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diff --git a/doc/rfc/rfc8458.txt b/doc/rfc/rfc8458.txt new file mode 100644 index 0000000..3738ee1 --- /dev/null +++ b/doc/rfc/rfc8458.txt @@ -0,0 +1,1011 @@ + + + + + + +Internet Engineering Task Force (IETF) J. Hakala +Request for Comments: 8458 The National Library of Finland +Obsoletes: 3188 October 2018 +Category: Informational +ISSN: 2070-1721 + + + Using National Bibliography Numbers as Uniform Resource Names + +Abstract + + National Bibliography Numbers (NBNs) are used by national libraries + and other organizations in order to identify resources in their + collections. NBNs are usually applied to resources that are not + catered for by established (standard) identifier systems such as + International Standard Book Number (ISBN). + + A Uniform Resource Name (URN) namespace for NBNs was established in + 2001 in RFC 3188. Since then, a number of European national + libraries have implemented URN:NBN-based systems. + + This document replaces RFC 3188 and defines how NBNs can be supported + within the updated URN framework. A revised namespace registration + (version 4) compliant to RFC 8141 is included. + +Status of This Memo + + This document is not an Internet Standards Track specification; it is + published for informational purposes. + + This document is a product of the Internet Engineering Task Force + (IETF). It represents the consensus of the IETF community. It has + received public review and has been approved for publication by the + Internet Engineering Steering Group (IESG). Not all documents + approved by the IESG are candidates for any level of Internet + Standard; see Section 2 of RFC 7841. + + Information about the current status of this document, any errata, + and how to provide feedback on it may be obtained at + https://www.rfc-editor.org/info/rfc8458. + + + + + + + + + + + +Hakala Informational [Page 1] + +RFC 8458 NBN URNs October 2018 + + +Copyright Notice + + Copyright (c) 2018 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 + + (https://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. + +Table of Contents + + 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 + 2. Conventions Used in This Document . . . . . . . . . . . . . . 5 + 3. Fundamental Namespace and Community Considerations for NBN . 5 + 3.1. The URN:NBN Namespace . . . . . . . . . . . . . . . . . . 5 + 3.2. Community Considerations for NBNs . . . . . . . . . . . . 6 + 4. National Bibliography Number URNs . . . . . . . . . . . . . . 7 + 4.1. Assignment . . . . . . . . . . . . . . . . . . . . . . . 7 + 4.2. Syntax . . . . . . . . . . . . . . . . . . . . . . . . . 8 + 4.2.1. Usage of r-component and q-component . . . . . . . . 10 + 4.2.2. Usage of f-component . . . . . . . . . . . . . . . . 10 + 4.3. Encoding Considerations and Lexical Equivalence . . . . . 10 + 4.4. Resolution and Persistence of NBN-based URNs . . . . . . 12 + 4.5. Additional Considerations . . . . . . . . . . . . . . . . 13 + 5. URN Namespace ID (NID) Registration for the National + Bibliography Number (NBN) . . . . . . . . . . . . . . . . . . 13 + 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 15 + 7. Security Considerations . . . . . . . . . . . . . . . . . . . 15 + 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 15 + 8.1. Normative References . . . . . . . . . . . . . . . . . . 15 + 8.2. Informative References . . . . . . . . . . . . . . . . . 16 + Appendix A. Significant Changes from RFC 3188 . . . . . . . . . 18 + Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 18 + Contributors . . . . . . . . . . . . . . . . . . . . . . . . . . 18 + Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 18 + + + + + + + + + +Hakala Informational [Page 2] + +RFC 8458 NBN URNs October 2018 + + +1. Introduction + + One of the basic permanent Uniform Resource Identifier (URI) schemes + (cf. [RFC3986] and [IANA-URI]) is Uniform Resource Name (URN). URNs + were originally defined in RFC 2141 [RFC2141]. In 2017, a revision + was adopted with new definitions and registration procedures + [RFC8141]. Any traditional identifier, when used within the URN + system, must have a namespace of its own that is registered with IANA + [IANA-URN]. National Bibliography Number (NBN) is one such + namespace, specified in 2001 in RFC 3188 [RFC3188]. + + This document describes the syntax and usage of NBN URNs and updates + the registration of the associated URN namespace. This document + additionally describes certain policy assumptions about how national + libraries and their partner organizations partition, delegate, and + manage the namespace. Violation of those assumptions could impact + the utility of the NBN URN namespace. + + URN:NBNs are