1 2 3 4 5 6 7Network Working Group K. Zeilenga, Ed. 8Request for Comments: 3866 OpenLDAP Foundation 9Obsoletes: 2596 July 2004 10Category: Standards Track 11 12 13 Language Tags and Ranges in the 14 Lightweight Directory Access Protocol (LDAP) 15 16Status of this Memo 17 18 This document specifies an Internet standards track protocol for the 19 Internet community, and requests discussion and suggestions for 20 improvements. Please refer to the current edition of the "Internet 21 Official Protocol Standards" (STD 1) for the standardization state 22 and status of this protocol. Distribution of this memo is unlimited. 23 24Copyright Notice 25 26 Copyright (C) The Internet Society (2004). 27 28Abstract 29 30 It is often desirable to be able to indicate the natural language 31 associated with values held in a directory and to be able to query 32 the directory for values which fulfill the user's language needs. 33 This document details the use of Language Tags and Ranges in the 34 Lightweight Directory Access Protocol (LDAP). 35 361. Background and Intended Use 37 38 The Lightweight Directory Access Protocol (LDAP) [RFC3377] provides a 39 means for clients to interrogate and modify information stored in a 40 distributed directory system. The information in the directory is 41 maintained as attributes of entries. Most of these attributes have 42 syntaxes which are human-readable strings, and it is desirable to be 43 able to indicate the natural language associated with attribute 44 values. 45 46 This document describes how language tags and ranges [RFC3066] are 47 carried in LDAP and are to be interpreted by LDAP implementations. 48 All LDAP implementations MUST be prepared to accept language tags and 49 ranges. 50 51 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 52 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 53 document are to be interpreted as described in BCP 14 [RFC2119]. 54 55 56 57 58Zeilenga Standards Track [Page 1] 59 60RFC 3866 Language Tags and Ranges in LDAP July 2004 61 62 63 This document replaces RFC 2596. Appendix A summaries changes made 64 since RFC 2596. 65 66 Appendix B discusses differences from X.500(1997) "contexts" 67 mechanism. 68 69 Appendix A and B are provided for informational purposes only. 70 71 The remainder of this section provides a summary of Language Tags, 72 Language Ranges, and Attribute Descriptions. 73 741.1. Language Tags 75 76 Section 2 of BCP 47 [RFC3066] describes the language tag format which 77 is used in LDAP. Briefly, it is a string of [ASCII] letters and 78 hyphens. Examples include "fr", "en-US" and "ja-JP". Language tags 79 are case insensitive. That is, the language tag "en-us" is the same 80 as "EN-US". 81 82 Section 2 of this document details use of language tags in LDAP. 83 841.2. Language Ranges 85 86 Section 2.5 of BCP 47 [RFC3066] describes the language ranges. 87 Language ranges are used to specify sets of language tags. 88 89 A language range matches a language tag if it is exactly equal to the 90 tag, or if it is exactly equal to a prefix of the tag such that the 91 first character following the prefix is "-". That is, the language 92 range "de" matches the language tags "de" and "de-CH" but not "den". 93 The special language range "*" matches all language tags. 94 95 Due to attribute description option naming restrictions in LDAP, this 96 document defines a different language range syntax. However, the 97 semantics of language ranges in LDAP are consistent with BCP 47. 98 99 Section 3 of this document details use of language ranges in LDAP. 100 1011.3. Attribute Descriptions 102 103 This section provides an overview of attribute descriptions in LDAP. 104 LDAP attributes and attribute descriptions are defined in [RFC2251]. 105 106 An attribute consists of a type, a set of zero or more associated 107 tagging options, and a set of one or more values. The type and the 108 options are combined into the AttributeDescription. 109 110 111 112 113 114Zeilenga Standards Track [Page 2] 115 116RFC 3866 Language Tags and Ranges in LDAP July 2004 117 118 119 AttributeDescriptions can also contain options which are not part of 120 the attribute, but indicate some other function (such as range 121 assertion or transfer encoding). 