Network Working Group D. Royer Internet-Draft IntelliCal Expires: April 25, 2006 October 22, 2005 iCalendar in XML Format (xCal-Basic) draft-royer-calsch-xcal-03 Status of this Memo By submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she is aware have been or will be disclosed, and any of which he or she becomes aware will be disclosed, in accordance with Section 6 of BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on April 25, 2006. Copyright Notice Copyright (C) The Internet Society (2005). Abstract The mailing list for discussion of this memo is "xCal@ INET-Consulting.com" and signup page at "http://INET-Conusulting.com/mailman/listinfo/xcal. This is a rerelease of an expired draft with updates and a much more simplivied approach. This approach uses an exact 1 to 1 mapping between iCalendar and xml objects. The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY" and "OPTIONAL" in this Royer Expires April 25, 2006 [Page 1] Internet-Draft xCal-Basic-RSS October 2005 document are to be interpreted as described in [KEYWORDS]. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Using XML For Representating iCalendar . . . . . . . . . . . . 4 2.1 XML Dependencies . . . . . . . . . . . . . . . . . . . . . 5 2.2 Working With Standard and XML iCalendar Representations . 5 2.2.1 Conversion . . . . . . . . . . . . . . . . . . . . . . 5 2.2.2 Mixed Use of Both Representations . . . . . . . . . . 5 2.3 Including Multiple iCalendar Objects . . . . . . . . . . . 5 2.4 Mapping Property Parameters to XML . . . . . . . . . . . . 6 2.5 Mapping VCALENDAR object Properties to XML . . . . . . . . 7 2.6 Mapping All Components to XML . . . . . . . . . . . . . . 8 2.7 Mapping All Values to XML . . . . . . . . . . . . . . . . 9 2.8 Emailing the iCalendar XML Representation . . . . . . . . 10 2.9 iCalendar XML Representation and File Systems . . . . . . 11 3. Example Usage . . . . . . . . . . . . . . . . . . . . . . . . 12 3.1 A well-formed and valid iCalendar XML document . . . . . . 12 3.2 Including binary content in attachments . . . . . . . . . 12 3.3 iCalendar XML document with multiple iCalendar objects . . 14 3.4 Using the iCalendar namespace . . . . . . . . . . . . . . 15 3.5 Publish meeting information . . . . . . . . . . . . . . . 15 3.6 Publish transparent annual event . . . . . . . . . . . . . 16 3.7 Meeting invitation . . . . . . . . . . . . . . . . . . . . 16 3.8 Publish busy time . . . . . . . . . . . . . . . . . . . . 17 3.9 Request busy time . . . . . . . . . . . . . . . . . . . . 18 3.10 Issue a CAP command . . . . . . . . . . . . . . . . . . . 18 4. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 19 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 20 6. Security Considerations . . . . . . . . . . . . . . . . . . . 21 7. Bibliography . . . . . . . . . . . . . . . . . . . . . . . . . 22 Author's Address . . . . . . . . . . . . . . . . . . . . . . . 22 Intellectual Property and Copyright Statements . . . . . . . . 23 Royer Expires April 25, 2006 [Page 2] Internet-Draft xCal-Basic-RSS October 2005 1. Introduction xCal is a representation of iCalendar objects in XML. xCal is not an alternative or next generation of iCalendar. This memo defines how to use XML to represent iCalendar objects in XML. These XML object can be embedded into other XML documents using the XML syntax here. xCal does represent iCalendar componnts, properties, and parameters as defined in iCalendar. As iCalendar evolves the one to one mapping of iCalendar objects into xCal will continue to work as this memo describes the mapping of iCalendar objects.. Within this memo the term "xCal" will mean the XML namespace usage as described in this memo. This format was selected to ease its translation back to the iCalendar format using an XSLT transform. (See project iCalendar on SourceForge.com - http://sourceforge.net/projects/icalendar/ ) NOTE: That [iCAL] is the definitive reference for the definition of iCalendar semantics. This memo only provides an alternative, XML representation for the standard syntax defined in [iCAL]. This memo does not introduce any semantics not already defined by [iCAL]. Royer Expires April 25, 2006 [Page 3] Internet-Draft xCal-Basic-RSS October 2005 2. Using XML For Representating iCalendar In iCalendar names can be in upper case, lower case, or mixed case. In xCal the predefined iCaledars names will be represented in lower case only as XML element and attribute names are case sensitive. Values to properties and parameters that are user specified may be in upper, lower, or mixed case. All iCalendar component names will be represented in xCal as XML element names in lower case. The "BEGIN:" iCalendar component are represen in xCal as the component name it self in lower