in production use in several European countries + including (in alphabetical order) Austria, Finland, Germany, Hungary, + Italy, the Netherlands, Norway, Sweden, and Switzerland. The URN:NBN + namespace is collectively managed by these national libraries. URN: + NBNs have been applied to diverse content including Web archives, + digitized materials, research data, and doctoral dissertations. They + can be used by national libraries and organizations cooperating with + them. + + As a part of the initial development of the URN system in the late + 1990s, the IETF URN Working Group agreed that it was important to + demonstrate that the URN syntax can accommodate existing identifier + systems. RFC 2288 [RFC2288] investigated the feasibility of using + ISBN, ISSN, and SICI (Serial Item and Contribution Identifier) as + URNs, with positive results; however, it did not formally register + corresponding URN namespaces. (For further discussion of how these + systems have evolved as URNs, see RFC 8254 [RFC8254].) This was in + part due to the still-evolving process to formalize criteria for + namespace definition documents and registration. The criteria were + consolidated later in the IETF, first in RFC 2611 [RFC2611], then RFC + 3406 [RFC3406], and now RFC 8141 [RFC8141]. + + URN namespaces have been registered for NBN, ISBN, and ISSN in RFCs + 3188 [RFC3188], 3187 [RFC3187], and 3044 [RFC3044], respectively. + ISBN and ISSN namespaces were made compliant with RFC 8141 [RFC8141] + in 2017 by publishing revised ISSN [ISSN-namespace] and ISBN + [ISBN-namespace] namespace registrations. + + + + + + +Hakala Informational [Page 3] + +RFC 8458 NBN URNs October 2018 + + + The term "National Bibliography Number" encompasses persistent local + identifier systems that national libraries and their partner + organizations use in addition to the more formally (and + internationally) established identifiers. These partner + organizations include universities and their libraries and other + subsidiaries, other research institutions, plus governmental and + public organizations. Some national libraries maintain a significant + number of these liaison relationships; for instance, the German + National Library had almost 400 by early 2018 [NBN-Resolving]. + + In practice, NBN differs from standard identifier systems such as + ISBN and ISSN because it is not a single identifier system with + standard-specified scope and syntax. Each NBN implementer creates + its own system with its own syntax and assignment rules. Each user + organization is also obliged to keep track of how NBNs are being + used; however, within the generic framework set in this document, + local NBN assignment policies may vary considerably. + + Historically, NBNs have been applied in the national bibliographies + to identify the resources catalogued into them. Prior to the + emergence of bibliographic standard identifiers in the early 1970s, + national libraries assigned NBNs to all catalogued publications. + + Since the late 1990s, the NBN scope has been extended to cover a vast + range of resources, both originally digital and digitized. Only a + small subset of these resources is catalogued in the national + bibliographies or other bibliographic databases. Digitized resources + and their component parts (such as still images in books or journal + articles) are examples of resources that may get NBNs. + + It is possible to extend the scope of the NBN much further. The + National Library of Finland is using them in the Finnish National + Ontology Service Finto to identify corporate names (see + <http://finto.fi/cn/en/>). Using NBNs to identify metadata elements + provides a stable basis for creation of linked data. + + Simple guidelines for using NBNs as URNs and the original namespace + registration were published in RFC 3188 [RFC3188]. The RFC at hand + replaces RFC 3188; sections discussing the methods by which URN:NBNs + should be resolved have been updated, unused features have been + eliminated, and the text is compliant with the stipulations of the + revised URN specification [RFC8141]. + + + + + + + + + +Hakala Informational [Page 4] + +RFC 8458 NBN URNs October 2018 + + +2. Conventions Used in This Document + + "NBN" refers to any National Bibliography Number identifier system + used by the national libraries (or equivalent organizations) and + other institutions, which use these identifiers with national + libraries' support and permission. + + In this memo, "URN:NBN" is used as a shorthand for "NBN-based URN". + + The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", + "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and + "OPTIONAL" in this document are to be interpreted as described in + BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all + capitals, as shown here. + +3. Fundamental Namespace and Community Considerations for NBN + +3.1. The URN:NBN Namespace + + NBNs are widely used to identify both hand-held and digital resources + in the collections of national libraries and other institutions that + are responsible for preserving the cultural heritage of their + constituents. Resources in these collections are usually preserved + for a long time (i.e., for centuries). While the preferred methods + for digital preservation may vary over time and depend on the + content, the favorite one has been migration. Whenever necessary, a + resource in an outdated file format is migrated into a more modern + file format. To the extent possible, all old versions of the + resource are also kept in order to alleviate the negative effects of + partially successful migrations and the gradual loss of original look + and feel that may accompany even fully successful migrations. When + NBN is used to identify manifestations and there are many of them for + a single work, local policy can require that each manifestation ought + to have its own NBN. + + NBNs are typically used to identify objects for which standard + identifiers such as ISBN are not applicable. However, NBNs can be + used for component resources even when the resource as a whole + qualifies for a standard identifier. For instance, if a digitized + book has an ISBN, JPEG image files of its pages might be assigned + NBNs. These URN:NBNs can be used as persistent links to the pages. + + The scope of standard identifier systems such as ISBN and ISSN is + limited; they are applicable only to certain kinds of resources. One + of the roles of the NBN is to fill in the gaps left by the standard + identifiers. Collectively, these identifiers and NBNs cover all + resources that national libraries and their partners need to include + in their collections. + + + +Hakala Informational [Page 5] + +RFC 8458 NBN URNs October 2018 + + + Section 4 below, and particularly Section 4.1, present a more + detailed overview of the structure of the NBN namespace, related + institutions, and the identifier assignment principles used. + +3.2. Community Considerations for NBNs + + National libraries are the key organizations providing persistent URN + resolution services for resources identified with NBNs, independent + of their form. As coordinators of NBN usage, national libraries have + allowed other organizations, such as university libraries or + governmental organizations, to assign NBNs to the resources these + organizations preserve for the long term. In such case, the national + library coordinates the use of NBNs at the national level. National + libraries can also provide URN resolution services and technical + services to other NBN users. These organizations are expected to + either establish their own URN resolution services or use the + technical infrastructure provided by the national library. URN:NBNs + are expected to be resolvable and support one or more resolution + services. + + Although NBNs can be used to identify component resources, the NBN + namespace does not specify a generic, intrinsic syntax for doing + that. However, there are at least two different ways in which + component resources can be taken into account within the NBN + namespace. + + The simplest and probably the most common approach is to assign a + separate NBN for each component resource, such as a file containing a + digitized page of a book, and make no provisions to make such NBNs + discernible in a systematic way from others. + + Second, if the stipulations of the URI generic syntax [RFC3986] and + the Internet media type specification [RFC2046] are met, in + accordance with the provisions in RFC 8141 [RFC8141], the URN + f-component can be attached to URN:NBNs in order to indicate the + desired location within the resource supplied by URN resolution. + + From the library community point of view, it is important that the + f-component is not a part of the Namespace-Specific String (NSS), and + therefore f-component attachment does not mean that the relevant + component part is identified. Moreover, the resolution process still + retrieves the entire resource even if there is an f-component. The + component part selection is applied by the resolution client (e.g., + browser) to the resource returned by the resolution process. In + other words, in this latter case the component parts are just logical + and physical parts of the identified resource whereas in the former + cases they are independently named entities. + + + + +Hakala Informational [Page 6] + +RFC 8458 NBN URNs October 2018 + + + Resources