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'5' ** Obsolete normative reference: RFC 1808 (ref. '6') (Obsoleted by RFC 3986) ** Obsolete normative reference: RFC 1738 (ref. '7') (Obsoleted by RFC 4248, RFC 4266) ** Obsolete normative reference: RFC 2052 (ref. '10') (Obsoleted by RFC 2782) -- No information found for draft-ietf-svrloc-advertise - is the name correct? -- Possible downref: Normative reference to a draft: ref. '11' ** Obsolete normative reference: RFC 2222 (ref. '12') (Obsoleted by RFC 4422, RFC 4752) == Outdated reference: A later version (-06) exists of draft-ietf-acap-spec-04 -- Unexpected draft version: The latest known version of draft-ietf-svrloc-lpr-scheme is -00, but you're referring to -01. (However, the state information for draft-ietf-svrloc-advertise is not up-to-date. The last update was unsuccessful) -- Possible downref: Normative reference to a draft: ref. '14' ** Obsolete normative reference: RFC 2044 (ref. '16') (Obsoleted by RFC 2279) -- Possible downref: Non-RFC (?) normative reference: ref. '17' -- Possible downref: Non-RFC (?) normative reference: ref. '18' -- Possible downref: Non-RFC (?) normative reference: ref. '19' Summary: 15 errors (**), 0 flaws (~~), 8 warnings (==), 14 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 1 Service Location Working Group Erik Guttman 2 INTERNET DRAFT Charles Perkins 3 James Kempf 4 12 March 1998 Sun Microsystems 6 Service Templates and service: Schemes 7 draft-ietf-svrloc-service-scheme-09.txt 9 Status of This Memo 11 This document is a submission by the Service Location Working Group 12 of the Internet Engineering Task Force (IETF). Comments should be 13 submitted to the srvloc@corp.home.net mailing list. 15 Distribution of this memo is unlimited. 17 This document is an Internet-Draft. Internet-Drafts are working 18 documents of the Internet Engineering Task Force (IETF), its areas, 19 and its working groups. Note that other groups may also distribute 20 working documents as Internet-Drafts. 22 Internet-Drafts are draft documents valid for a maximum of six months 23 and may be updated, replaced, or obsoleted by other documents at 24 any time. It is inappropriate to use Internet-Drafts as reference 25 material or to cite them other than as ``work in progress.'' 27 To learn the current status of any Internet-Draft, please check 28 the ``1id-abstracts.txt'' listing contained in the Internet-Drafts 29 Shadow Directories on ftp.is.co.za (Africa), ftp.nordu.net (North 30 Europe), ftp.nis.garr.it (South Europe), munnari.oz.au (Pacific Rim), 31 ds.internic.net (US East Coast), or ftp.isi.edu (US West Coast). 33 Abstract 35 The "service:" URL scheme name is used to define URLs (called 36 "service: URLs" in this document) that are primarily intended to 37 be used by the Service Location Protocol in order to distribute 38 service access information. These schemes provide an extensible 39 framework for client-based network software to obtain configuration 40 information required to make use of network services. When 41 registering a service: URL, the URL is accompanied by a set of 42 well-defined attributes which define the service. These attributes 43 convey configuration information to client software, or service 44 characteristics meaningful to end users. 46 This document describes a formal procedure for defining and 47 standardizing new service types and attributes for use with the 48 "service:" scheme. The formal descriptions of service types and 49 attributes are templates that are human and machine understandable. 50 They SHOULD be used by administrative tools to parse service 51 registration information and by client applications to provide 52 localized translations of service attribute strings. 54 Contents 56 Status of This Memo i 58 Abstract i 60 1. Introduction 1 61 1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 2 62 1.2. Service Location Protocol . . . . . . . . . . . . . . . . 3 64 2. Service URL Syntax and Semantics 3 65 2.1. Service URL Syntax . . . . . . . . . . . . . . . . . . . 3 66 2.2. Service URL Semantics . . . . . . . . . . . . . . . . . . 5 67 2.3. Use of service: URLs . . . . . . . . . . . . . . . . . . 7 68 2.4. Specifying the Service Type-Specific URL Syntax . . . . . 7 69 2.5. Accommodating Abstract Service Types . . . . . . . . . . 8 70 2.5.1. Advertising Abstract Service Types . . . . . . . 8 72 3. Syntax and Semantics of Service Type Specifications 9 73 3.1. Syntax of Service Type Templates . . . . . . . . . . . . 10 74 3.2. Semantics of Service Type Templates . . . . . . . . . . . 12 75 3.2.1. Definition of a Service Template . . . . . . . . 12 76 3.2.2. Service Type . . . . . . . . . . . . . . . . . . 13 77 3.2.3. Service Type Language . . . . . . . . . . . . . . 13 78 3.2.4. Version Number . . . . . . . . . . . . . . . . . 14 79 3.2.5. Description . . . . . . . . . . . . . . . . . . . 14 80 3.2.6. Syntax of the Service Type-specific URL Part . . 14 81 3.2.7. Attribute Definition . . . . . . . . . . . . . . 15 83 4. A Process For Standardizing New Service Types 19 85 5. IANA Considerations 20 87 6. Internationalization Considerations 21 88 6.1. Language Identification and Translation . . . . . . . . . 21 90 7. Security Considerations 22 92 A. Service Template Examples 22 93 A.1. FOO . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 94 A.2. Abstract Service Type: Net-Transducer . . . . . . . . . 23 95 A.3. Concrete Service Type: Net-Transducer:Thermometer . . . 24 96 A.4. service: URLs and SLP . . . . . . . . . . . . . . . . . . 25 98 B. Full Copyright Statement 27 99 C. Acknowledgments 27 101 1. Introduction 103 This document describes a URL scheme, called service: URL, which 104 defines network access information for network services using a 105 formal notation. In addition it describes how to define a set of 106 attributes to associate with a service: URL. These attributes will 107 allow end users and programs to select between network services of 108 the same type that have different capabilities. The attributes 109 are defined in a template document that is readable by people and 110 machines. 112 A client uses attributes to select a particular service. Service 113 selection occurs by obtaining the service: URL that offers the right 114 configuration for the client. Service type templates define the 115 syntax of service: URLs for a particular service type, as well as the 116 attributes which accompany a service: URL in a service registration. 118 Templates are used for the following distinct purposes: 120 1. Standardization 122 The template is reviewed before it is standardized. Once it is 123 standardized, all versions of the template are archived by IANA. 125 2. Service Registration 127 Servers making use of the Service Location Protocol [15] register 128 themselves and their attributes. They use the templates to 129 generate the service registrations. In registering, the service 130 must use the specified values for its attributes. 132 3. Client presentation of Service Information 134 Client applications may display service information. The 135 template provides type information and explanatory text which may 136 be helpful in producing user interfaces. 138 4. Internationalization 140 Entities with access to the template for a given service type in 141 two different languages may translate between the two languages. 