Definition of a Uniform Resource Name (URN) Namespace for the Schema for Academia (SCHAC)

The SCHAC international activity was born inside the TF-EMC2 middleware task force of the Trans European Research and Education Network Association. The initial aim of SCHAC was to harmonise the disjoint person schemas of the participating countries in order to have a common way for expressing data about persons, exchanged between educational organizations. SCHAC, as other person schemas, is designed to ease the sharing of information about a given individual between parties, mostly, but not limited to, educational and research institutions. The main aims of this sharing are: to provide resources to individuals and to allow said individuals to move, virtually and physically, between such institutions. Thus, the SCHAC schema was defined with input from all participants' national person schemas. SCHAC does not supplant other person schemas such as organizationalPerson , inetOrgPerson or eduPerson , it extends those where needed for the pourposes of Higher Education outside the United States. This characteristic has made SCHAC, originally an European effort, useful for groups outside Europe.

schac Registration Version Number 1 Registration Date: 2008-11-07 European Committee for Academic Middleware TERENA ATTN: Licia Florio Singel Amsterdam The Netherlands Email: florio@terena.org Phone: Contact: Victoriano Giralt Affiliation: University of Malaga Central ICT Services Blvd. Louis Pasteur, 33 Campus de Teatinos 29071 Malaga Spain Email: victoriano@uma.es Phone: +34 95 213 2366 The Namespace Specific Strings (NSS) of all URNs assigned by SCHAC will conform to the syntax defined in section 2.2 of RFC 2141, "URN Syntax". In addition, all SCHAC URN NSSs will consist of a left-to-right series of tokens delimited by colons. The left-to-right sequence of colon-delimited tokens corresponds to descending nodes in a tree. To the right of the lowest naming authority node, there may be zero, one, or more levels of hierarchical naming nodes terminating in a rightmost leaf node. See the section below entitled "Identifier assignment" for more on the semantics of NSSs. This syntax convention is captured in the following normative ABNF rules for SCHAC NSSs (see RFC 5234):

The exclusion of the colon from the list of "other" characters means that the colon can only occur as a delimiter between string tokens. Note that this ABNF rule set guarantees that any valid SCHAC NSS is also a valid RFC 2141 NSS. None. It is the responsibility of TERENA to guarantee uniqueness of the names of immediately subordinate naming authorities. Each lower-level naming authority in turn inherits the responsibility of guaranteeing uniqueness of names in their branch of the naming tree. TERENA bears ultimate responsibility for maintaining the usability of SCHAC URNs over time. This responsibility may be delegated to subordinate naming authorities per the discussion in the section below on identifier assignment. That section provides a mechanism for the delegation to be revoked in the case a subordinate naming authority ceases to function. TERENA will create an initial series of immediately subordinate naming authorities, and will define a process for adding to that list of authorities. Each country with a representative in SCHAC will be invited to designate a naming authority. Country specific namespaces based on the country Internet TLD will be assigned then to the designated authority. The subordinated namespaces int and eu will remain under TERENA authority, controlled by the SCHAC activity members, for entities of global international or European interest. There is also the possibility of granting subordinate namespaces to multi-country organizations, in this case the organizational Internet FQDN will be used as prefix. As an example, an European level interest entity would be any value related to information used in the Higher Education European Space, or the so called Bologna process. Such entities will belong in the eu subordinate namespace. Global international entities could encompass values related to the Grid comunity or values useful both for some European and Australian universities. Such entities would belong in the int subordinate namespace. Examples of multicountry organizations include TERENA itself or an association like EPI (educationalpolicy.org) that has members from Australia, Canada and the US. URNs intended for values of SCHAC attributes will include the attribute name immediately after the NSS prefix, before any geographical namespace delegation, such that any string can convey information about the attribute for which it is a value. For example, values for schacUserStatus, will be of the from:

urn:schac:UserStatus:int: urn:schac:UserStatus:au: or urn:schac:UserStatus:terena.org Automated registry publication mechanisms will be provided if at all possible, based on the work on distributed URN registries done by the TF-EMC2 task force members. Institutions and communities affiliated with SCHAC participants may request that they be granted subordinate naming authority status. Uniqueness of this namespaces under each country authority will be based on the requestor's Internet FQDN. This subordination procedure SHOULD be carried along the delegation chain, i.e., all entities that receive a delegated namespace MUST have a valid FQDN and MUST publish an Internet accessible URN value registry, if at all possible based on the URN registry mechanisms designed by the TF-EMC2 task force members. On at least an annual basis, TERENA will contact the liaisons or directors of each immediately subordinate naming authority. If there is no response, or if the respondent indicates that they wish to relinquish naming authority, the authority over that branch of the tree reverts to TERENA. This process will be enforced recursively by each naming authority on its subordinates. This process guarantees that responsibility for each branch of the tree will lapse for less than one year, at worst, before being reclaimed by a superior authority. Lexical equivalence of two SCHAC namespace specific strings (NSSs) is defined below as an exact, case-sensitive string match. TERENA will assign names of immediately subordinate naming authorities in lowercase only. This forestalls the registration of two SCHAC-subordinate naming authorities whose names differ only in case. Attribute names will use the same mixed case format as in the schema definition. TERENA will maintain a registry of all SCHAC assigned URN values, both final and for delegation, on its Web site: https://www.terena.org/urn Delegation entries will have a pointer to the registry of the subordinate naming authority. This SHOULD recurse down the delegation tree, but registries for several delegated namespaces MAY be maintained by a single naming authority. All registries MUST publish their URNs over an HTTPS link. The registries SHOULD present a certificate from a CA that is included in the majority of browsers, like TERENA SCS certificates. Lexical equivalence of two SCHAC Namespace Specific Strings (NSSs) is defined as an exact, case-sensitive string match. All SCHAC NSSs fully conform to RFC 2141 syntax rules for NSSs. As specified in the "Identifier resolution" section above, TERENA will maintain an index of all SCHAC assigned URNs on its Web site https://www.terena.org/urn. Presence in that registry or in any subordinate one implies that a given URN is valid. Delegated naming authorities MUST guarantee that values are valid in their assigned spaces. Global.

There are no additional security considerations beyond those normally associated with the use and resolution of URNs in general. In order to guarantee the validity and origin of SCHAC-NSS URN values, they MUST be published over HTTPS links.

Registration of an Namespace Identifier (NID) specific to SCHAC is reasonable given the following considerations: SCHAC would like to assign URNs to some very fine-grained objects. This does not seem to be the primary intended use of the XMLORG namespace (RFC 3120) , or the more tightly controlled OASIS namespace (RFC 3121) . SCHAC seeks naming autonomy. SCHAC is not a member of OASIS, so becoming a subordinate naming authority under the OASIS URN space is not an option. There is the MACE namespace but the SCHAC development is done outside MACE activity scope and thus the attributes and values do not belong into MACE namespace. Using the MACE namespace requires the schac namespace to be placed under one of the SCHAC participants namespace, which hinders its global scope. SCHAC will want to assign URNs to non-XML objects as well. That is another reason that XMLORG may not be an appropriate higher-level naming authority for SCHAC. Some of the already defined SCHAC attribute values have been assigned URNs under the urn:mace:terena.org namespace. These values will enter a deprecation cycle, with clear indication of them being replaced by values under the new namespace once it is assigned. Anyhow, RFC 3406 (which replaced RFC 2611) includes an explicit statement that two or more URNs may point to the same resource.

The assignment and use of identifiers within the namespace are open, and the related rule is established by the SCHAC activity members. Registration agencies (the next level naming authorities) will be the National Research and Education Networks and established organizational cross-border organizations that participate in SCHAC. It is expected that the majority of the European NRENs, their constituencies, participants in the Australian Access Federation and some other international activities make use of the SCHAC namespace. After the establishment of the SCHAC namespace, TERENA will, as soon as practical, establish a registry service (analogously to other distributed pan-European services, like eduroam, PerfSONAR, etc.) for the namespace clients.

In accordance with BCP 66 , IANA is asked to register the Formal URN Namespace 'schac' in the Registry of URN Namespaces, using the registration template presented in Section 2 of this document. Note to RFC Editor: this section may be removed on publication as an RFC.