identified by NBNs are not always available in the + Internet. If one is not, the URN:NBN can resolve to a surrogate such + as a metadata record describing the identified resource. + + Section 4 below, and particularly Section 4.4, presents a detailed + overview of the application of the URN:NBN namespace as well as the + principles of, and systems used for, the resolution of NBN-based + URNs. + +4. National Bibliography Number URNs + +4.1. Assignment + + National Bibliography Number (NBN) is a generic term referring to a + group of identifier systems administered by national libraries and + institutions authorized by them. The NBN assignment is typically + performed by the organization hosting the resource. National + libraries are committed to permanent preservation of their deposit + collections. + + Assignment of NBN-based URNs is controlled on a national level by the + national library (or national libraries, if there is more than one). + National guidelines can differ, but the identified resources + themselves are usually persistent. + + Different national URN:NBN assignment policies have resulted in + varying levels of control of the assignment process. Manual URN:NBN + assignment by the library personnel provides the tightest control, + especially if the URN:NBNs cover only resources catalogued into the + national bibliography. In most national libraries, the scope of + URN:NBN is already much broader than this. Usage rules can vary + within one country, from one URN:NBN sub-namespace to the next. + + Each national library uses NBNs independently of other national + libraries; apart from this document, there are no guidelines that + specify or control NBN usage. As such, NBNs are unique only on the + national level. When used as URNs, base NBN strings MUST be + augmented with a controlled prefix, which is the particular nation's + ISO 3166-1 alpha-2 two-letter country code (referred to as "ISO + country code" below) [ISO3166-1]. These prefixes guarantee + uniqueness of the URN:NBNs at the global scale [ISO3166MA]. + + National libraries using URN:NBNs usually specify local assignment + policies for themselves. Such policy can limit the URN:NBN usage to, + e.g., the resources stored in the national library's digital + collections or databases. Although this specification does not + + + + + +Hakala Informational [Page 7] + +RFC 8458 NBN URNs October 2018 + + + specify principles for URN:NBN assignment policies that can be + applied, NBNs assigned to short-lived resources should not be made + URN:NBNs unless such policy can be justified. + + URN:NBN assignment policy can clarify, for instance, the local policy + concerning identifier assignment to component parts of resources and + can specify, with sufficient detail, the syntax of local component + identifiers (if there is one as a discernible part of the NBNs). The + policy can also cover any employed extensions to the default NBN + scope. + + NBNs as such are locally but not globally unique; two national + libraries can assign the same NBN to different resources. A prefix, + based on the ISO country code as described above, guarantees the + global uniqueness of URN:NBNs. Once an NBN has been assigned to a + resource, it MUST be persistent, and therefore URN:NBNs are + persistent as well. + + A URN:NBN, once it has been generated from a NBN, MUST NOT be reused + for another resource. + + Users of the URN:NBN namespace MUST ensure that they do not assign + the same URN:NBN twice. Different policies can be applied to + guarantee this. For instance, NBNs and corresponding URN:NBNs can be + assigned sequentially by programs in order to avoid human mistakes. + It is also possible to use printable representations of checksums + such as SHA-1 [RFC6234] as NBNs. + +4.2. Syntax + + The Namespace-Specific String (NSS) will consist of three parts: + + o a prefix consisting of an ISO 3166-1 alpha-2 country code and + optional sub-namespace code(s) separated by a colon(s); + + o a hyphen (-) as the delimiting character; and, + + o an NBN string assigned by the national library or sub-delegated + authority. + + + + + + + + + + + + +Hakala Informational [Page 8] + +RFC 8458 NBN URNs October 2018 + + + The following formal definition uses ABNF [RFC5234]. + + nbn-nss = prefix "-" nbn-string + + prefix = iso-cc *( ":" subspc ) + ; The entire prefix is case insensitive. + + iso-cc = 2ALPHA + ; Alpha-2 country code as assigned by part 1 of ISO 3166 + ; (identifies the national library to which the branch + ; is delegated). + + subspc = 1*(ALPHA / DIGIT) + ; As assigned by the respective national library. + + nbn-string = path-rootless + ; The "path-rootless" rule is defined in RFC 3986. + ; Syntax requirements