143 A service may register itself in more than one language using 144 templates, though it has been configured by an operator who 145 registered service attributes in a single language. 147 All grammar encoding follows the Augmented BNF (ABNF) [9] for syntax 148 specifications. 150 1.1. Terminology 152 This section introduces some terminology for describing service: 153 URLs. 155 service scheme 157 A URL scheme whose name starts with the string "service:" and 158 is followed by the service type name, constructed according to 159 the rules in this document. An example is "service:lpr:" for 160 the lpr print service [14]. 162 service: URL 164 A URL constructed according to the service scheme definition. 165 It typically provides at least the following: The name of an 166 access protocol, and an address locating this service. The 167 service: URL may include url path information specific to the 168 type of service, as well as attribute information encoded 169 according to the URL grammar. The service: URL is used by 170 the Service Location Protocol to register and discover the 171 location of services. It may be used by other protocols and in 172 documents as well. 174 service type 176 A name identifying the semantics by which the remainder of 177 the service: URL is to be understood. It may denote either a 178 particular network protocol, or an abstract service associated 179 with a variety of protocols. If the service type denotes a 180 particular protocol, then the service type name SHOULD either 181 be assigned the name of a particular well known port [3] by 182 convention or be the Assigned Numbers name for the service [1]. 184 abstract service type 186 A service type name which is associated with a variety of 187 different protocols. An example is given in Section A. 188 Section 2 discusses various ways that abstract types can be 189 accommodated. 191 service registration 193 A service: URL and optionally a set of attributes comprise 194 a service registration. This registration is made by or on 195 behalf of a given service. The URL syntax and attributes must 196 conform to the service template for the registered service. 198 service template 200 A formal description of the service attributes and service 201 scheme associated with a particular service type. 203 1.2. Service Location Protocol 205 The Service Location Protocol [15] allows service: URLs to be 206 registered and discovered, though service: URLs may be also used in 207 other contexts. 209 Client applications discover service registrations by issuing queries 210 for services of a particular type, specifying the attributes of 211 the service: URLs to return. Clients retrieve the attributes of a 212 particular service by supplying its service: URL. Attributes for all 213 service registrations of a particular type can also be retrieved. 215 Services may register themselves, or registrations may be made on 216 their behalf. These registrations contain a service: URL, and 217 possibly attributes and digital signatures. 219 2. Service URL Syntax and Semantics 221 This section describes the syntax and semantics of service: URLs. 223 2.1. Service URL Syntax 225 The syntax of the service: URL MUST conform to [6]. The only 226 exception is that the field has been omitted from the 227 production, since plain text transmission of passwords is 228 now discouraged. Note that the syntax for the field depends 229 upon the service type definition. The field is the service 230 access point, and describes how to access the service. In addition, 231 although both upper case and lower case characters are recognized in 232 the field for convenience, the name is case-folded 233 into lower case. Service types are therefore not distinguished on 234 the basis of case, so, for example, "http" and "HTTP" designate the 235 same service type. This is consistent with general URL practice, as 236 outlined in [7]. 238 The ABNF for a service: URL is: 240 service: URL = "service:" service-type ":" sap 241 service-type = abstract-type ":" url-scheme / concrete-type 242 abstract-type = type-name [ "." naming-auth ] 243 concrete-type = protocol [ "." naming-auth ] 244 type-name = resname 245 naming-auth = resname 246 url-scheme = resname 247 ; A recognized URL scheme name, standardized 248 ; either through common practice or through 249 ; approval of a standards body. 250 resname = alpha [ 1*(alpha / digit / "+" / "-") ] 251 sap = site [url-part] 252 site = ipsite / atsite / ipxsite 253 ipsite = "//" [ [ user "@" ] hostport ] 254 hostport = host [ ":" port ] 255 host = hostname / hostnumber 256 hostname = *( domainlabel "." ) toplabel 257 alphanum = alpha / digit 258 domainlabel = alphanum / alphanum *[alphanum / "-"] alphanum 259 toplabel = alpha / alpha *[ alphanum / "-" ] alphanum 260 hostnumber = ipv4-number / ipv6-number 261 ipv4-number = 1*3digit 3("." 1*3digit) 262 ipv6-number = 32hex 263 3digit = digit digit digit 264 port = 1*digit 265 ; A port number must be included if the 266 ; protocol field does not have an IANA 267 ; assigned port number. 268 user = *[ uchar / ";" / "+" / "&" / "=" ] 269 ipxsite = "/ipx/" ipx-net ":" ipx-node ":" ipx-socket 270 ipx-net = 8 HEXDIGIT 271 ipx-node = 12 HEXDIGIT 272 ipx-socket = 4 HEXDIGIT 273 atsite = "/at/" at-object ":" at-type "" at-zone 274 at-object = 1*31apple-char 275 at-type = 1*31apple-char 276 at-zone = 1*31apple-char 277 apple-char = alpha / digit / safe / escaped 278 = ; AppleAscii [17] values that are not 279 = ; from the restricted range must be escaped. 280 = ; NOTE: The escaped values do NOT correspond 281 = ; to UTF8 values here: They are AppleAscii 282 = ; bytes. 283 url-part = [ url-path ] [ attr-list ] 284 url-path = 1 * ( "/" *xchar ) 285 ; Each service type must define its 286 ; own syntax consistent 287 ; with [6]. 288 attr-list = 1 * ( ";" attr-asgn ) 289 attr-asgn = attr-id / attr-id "=" attr-value 290 safe = "$" / "-" / "_" / "." / "~" 291 extra = "!" / "*" / "'" / "(" / ")" / "," / "+" 292 uchar = unreserved / escaped 293 xchar = unreserved / reserved / escaped 294 escaped = "%" hex hex 295 hex "a" / "b" / "c" / "d" / "e" / digit 296 reserved = ";" / "/" / "?" / ":" / "@" / "&" / "=" / "+" 297 unreserved = alpha / digit / safe / extra 299 IPX addresses [19] are composed of a network, node and socket number. 300 The IPX network number is a four-byte number, in network order and 301 expressed in hexadecimal, that signifies an IPX subnet. The node 302 element represents a network interface card. It is a six-byte 303 number, expressed in hexadecimal, that is usually the same as the 304 node ID of the interface card. The socket element represents a 305 specific service access point, given an IPX network and node. IPX 306 sockets are analogous to TCP/IP ports, and are not to be confused 307 with Berkely sockets. 309 AppleTalk addresses [18] are composed of an object, type and zone. 310 The object is a human readable string. The type is an identifier, 311 not intentended for human readability. The zone refers to the 312 AppleTalk Zone name, which is also human readable. The characters 313 composing these names are drawn from the AppleAscii character 314 set [17]. Thus, they do not equate to escaped ASCII or UTF8 315 characters. The characters "=" and "*" are reserved and may not be 316 included in the names even in binary form. 318 In cases besides the AppleTalk grammar, some characters must be 319 escaped before use. To escape any character, precede the two digits 320 indicating its ASCII value by '%'. 