 | | | | code | | | | | | | Schulzrinne Expires August 8, 2004 [Page 7] Internet-Draft DHCP Civil February 2004 | 25 | | type of place | | | | | | | | 26 | | floor | | | | | | | | 27 | | room number | | +----------------+----------------+----------------+----------------+ The CA types labeled in the second column correspond to items from the NENA "Recommended Formats & Protocols For ALI Data Exchange, ALI Response & GIS Mapping" [8], but are applicable to most countries. The "NENA" column refers to the data dictionary name in Exhibit 18 of [8]. The NAM object is used to aid user location ("Joe Miller" "Alice's Dry Cleaning"). It does not identify the person using a communications device, but rather the person or organization associated with the address. For POD and PRD, in English-speaking countries, the abbreviations N, E, S, W, and NE, NW, SE, SW should be used. STS designates a street suffix. In the United States (US), the abbreviations recommended by the United States Postal Service Publication 28 [7], Appendix C, SHOULD be used. The "type of place" item indicates whether the location is a 'home', 'office' or 'public', using text strings. Additional text strings can be registered with IANA and correspond to the "placetype" element in [9]. The "privacy" object can have the string values: public: Others may be able to see or hear the communications. private: Inappropriate individuals are not likely to see or hear the communications. quiet: The location is a place such as a library, restaurant, place-of-worship, or theater that discourages noise, conversation and other distractions. Additional string values can be registered with IANA using the registry established in [9]. The DHCP long-options mechanism described in RFC 3396 [3] MUST be used if the civil address option exceeds the maximum DHCP option size of 255 octets. Schulzrinne Expires August 8, 2004 [Page 8] Internet-Draft DHCP Civil February 2004 5. Security Considerations The information in this option may be used for a variety of tasks. In some cases, integrity of the information may be of great importance. In such cases, DHCP authentication in RFC3118 [4] SHOULD be used to protect the integrity of the DHCP options. Schulzrinne Expires August 8, 2004 [Page 9] Internet-Draft DHCP Civil February 2004 Normative References [1] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [2] Droms, R., "Dynamic Host Configuration Protocol", RFC 2131, March 1997. [3] Lemon, T. and S. Cheshire, "Encoding Long Options in the Dynamic Host Configuration Protocol (DHCPv4)", RFC 3396, November 2002. [4] Droms, R. and W. Arbaugh, "Authentication for DHCP Messages", RFC 3118, June 2001. [5] Sugano, H. and S. Fujimoto, "Presence Information Data Format (PIDF)", draft-ietf-impp-cpim-pidf-08 (work in progress), May 2003. Schulzrinne Expires August 8, 2004 [Page 10] Internet-Draft DHCP Civil February 2004 Informative References [6] Polk, J., Schnizlein, J. and M. Linsner, "Dynamic Host Configuration Protocol Option for Coordinate-based Location Configuration Information", draft-ietf-geopriv-dhcp-lci-option-03 (work in progress), December 2003. [7] United States Postal Service, "Postal Addressing Standards", November 2000. [8] National Emergency Number Assocation, "NENA Recommended Formats and Protocols For ALI Data Exchange, ALI Response and GIS Mapping", NENA NENA-02-010, January 2002. [9] Schulzrinne, H., "RPID -- Rich Presence Information Data Format", draft-ietf-simple-rpid-00 (work in progress), July 2003. Author's Address Henning Schulzrinne Columbia University Department of Computer Science 450 Computer Science Building New York, NY 10027 US Phone: +1 212 939 7042 EMail: hgs+simple@cs.columbia.edu URI: http://www.cs.columbia.edu Schulzrinne Expires August 8, 2004 [Page 11] Internet-Draft DHCP Civil February 2004 Appendix A. Acknowledgments Rohan Mahy and Stefan Berger provided helpful comments. 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