specified in RFC 8141 MUST be + ; taken into account. + + A colon SHOULD be used within the prefix only as a delimiting + character between the ISO 3166-1 country code and sub-namespace + code(s), which splits the national namespace into smaller parts. + + The structure (if any) of the nbn_string is determined by the + authority for the prefix. Whereas the prefix is regarded as case + insensitive, NBN strings can be case sensitive at the preference of + the assigning authority; parsers therefore MUST treat these as case + sensitive, and any case mapping needed to introduce case + insensitivity is the responsibility of the relevant resolution + system. + + A hyphen SHOULD be used as the delimiting character between the + prefix and the NBN string. Within the NBN string, a hyphen MAY be + used for separating different sections of the identifier from one + another. + + All two-letter codes are reserved by the ISO 3166 Maintenance Agency + for either existing or possible future ISO country codes (or for + private use). + + Sub-namespace identifiers MUST be registered on the national level by + the national library that assigned the identifier. The list of such + identifiers can be made publicly available via the Web. + + Note that because case mapping for ASCII letters is completely + reversible and does not lose information, the case used in case- + insensitive matching is a local matter. Implementations can convert + + + +Hakala Informational [Page 9] + +RFC 8458 NBN URNs October 2018 + + + to lower or upper case as they see fit; they only need to do it + consistently. + +4.2.1. Usage of r-component and q-component + + URN:NBN resolvers do not currently support the use of either + r-component or q-component. + + Resolution services based on r-component can be implemented in the + future when the r-component syntax and semantics have been specified. + +4.2.2. Usage of f-component + + If URN:NBN resolves to the identified resource and the media type of + the resource supports f-component usage, it can be used to indicate a + location within the identified resource. Persistence is achieved if + the URN:NBN is assigned to one and only one version of a resource, + such as a PDF/A version of a book. + + The URN:NBN namespace does not impose any restrictions of its own on + f-component usage. + +4.3. Encoding Considerations and Lexical Equivalence + + Expressing NBNs as URNs is usually straightforward, as normally only + ASCII characters are used in NBN strings. If this is not the case, + non-ASCII characters in NBNs MUST be translated into canonical form + as specified in RFC 8141. If a national library uses NBNs that can + contain percent-encoded characters higher than U+007F, the library + needs to carefully define the canonical transformation from these + NBNs into URNs, including normalization forms. + + When an NBN is used as a URN, the NSS MUST consist of three parts: + + o a prefix, structured as a primary prefix, which is a two-letter + ISO 3166-1 country code of the library's country, and zero or more + secondary prefixes that are each indicated by a delimiting colon + character (:) and a sub-namespace identifier; + + o a hyphen (-) as a delimiting character; and, + + o the NBN string. + + Different delimiting characters are not semantically equivalent. + + The syntax and roles of the three parts listed above are described in + Section 4.2. + + + + +Hakala Informational [Page 10] + +RFC 8458 NBN URNs October 2018 + + + If there are several national libraries in one country, these + libraries MUST agree on how to divide the national namespace between + themselves using this method before the URN:NBN assignment begins in + any of these libraries. + + A national library MAY also assign URN:NBN sub-namespaces to trusted + organizations such as universities or government institutions. The + sub-namespace MAY be further divided by the partner organization. + All sub-namespace identifiers used within a country-code-based + namespace MUST be registered on the national level by the national + library that assigned the code. The national register of these codes + SHOULD be made available online. + + Being part of the prefix, sub-namespace identifier strings are case- + insensitive. They MUST NOT contain any colons or hyphens. + + Formally, two URN:NBNs are lexically equivalent if they are octet- + by-octet equal after the following (conceptional) preprocessing: + + 1. convert all characters in the leading "urn:nbn:" token to a + single case; + + 2. convert all characters in the prefix (country code and its + optional sub-divisions) to a single case; and, + + 3. convert all characters embedded in any percent-encodings to a + single case. + + Models (indicated