322 2.2. Service URL Semantics 324 The service scheme-specific information following the "service:" 325 URL scheme identifier provides information necessary to access the 326 service. As described in the previous subsection, the form of a 327 service: URL is as follows: 329 service: URL = "service:" service-type ":" sap 331 where has the following form: 333 /addr-family/addr-spec/url-path;attr-list 335 The field includes the field. As 336 discussed in Section 1, the can be either a concrete 337 protocol name, or an abstract type name. 339 The field includes a site specification (the 340 field) in the format specified by [6]. The field 341 is typically either a domain name (DNS) or an IP network protocol 342 address for the service, and possibly a port number. Note that use 343 of DNS hostnames is preferred for ease of renumbering. The 344 field can be null if other information in the service URL or service 345 attributes is sufficient to use the service. 347 The field allows more information to be provided (by way of 348 and ) that can uniquely locate the service 349 or resource if the is not sufficient for that purpose. 350 For IP addresses, is empty, the field begins 351 with "//". Other address families supported are IPX [19] and 352 AppleTalk [?]. 354 An field appears at the end of the field, 355 but is never required to exist in any service location registration. 356 The field is composed of a list of semicolon (";") 357 separated attribute assignments of the form: 359 attr-id "=" attr-value 361 or for keyword attributes: 363 attr-id 365 Attributes are part of service: URLs when the attributes are required 366 to access a particular service. For instance, an ACAP [13] service 367 might require that the client authenticate with it through Kerberos. 368 Including an attribute in the service registration allows the ACAP 369 client to make use of the correct SASL [12] authentication mechanism. 370 The ACAP server's registration might look like: 372 service:acap://some.where.net;authentication=KERBEROSV4 374 Note that there can be other attributes of an ACAP server which 375 are not appropriate to include in the URL. For instance, the list 376 of users who have access to the server is useful for selecting an 377 ACAP server, but is not required for a client to use the registered 378 service. 380 Attributes associated with the service: URL are not typically 381 included in the service: URL. They are stored and retrieved using 382 other mechanisms. The service: URL is uniquely identified with a 383 particular service agent or resource, and is used when registering or 384 requesting the attribute information. The Service Location Protocol 385 specifies how such information is registered by network services and 386 obtained by client software. 388 2.3. Use of service: URLs 390 The service: URL is intended to allow arbitrary client/server and 391 peer to peer systems to make use of a standardized dynamic service 392 access point discovery mechanism. 394 It is intended that service: URLs be selected according to the 395 suitability of associated attributes. A client application can 396 obtain the URLs of several services of the same type and distinguish 397 the most preferable among them by means of their attributes. The 398 client uses the service: URL to communicate directly to a service. 400 Attributes are specified with a formal service template syntax 401 described in Section 3. If a service: URL registration includes 402 attributes, the registering agent SHOULD also keep track of the 403 attributes which characterize the service. 405 Registrations can be checked against the formal attribute 406 specification defined in the template by the client or agent 407 representing the client. Service registration are typically done 408 using the Service Location Protocol [15] (SLP). SLP provides a 409 mechanism for service: URLs to be obtained dynamically, according to 410 the service's attributes. 412 It is also possible to obtain service: URLs from documents and using 413 other protocols. In this case, the URL may not be accompanied by 414 the service attributes. The context in which the URL appears should 415 make it clear, if possible, when the service is appropriate to use. 416 For example, in a mail message, a service might be recommended for 417 use when the user is in a branch office. Or, an HTML document might 418 include a service: URL as a pointer to a service, describing in text 419 what the service does and who is authorized to use it. 421 2.4. Specifying the Service Type-Specific URL Syntax 423 When a service type is specified, the specification includes the 424 definition of the syntax for all URLs that are registered by services 425 of that particular type. For instance, the "lpr" service type may be 426 defined with service: URLs in the following form: 428 service:printer:lpr://
/ 430 The section of the URL after the address of the printer: 432 "/" 434 is specific to the lpr service type and corresponds to the 435 field of the general service: URL syntax. This part is 436 specified when the lpr service type is specified. 438 2.5. Accommodating Abstract Service Types 440 An abstract service type is a service type that can be implemented by 441 a variety of different service agents. 443 In order to register an service: URL for an abstract service type the 444 'abstract-type' grammar rule described in section 3.1 is used. This 445 will result in a URL which includes enough information to use the 446 service, namely, the protocol, address and path information. Unlike 447 'concrete' service: URLs, however, the service type is not enough 448 to determine the service access. Rather, an abstract service type 449 denotes a class of service types. The following subsection discusses 450 this point in more detail. 452 2.5.1. Advertising Abstract Service Types 454 Some services may make use of several protocols that are in common 455 use and are distinct services in their own right. In these cases an 456 abstract service type is appropriate. What is essential is that all 457 the required information for the service is clearly defined. 459 For example, suppose a network service is being developed for 460 dynamically loading device drivers. The client requires the 461 following three pieces of information before it can successfully load 462 and instantiate the driver: 464 1. The protocol used to load the driver code, for example, "ftp", 465 "http" or "tftp" 467 2. A pathname identifying where the driver code is located, for 468 example "/systemhost/drivers/diskdrivers.drv", 470 3. The name of the driver, for example, "scsi". 472 The temptation is to form the first two items into a URL and embed 473 that into a service: URL. As an example which should be avoided, 475 service:ftp:/x3.bean.org/drivers/diskdrivers.drv;driver=scsi 477 is a service: URL which seems to indicate where to obtain the driver. 479 Rather, an abstract service-type SHOULD be used. The service type is 480 not "ftp", as the example indicates. Rather, it is "device-drivers". 