122 123 An AttributeDescription with one or more tagging options is a direct 124 subtype of each AttributeDescription of the same type with all but 125 one of the tagging options. If the AttributeDescription's type is a 126 direct subtype of some other type, then the AttributeDescription is 127 also a direct subtype of the AttributeDescription which consists of 128 the supertype and all of the tagging options. That is, 129 "CN;x-bar;x-foo" is a direct subtype of "CN;x-bar", "CN;x-foo", and 130 "name;x-bar;x-foo". Note that "CN" is a subtype of "name". 131 1322. Use of Language Tags in LDAP 133 134 This section describes how LDAP implementations MUST interpret 135 language tags in performing operations. 136 137 Servers which support storing attributes with language tag options in 138 the Directory Information Tree (DIT) SHOULD allow any attribute type 139 it recognizes that has the Directory String, IA5 String, or other 140 textual string syntaxes to have language tag options associated with 141 it. Servers MAY allow language options to be associated with other 142 attributes types. 143 144 Clients SHOULD NOT assume servers are capable of storing attributes 145 with language tags in the directory. 146 147 Implementations MUST NOT otherwise interpret the structure of the tag 148 when comparing two tags, and MUST treat them simply as strings of 149 characters. Implementations MUST allow any arbitrary string which 150 conforms to the syntax defined in BCP 47 [RFC3066] to be used as a 151 language tag. 152 1532.1. Language Tag Options 154 155 A language tag option associates a natural language with values of an 156 attribute. An attribute description may contain multiple language 157 tag options. An entry may contain multiple attributes with same 158 attribute type but different combinations of language tag (and other) 159 options. 160 161 A language tag option conforms to the following ABNF [RFC2234]: 162 163 language-tag-option = "lang-" Language-Tag 164 165 166 167 168 169 170Zeilenga Standards Track [Page 3] 171 172RFC 3866 Language Tags and Ranges in LDAP July 2004 173 174 175 where the Language-Tag production is as defined in BCP 47 [RFC3066]. 176 This production and those it imports from [RFC2234] are provided here 177 for convenience: 178 179 Language-Tag = Primary-subtag *( "-" Subtag ) 180 181 Primary-subtag = 1*8ALPHA 182 183 Subtag = 1*8(ALPHA / DIGIT) 184 185 ALPHA = %x41-5A / %x61-7A ; A-Z / a-z 186 187 DIGIT = %x30-39 ; 0-9 188 189 A language tag option is a tagging option. A language tag option has 190 no effect on the syntax of the attribute's values nor their transfer 191 encoding. 192 193 Examples of valid AttributeDescription: 194 195 givenName;lang-en-US 196 CN;lang-ja 197 SN;lang-de;lang-gem-PFL 198 O;lang-i-klingon;x-foobar 199 description;x-foobar 200 CN 201 202 Notes: The last two have no language tag options. The x-foobar 203 option is fictious and used for example purposes. 204 2052.2. Search Filter 206 207 If language tag options are present in an AttributeDescription in an 208 assertion, then for each entry within scope, the values of each 209 attribute whose AttributeDescription consists of the same attribute 210 type or its subtypes and contains each of the presented (and possibly 211 other) options is to be matched. 212 213 Thus, for example, a filter of an equality match of type 214 "name;lang-en-US" and assertion value "Billy Ray", against the 215 following directory entry: 216 217 dn: SN=Ray,DC=example,DC=com 218 objectClass: person DOES NOT MATCH (wrong type) 219 objectClass: extensibleObject DOES NOT MATCH (wrong type) 220 name;lang-en-US: Billy Ray MATCHES 221 name;lang-en-US: Billy Bob DOES NOT MATCH (wrong value) 222 CN;lang-en-US: Billy Ray MATCHES 223 224 225 226Zeilenga Standards Track [Page 4] 227 228RFC 3866 Language Tags and Ranges in LDAP July 2004 229 230 231 CN;lang-en-US;x-foobar: Billy Ray MATCHES 232 CN;lang-en;x-foobar: Billy Ray DOES NOT MATCH (differing lang-) 233 CN;x-foobar: Billy Ray DOES NOT MATCH (no lang-) 234 name: Billy Ray DOES NOT MATCH (no lang-) 235 SN;lang-en-GB;lang-en-US: Billy Ray MATCHES 236 SN: Ray DOES NOT MATCH (no lang-, 237 wrong value) 238 239 Note that "CN" and "SN" are subtypes of "name". 240 241 It is noted that providing a language tag option in a search filter 242 AttributeDescription will filter out desirable values where the tag 243 does not match exactly. For example, the filter (name;lang-en=Billy 244 Ray) does NOT match the attribute "name;lang-en-US: Billy Ray". 