2004/id/draft-ietf-uri-urn-syntax-00.txt


IETF URI Working Group                                         Paul E. Hoffman
Internet-Draft                                               Proper Publishing
draft-ietf-uri-urn-syntax-00                                   Ron Daniel, Jr.
Expires October 21, 1995                        Los Alamos National Laboratory


                             Generic URN Syntax

Status of this memo

This document is an Internet-Draft. 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.
Internet-Drafts may be updated, replaced, or obsoleted by other documents
at any time. It s not appropriate to use Internet- Drafts as reference
material or to cite them other than as a "working draft" or "work in
progress."

To learn the current status of any Internet-Draft, please check the
1id-abstracts.txt listing contained n the Internet-Drafts Shadow
Directories on ds.internic.net, nic.nordu.net, ftp.isi.edu or
munnari.oz.au.

Abstract

This document defines the syntax for Uniform Resource Names (URNs). This
syntax is basically the same as the URN syntax described in RFC 1630.

This document does not cover any specific resolution schemes or the format
of resolution results. It is expected that these issues (and other
URN-related topics) will be covered in different Internet Drafts submitted
to the IETF URI Working Group.

1. Introduction

A URN (Uniform Resource Name) is the name of a resource within the context
of a larger Internet information architecture known as Uniform Resource
Identification [URIS]. The minimum set of requirements for URNs are
described in [URNR]. An overview of URN resolution is given in [URNO].

2. Syntax

URNs are simple text strings. A URN consists of two fields seperated by a
colon (:). The two fields are:
 - The type of naming authority of the URN, called the SchemeID
 - The name of the element for the URN, called the ElementID

When URNs appear in free text, or in other places where it is not known
that they are URNs, they should be shown in a separate syntactic wrapper.
The start of the wrapper is an opening angle backet (<), the string "URN"
(the case of the letters does not matter), and a delimiting colon (:). The
tail of the wrapper is a closing angle bracket (>). Freestanding URNs that
include any white space must be wrapped in this fashion.

For example, a URN stored in a database might look like:
     x-dns-2:library.bigstate.edu:aj17-mcc

The same URN, appearing in a mail message, would look like
     <urn:x-dns-2:library.bigstate.edu:aj17-mcc>

The first and SchemeID fields are case insensitive. The case sensitivity
and character set of the ElementID field depends on the value of the
SchemeID field. White space (the characters Space, Tab, CR, and LF) is
allowed but is not significant within a URN.

URNs are often displayed and transmitted in the same media as URLs. In
order to minimize problems with interoperability, encoding of characters in
URNs follow the same rules used by URLs in [URL].

2.1 SchemeIDs

The SchemeID field describes what kind of naming authority is used. This is
the authority by which the ElementIDs are defined.

SchemeIDs are case insensitive identifiers of the URN resolution scheme
used to resolve a URN. SchemeIDs starting with the characters "x-" are
reserved for experimental purposes. Because all URN schemes are currently
experimental, all URN SchemeIDs should begin with "x-" until the schemes
are approved by the IETF URI Working Group. The Internet Assigned Numbers
Authority (IANA) will maintain a registry of SchemeIDs.

2.2 ElementIDs

The ElementID is the element that will be resolved. It is important to note
that this is not the "name" part of the URN: the combination of the three
fields in a URN is the only definition of the resource's name. For example,
consider the two URNs:
<urn:x-dns-2:physics.bigstate.edu:thesis12>
<urn:x-wlnk:physics.bigstate.edu:thesis12>
They might be names of completely different Internet resources, similar
resources, or even the same resource. However, even though the ElementIDs
are the same in the two URNs, the two URNs are different.

For all Element IDs in all SchemeIDs, the characters "#" (hex 23) and "?"
(hex 3F) are reserved for future use. Also, ">" (hex 3E) is reserved since
it is the wrapper closing character. The ":" (hex 3A) character is not
reserved, but its semantics of seperating fields should not be casually
ignored.

3. Security Implications

Although there are security implications in resolving URNs, there are no
security implications in defining their syntax.

4. References

[URIS] RFC 1630, "Universal Resource Identifiers in WWW".

[URL] RFC 1738, "Uniform Resource Locators (URL)".

[URNO] Internet-Draft, "URN Resolution Overview". The name of the draft at
the time of this writing is "draft-ietf-uri-urn-res-descrip-00".

[URNR] RFC 1737, "Functional Requirements for Uniform Resource Names".

5. Author Contact Information

Paul E. Hoffman
Proper Publishing
127 Segre Place
Santa Cruz, CA, USA  95060
voice:  (408) 426-6222
phoffman@proper.com

Ron Daniel Jr.
MS B287
Los Alamos National Laboratory
Los Alamos, NM, USA 87545
voice:  (505) 665-0597
fax:  (505) 665-4939
rdaniel@lanl.gov