481 The service: URL that should be used, consistent with the rules in 482 section [6], is the following: 484 service:device-drivers:ftp://x3.bean.org/drivers/diskdrivers.drv; 485 driver=scsi;platform=sys3.2-rs3000 487 Other URLs for the same service using other protocols are also 488 supported, as in: 490 service:device-drivers:tftp://x2.bean.org/vol3/disk/drivers.drv; 491 driver=scsi;platform=sys3.2-rs3000 493 service:device-drivers:http://www.bean.org/drivers/drivpak.drv; 494 driver=scsi;platform=sys3.2-rs3000 496 Using SLP, a search for the service type "device-drivers" may return 497 all of the three URLs listed above. The client selects the most 498 appropriate access protocol for the desired resource. 500 The fundamental requirement is that the abstract service type MUST 501 be well specified. This requirement is imposed so that program code 502 or human users have enough information to access the service. In 503 every case, a well-specified abstract type will include either an 504 access protocol and a network address where the service is available, 505 or an embedded URL for a standardized URL scheme that describes 506 how to access the service. In the example above, there are three 507 further requirements: A URL path is included for access protocols 508 indicating the document to download, and two attributes are included 509 to characterize the driver. 511 3. Syntax and Semantics of Service Type Specifications 513 Service type specifications are documents in a formal syntax defining 514 properties important to service registration. These properties are: 516 1. General information on the service type specification itself, 518 2. The syntax of the service type-specific part of the service URL, 520 3. The definition of attributes associated with a service. 522 The service type specification document is the service type template. 524 The following subsections describe the syntax and semantics of 525 service type templates. 527 3.1. Syntax of Service Type Templates 529 Service template documents are encoded in a simple form. They may be 530 translated into any language or character set, but the template used 531 for standardization MUST be encoded in the ASCII subset of UTF8 [16] 532 and be in English. 534 A template document begins with a block of text assigning values to 535 five document identification items. The five identification items 536 can appear in any order within the block, but conventionally the 537 "type" item, which assigns the service type name, occurs at the very 538 top of the document in order to provide context for the rest of 539 the the document. The attribute definition item occurs after the 540 document identification items. 542 All items end with a blank line. The reserved characters are ";", 543 "%", "=", ",", "#", LF, and CR. Reserved characters MUST be escaped. 544 The escape sequence is the same as described in [6]. 546 The service template is encoded in a UTF8 character set, but 547 submitted as a part of an internet-draft, which is encoded in ASCII 548 characters. All characters which are outside of the ASCII range MUST 549 be escaped using the % HEX HEX syntax. For example, the letter e 550 accent aigue would be represented as "%c3%a9". Unfortunately, this 551 will detract from the readability of the service template in the 552 internet draft. Hopefully some public domain tools will emerge for 553 translating escaped UTF8 characters into humanly readable ones. 555 Values in value lists are separated by commas. A value list is 556 terminated by a newline not preceded by a comma. If the newline is 557 preceded by a comma, the value list is interpreted to continue onto 558 the next line. 560 Attribute identifiers, attribute type names, and flags are all 561 case insensitive. For ease of presentation, upper and lower case 562 characters can be used to represent these in the template document. 563 Newlines are significant in the grammar. They delimit one item from 564 another, as well as separating parts of items internally. 566 String values are considered to be a sequence of non-whitespace 567 tokens potentially with embedded whitespace, separated from each 568 other by whitespace. Commas delimit lists of strings. String values 569 are trimmed so as to reduce any sequence of white space interior to a 570 string to a single white space. Preceding or trailing white space is 571 removed. For example: 573 " some value , another example " 575 is trimmed to 576 "some value" and "another example". 578 Note that there can be no ambiguity in string tokenization because 579 values in value lists are separated by a comma. String tokens are 580 not delimited by double quotes (") as is usually the case with 581 programming languages. 583 Attribute tags and values are useful for directory look-up. In this 584 case, decoding of character escapes and trimming white space MUST 585 be performed before string matching. In addition, string matching 586 SHOULD be case insensitive. 588 Templates obey the following ABNF [9] grammar: 590 template = tem-attrs attr-defs 591 tem-attrs = schemetype schemevers schemelang 592 schemetext schemeurl 593 schemetype = "type" "=" scheme termdef 594 schemevers = "version" "=" version-no termdef 595 schemelang = "language" "=" langtag termdef 596 schemetext = "description" "=" newline desc-text termdef 597 schemeurl = "url-syntax" "=" newline url-bnf termdef 598 url-bnf = *[ com-chars ] 599 ; An ABNF describing the production 600 ; in the service: URL grammar of Section 2.1. 601 scheme = service-type [ "." naming-auth ] 602 service-type = scheme-name 603 naming-auth = scheme-name 604 scheme-name = alpha [1*schemechar] [ "." 1*schemechar ] 605 schemechar = alpha / digit / "-" / "+" / 606 version-no = 1*digit "." 1*digit 607 langtag = 2*lower-alpha ;see [4] 608 desc-text = *[ com-chars ] 609 ; A block of free-form text for reading by 610 ; people describing the service in a short, 611 ; informative manner. 612 termdef = newline newline 613 attr-defs = *( attr-def / keydef ) 614 attr-def = id "=" attrtail 615 keydef = id "=" "keyword" newline [help-text] newline 616 attrtail = type flags newline [value-list] [help-text] 617 [value-list] newline 618 id = 1*attrchar 619 type = "string" / "integer" / "boolean" / "opaque" 620 flags = ["m"/"M"] ["l"/"L"] ["o"/"O"] ["x"/"X"] 621 value-list = value newline / value "," value-list / 622 value "," newline value-list 623 help-text = 1*( "#" help-line ) 624 ; A block of free-form text for reading by 625 ; people describing the attribute and 626 ; its values. 627 help-line = *[ com-chars ] newline 628 attrchar = schemechar / ":" / "_" / "$" / "~" / "@" / "." / 629 "|" / "<" / ">" / "*" / "&" 630 value = string / integer / boolean / opaque 631 string = safe-char *[safe-char / white-sp] safe-char 632 integer = [ "+" | "-" ] 1*digit 633 boolean = "true" / "false" 634 opaque = "\FF" 1*( "\" hex hex) 635 ; Each byte of the opaque value is expressed 636 ; as a pair of hexidecimal digits. 637 com-chars = safe-char / white-sp / "," / ";"/ "%" 638 safe-char = attrchar / escaped / " " / "!" / '"' / "'" / 639 "|" / "(" / ")" / "+" / "-" / "." / ":" / 640 "=" / "?" / "[" / "]" / "{" / "/" / "{" / 641 "$" 642 ; All UTF8 printable characters are 643 ; included except ",", "%", ";", and "#". 