case. (BEGIN:VEVENT becomes ). All iCalendar property names will be represented in xCal as XML element names in lower case. All iCalendar parameter names will be represented in xCal as XML attribute names in lower case. All iCalendar property and parameter values will be represented in xCal unchanged. BEGIN:VCALENDAR VERSION:2.0 PRODID:-//hacksw/handcal//NONSGML v1.0//EN BEGIN:VEVENT DTSTART:19970714T170000Z DTEND:19970715T035959Z SUMMARY;LANGUAGE="en_US":Bastille Day Party END:VEVENT END:VCALENDAR Is represented in xCal as: 2.0 -//hacksw/handcal//NONSGML v1.0//EN 19970714T170000Z 19970715T035959Z Bastille Day Party Royer Expires April 25, 2006 [Page 4] Internet-Draft xCal-Basic-RSS October 2005 2.1 XML Dependencies This memo specifies the XML representation for the standard iCalendar format defined by [iCAL]. There are no XML dependencies other than the [XML] and the [XMLNS] recommendations. 2.2 Working With Standard and XML iCalendar Representations This memo defines an alternative, XML representation for the standard iCalendar format defined in [iCAL]. This alternative representation provides the same semantics as that defined in the standard format. It is the goal of this memo to allow all [iCAL] extensions and modifications to be translated into and from this XML format. 2.2.1 Conversion The standard format can be converted to and from this XML format without loss of any calendaring information. When the XML representation was defined, every attempt was made to use existing component, property and parameter naming conventions. This greatly facilitates transformations between the two representations. 2.2.2 Mixed Use of Both Representations As previously indicated, conversion between the standard and XML representations of iCalendar is a straightforward process. In addition, mixed use of both representations is also possible using MIME objects. With the use of the MIME multipart content-types, compound MIME entities containing a mix of the standard and XML representations can be specified. This capability is useful in applications where both representations might be encountered. In addition, this capability demonstrates the isomeric nature of the two representations. XML applications conforming to this specification MUST be able to properly parse and process a MIME multipart entity containing the MIME type associated with this iCalendar XML document type. Internet applications conforming to this memo MUST only send the iCalendar XML document in a "multipart/alternative" MIME entity that also contains an equivalent iCalendar object in the standard format defined by [iCAL]. This restriction will guarantee that the iCalendar object can also be processed by Internet applications that only support the standard iCalendar representation. 2.3 Including Multiple iCalendar Objects The iCalendar format has the capability for including multiple, Royer Expires April 25, 2006 [Page 5] Internet-Draft xCal-Basic-RSS October 2005 individual iCalendar objects in a single data stream, as can be needed by [iTIP]. The XML representation can support this also. Individual iCalendar objects are specified by the "vcalendar" element type. One or more "vcalendar" element types are permitted within the parent element type, called "iCalendar". For example: 2.0 2.0 > 2.4 Mapping Property Parameters to XML The property parameters defined in the standard iCalendar format are represented in the XML representation as an attribute on element types. The following table specifies some of the attribute name corresponding to each property parameter. This is true for all iCalendar object parameters defined in any iCalendar specification. The property and paramater names will be all lower case. Here are some iCalendar parameter names and how they are mapped to their lower case xCal names. NOTE: that the iCalendar "language" parameter is converted to the "xml:lang" attribute as an exception to the one to one mapping. Royer Expires April 25, 2006 [Page 6] Internet-Draft xCal-Basic-RSS October 2005 +----------------+----------------+ | Property | Attribute | | Parameter Name | Name | +----------------+----------------+ | ALTREP | altrep | | CN | cn | | CUTYPE | cutype | | DELEGATED-FROM | delegated-from | | DELEGATED-TO | delegated-to | | DIR | dir | | FMTTYPE | fmttype | | FBTYPE | fbtype | | LANGUAGE | xml:lang | | MEMBER | member | | PARTSTAT | partstat | | RANGE | range | | RELATED | related | | RELTYPE | reltype | | ROLE | role | | RSVP | rsvp | | SENT-BY | sent-by | | TZID | tzid | | VALUE | value | | X-... | x-... | | ..... | ..... | +----------------+----------------+ 2.5 Mapping VCALENDAR object Properties to XML Calendar properties defined in the standard iCalendar format provide information about an iCalendar object, as