245 246 If the server does not support storing attributes with language tag 247 options in the DIT, then any assertion which includes a language tag 248 option will not match as such it is an unrecognized attribute type. 249 No error would be returned because of this; a presence assertion 250 would evaluate to FALSE and all other assertions to Undefined. 251 252 If no options are specified in the assertion, then only the base 253 attribute type and the assertion value need match the value in the 254 directory. 255 256 Thus, for example, a filter of an equality match of type "name" and 257 assertion value "Billy Ray", against the following directory entry: 258 259 dn: SN=Ray,DC=example,DC=com 260 objectClass: person DOES NOT MATCH (wrong type) 261 objectClass: extensibleObject DOES NOT MATCH (wrong type) 262 name;lang-en-US: Billy Ray MATCHES 263 name;lang-en-US: Billy Bob DOES NOT MATCH (wrong value) 264 CN;lang-en-US;x-foobar: Billy Ray MATCHES 265 CN;lang-en;x-foobar: Billy Ray MATCHES 266 CN;x-foobar: Billy Ray MATCHES 267 name: Billy Ray MATCHES 268 SN;lang-en-GB;lang-en-US: Billy Ray MATCHES 269 SN: Ray DOES NOT MATCH (wrong value) 270 2712.3. Requested Attributes in Search 272 273 Clients can provide language tag options in each AttributeDescription 274 in the requested attribute list in a search request. 275 276 If language tag options are provided in an attribute description, 277 then only attributes in a directory entry whose attribute 278 descriptions have the same attribute type or its subtype and contains 279 280 281 282Zeilenga Standards Track [Page 5] 283 284RFC 3866 Language Tags and Ranges in LDAP July 2004 285 286 287 each of the presented (and possibly other) language tag options are 288 to be returned. Thus if a client requests just the attribute 289 "name;lang-en", the server would return "name;lang-en" and 290 "CN;lang-en;lang-ja" but not "SN" nor "name;lang-fr". 291 292 Clients can provide in the attribute list multiple 293 AttributeDescriptions which have the same base attribute type but 294 different options. For example, a client could provide both 295 "name;lang-en" and "name;lang-fr", and this would permit an attribute 296 with either language tag option to be returned. Note there would be 297 no need to provide both "name" and "name;lang-en" since all subtypes 298 of name would match "name". 299 300 If a server does not support storing attributes with language tag 301 options in the DIT, then any attribute descriptions in the list which 302 include language tag options are to be ignored, just as if they were 303 unknown attribute types. 304 305 If a request is made specifying all attributes or an attribute is 306 requested without providing a language tag option, then all attribute 307 values regardless of their language tag option are returned. 308 309 For example, if the client requests a "description" attribute, and a 310 matching entry contains the following attributes: 311 312 objectClass: top 313 objectClass: organization 314 O: Software GmbH 315 description: software products 316 description;lang-en: software products 317 description;lang-de: Softwareprodukte 318 319 The server would return: 320 321 description: software products 322 description;lang-en: software products 323 description;lang-de: Softwareprodukte 324 3252.4. Compare 326 327 Language tag options can be present in an AttributeDescription used 328 in a compare request AttributeValueAssertion. This is to be treated 329 by servers the same as the use of language tag options in a search 330 filter with an equality match, as described in Section 2.2. If there 331 is no attribute in the entry with the same attribute type or its 332 subtype and contains each of the presented (or possibly other) 333 language tag options, the noSuchAttributeType error will be returned. 334 335 336 337 338Zeilenga Standards Track [Page 6] 339 340RFC 3866 Language Tags and Ranges in LDAP July 2004 341 342 343 Thus, for example, a compare request of type "name" and assertion 344 value "Johann", against an entry containing the following attributes: 345 346 objectClass: top 347 objectClass: person 348 givenName;lang-de-DE: Johann 349 CN: Johann Sibelius 350 SN: Sibelius 351 352 would cause the server to return compareTrue. 353 354 However, if the client issued a compare request of type 355 "name;lang-de" and assertion value "Johann" against the above entry, 356 the request would fail with the noSuchAttributeType error. 