644 escaped = "%" hex hex 645 hex = digit / "A" / "B" / "C" / "D" / "E" / 646 "a" / "b" / "c" / "d" / "e" 647 white-sp = space / tab 648 newline = CR / ( CR LF ) 650 3.2. Semantics of Service Type Templates 652 The service type template defines the service attributes and service: 653 URL syntax for a particular service type. The attribute definition 654 includes the attribute type, default values, allowed values and other 655 information. 657 3.2.1. Definition of a Service Template 659 There are six items included in the service template. The semantics 660 of each item is summarized below. 662 - type 664 The scheme name of the service scheme. The scheme name consists 665 of the service type name and an optional naming authority name, 666 separated from the service type name by a period. See 3.2.2 for 667 the conventions governing service type names. 669 - version 670 The version number of the service type specification. 672 - language 674 The language of the service type specification. 676 - description 678 A description of the service suitable for inclusion in text read 679 by people. 681 - url-syntax 683 The syntax of the service type-specific URL part of the service: 684 URL. 686 - attribute definitions 688 A collection of zero or more definitions for attributes 689 associated with the service in service registrations. 691 Each of the following subsections deals with one of these items. 693 3.2.2. Service Type 695 The service scheme consists of the service type name and an optional 696 naming authority name separated from the service type name by a 697 period. The service scheme is a string that is appended to the 698 'service:' URL scheme identifier, and is the value of the "type" 699 item in the template document. If the naming authority name is 700 absent it is assumed to be IANA. 702 3.2.3. Service Type Language 704 The service type language is a RFC 1766 Language Tag defining the 705 language of the template [4] and is the value of the "language" item. 707 3.2.4. Version Number 709 The version number of the service type template is the value of the 710 "version" item. A draft proposal starts at 0.0, and the minor number 711 increments once per revision. A standardized template starts at 1.0. 712 Additions of optional attributes add one to the minor number, and 713 additions of required attributes, changes of definition, or removal 714 of attributes add one to the major number. The intent is that an 715 old service template still accurately, if incompletely, defines the 716 attributes of a service registration if the template only differs 717 from the registration in its minor version. See Section 4 for more 718 detail on how to use the version attribute. 720 3.2.5. Description 722 The description is a block of text readable by people in the language 723 of the template and is the value of the "description" item. It 724 should be sufficient to identify the service to human readers and 725 provide a short, informative description of what the service does. 727 If the service type corresponds to a particular protocol, the 728 protocol specification must be cited here. The protocol need not be 729 a standardized protocol. The template might refer to a proprietary 730 specification, and refer the reader of the template to a contact 731 person for further information. 733 3.2.6. Syntax of the Service Type-specific URL Part 735 The syntax of the service type-specific part of the service: 736 URL is provided in the template document as the value of the 737 "url-syntax" item. The field of the service: URL is 738 designed to provide additional information to locate a service when 739 the field is not sufficient. The field 740 distinguishes URLs of a particular service type from those of another 741 service type. For instance, in the case of the lpr service type, the 742 must include the queue name [14], but other service types 743 may not require this information. 745 The syntax for the field MUST accompany the definition 746 of a new service type, unless the URL scheme has already been 747 standardized and is not a service: URL. The syntax is included in the 748 template document as an ABNF [9] following the rules for URL syntax 749 described in [6]. There is no requirement for a service scheme to 750 support a . The field can be very simple, 751 or even omitted. If the URL scheme has already been standardized, 752 the "url-syntax" item SHOULD include a reference to the appropriate 753 standardization documents. Abstract service types may defer this 754 field to the template documents describing their concrete instances. 756 3.2.7. Attribute Definition 758 The bulk of the template is typically devoted to defining service 759 type-specific attributes. An attribute definition precisely 760 specifies the attribute's type, other restrictions on the attribute 761 (whether it is multi-valued, optional, etc), some text readable by 762 people describing the attribute, and lists of default and allowed 763 values. The only required information is the attribute's type, the 764 rest are optional. Registration, deregistration and the use of 765 attributes in queries can be accomplished using the Service Location 766 Protocol [15] or other means, and discussion of this is beyond the 767 scope of the document. 769 Attributes are used to convey information about a given service for 770 purposes of differentiating different services of the same type. 771 They convey information to be used in the selection of a particular 772 service to establish communicate with, either through a program 773 offering a human interface or programmatically. Attributes can be 774 encoded in different character sets and in different languages. The 775 procedure for doing this is described in Section 6. 777 An attribute definition begins with the specification of the 778 attribute's identifier and ends with a single empty line. Attributes 779 definitions have five components (in order of appearance in a 780 definition): 782 1. An attribute identifier which acts as the name of the attribute, 784 2. Attribute descriptors (type and flags), 786 3. An optional list of values which are assigned to the attribute by 787 default, 789 4. An optional block of text readable by people providing a short, 790 informative description of the attribute, 792 5. An optional list of allowed values which restrict the value or 793 values the attribute can take on. 795 3.2.7.1. The Attribute Identifier 797 An attribute definition starts with the specification of the 798 attribute's identifier. The attribute's identifier functions as the 799 name of the attribute. Note that the characters used to compose an 800 attribute identifier are restricted to those characters considered 801 unrestricted for inclusion in a URL according to [6]. The reason 802 is that services can display prominent attributes in their service: 803 URL registrations. Each attribute identifier must be unique in the 804 template. Since identifiers are case folded, upper case and lower 805 case characters are the same. 807 3.2.7.2. The Attribute Type 809 Attributes can have one of five different types: string, integer, 810 boolean, opaque, or keyword. The attribute's type specification is 811 separated from the attribute's identifier by an equal sign ("=") and 812 follows the equal sign on the same line. The string, signed integer, 813 and boolean types have the standard programming language or database 814 semantics. Integers are restricted to those signed values that can 815 be represented in 32 bits. The character set used to represent 816 strings is not specified at the time the template is defined, but 817 rather is determined by the service registration. Booleans have 818 the standard syntax. Opaques are escaped bytes that can be used 819 to represent any other kind of data. Keywords are attributes that 820 have no characteristics other than their existence (and possibly the 821 descriptive text in their definition). 