a whole. The calendar properties are represented in the XML representation as element types as shown in lower case. Here is a list of some iCalendar properties and them mapped to xCal lower case names: +------------------+------------------+ | Calendar | Tag | | Property Name | Name | +------------------+------------------+ | ACTION | action | | ATTACH | attach | | ATTENDEE | attendee | | CALSCALE | calscale | | CATEGORIES | categories | | CLASS | class | | COMMENT | comment | | COMPLETED | completed | Royer Expires April 25, 2006 [Page 7] Internet-Draft xCal-Basic-RSS October 2005 | CONTACT | contact | | CREATED | created | | DESCRIPTION | description | | DTEND | dtend | | DTSTART | dtstart | | DTSTAMP | dtstamp | | DUE | due | | DURATION | duration | | EXDATE | exdate | | EXRULE | exrule | | FREEBUSY | freebusy | | GEO | geo | | LAST-MODIFIED | last-modified | | LOCATION | location | | METHOD | method | | ORGANIZER | organizer | | PERCENT-COMPLETE | percent-complete | | PRIORITY | priority | | PRODID | prodid | | RECURRENCE-ID | recrrence-id | | RDATE | rdate | | RELATED-TO | related-to | | REPEAT | repeat | | RESORCES | resources | | RRULE | rrule | | SEQUENCE | sequence | | STATUS | status | | SUMMARY | summary | | TRANSP | transp | | TRIGGER | trigger | | TZID | tzid | | TZNAME | tzname | | TZOFFSETTO | tzoffsetto | | TZOFFSETFROM | tzoffsetfrom | | TZURL | tzurl | | URL | url | | UID | uid | | VERSION | version | | X-... | x-... | | ... | ... | +------------------+------------------+ The semantics for these are as specified for the corresponding calendar property in [iCAL]. 2.6 Mapping All Components to XML All components in xCal are mapped to their component name without the Royer Expires April 25, 2006 [Page 8] Internet-Draft xCal-Basic-RSS October 2005 BEGIN tag. This example show how many component names are mapped to xCal lower case names: +----------------+-------------+------------------------------+ | Component | Element | Example | +----------------+-------------+------------------------------+ | VEVENT | vevent | ... | | VTODO | vtodo | ... | | VJOURNAL | vjournal | ... | | VTIMEZONE | vtimezone | ... | | STANDARD | standard | ... | | DAYLIGHT | daylight | ... | | X-... | x-... | ... | | ... | ... | ... | +----------------+-------------+------------------------------- 2.7 Mapping All Values to XML The [iCAL] specification specifies that the equivalent component properties to the "comment", "description", "location", "summary" and "contact" element types can contain formatted content, such as is specified by multiple lines of text. In such cases, the formatted text should be specified using standard XML escaping. Values MUST NOT be mapped to lower case. iCalendar property values and iCalendar parameter values are used without lower case conversion. Vaues that have characters forbidden by XML MUST be encoded using standard XML escaping mechanisms. Values that containe XML tags like in this example: DESCRIPTION:How to map xml DESCRIPTION into an XML element. Would be encoded using standard XML encoding as shown here: How to map xml DESCRIPTION into an XML <description> element. Royer Expires April 25, 2006 [Page 9] Internet-Draft xCal-Basic-RSS October 2005 2.8 Emailing the iCalendar XML Representation It is expected that iCalendar XML documents will need to be sent over SMTP/MIME email. The "text/xml" and "application/xml" content-types have been registered for XML documents. However, use of these content-type definitions present some problems for XML applications such as calendaring and scheduling. The "text/xml" and "application/xml" content-type definitions do not provide for any header field parameters to identify the type of XML document contained in the MIME entity. This means that a recipient mail user agent must (MUA) open up each "text/xml" or "application/ xml" content in order to determine what object handler is needed to process the information. To a MUA, all XML documents look like just plain "text/xml" or "application/xml" content. Additionally, it is accepted practice for a MUA to provide iconic feedback to the user for individual content-types that are supported by the MUA. For example, not only would feedback be provided for a calendaring and scheduling content. Some further unique identification would also be provided for each different scheduling message; such as a meeting invitation, response to an invitation, reschedule notice, cancellation notice, etc. In such cases, acceptable performance by the MUA is dependent on the existence of header field information, such as it provided in the definition of the "text/calendar" content-type by [iCAL]. Internet application conforming to this memo MUST identify iCalendar XML documents with the experimental