line break inserted for readability): + + URN:NBN:<ISO 3166 alpha-2 country code>-<assigned NBN string> + + URN:NBN:<ISO 3166 alpha-2 country code>:<sub-namespace code>-\ + <assigned NBN string> + + Examples: + + URN:NBN:fi-fe201003181510 + + urn:nbn:ch:bel-9039 + + urn:nbn:se:uu:diva-3475 + + urn:nbn:hu-3006 + + + + + + + +Hakala Informational [Page 11] + +RFC 8458 NBN URNs October 2018 + + +4.4. Resolution and Persistence of NBN-based URNs + + Eventually, URNs might be resolved with the help of a Global Resolver + Discovery Service (GRDS), and URN:NBN syntax makes it possible to + locate the relevant resolver. Since no GRDS system has been + installed yet in the Internet, URN:NBNs are embedded in HTTP URIs in + order to make them actionable in the present Internet. In these HTTP + URIs, the authority part must point to the appropriate URN resolution + service. For instance, in Finland, the address of the national URN + resolver is <http://urn.fi>. Thus, the HTTP URI for the Finnish URN + in the example above is <http://urn.fi/URN:NBN:fi-fe201003181510>. + + The country-code-based prefix part of the URN:NBN namespace-specific + string will provide a hint needed to find the correct resolution + service for URN:NBNs from the GRDS when it is established. + + There are three interrelated aspects of persistence that need to be + discussed: persistence of the objects itself, persistence of the + identifier, and persistence of the URN resolvers. + + NBNs have traditionally been assigned to printed resources, which + tend to be persistent. In contrast, digital resources require + frequent migrations to guarantee accessibility. Although it is + impossible to estimate how often migrations are needed, hardware and + software upgrades take place frequently, and a lifetime exceeding + 10-20 years can be considered as long. + + However, it is a common practice to keep also the original and + previously migrated versions of resources. Therefore, even outdated + versions of resources can be available in digital archives, no matter + how old or difficult to use they have become. + + If all versions of a resource are kept, a user who requires + authenticity can retrieve the original version of the resource, + whereas a user to whom the ease of use is a priority is likely to be + satisfied with the latest version. In order to enable the users to + find the best match, a national library can link all manifestations + of a resource to each other so as to make a user aware of them. + + Thus, even if specific versions of digital resources are not normally + persistent, persistent identifiers such as URN:NBNs support + information architectures that enable persistent access to any + version of the resource, including ones that can only be utilized by + using digital archaeology tools such as custom-made applications to + render the resource. + + + + + + +Hakala Informational [Page 12] + +RFC 8458 NBN URNs October 2018 + + + Persistence of URN resolvers themselves is mainly an organizational + issue that is related to the persistence of organizations maintaining + them. As URN:NBN resolution services will be supplied (primarily) by + the national libraries, these services are likely to be long lived. + +4.5. Additional Considerations + + It is a good idea to apply URN:NBNs (or other persistent identifiers) + to all resources that have been prioritized in the organization's + digital preservation plan. + + Assignment of URN:NBNs to resources that are known to not be + persistent should be considered carefully. URN:NBNs can, however, be + applied to resources that have a low-level preservation priority and + will not be migrated to more modern file formats or preserved via + emulation. + + If the identified version of a resource has disappeared, the + resolution process can supply a surrogate if one exists. A surrogate + can be, for instance, a more modern digital version of the original + electronic resource. + +5. URN Namespace ID (NID) Registration for the National Bibliography + Number (NBN) + + This URN namespace registration describes how National Bibliography + Numbers (NBNs) can be supported within the URN framework; it uses the + updated IANA template specified in RFC 8141. + + Namespace Identifier: NBN + This namespace ID was formally assigned to the National + Bibliography Number in October 2001, when the namespace was + registered officially [RFC3188]. Utilization of URN:NBNs had + started in demo systems already in 1998. Since 2001, tens of + millions of URN:NBNs have been assigned. The number of users of + the namespace has grown in two ways: new national libraries have + started using NBNs, and many national libraries using the system + have formed new