823 Keyword and boolean attributes impose restrictions on the following 824 parts of the attribute definition. Keyword attribute definitions 825 MUST have no flag information following the type definition, nor any 826 default or allowed values list. Boolean attributes are single value 827 only, i.e., multi-valued boolean attributes are not allowed. 829 3.2.7.3. Attribute Flags 831 Flags determine other characteristics of an attribute. With the 832 exception of keyword attributes, which may not have any flags, 833 flags follow the attribute type on the same line as the attribute 834 identifier, and are separated from each other by whitespace. Flags 835 may appear in any order after the attribute type. Other information 836 must not follow the flags, and only one flag identifier of a 837 particular flag type is allowed per attribute definition. 839 The semantics of the flags are as follows: 841 - o or O 843 Indicates that the attribute is optional. If this flag is 844 missing, the attribute is required in every service registration. 846 - m or M 848 Indicates that the attribute can take on multiple values. If 849 this flag is present, every value in a multi-valued attribute 850 has the same type as the type specified in the type part of the 851 attribute definition. Boolean attributes must not include this 852 flag. 854 - l or L 855 Indicates that attribute is literal, i.e. is not meant to be 856 translated into other languages. If this flag is present, the 857 attribute is not considered to be readable by people and should 858 not be translated when the template is translated. See Section 6 859 for more information about translation. 861 - x or X 863 Indicates that clients SHOULD include the indicated attribute 864 in requests for services. Neglecting to include this attribute 865 will not sufficiently differentiate the service. If services are 866 obtained without selecting this attribute they will quite likely 867 be useless to the client. 869 The values for multivalued attributes are an unordered set. 870 Deletions of individual values from a multivalued attribute are not 871 supported, and deletion of the attribute causes the entire set of 872 values to be removed. 874 3.2.7.4. Default Value or List 876 If the attribute definition includes a default value or, in the 877 case of multivalued attributes, a default values list, it begins 878 on the second line of the attribute definition and continues 879 over the following lines until a line ends without a comma. As a 880 consequence, newlines cannot be embedded in values unless escaped. 881 See Section 2.1. 883 Particular attribute types and definitions restrict the default 884 values list. Keyword attributes must not have a list of defaults. 885 If an optional attribute's definition has an allowed values list, 886 then a default value or list is not optional but required. The 887 motivation for this is that defining an attribute with an allowed 888 values list is meant to restrict the values the attribute can take 889 on, and requiring a default value or list assures that the default 890 value is a member of the given set of allowed values. 892 The default value or list indicates what values the attribute is 893 given if no values are assigned to the attribute when a service 894 is registered. If an optional attribute's definition includes no 895 default value or list, the following defaults are assigned: 897 1. String values are assigned the empty string, 899 2. Integer values are assigned zero, 901 3. Boolean values are assigned false, 902 4. Opaque values are assigned a byte array containing no values, 904 5. Multi-valued attributes are initialized with a single value. 906 For purposes of translating nonliteral attributes, the default values 907 list is taken to be an ordered set, and translations MUST maintain 908 that order. 910 3.2.7.5. Descriptive Text 912 Immediately after the default values list, if any, a block of 913 descriptive text SHOULD be included in the attribute definition. 914 This text is meant to be readable by people, and should include 915 a short, informative description of the attribute. It may also 916 provide additional information, such as a description of the allowed 917 values. This text is primarily designed for display by interactive 918 browsing tools. The descriptive text is set off from the surrounding 919 definition by a crosshatch character ("#") at the beginning of 920 the line. The text should not, however, be treated as a comment 921 by parsing and other tools, since it is an integral part of the 922 attribute definition. Within the block of descriptive text, the text 923 is transferred verbatim, including indentation and line breaks, so 924 any formatting is preserved. 926 3.2.7.6. Allowed Values List 928 Finally, the attribute definition concludes with an optional 929 allowed values list. The allowed values list, if any, follows the 930 descriptive text, or, if the descriptive text is absent, the initial 931 values list. The syntax of the allowed values list is identical to 932 that of the initial values list. The allowed values list is also 933 terminated by a line that does not end in a comma. If the allowed 934 values list is present, assignment to attributes is restricted to 935 members of the list. 937 As with the default values list, the allowed values list is also 938 considered to be an ordered set for purposes of translation. 940 3.2.7.7. Conclusion of An Attribute Definition 942 An attribute definition concludes with a single empty line. 944 4. A Process For Standardizing New Service Types 946 New service types can be suggested simply by providing a service type 947 template and a short description about how to use the service. The 948 template MUST have its "version" template attribute set to 0.0. 950 MAJOR revision numbers come before the '.', MINOR revision numbers 951 come after the '.'. 953 The minor version number increments once with each change until it 954 achieves 1.0. There is no guarantee any version of the service 955 template is backward compatible before it reaches 1.0. 957 Once a service template has reached 1.0, the definition is "frozen" 958 for that version. New templates must be defined, of course, to 959 refine that definition, but the following rules must be followed: 961 A MINOR revision number signifies the introduction of a compatible 962 change. A MAJOR revision number signifies the introduction of an 963 incompatible change. This is formalized by the following rules: 965 - Any new optional attribute defined for the template increases 966 the minor version number by one. All other attributes for the 967 version must continue to be supported as before. A client which 968 supports 1.x can still use later versions of 1.y (where x "." "." 