357 358 If the server does not support storing attributes with language tag 359 options in the DIT, then any comparison which includes a language tag 360 option will always fail to locate an attribute, and 361 noSuchAttributeType will be returned. 362 3632.5. Add Operation 364 365 Clients can provide language options in AttributeDescription in 366 attributes of a new entry to be created. 367 368 A client can provide multiple attributes with the same attribute type 369 and value, so long as each attribute has a different set of language 370 tag options. 371 372 For example, the following is a valid request: 373 374 dn: CN=John Smith,DC=example,DC=com 375 objectClass: residentialPerson 376 CN: John Smith 377 CN;lang-en: John Smith 378 SN: Smith 379 SN;lang-en: Smith 380 streetAddress: 1 University Street 381 streetAddress;lang-en-US: 1 University Street 382 streetAddress;lang-fr: 1 rue Universite 383 houseIdentifier;lang-fr: 9e etage 384 385 If a server does not support storing language tag options with 386 attribute values in the DIT, then it MUST treat an 387 AttributeDescription with a language tag option as an unrecognized 388 attribute. If the server forbids the addition of unrecognized 389 attributes then it MUST fail the add request with an appropriate 390 result code. 391 392 393 394Zeilenga Standards Track [Page 7] 395 396RFC 3866 Language Tags and Ranges in LDAP July 2004 397 398 3992.6. Modify Operation 400 401 A client can provide language tag options in an AttributeDescription 402 as part of a modification element in the modify operation. 403 404 Attribute types and language tag options MUST match exactly against 405 values stored in the directory. For example, if the modification is 406 a "delete", then if the stored values to be deleted have language tag 407 options, then those language tag options MUST be provided in the 408 modify operation, and if the stored values to be deleted do not have 409 any language tag option, then no language tag option is to be 410 provided. 411 412 If the server does not support storing language tag options with 413 attribute values in the DIT, then it MUST treat an 414 AttributeDescription with a language tag option as an unrecognized 415 attribute, and MUST fail the request with an appropriate result code. 416 4173. Use of Language Ranges in LDAP 418 419 Since the publication of RFC 2596, it has become apparent that there 420 is a need to provide a mechanism for a client to request attributes 421 based upon set of language tag options whose tags all begin with the 422 same sequence of language sub-tags. 423 424 AttributeDescriptions containing language range options are intended 425 to be used in attribute value assertions, search attribute lists, and 426 other places where the client desires to provide an attribute 427 description matching of a range of language tags associated with 428 attributes. 429 430 A language range option conforms to the following ABNF [RFC2234]: 431 432 language-range-option = "lang-" [ Language-Tag "-" ] 433 434 where the Language-Tag production is as defined in BCP 47 [RFC3066]. 435 This production and those it imports from [RFC2234] are provided in 436 Section 2.1 for convenience. 437 438 A language range option matches a language tag option if the language 439 range option less the trailing "-" matches exactly the language tag 440 or if the language range option (including the trailing "-") matches 441 a prefix of the language tag option. Note that the language range 442 option "lang-" matches all language tag options. 443 444 445 446 447 448 449 450Zeilenga Standards Track [Page 8] 451 452RFC 3866 Language Tags and Ranges in LDAP July 2004 453 454 455 Examples of valid AttributeDescription containing language range 456 options: 457 458 givenName;lang-en- 459 CN;lang- 460 SN;lang-de-;lang-gem- 461 O;lang-x-;x-foobar 462 463 A language range option is not a tagging option. Attributes cannot 464 be stored with language range options. Any attempt to add or update 465 an attribute description with a language range option SHALL be 466 treated as an undefined attribute type and result in an error. 467 468 A language range option has no effect on the transfer encoding nor on 469 the syntax of the attribute values. 