Network Working Group M. Thomson
Request for Comments: 5139 J. Winterbottom
Updates: 4119 Andrew
Category: Standards Track February 2008
Revised Civic Location Format for
Presence Information Data Format Location Object (PIDF-LO)
Status of This Memo
This document specifies an Internet standards track protocol for the
Internet community, and requests discussion and suggestions for
improvements. Please refer to the current edition of the "Internet
Official Protocol Standards" (STD 1) for the standardization state
and status of this protocol. Distribution of this memo is unlimited.
Abstract
This document defines an XML format for the representation of civic
location. This format is designed for use with Presence Information
Data Format Location Object (PIDF-LO) documents and replaces the
civic location format in RFC 4119. The format is based on the civic
address definition in PIDF-LO, but adds several new elements based on
the civic types defined for Dynamic Host Configuration Protocol
(DHCP), and adds a hierarchy to address complex road identity
schemes. The format also includes support for the xml:lang language
tag and restricts the types of elements where appropriate.
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RFC 5139 Revised Civic LO February 2008
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Changes from PIDF-LO . . . . . . . . . . . . . . . . . . . . . 3
3.1. Additional Civic Address Types . . . . . . . . . . . . . . 3
3.2. New Thoroughfare Elements . . . . . . . . . . . . . . . . 4
3.2.1. Street Numbering . . . . . . . . . . . . . . . . . . . 5
3.2.2. Directionals and Other Qualifiers . . . . . . . . . . 5
3.3. Country Element . . . . . . . . . . . . . . . . . . . . . 6
3.4. A1 Element . . . . . . . . . . . . . . . . . . . . . . . . 6
3.5. Languages and Scripts . . . . . . . . . . . . . . . . . . 6
3.5.1. Converting from the DHCP Format . . . . . . . . . . . 7
3.5.2. Combining Multiple Elements Based on Language
Preferences . . . . . . . . . . . . . . . . . . . . . 7
3.6. Whitespace . . . . . . . . . . . . . . . . . . . . . . . . 7
4. Civic Address Schema . . . . . . . . . . . . . . . . . . . . . 8
5. Example . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
6. Security Considerations . . . . . . . . . . . . . . . . . . . 10
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10
7.1. URN sub-namespace registration for
'urn:ietf:params:xml:ns:pidf:geopriv10:civicAddr' . . . . 10
7.2. XML Schema Registration . . . . . . . . . . . . . . . . . 11
7.3. CAtype Registry Update . . . . . . . . . . . . . . . . . . 11
8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 12
8.1. Normative References . . . . . . . . . . . . . . . . . . . 12
8.2. Informative References . . . . . . . . . . . . . . . . . . 12
Appendix A. Acknowledgements . . . . . . . . . . . . . . . . . . 13
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RFC 5139 Revised Civic LO February 2008
1. Introduction
Since the publication of the original PIDF-LO civic specification, in
[RFC4119], it has been found that the specification is lacking a
number of additional parameters that can be used to more precisely
specify a civic location. These additional parameters have been
largely captured in [RFC4776].
This document revises the GEOPRIV civic form to include the
additional civic parameters captured in [RFC4776]. The document also
introduces a hierarchical structure for thoroughfare (road)
identification, which is employed in some countries. New elements
are defined to allow for even more precision in specifying a civic
location.
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 [RFC2119].
The term "thoroughfare" is used in this document to describe a road
or part of a road or other access route along which a final point is
identified. This is consistent with the definition used in
[UPU-S42].
3. Changes from PIDF-LO
3.1. Additional Civic Address Types
[RFC4776] provides a full set of parameters that may be used to
describe a civic location. Specifically, [RFC4776] lists several
civic address types (CAtypes) that require support in the formal
PIDF-LO definition that are not in [RFC4119].
These changes include new elements that are required to support more
complex structures for naming street addresses. This is described in
more detail in Section 3.2.
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RFC 5139 Revised Civic LO February 2008
+-----------+--------+-------------------------------+--------------+
| New Field | CAtype | Description | Example |
+-----------+--------+-------------------------------+--------------+
| BLD | 25 | Building (structure) | Hope Theatre |
| | | | |
| UNIT | 26 | Unit (apartment, suite) | 12a |
| | | | |
| ROOM | 28 | Room | 450F |
| | | | |
| PLC | 29 | Place-type | office |
| | | | |
| PCN | 30 | Postal community name | Leonia |
| | | | |
| POBOX | 31 | Post office box (P.O. box) | U40 |
| | | | |
| ADDCODE | 32 | Additional Code | 13203000003 |
| | | | |
| SEAT | 33 | Seat (desk, cubicle, | WS 181 |
| | | workstation) | |
| | | | |
| RD | 34 | Primary road or street | Broadway |
| | | | |
| RDSEC | 35 | Road section | 14 |
| | | | |
| RDBR | 36 | Road branch | Lane 7 |
| | | | |
| RDSUBBR | 37 | Road sub-branch | Alley 8 |
| | | | |
| PRM | 38 | Road pre-modifier | Old |
| | | | |
| POM | 39 | Road post-modifier | Extended |
+-----------+--------+-------------------------------+--------------+
Table 1: New Civic PIDF-LO Types
A complete description of these types is included in [RFC4776].