1029 Each of these fields are defined in Section 2. They correspond 1030 to the values of the template fields "type", "version" and 1031 "lang". The files for the example templates in this 1032 document are called "foo.0.0.en", "Net-Transducer.0.0.en" and 1033 "Net-Transducer:Thermomoter.0.0.en". See Section A. 1035 The reviewer will ensure that the template submission to IANA has the 1036 correct version number in the "version" and "lang" fields. 1038 No service type template will be accepted for inclusion in the 1039 service template registry unless the Internet Draft submitted 1040 includes a security considerations section and contact information 1041 for the template document author. 1043 The IANA will maintain a registry containing both the service type 1044 templates, and the template description document containing the 1045 service type template, including all previous versions. The IANA 1046 will receive notice by email from the reviewers, which will contain a 1047 reference to the Internet Draft that contains the service template. 1048 This Internet Draft will be edited to remove the Internet Draft 1049 headers and replace them with a simple header stating "This document 1050 contains a Service Type Template." 1052 Neither the reviewer nor the IANA will take any position on claims of 1053 copyright or trademark issues with regard to templates.' 1055 6. Internationalization Considerations 1057 The service: URL must be encoded using the rules set forth in [6]. 1058 The character set encoding is limited to specific ranges within the 1059 US-ASCII character set [5]. 1061 The template is encoded in UTF8 characters. 1063 6.1. Language Identification and Translation 1065 The language used in attribute strings should be identified using the 1066 "language" template item as defined by [4]. 1068 A program can translate a service registration from one language to 1069 another provided it has both the template of the language for the 1070 registration and the template of the desired target language. All 1071 standardized attributes are in the same order in both templates. 1072 All non-arbitrary strings, including the descriptive help text, is 1073 directly translatable from one language to another. Non-literal 1074 attribute definitions, attribute identifiers, attribute type names, 1075 attribute flags, and the boolean constants "true" and "false" are 1076 never translated. Translation of attribute identifiers is prohibited 1077 because, as with domain names, they can potentially be part of a 1078 service: URL and therefore their character set is restricted. In 1079 addition, as with variable identifiers in programming languages, they 1080 could become embedded into program code. 1082 All strings used in attribute values are assumed translatable unless 1083 explicitly defined as being literal, so that best effort translation 1084 (see below) does not modify strings which are meant to be interpreted 1085 by a program, not a person. 1087 There are two ways to go about translation: standardization and best 1088 effort. 1090 When the service type is standardized, more than one document can 1091 be submitted for review. One service type description is approved 1092 as a master, so that when a service type template is updated in one 1093 language, all the translations (at least eventually) reflect the same 1094 semantics. 1096 If no document exists describing the standard translation of the 1097 service type, a 'best effort' translation for strings should be done. 1099 7. Security Considerations 1101 Service type templates provide information that is used to interpret 1102 information obtained by the Service Location Protocol. If these 1103 templates are modified or false templates are distributed, services 1104 may not correctly register themselves, or clients might not be able 1105 to interpret service information. 1107 The service: URLs themselves specify the service access point and 1108 protocol for a particular service type. These service: URLs could 1109 be distributed and indicate the location of a service other than 1110 that normally want to used. The Service Location Protocol [15] 1111 distributes service: URLs and has an authentication mechanism that 1112 allows service: URLs of registered services to be signed and for the 1113 signatures to be verified by clients. 1115 Each Service Template will include a security considerations section 1116 which will describe security issues with using the service scheme for 1117 the specific Service Type. 1119 A. Service Template Examples 1121 The text in the template example sections is to be taken as being a 1122 single file. They are completely fictitious (ie. the examples do 1123 not represent real services). 1125 The FOO example shows how to use service templates for an application 1126 that has very few attributes. Clients request the FOO server where 1127 their user data is located by including their user name as the value 1128 of the user attribute. 1130 The Net-Transducer example shows how abstract service types are 1131 defined and how a corresponding concrete instance is defined. A 1132 system might support any of several NetTransducer services. Here we 1133 give only one concrete instance of the abstract type. 1135 It is not necessary to register concrete templates for an abstract 1136 service type if the abstract service type template is completely 1137 clear as to what possible values can be used as a concrete type, and 1138 what their interpretation is. 1140 A.1. FOO 1142 -------------------------template begins here----------------------- 1143 type=FOO 1145 version=0.0 1147 lang=en 1149 description= 1150 The FOO service URL provides the location of an FOO service. 1152 url-syntax= 1153 url-path= ; There is no URL path defined for a FOO URL. 1155 users= string M L O 1156 # The list of all users which the FOO server supports. 1158 groups= string M L O 1159 # The list of all groups which the FOO server supports. 1160 --------------------------template ends here------------------------ 1162 The Internet Draft describing the FOO scheme template must indicate 1163 contact information and security considerations, e.g., 1165 contact="Erik Guttman" 1167 security considerations= 1168 If the USER and GROUPS attributes are included a 1169 possibility exists that the list of identities for users or groups 1170 can be discovered. This information would otherwise be difficult 1171 to discover. 1173 A.2. Abstract Service Type: Net-Transducer 1175 The Internet Draft for the service type template contains the 1176 following text: 1178 -------------------------template begins here----------------------- 1179 type=Net-Transducer 1181 version=0.0 1183 lang=en 1184 description= 1185 This is an abstract service type. The purpose of the Net- 1186 Transducer service type is to organize into a single category 1187 all network enabled Transducers which have certain properties. 1189 url-syntax= 1190 url-path= ; Depends on the concrete service type. 1191 ; See these templates. 1193 sample-units= string L 1194 # The units of sample that the Transducer provides, for instance 1195 # C (degrees Celsius), V (Volts), kg (Kilograms), etc. 1197 sample-resolution= string L 1198 # The resolution of the Transducer. For instance, 10^-3 means 1199 # that the Transducer has resolution to 0.001 unit. 1201 sample-rate= integer L 1202 # The speed at which samples are obtained per second. For 1203 # instance 1000 means that one sample is obtained every millisecond. 