liaisons. + + Version: 4 + + Date: 2018-04-09 + + + + + + + + + +Hakala Informational [Page 13] + +RFC 8458 NBN URNs October 2018 + + + Registrant: + Name: Juha Hakala + Affiliation: Senior Adviser, The National Library of Finland + Email: juha.hakala@helsinki.fi + Postal: P.O. Box 15, 00014 Helsinki University, Finland + Web URL: http://www.nationallibrary.fi/ + + The National Library of Finland registered the namespace on behalf + of the Conference of the European National Librarians (CENL) and + Conference of Directors of National Libraries (CDNL). The NBN + namespace is available for free for the national libraries. They + can allow other organizations to assign URN:NBNs and use the + resolution services established by the library for free or for a + fee. The fees, if collected, can be based on, e.g., the + maintenance costs of the system. + + Purpose: See Section 3 of RFC 8458 + + Syntax: See Section 4.2 of RFC 8458 + + Assignment: See Section 4.1 of RFC 8458 + + Security and Privacy: See Section 7 of RFC 8458 + + Interoperability: + National libraries and their partners usually apply URN:NBNs if a + standard identifier such as ISBN is not applicable for the + resource to be identified. Some overlap with other URN namespaces + is possible. + + URN:NBNs may contain characters which must be percent-encoded, but + usually they consist of printable ASCII characters only. + + Resolution: See Section 4.4 of RFC 8458 + + Documentation: RFC 8458 + + Revision Information: + This version of the URN:NBN namespace registration has been + updated to use the revised definition of URN syntax from RFC 8141, + although usage of r-components is not specified yet. In addition, + non-ISO 3166 (country code) based NBNs have been deleted due to + lack of deployment. The entire NBN prefix is now specified to be + case insensitive in accordance with established practice. This + version also includes numerous clarifications based on actual + usage of URN:NBNs. + + + + + +Hakala Informational [Page 14] + +RFC 8458 NBN URNs October 2018 + + +6. IANA Considerations + + IANA has updated the existing registration of the formal URN + namespace, "NBN", using the template given above in Section 5. + +7. Security Considerations + + This document defines means of encoding NBNs as URNs. A URN + resolution service for NBN-based URNs is depicted but only at a + generic level; thus, questions of secure or authenticated resolution + mechanisms and authentication of users are out of scope of this + document. + + Although no validation mechanisms are specified on the global level + (beyond a routine check of those characters that require special + encoding when employed in URIs), NBNs assigned by any given authority + can have a well-specified and rich syntax (including, e.g., fixed + length and checksum). In such cases, it is possible to validate the + correctness of NBNs programmatically. + + Issues regarding intellectual property rights associated with objects + identified by the URN:NBNs are beyond the scope of this document, as + are questions about rights to the databases that might be used to + construct resolution services. + + Beyond the generic security considerations laid out in the underlying + documents listed in the Normative References, no specific security + threats have been identified for NBN-based URNs. + +8. References + +8.1. Normative References + + [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate + Requirement Levels", BCP 14, RFC 2119, + DOI 10.17487/RFC2119, March 1997, + <https://www.rfc-editor.org/info/rfc2119>. + + [RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform + Resource Identifier (URI): Generic Syntax", STD 66, + RFC 3986, DOI 10.17487/RFC3986, January 2005, + <https://www.rfc-editor.org/info/rfc3986>. + + [RFC5234] Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax + Specifications: ABNF", STD 68, RFC 5234, + DOI 10.17487/RFC5234, January 2008, + <https://www.rfc-editor.org/info/rfc5234>. + + + + +Hakala Informational [Page 15] + +RFC 8458 NBN URNs October 2018 + + + [RFC8141] Saint-Andre, P. and J. Klensin, "Uniform Resource Names + (URNs)", RFC 8141, DOI 10.17487/RFC8141, April 2017, + <https://www.rfc-editor.org/info/rfc8141>. + + [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC + 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, + May 2017, <https://www.rfc-editor.org/info/rfc8174>. + +8.2. Informative References + + [IANA-URI] IANA, "Uniform Resource Identifier (URI) Schemes", + <http://www.iana.org/assignments/uri-schemes>. + + [IANA-URN] IANA, "Uniform Resource Names (URN) Namespaces", + <http://www.iana.org/assignments/urn-namespaces>. + + [ISBN-namespace] + Griffiths, S., "Namespace Registration for