470 471 Servers SHOULD support assertion of language ranges for any attribute 472 type which they allow to be stored with language tags. 473 4743.1. Search Filter 475 476 If a language range option is present in an AttributeDescription in 477 an assertion, then for each entry within scope, the values of each 478 attribute whose AttributeDescription consists of the same attribute 479 type or its subtypes and contains a language tag option matching the 480 language range option are to be returned. 481 482 Thus, for example, a filter of an equality match of type 483 "name;lang-en-" and assertion value "Billy Ray", against the 484 following directory entry: 485 486 dn: SN=Ray,DC=example,DC=com 487 objectClass: person DOES NOT MATCH (wrong type) 488 objectClass: extensibleObject DOES NOT MATCH (wrong type) 489 name;lang-en-US: Billy Ray MATCHES 490 name;lang-en-US: Billy Bob DOES NOT MATCH (wrong value) 491 CN;lang-en-US: Billy Ray MATCHES 492 CN;lang-en-US;x-foobar: Billy Ray MATCHES 493 CN;lang-en;x-foobar: Billy Ray MATCHES 494 CN;x-foobar: Billy Ray DOES NOT MATCH (no lang-) 495 name: Billy Ray DOES NOT MATCH (no lang-) 496 SN;lang-en-GB;lang-en-US: Billy Ray MATCHES 497 SN: Ray DOES NOT MATCH (no lang-, 498 wrong value) 499 500 Note that "CN" and "SN" are subtypes of "name". 501 502 503 504 505 506Zeilenga Standards Track [Page 9] 507 508RFC 3866 Language Tags and Ranges in LDAP July 2004 509 510 511 If the server does not support storing attributes with language tag 512 options in the DIT, then any assertion which includes a language 513 range option will not match as it is an unrecognized attribute type. 514 No error would be returned because of this; a presence filter would 515 evaluate to FALSE and all other assertions to Undefined. 516 5173.2. Requested Attributes in Search 518 519 Clients can provide language range options in each 520 AttributeDescription in the requested attribute list in a search 521 request. 522 523 If a language range option is provided in an attribute description, 524 then only attributes in a directory entry whose attribute 525 descriptions have the same attribute type or its subtype and a 526 language tag option matching the provided language range option are 527 to be returned. Thus if a client requests just the attribute 528 "name;lang-en-", the server would return "name;lang-en-US" and 529 "CN;lang-en;lang-ja" but not "SN" nor "name;lang-fr". 530 531 Clients can provide in the attribute list multiple 532 AttributeDescriptions which have the same base attribute type but 533 different options. For example a client could provide both 534 "name;lang-en-" and "name;lang-fr-", and this would permit an 535 attribute whose type was name or subtype of name and with a language 536 tag option matching either language range option to be returned. 537 538 If a server does not support storing attributes with language tag 539 options in the DIT, then any attribute descriptions in the list which 540 include language range options are to be ignored, just as if they 541 were unknown attribute types. 542 5433.3. Compare 544 545 Language range options can be present in an AttributeDescription used 546 in a compare request AttributeValueAssertion. This is to be treated 547 by servers the same as the use of language range options in a search 548 filter with an equality match, as described in Section 3.1. If there 549 is no attribute in the entry with the same subtype and a matching 550 language tag option, the noSuchAttributeType error will be returned. 551 552 Thus, for example, a compare request of type "name;lang-" and 553 assertion value "Johann", against the entry with the following 554 attributes: 555 556 557 558 559 560 561 562Zeilenga Standards Track [Page 10] 563 564RFC 3866 Language Tags and Ranges in LDAP July 2004 565 566 567 objectClass: top 568 objectClass: person 569 givenName;lang-de-DE: Johann 570 CN: Johann Sibelius 571 SN: Sibelius 572 573 will cause the server to return compareTrue. (Note that the language 574 range option "lang-" matches any language tag option.) 575 576 However, if the client issued a compare request of type 577 "name;lang-de" and assertion value "Sibelius" against the above 578 entry, the request would fail with the noSuchAttributeType error. 579 580 If the server does not support storing attributes with language tag 581 options in the DIT, then any comparison which includes a language 582 range option will always fail to locate an attribute, and 583 noSuchAttributeType will be returned. 