3.2. New Thoroughfare Elements
In some countries, a thoroughfare can be broken up into sections, and
it is not uncommon for street numbers to be repeated between
sections. A road section identifier is required to ensure that an
address is unique. For example, "West Alice Parade" in the figure
below has 5 sections, each numbered from 1; unless the section is
specified, "7 West Alice Parade" could exist in 5 different places.
The "RDSEC" element is used to specify the section.
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Minor streets can share the same name, so that they can only be
distinguished by the major thoroughfare with which they intersect.
For example, both "West Alice Parade, Section 3" and "Bob Street"
could both be intersected by a "Carol Lane". The "RDBR" element is
used to specify a road branch where the name of the branch does not
uniquely identify the road. Road branches MAY also be used where a
major thoroughfare is split into sections.
Similar to the way that a road branch is associated with a road, a
road sub-branch is associated with a road branch. The "RDSUBBR"
element is used to identify road sub-branches.
The "A6" element is retained for use in those countries that require
this level of detail. Where "A6" was previously used for street
names in [RFC4119], it MUST NOT be used; the "RD" element MUST be
used for thoroughfare data.
The following figure shows a fictional arrangement of roads where
these new thoroughfare elements are applicable.
| ||
| ---------------||
| Carol La. Carol La. || Bob
| || St.
| West Alice Pde. ||
==========/=================/===============/==========||===========
Sec.1 Sec.2 Sec.3 | Sec.4 || Sec.5
| ||
----------| Carol ||
Alley 2 | La. ||
| ||
3.2.1. Street Numbering
The introduction of new thoroughfare elements affects the
interpretation of several aspects of more specific civic address
data. In particular, street numbering (the "HNO" element) applies to
the most specific road element specified, that is, the first
specified element from "RDSUBBR", "RDBR", "RDSEC", or "RD".
3.2.2. Directionals and Other Qualifiers
The "PRM", "POM", "PRD", "POD", and "STS" elements always apply to
the value of the "RD" element only. If road branches or sub-branches
require street suffixes or qualifiers, they MUST be included in the
"RDBR" or "RDSUBBR" element text.
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3.3. Country Element
The "country" element differs from that defined in [RFC4119] in that
it now restricts the value space of the element to two uppercase
characters, which correspond to the alpha-2 codes in [ISO.3166-1].
3.4. A1 Element
The "A1" element is used for the top-level subdivision within a
country. In the absence of a country-specific guide on how to use
the A-series of elements, the second part of the ISO 3166-2 code
[ISO.3166-2] for a country subdivision SHOULD be used. The ISO
3166-2 code is formed of a country code and hyphen plus a code of
one, two, or three characters or numerals. For the "A1" element, the
leading country code and hyphen are omitted and only the subdivision
code is included.
For example, the codes for Canada include CA-BC, CA-ON, CA-QC;
Luxembourg has just three single-character codes, LU-D, LU-G, and
LU-L; Australia uses both two- and three-character codes, AU-ACT,
AU-NSW, AU-NT; and France uses numerical codes for mainland France
and letters for territories, FR-75, FR-NC. This results in the
following fragments:
CAON
LUL
AUACT
FR75
3.5. Languages and Scripts
The XML schema defined for civic addresses allows for the addition of
the "xml:lang" attribute to all elements except "country" and "PLC",
which both contain language-neutral values. The range of allowed
values for "country" is defined in [ISO.3166-1]; the range of allowed
values for "PLC" is described in the IANA registry defined by
[RFC4589].
The "script" field defined in [RFC4776] is omitted in favor of using
the "xml:lang" attribute with a script subtag [RFC4646].
It is RECOMMENDED that each "civicAddress" element use one language
only, or a combination of languages that is consistent. Where a
civic location is represented in multiple languages, multiple
"civicAddress" elements SHOULD be included in the PIDF-LO document.
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For civic addresses that form a complex to describe the same
location, these SHOULD be inserted into the same tuple.
3.5.1. Converting from the DHCP Format
The DHCP format for civic addresses [RFC4776] permits the inclusion
of an element multiple times with different languages or scripts.
However, this XML form only permits a single instance of each
element. Multiple "civicAddress" elements are required if any
element is duplicated with different languages. If the same language
and script are used for all elements, or no elements are duplicated,
the format can be converted into a single civic address.
Where there are duplicated elements in different languages, a
"civicAddress" element is created for each language that is present.
All elements that are in that language are included. Elements that
are language independent, like the "country" and "PLC" elements, are
added to all "civicAddress" elements.
3.5.2. Combining Multiple Elements Based on Language Preferences
If the receiver of the XML representation is known, and that receiver
has indicated language preferences, a single XML format can be
constructed using those preferences. For example, language
preferences can be indicated by the "Accept-Language" header in the
SIP or HTTP protocols.