International + Standard Book Number (ISBN) ISO 2108:2017", + <https://www.iana.org/assignments/urn-formal/isbn>. + + [ISO3166-1] + ISO, "Codes for the representation of names of countries + and their subdivisions -- Part 1: Country codes", + ISO 3166-1:2013, November 2013, + <https://www.iso.org/standard/63545.html>. + + [ISO3166MA] + ISO, "ISO 3166 Country Codes", + <https://www.iso.org/iso/country_codes.htm>. + + [ISSN-namespace] + Bequet, G., "Namespace Registration for International + Standard Serial Number (ISSN) and Linking ISSN (ISSN-L) + based on ISO 3297:2007", June 2017, + <https://www.iana.org/assignments/urn-formal/issn>. + + [NBN-Resolving] + Deutsche Nationalbibliothek, "URN:NBN Resolver fuer + Deutschland und Schweiz: Information ueber Partner + Institutionen", <https://nbn-resolving.org/institutions>. + + [PERSID] PersID initiative, 2009-2011, "persid: Building a + persistent identifier infrastructure", + <http://www.persid.org>. + + + + + + +Hakala Informational [Page 16] + +RFC 8458 NBN URNs October 2018 + + + [RFC2046] Freed, N. and N. Borenstein, "Multipurpose Internet Mail + Extensions (MIME) Part Two: Media Types", RFC 2046, + DOI 10.17487/RFC2046, November 1996, + <https://www.rfc-editor.org/info/rfc2046>. + + [RFC2141] Moats, R., "URN Syntax", RFC 2141, DOI 10.17487/RFC2141, + May 1997, <https://www.rfc-editor.org/info/rfc2141>. + + [RFC2288] Lynch, C., Preston, C., and R. Daniel, "Using Existing + Bibliographic Identifiers as Uniform Resource Names", + RFC 2288, DOI 10.17487/RFC2288, February 1998, + <https://www.rfc-editor.org/info/rfc2288>. + + [RFC2611] Daigle, L., van Gulik, D., Iannella, R., and P. Faltstrom, + "URN Namespace Definition Mechanisms", BCP 33, RFC 2611, + DOI 10.17487/RFC2611, June 1999, + <https://www.rfc-editor.org/info/rfc2611>. + + [RFC3044] Rozenfeld, S., "Using The ISSN (International Serial + Standard Number) as URN (Uniform Resource Names) within an + ISSN-URN Namespace", RFC 3044, DOI 10.17487/RFC3044, + January 2001, <https://www.rfc-editor.org/info/rfc3044>. + + [RFC3187] Hakala, J. and H. Walravens, "Using International Standard + Book Numbers as Uniform Resource Names", RFC 3187, + DOI 10.17487/RFC3187, October 2001, + <https://www.rfc-editor.org/info/rfc3187>. + + [RFC3188] Hakala, J., "Using National Bibliography Numbers as + Uniform Resource Names", RFC 3188, DOI 10.17487/RFC3188, + October 2001, <https://www.rfc-editor.org/info/rfc3188>. + + [RFC3406] Daigle, L., van Gulik, D., Iannella, R., and P. Faltstrom, + "Uniform Resource Names (URN) Namespace Definition + Mechanisms", RFC 3406, DOI 10.17487/RFC3406, October 2002, + <https://www.rfc-editor.org/info/rfc3406>. + + [RFC6234] Eastlake 3rd, D. and T. Hansen, "US Secure Hash Algorithms + (SHA and SHA-based HMAC and HKDF)", RFC 6234, + DOI 10.17487/RFC6234, May 2011, + <https://www.rfc-editor.org/info/rfc6234>. + + [RFC8254] Klensin, J. and J. Hakala, "Uniform Resource Name (URN) + Namespace Registration Transition", RFC 8254, + DOI 10.17487/RFC8254, October 2017, + <https://www.rfc-editor.org/info/rfc8254>. + + + + + +Hakala Informational [Page 17] + +RFC 8458 NBN URNs October 2018 + + +Appendix A. Significant Changes from RFC 3188 + + Numerous clarifications have been made based on a decade of + experience with RFC 3188. + + NBNs that are not based on ISO 3166 (country codes) have been removed + due to lack of usage. + + In accordance with established practice, the whole NBN prefix is now + declared case insensitive. + + The document is based on the new URN syntax specification, RFC 8141. + + Use of query components and fragment components with this namespace + is now specified in accordance with RFC 8141. + +Acknowledgements + + Revision of RFC 3188 started during the project PersID [PERSID]. + Later, the revision was included in the charter of the URNbis Working + Group and worked on in that group in parallel with what became RFCs + 8141 and 8254. The author wishes to thank his colleagues in the + PersID project and the URNbis participants for their support and + review comments. + + Tommi Jauhiainen has provided feedback on an early draft version of + this document. The author wishes to thank Tommi Jauhiainen, Bengt + Neiss, and Lars Svensson for the comments they have provided to + various draft versions of this document. + + John Klensin provided significant editorial and advisory support for + later draft versions of the document. + +Contributors + + This document would not have been possible without contributions by + Alfred Hoenes. + +Author's Address + + Juha Hakala + The National Library of Finland + P.O. Box 26 + FIN-00014 Helsinki University + Finland + + Email: juha.hakala@helsinki.fi + + + + +Hakala Informational [Page 18] + |