584 5854. Discovering Language Option Support 586 587 A server SHOULD indicate that it supports storing attributes with 588 language tag options in the DIT by publishing 1.3.6.1.4.1.4203.1.5.4 589 as a value of the root DSE. 590 591 A server SHOULD indicate that it supports language range matching of 592 attributes with language tag options stored in the DIT by publishing 593 1.3.6.1.4.1.4203.1.5.5 as a value of the "supportedFeatures" 594 [RFC3674] attribute in the root DSE. 595 596 A server MAY restrict use of language tag options to a subset of the 597 attribute types it recognizes. This document does not define a 598 mechanism for determining which subset of attribute types can be used 599 with language tag options. 600 6015. Interoperability with Non-supporting Implementations 602 603 Implementators of this specification should take care that their use 604 of language tag options does not impede proper function of 605 implementations which do not support language tags. 606 607 Per RFC 2251, "an AttributeDescription with one or more options is 608 treated as a subtype of the attribute type without any options." A 609 non-supporting server will treat an AttributeDescription with any 610 language tag options as an unrecognized attribute type. A non- 611 supporting client will either do the same, or will treat the 612 AttributeDescription as it would any other unknown subtype. 613 Typically, non-supporting clients simply ignore unrecognized subtypes 614 (and unrecognized attribute types) of attributes they request. 615 616 617 618Zeilenga Standards Track [Page 11] 619 620RFC 3866 Language Tags and Ranges in LDAP July 2004 621 622 623 To ensure proper function of non-supporting clients, supporting 624 clients SHOULD ensure that entries they populate with tagged values 625 are also populated with non-tagged values. 626 627 Additionally, supporting clients SHOULD be prepared to handle entries 628 which are not populated with tagged values. 629 6306. Security Considerations 631 632 Language tags and range options are used solely to indicate the 633 native language of values and in querying the directory for values 634 which fulfill the user's language needed. These options are not 635 known to raise specific security considerations. However, the reader 636 should consider general directory security issues detailed in the 637 LDAP technical specification [RFC3377]. 638 6397. IANA Considerations 640 641 Registration of these protocol mechanisms [RFC3383] has been 642 completed by the IANA. 643 644 Subject: Request for LDAP Protocol Mechanism Registration 645 Object Identifier: 1.3.6.1.4.1.4203.1.5.4 646 Description: Language Tag Options 647 Object Identifier: 1.3.6.1.4.1.4203.1.5.5 648 Description: Language Range Options 649 Person & email address to contact for further information: 650 Kurt Zeilenga <kurt@openldap.org> 651 Usage: Feature 652 Specification: RFC 3866 653 Author/Change Controller: IESG 654 Comments: none 655 656 These OIDs were assigned [ASSIGN] by OpenLDAP Foundation, under its 657 IANA-assigned private enterprise allocation [PRIVATE], for use in 658 this specification. 659 6608. Acknowledgments 661 662 This document is a revision of RFC 2596 by Mark Wahl and Tim Howes. 663 RFC 2596 was a product of the IETF ASID and LDAPEXT working groups. 664 This document also borrows from a number of IETF documents including 665 BCP 47 by H. Alvestrand. 666 667 668 669 670 671 672 673 674Zeilenga Standards Track [Page 12] 675 676RFC 3866 Language Tags and Ranges in LDAP July 2004 677 678 6799. References 680 6819.1. Normative References 682 683 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 684 Requirement Levels", BCP 14, RFC 2119, March 1997. 685 686 [RFC2234] Crocker, D., Ed. and P. Overell, "Augmented BNF for 687 Syntax Specifications: ABNF", RFC 2234, November 1997. 688 689 [RFC2251] Wahl, M., Howes, T. and S. Kille, "Lightweight 690 Directory Access Protocol (v3)", RFC 2251, December 691 1997. 692 693 [RFC3066] Alvestrand, H., "Tags for the Identification of 694 Languages", BCP 47, RFC 3066, January 2001. 695 696 [RFC3377] Hodges, J. and R. Morgan, "Lightweight Directory Access 697 Protocol (v3): Technical Specification", RFC 3377, 698 September 2002. 699 700 [RFC3674] Zeilenga, K., "Feature Discovery in Lightweight 701 Directory Access Protocol (LDAP)", RFC 3674, December 702 2003. 