content-type "application/ calendar+xml". content-type:application/calendar+xml The content-type can also include the "optinfo" parameter to specify any other optional iCalendar information. The semantics of these content-type parameters is as defined in [iCAL]. Internet applications conforming to this memo MUST only send the iCalendar XML document in a "multipart/alternative" MIME entity that also contains an equivalent iCalendar object in the standard format defined by [iCAL]. This restrict will guarantee that the iCalendar object can also be processed by internet applications that only support the standard iCalendar format. An XML application supporting the iCalendar XML document type MUST be able to receive and properly process the "application/calendar+xml" document contained within a "multipart" message content-type. Royer Expires April 25, 2006 [Page 10] Internet-Draft xCal-Basic-RSS October 2005 2.9 iCalendar XML Representation and File Systems The iCalendar XML documents will be stored in file systems. The accepted practice for file extensions for XML documents is the text "XML". However, in order to uniquely identify iCalendar XML documents for file association with applications that can directly process this document type, it is RECOMMENDED that the file extension be the text "XCS". Royer Expires April 25, 2006 [Page 11] Internet-Draft xCal-Basic-RSS October 2005 3. Example Usage The following sections provide various examples of iCalendar XML documents. 3.1 A well-formed and valid iCalendar XML document The following is a simple example of a iCalendar XML document. This document is both a well-formed and valid XML document. The iCalendar object specifies an appointment. PUBLISH 2.0 -//HandGen//NONSGML vGen v1.0//EN 19981116T150000@cal10.host.com 19981116T145958Z Project XYZ Review Conference Room 23A 19981116T163000Z 19981116T190000Z 1998-ABC Corp-1234 Appointment,Work 3.2 Including binary content in attachments The following is an example of a valid iCalendar XML document that also includes an external reference to an attachment. The iCalendar object specifies a meeting invitation with an attachment. Royer Expires April 25, 2006 [Page 12] Internet-Draft xCal-Basic-RSS October 2005 REQUEST 2.0 -//HandGen//NONSGML vGen v1.0//EN 19981211T133000@cal1.host.com 19981211T132928Z cap://host.com/jim 19981212T150000Z 19981212T160000Z Department Meeting Conference Room 23A jim@host.com MAILTO:joe@host.com MAILTO:steve@host.com http://host.com/pub/photos/holiday.jpg The following is an example of a well-formed and valid iCalendar XML document that includes an attachment as inline binary content. The iCalendar object specifies a meeting invitation with an attachment. Royer Expires April 25, 2006 [Page 13] Internet-Draft xCal-Basic-RSS October 2005 REQUEST 2.0 -//HandGen//NONSGML vGen v1.0//EN 19981211T133000@cal1.host.com 19981211T132928Z MAILTO:jim@host.com 19981212T150000Z 19981212T160000Z Department Meeting Conference Room 23A MAILTO:jim@host.com MAILTO:joe@host.com MAILTO:steve@host.com MIICajCCAdOgAwIBAgI CBEUwDQEEBQAwdzELMAkGA1UEBhMCVVMxLDAqBgNVBAoTI05ldHNjYXB lIEjYXRpb25z...and so on...IENvcnBvc== 3.3 iCalendar XML document with multiple iCalendar objects The following is an example of a well-formed and valid iCalendar XML document that includes more than one iCalendar object. Royer Expires April 25, 2006 [Page 14] Internet-Draft xCal-Basic-RSS October 2005 PUBLISH 2.0 -//HandGen//NONSGML vGen v1.0//EN 2.0 -//HandGen//NONSGML vGen v1.0//EN PUBLISH 19981009T233010@cal1.host.com 19981009T233000Z 19981120T133000Z 19981122T183000Z IT Conference Downtowner Hotel 3.4 Using the iCalendar namespace The following is an example of a snippet of a XML document that includes elements from the iCalendar name-space. xmlns:pdi="http://pdi.org/schema"> 19981123T133000Z 19981123T203000Z 1234567 999.99 3.5 Publish meeting information The following is a snippet of an iCalendar XML document that publishes information about a meeting. Royer Expires April 25, 2006 [Page 15] Internet-Draft xCal-Basic-RSS October 2005 2.0 -//hacksw/handcal//NONSGML 1.0//EN PUBLISH 19970901T130000Z-123401@host.com 19970901T130000Z 19970903T163000Z 19970903T190000Z Annual Employee Review PRIVATE Business,Human Resources 3.6 Publish transparent annual event The following is a snippet of an iCalendar XML document that publishes information about an annually repeating event that is transparent to busy time searches. 