Internet Engineering Task Force Internet Draft H. Schulzrinne Columbia U. draft-schulzrinne-geopriv-dhcp-civil-00.txt December 5, 2002 Expires: March 2003 DHCP Option for Civil Location 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 To view the list Internet-Draft Shadow Directories, see http://www.ietf.org/shadow.html. H. Schulzrinne [Page 1] Internet Draft DHCP Option for Civil Addresses December 5, 2002 Abstract This document specifies a Dynamic Host Configuration Protocol option for the civil (country, street and community) location of the client. 1 Terminology In this document, the key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" are to be interpreted as described in RFC 2119 [1] and indicate requirement levels for compliant implementations. 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. This is commonly, but not necessearily, closely related to the postal address, used by the local postal service to deliver mail. However, not all postal addresses correspond to street addresses. For example, the author's address is a postal address that does not appear on any street or building sign. Naturally, post office boxes would be unsuitable for the purposes described here. A related draft [7] 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. H. Schulzrinne [Page 2] Internet Draft DHCP Option for Civil Addresses December 5, 2002 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) [3]. It is anticipated that other countries can reuse many of the data elements. 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 country code in capital ASCII letter, 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) SHOULD NOT be H. Schulzrinne [Page 3] Internet Draft DHCP Option for Civil Addresses December 5, 2002 used unless it is known that the DHCP client is in close physical proximity to the server or network element. In some cases, the local wiring plant makes it difficult to ascertain the device location with certainty. In that case, it is still preferable to indicate the DHCP server, Ethernet switch or router, but indicate the uncertainty. This avoids that the emergency responders try to break into the LAN closet. 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. 4 Civil Address Components We define the following initial CA types. They correspond to items from the NENA "Recommended Formats & Protocols For ALI Data Exchange, ALI Response & GIS Mapping" [3], but are applicable to most countries. CAtype NENA country description examples ____________________________________________________________________________________ 1 CNA some county name BERGEN 2 HNO all house number 123 3 HNS all house number suffix A, 1/2 4 LMK all landmark or vanity address SHADELAND CRESCENT APTS 5 LOC all additional location information APT 17 6 MCN all civil community name FAIRVIEW HEIGHTS 7 NAM all name (residence and office occupant) JOE'S BARBERSHOP 8 PCN all postal community name BELLEVILLE 9 POD all trailing street suffix SW 10 PRD all leading street direction N 11 STN all street name MAIN 12 STA some state, province or region TX, ON 13 STS all street suffix AVE 14 ZIP all postal/zip code 10027-1234 15 some district Not all elements are applicable in all countries. In particular, elements marked as "some" are not commonly used across countries. H. Schulzrinne [Page 4] Internet Draft DHCP Option for Civil Addresses December 5, 2002 All elements are OPTIONAL and can appear in any order. Abbreviations do not need a trailing period. The "NENA" column refers to the data dictionary name in Exhibit 18 of [3]. Some additional remarks on specific items: CNA: CNA refers to a group of towns, cities or villages. In the United States, these are called counties or parishes, in India, these are called districts, in Portugal 'territorial sub-division', in Germany MCN: The civil community name reflects the political boundaries. These may differ from postal delivery assignments, captured in PCN, for historical or practical reasons. NAM: The NAM object is used to aid user location ("Joe Miller" "Alice's Dry Cleaning"). It does not identify the caller, but rather the person or organization associated with the address. POD, PRD: In English-speaking countries, the abbreviations N, E, S, W, and NE, NW, SE, SW should be used. STA: In the United States (US), the two-letter state and possession abbreviations recommended by the United States Postal Service Publication 28 [4], Appendix B, SHOULD be used. In China (CN), STA is used for the five autonomous regions. In Portugal (PT), STA identifies the territorial subdivision. STS: In the United States (US), the abbreviations recommended by the United States Postal Service Publication 28 [4], Appendix C, SHOULD be used. 15 (District): This is a sub-unit of a community or city and is used, for example, in China (CN) and India (IN) ("locality" or "neighborhood"). The mechanism described in RFC 3396 [5] can be used if the civil address option exceeds the maximum DHCP option size of 255 octets. 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 [6] SHOULD be used to protect the integrity of the DHCP options. H. Schulzrinne [Page 5] Internet Draft DHCP Option for Civil Addresses December 5, 2002 6 Acknowledgments Your name here. 7 Authors' Addresses Henning Schulzrinne Dept. of Computer Science Columbia University 1214 Amsterdam Avenue New York, NY 10027 USA electronic mail: schulzrinne@cs.columbia.edu 8 Normative References [1] S. Bradner, "Key words for use in RFCs to indicate requirement levels," RFC 2119, Internet Engineering Task Force, Mar. 1997. [2] R. Droms, "Dynamic host configuration protocol," RFC 2131, Internet Engineering Task Force, Mar. 1997. [3] National Emergency Number Association, "Nena recommended formats & protocols for ali data exchange, ali response & gis mapping," Standard NENA-02-010, NENA, Washington, DC, 2002 Jan. [4] United States Postal Service, "Postal addressing standards," Publication 28, USPS, Washington, DC, Nov. 2000. [5] T. Lemon and S. Cheshire, "Encoding long options in the dynamic host configuration protocol (DHCPv4)," RFC 3396, Internet Engineering Task Force, Nov. 2002. [6] R. Droms and W. Arbaugh, eds., "Authentication for DHCP messages," RFC 3118, Internet Engineering Task Force, June 2001. 9 Informative References [7] J. Polk et al., "DHCP option for geographic location," Internet Draft, Internet Engineering Task Force, Oct. 2002. Work in progress. Full Copyright Statement Copyright (c) The Internet Society (2002). All Rights Reserved. This document and translations of it may be copied and furnished to others, and derivative works that comment on or otherwise explain it H. Schulzrinne [Page 6] Internet Draft DHCP Option for Civil Addresses December 5, 2002 or assist in its implementation may be prepared, copied, published and distributed, in whole or in part, without restriction of any kind, provided that the above copyright notice and this paragraph are included on all such copies and derivative works. However, this document itself may not be modified in any way, such as by removing the copyright notice or references to the Internet Society or other Internet organizations, except as needed for the purpose of developing Internet standards in which case the procedures for copyrights defined in the Internet Standards process must be followed, or as required to translate it into languages other than English. The limited permissions granted above are perpetual and will not be revoked by the Internet Society or its successors or assigns. This document and the information contained herein is provided on an "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Acknowledgement Funding for the RFC Editor function is currently provided by the Internet Society. H. Schulzrinne [Page 7] Table of Contents 1 Terminology ......................................... 2 2 Introduction ........................................ 2 3 Format of the DHCP Civil Location Option ............ 3 4 Civil Address Components ............................ 4 5 Security Considerations ............................. 5 6 Acknowledgments ..................................... 6 7 Authors' Addresses .................................. 6 8 Normative References ................................ 6 9 Informative References .............................. 6 H. Schulzrinne [Page 1]