703 704 [ASCII] Coded Character Set--7-bit American Standard Code for 705 Information Interchange, ANSI X3.4-1986. 706 7079.2. Informative References 708 709 [X.501] International Telecommunication Union - 710 Telecommunication Standardization Sector, "The 711 Directory -- Models," X.501(1997). 712 713 [RFC3383] Zeilenga, K., "Internet Assigned Numbers Authority 714 (IANA) Considerations for Lightweight Directory Access 715 Protocol (LDAP)", BCP 64, RFC 3383, September 2002. 716 717 [ASSIGN] OpenLDAP Foundation, "OpenLDAP OID Delegations", 718 http://www.openldap.org/foundation/oid-delegate.txt. 719 720 [PRIVATE] IANA, "Private Enterprise Numbers", 721 http://www.iana.org/assignments/enterprise-numbers. 722 723 724 725 726 727 728 729 730Zeilenga Standards Track [Page 13] 731 732RFC 3866 Language Tags and Ranges in LDAP July 2004 733 734 735Appendix A. Differences from RFC 2596 736 737 This document adds support for language ranges, provides a mechanism 738 that a client can use to discover whether a server supports language 739 tags and ranges, and clarifies how attributes with multiple language 740 tags are to be treated. This document is a significant rewrite of 741 RFC 2596. 742 743Appendix B. Differences from X.500(1997) 744 745 X.500(1997) [X.501] defines a different mechanism, contexts, as the 746 means of representing language tags (codes). This section summarizes 747 the major differences in approach. 748 749 a) An X.500 operation which has specified a language code on a value 750 matches a value in the directory without a language code. 751 752 b) LDAP references BCP 47 [RFC3066], which allows for IANA 753 registration of new tags as well as unregistered tags. 754 755 c) LDAP supports language ranges (new in this revision). 756 757 d) LDAP does not allow language tags (and ranges) in distinguished 758 names. 759 760 e) X.500 describes subschema administration procedures to allow 761 language codes to be associated with particular attributes types. 762 763Editor's Address 764 765 Kurt D. Zeilenga 766 OpenLDAP Foundation 767 768 EMail: Kurt@OpenLDAP.org 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786Zeilenga Standards Track [Page 14] 787 788RFC 3866 Language Tags and Ranges in LDAP July 2004 789 790 791Full Copyright Statement 792 793 Copyright (C) The Internet Society (2004). This document is subject 794 to the rights, licenses and restrictions contained in BCP 78, and 795 except as set forth therein, the authors retain all their rights. 796 797 This document and the information contained herein are provided on an 798 "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS 799 OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET 800 ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, 801 INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE 802 INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED 803 WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. 804 805Intellectual Property 806 807 The IETF takes no position regarding the validity or scope of any 808 Intellectual Property Rights or other rights that might be claimed to 809 pertain to the implementation or use of the technology described in 810 this document or the extent to which any license under such rights 811 might or might not be available; nor does it represent that it has 812 made any independent effort to identify any such rights. Information 813 on the procedures with respect to rights in RFC documents can be 814 found in BCP 78 and BCP 79. 815 816 Copies of IPR disclosures made to the IETF Secretariat and any 817 assurances of licenses to be made available, or the result of an 818 attempt made to obtain a general license or permission for the use of 819 such proprietary rights by implementers or users of this 820 specification can be obtained from the IETF on-line IPR repository at 821 http://www.ietf.org/ipr. 822 823 The IETF invites any interested party to bring to its attention any 824 copyrights, patents or patent applications, or other proprietary 825 rights that may cover technology that may be required to implement 826 this standard. Please address the information to the IETF at ietf- 827 ipr@ietf.org. 828 829Acknowledgement 830 831 Funding for the RFC Editor function is currently provided by the 832 Internet Society. 833 834 835 836 837 838 839 840 841 842Zeilenga Standards Track [Page 15] 843 844