1205 --------------------------template ends here------------------------ 1207 In addition, the following format might be used for the needed 1208 contact and security considerations information. 1209 .......... 1211 contact="Erik Guttman" 1213 security considerations= 1214 See the security considerations of the concrete service types. 1216 A.3. Concrete Service Type: Net-Transducer:Thermometer 1218 -------------------------template begins here----------------------- 1219 type=service:Net-Transducer:Thermometer 1221 version=0.0 1223 lang=en 1225 description= 1226 The Thermometer is a Net-Transducer capable of reading temperature. 1227 The data is read by opening a TCP connection to one of the ports 1228 in the service URL and reading an ASCII string until an NULL 1229 character is encountered. The client may continue reading data at 1230 no faster than the sample-rate, or close the connection. 1232 url-syntax= 1233 url-path = ; ports 1234 port-list = ";ports=" port-list 1235 ports = port / port "," ports 1236 ; See the Service URL production rule. 1237 ; These are the ports connections can be made on. 1239 location-description=string 1240 # The location where the Thermometer is located. 1242 operator=string O 1243 # The operator to contact to have the Thermometer serviced. 1245 --------------------------template ends here------------------------ 1247 ......... 1249 contact="Erik Guttman" 1251 security considerations= 1252 There is no authentication of the Transducer output. Thus, 1253 the Thermometer output could easily be spoofed. 1255 A.4. service: URLs and SLP 1257 A user with an FOO enabled calendar application should not be 1258 bothered with knowing the address of their FOO server. The 1259 calendar client program can use SLP to obtain the FOO service: URL 1260 automatically, say 'service:foo://server1.nosuch.org', by issuing 1261 a Service Request. In the event that this FOO server failed, the 1262 Calendar client can issue the same service request again to find the 1263 backup FOO server, say 'service:foo://server2.nosuch.org'. In both 1264 cases, the service: URL conforms to the FOO service template as do 1265 the associated attributes (user and group.) 1267 A network thermometer could be advertised as: 1269 URL = service:net-transducer:thermometer://v33.test/ports=3211 1270 Attributes = (location-description=Missile bay 32), 1271 (operator=Joe Agent), (sample-units=C), 1272 (sample-resolution=10^-1),(sample-rate=10) 1274 This might be very useful for a technician who wanted to find a 1275 Thermometers in Missile bay 32, for example. 1277 B. Full Copyright Statement 1279 Copyright (C) The Internet Society (1997). All Rights Reserved. 1281 This document and translations of it may be copied and furnished to 1282 others, and derivative works that comment on or otherwise explain it 1283 or assist in its implmentation may be prepared, copied, published 1284 and distributed, in whole or in part, without restriction of any 1285 kind, provided that the above copyright notice and this paragraph 1286 are included on all such copies and derivative works. However, 1287 this document itself may not be modified in any way, such as by 1288 removing the copyright notice or references to the Internet Society 1289 or other Internet organizations, except as needed for the purpose 1290 of developing Internet standards in which case the procedures 1291 for copyrights defined in the Internet Standards process must be 1292 followed, or as required to translate it into languages other than 1293 English. 1295 The limited permissions granted above are perpetual and will not be 1296 revoked by the Internet Society or its successors or assigns. 1298 This document and the information contained herein is provided on an 1299 "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING 1300 TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING 1301 BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION 1302 HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF 1303 MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE." 1305 C. Acknowledgments 1307 Ryan Moats suggestions were very useful in producing this document. 1308 Thanks to Michael Day, Leland Wallace and Ryan Moats for assisting 1309 with the IPX and AppleTalk address syntax portions of this document. 1311 References 1313 [1] Protocol and service names, October 1994. 1314 ftp://ftp.isi.edu/in-notes/iana/assignments/service-names. 1316 [2] Address family numbers, October 1995. 1317 ftp://ftp.isi.edu/in-notes/iana/assignments/address-family-numbers. 1319 [3] Port numbers, July 1997. 1320 ftp://ftp.isi.edu/in-notes/iana/assignments/port-numbers. 1322 [4] H. Alvestrand. Tags for the Identification of Languages. RFC 1323 1766, March 1995. 1325 [5] ANSI. Coded Character Set -- 7-bit American Standard code for 1326 Information Interchange. X3.4-1986, 1986. 1328 [6] T. Berners-Lee, R. Fielding, and L. Masinter. Uniform Resource 1329 Locators (URL): Generic Syntax and Semantics. RFC1738 as 1330 amended by RFC1808 1332 [7] T. Berners-Lee, L. Masinter, and M. McCahill. Uniform Resource 1333 Locators (URL). RFC 1738, December 1994. 1335 [8] N. Freed and N. Borenstein. Multipurpose Internet Mail 1336 Extensions (MIME) Part One: Format of Internet Message Bodies. 1337 RFC 2045, November 1996. 1339 [9] D. Crocker and P Overell. Augmented BNF for Syntax 1340 Specifications: ABNF. draft-ietf-drums-abnf-04.txt, September 1341 1997. (work in progress). 1343 [10] A. Gulbrandsen and P. Vixie. A DNS RR for specifying the 1344 location of services (DNS SRV). RFC 2052, October 1996. 1346 [11] R. Moats and M. Hamilton. Finding Stuff (Providing information 1347 to support service discovery). draft-ietf-svrloc-advertise-00.txt, 1348 February 1997. (work in progress). 1350 [12] J. Myers. Simple Authentication and Security Layer (SASL). RFC 1351 2222, October 1997. 1353 [13] J. G. Myers. ACAP -- Application Configuration Access Prototol. 1354 draft-ietf-acap-spec-04.txt, June 1997. (work in progress). 1356 [14] Pete St. Pierre. Definition of lpr: URLs for use with Service 1357 Location. draft-ietf-svrloc-lpr-scheme-01.txt, November 1997. 1358 (work in progress). 1360 [15] J. Veizades, E. Guttman, C. Perkins, and S. Kaplan. Service 1361 Location Protocol. RFC 2165, July 1997. 1363 [16] F. Yergeau. UTF-8, a transformation format of unicode and ISO 1364 10646. RFC 2044, October 1996. 1366 [17] Apple Computer. Inside Macintosh: Text Addison Wesley, 1993 1368 [18] G. Sidhu, R .Andrews, A. Oppenheimer Inside AppleTalk, Second 1369 Edition Addison Wesley, 1991 1371 [19] Novell, Inc. IPX RIP and SAP Router Specification Part Number 1372 107-000029-001, Version 1.30, May 23, 1996 1374 Authors' Addresses 1376 Questions about this memo can be directed to: 1378 Erik Guttman Charles E. Perkins James Kempf 1379 Sun Microsystems Sun Microsystems Sun Microsystems 1380 Bahnstr. 2 901 San Antonio Rd. 901 San Antonio Rd. 1381 74915 Waibstadt Palo Alto, CA, 94303 Palo Alto, CA, 94303 1382 Germany USA USA 1383 +49 7263 911484 1 650 786 6464 1 650 786 5890 1384 1 650 786 6445 (fax) 1 650 786 6445 (fax) 1385 erik.guttman@sun.com charles.perkins@sun.com james.kempf@sun.com