1
2	IETF URI Working Group Paul E. Hoffman
3	Internet-Draft Proper Publishing
4	draft-ietf-uri-urn-syntax-00 Ron Daniel, Jr.
5	Expires October 21, 1995 Los Alamos National Laboratory
6
7
8	Generic URN Syntax
9
10	Status of this memo
11
12	This document is an Internet-Draft. Internet-Drafts are working documents
13	of the Internet Engineering Task Force (IETF), its areas, and its working
14	groups. Note that other groups may also distribute working documents as
15	Internet-Drafts.
16
17	Internet-Drafts are draft documents valid for a maximum of six months.
18	Internet-Drafts may be updated, replaced, or obsoleted by other documents
19	at any time. It s not appropriate to use Internet- Drafts as reference
20	material or to cite them other than as a "working draft" or "work in
21	progress."
22
23	To learn the current status of any Internet-Draft, please check the
24	1id-abstracts.txt listing contained n the Internet-Drafts Shadow
25	Directories on ds.internic.net, nic.nordu.net, ftp.isi.edu or
26	munnari.oz.au.
27
28	Abstract
29
30	This document defines the syntax for Uniform Resource Names (URNs). This
31	syntax is basically the same as the URN syntax described in RFC 1630.
32
33	This document does not cover any specific resolution schemes or the format
34	of resolution results. It is expected that these issues (and other
35	URN-related topics) will be covered in different Internet Drafts submitted
36	to the IETF URI Working Group.
37
38	1. Introduction
39
40	A URN (Uniform Resource Name) is the name of a resource within the context
41	of a larger Internet information architecture known as Uniform Resource
42	Identification [URIS]. The minimum set of requirements for URNs are
43	described in [URNR]. An overview of URN resolution is given in [URNO].
44
45	2. Syntax
46
47	URNs are simple text strings. A URN consists of two fields seperated by a
48	colon (:). The two fields are:
49	- The type of naming authority of the URN, called the SchemeID
50	- The name of the element for the URN, called the ElementID
51
52	When URNs appear in free text, or in other places where it is not known
53	that they are URNs, they should be shown in a separate syntactic wrapper.
54	The start of the wrapper is an opening angle backet (<), the string "URN"
55	(the case of the letters does not matter), and a delimiting colon (:). The
56	tail of the wrapper is a closing angle bracket (>). Freestanding URNs that
57	include any white space must be wrapped in this fashion.
58
59	For example, a URN stored in a database might look like:
60	x-dns-2:library.bigstate.edu:aj17-mcc
61
62	The same URN, appearing in a mail message, would look like
63	<urn:x-dns-2:library.bigstate.edu:aj17-mcc>
64
65	The first and SchemeID fields are case insensitive. The case sensitivity
66	and character set of the ElementID field depends on the value of the
67	SchemeID field. White space (the characters Space, Tab, CR, and LF) is
68	allowed but is not significant within a URN.
69
70	URNs are often displayed and transmitted in the same media as URLs. In
71	order to minimize problems with interoperability, encoding of characters in
72	URNs follow the same rules used by URLs in [URL].
73
74	2.1 SchemeIDs
75
76	The SchemeID field describes what kind of naming authority is used. This is
77	the authority by which the ElementIDs are defined.
78
79	SchemeIDs are case insensitive identifiers of the URN resolution scheme
80	used to resolve a URN. SchemeIDs starting with the characters "x-" are
81	reserved for experimental purposes. Because all URN schemes are currently
82	experimental, all URN SchemeIDs should begin with "x-" until the schemes
83	are approved by the IETF URI Working Group. The Internet Assigned Numbers
84	Authority (IANA) will maintain a registry of SchemeIDs.
85
86	2.2 ElementIDs
87
88	The ElementID is the element that will be resolved. It is important to note
89	that this is not the "name" part of the URN: the combination of the three
90	fields in a URN is the only definition of the resource's name. For example,
91	consider the two URNs:
92	<urn:x-dns-2:physics.bigstate.edu:thesis12>
93	<urn:x-wlnk:physics.bigstate.edu:thesis12>
94	They might be names of completely different Internet resources, similar
95	resources, or even the same resource. However, even though the ElementIDs
96	are the same in the two URNs, the two URNs are different.
97
98	For all Element IDs in all SchemeIDs, the characters "#" (hex 23) and "?"
99	(hex 3F) are reserved for future use. Also, ">" (hex 3E) is reserved since
100	it is the wrapper closing character. The ":" (hex 3A) character is not
101	reserved, but its semantics of seperating fields should not be casually
102	ignored.
103
104	3. Security Implications
105
106	Although there are security implications in resolving URNs, there are no
107	security implications in defining their syntax.
108
109	4. References
110
111	[URIS] RFC 1630, "Universal Resource Identifiers in WWW".
112
113	[URL] RFC 1738, "Uniform Resource Locators (URL)".
114
115	[URNO] Internet-Draft, "URN Resolution Overview". The name of the draft at
116	the time of this writing is "draft-ietf-uri-urn-res-descrip-00".
117
118	[URNR] RFC 1737, "Functional Requirements for Uniform Resource Names".
119
120	5. Author Contact Information
121
122	Paul E. Hoffman
123	Proper Publishing
124	127 Segre Place
125	Santa Cruz, CA, USA 95060
126	voice: (408) 426-6222
127	phoffman@proper.com
128
129	Ron Daniel Jr.
130	MS B287
131	Los Alamos National Laboratory
132	Los Alamos, NM, USA 87545
133	voice: (505) 665-0597
134	fax: (505) 665-4939
135	rdaniel@lanl.gov
136
137