All elements that have only one value, irrespective of language, are
used. Where multiple values exist, each value is assigned a
weighting based on the language preferences. The value with the
highest weighting is selected. An arbitrary value is selected if two
values have the same preference, if there is no preference for the
available languages, or if there are conflicting values with the same
language.
3.6. Whitespace
The XML schema [W3C.REC-xmlschema-2-20041028] defined in Section 4
uses a base type of "token" instead of "string" as used in [RFC4119].
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RFC 5139 Revised Civic LO February 2008
The "token" type ensures that whitespace within instance documents is
normalized and collapsed before being passed to a processor. This
ensures that the following fragments are considered equivalent by XML
processors:
North Wollongong
North
Wollongong
North Wollongong
Whitespace may still be included in values by using character
references, such as " ".
4. Civic Address Schema
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RFC 5139 Revised Civic LO February 2008
5. Example
AU
NSW
Wollongong
North Wollongong
FlindersStreet
Campbell Street
Gilligan's Island
Corner
Video Rental Store
2500
Westerns and Classics
store
Private Box 15
6. Security Considerations
The XML representation described in this document is designed for
inclusion in a PIDF-LO document. As such, it is subject to the same
security considerations as are described in [RFC4119].
Considerations relating to the inclusion of this representation in
other XML documents are outside the scope of this document.
7. IANA Considerations
7.1. URN sub-namespace registration for
'urn:ietf:params:xml:ns:pidf:geopriv10:civicAddr'
This document defines a new XML namespace (as per the guidelines in
[RFC3688]) that has been registered with IANA.
URI: urn:ietf:params:xml:ns:pidf:geopriv10:civicAddr
Registrant Contact: IETF, GEOPRIV working group (geopriv@ietf.org),
Martin Thomson (martin.thomson@andrew.com).
Thomson & Winterbottom Standards Track [Page 10]
RFC 5139 Revised Civic LO February 2008
XML:
BEGIN
GEOPRIV Civic Address
Format for Distributing Civic Address in GEOPRIV
urn:ietf:params:xml:ns:pidf:geopriv10:civicAddr
See
RFC5139.
END
7.2. XML Schema Registration
This section registers an XML schema as per the procedures in
[RFC3688].
URI: urn:ietf:params:xml:schema:pidf:geopriv10:civicAddr
Registrant Contact: IETF, GEOPRIV working group (geopriv@ietf.org),
Martin Thomson (martin.thomson@andrew.com).
The XML for this schema can be found as the entirety of Section 4
of this document.
7.3. CAtype Registry Update
This document updates the civic address type registry established by
[RFC4776]. The "PIDF" column of the CAtypes table has been updated
to include the types shown in the first column of Table 1.
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RFC 5139 Revised Civic LO February 2008
8. References
8.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[W3C.REC-xmlschema-2-20041028]
Biron, P. and A. Malhotra, "XML Schema Part 2: Datatypes
Second Edition", World Wide Web Consortium
Recommendation REC-xmlschema-2-20041028, October 2004,
.
[RFC4119] Peterson, J., "A Presence-based GEOPRIV Location Object
Format", RFC 4119, December 2005.
[RFC4589] Schulzrinne, H. and H. Tschofenig, "Location Types
Registry", RFC 4589, July 2006.
[RFC4646] Phillips, A. and M. Davis, "Tags for Identifying
Languages", BCP 47, RFC 4646, September 2006.
[RFC4776] Schulzrinne, H., "Dynamic Host Configuration Protocol
(DHCPv4 and DHCPv6) Option for Civic Addresses
Configuration Information", RFC 4776, November 2006.
[ISO.3166-1] International Organization for Standardization, "Codes
for the representation of names of countries and their
subdivisions - Part 1: Country codes", ISO Standard
3166- 1:1997, 1997.
[ISO.3166-2] International Organization for Standardization, "Codes
for the representation of names of countries and their
subdivisions - Part 2: Country subdivision code",
ISO Standard 3166-2:1998, 1998.
8.2. Informative References
[RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
January 2004.
[UPU-S42] Universal Postal Union (UPU), "International Postal
Address Components and Templates", UPS SB42-4,
July 2004.
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Appendix A. Acknowledgements
The authors would like to thank Henning Schulzrinne for his
assistance in defining the additional civic address types,
particularly his research into different addressing schemes that led
to the introduction of the thoroughfare elements. Rohan Mahy
suggested the ISO 3166-2 recommendation for A1. In addition, we
would like to thank Jon Peterson for his work in defining the
PIDF-LO.
Authors' Addresses
Martin Thomson
Andrew
PO Box U40
Wollongong University Campus, NSW 2500
AU
Phone: +61 2 4221 2915
EMail: martin.thomson@andrew.com
URI: http://www.andrew.com/
James Winterbottom
Andrew
PO Box U40
Wollongong University Campus, NSW 2500
AU
Phone: +61 2 4221 2938
EMail: james.winterbottom@andrew.com
URI: http://www.andrew.com/
Thomson & Winterbottom Standards Track [Page 13]
RFC 5139 Revised Civic LO February 2008
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Thomson & Winterbottom Standards Track [Page 14]