2.0 PUBLISH 19990101T125957Z-123403@host.com 19990101T130000Z 19991102 Our Blissful Anniversary CONFIDENTIAL TRANSPARENT Anniversary,Personal,Special Occasion FREQ=YEARLY 3.7 Meeting invitation The following is a snippet of an iCalendar XML document that specifies an invitation for a meeting. The meeting occurs on the first Monday of each year for five years. Royer Expires April 25, 2006 [Page 16] Internet-Draft xCal-Basic-RSS October 2005 REQUEST 2.0 -//hacksw/handcal//NONSGML 1.0//EN 19981220T130000Z-123403@host.com 19981220T130050Z MAILTO:corprel@host.com 19990104T140000Z 19990104T220000Z Annual Stockholders Meeting One Corporate Drive, Wilmington, DL MAILTO:mrbig@host.com CAP:host.com/stockholders Business,Meeting,Special Occasion FREQ=YEARLY;COUNT=5;BYDAY=1MO 3.8 Publish busy time The following is an iCalendar XML document that publishes busy time information. The default value for the "method" attribute is "PUBLISH" and does not need to be specified in this example. 2.0 -//hacksw/handcal//NONSGML 1.0//EN 19980313T133000@ical1.host.com 19990104T133010Z CAP:host.com/jsmith 19980313T141711Z 19980410T141711Z jsmith.ifb 19980314T233000Z/19980315T003000Z 19980316T153000Z/19980316T163000Z 19980318T030000Z/19980318T040000Z Royer Expires April 25, 2006 [Page 17] Internet-Draft xCal-Basic-RSS October 2005 3.9 Request busy time The following is a snippet of an iCalendar XML document that requests a calendar user's busy time information. REQUEST 2.0 -//hacksw/handcal//NONSGML 1.0//EN 19970901T083000@ical1.host.com 19970901T083000Z MAILTO:jane_doe@host1.com 19971015T050000Z 19971016T050000Z MAILTO:john_public@host2.com 3.10 Issue a CAP command The following is a snippet of an iCalendar XML document that issues a CAP command to delete a UID. 2.0 -//hacksw/handcal//NONSGML 1.0//EN relcalid-22 DELETE SELECT VEVENT FROM VAGENDA WHERE UID = 'abcd12345' Royer Expires April 25, 2006 [Page 18] Internet-Draft xCal-Basic-RSS October 2005 4. Acknowledgments The following have participated in the drafting and discussion of this memo: Greg FitzPatrick, Charles Goldfarb, Paul Hoffman, Lisa Lippert, Thomas Rowe. Royer Expires April 25, 2006 [Page 19] Internet-Draft xCal-Basic-RSS October 2005 5. IANA Considerations TODO - registration if application/calendar+xml Royer Expires April 25, 2006 [Page 20] Internet-Draft xCal-Basic-RSS October 2005 6. Security Considerations CDATA Sections - - A XML iCalendar document may contain CDATA sections to represent content for specific element types. The CDATA section specifies arbitrary character data that is not meant to be interpretted. It is not scanned by the XML parser for markup. While this memo restricts that any CDATA section MUST NOT contain markup or other such alternate representation for the property value, in general, CDATA section from a non-conformant implementation can contain content such as HTML markup. HTML text can be used to invoke programs. Implementors should be aware that this may leave an implementation open to malicious attack that might occur as a result of executing the markup in the CDATA section. PROCEDURAL ALARMS - - A XML iCalendar document can be created that contains a "VEVENT" calendar component with "VALARM" calendar components. The "VALARM" calendar component can be of type PROCEDURE and can have an attachment containing some sort of executable program. Implementations that incorporate these types of alarms are subject to any virus or malicious attack that might occur as a result of executing the attachment. ATTACHMENTS - - A XML iCalendar document can include references to Uniform Resource Locators that can be programmed resources. Implementers and users of this memo should be aware of the network security implications of accepting and parsing such information. In addition, the security considerations observed by implementations of electronic mail systems should be followed for this memo. Royer Expires April 25, 2006 [Page 21] Internet-Draft xCal-Basic-RSS October 2005 7. Bibliography [BASIC] D. Royer, "Basic Internet Calendaring and Scheduling Core Object Specification", Internet Draft, http://www.internic.net/ internet-drafts/draft-royer-ical-basic-03.txt, June 2005. [ISO9070] "Information Technology_SGML Support Facilities_ Registration Procedures for Public Text Owner Identifiers", ISO/IEC 9070, Second Edition, International Organization for Standardization, April 1991. [MIME] N. Freed, N. Borenstein, "Multipurpose Internet Mail Extensions (MIME) - Part One: Format of Internet Message Bodies", RFC 2045, November 1996. [KEYWORDS] S. Bradner, "Key words for use in RFCs to Indicate Requirement Levels", RFC 2119, http://www.ietf.org/rfc/rfc2119.txt, March 1997. [iCAL] F. Dawson and D. Stenerson, "Internet Calendaring and Scheduling Core Object Specification (iCalendar)", RFC 2445, http://www.ietf.org/rfc/rfc2445.txt, November 1998. This is the current version of iCalednar used in examples in this memo. [iTIP] S. Silverbert, S. Mansour, F. Dawson, R. Hopson, "iCalendar Transport-Independent Interoperability Protocol"", RFC 2446, http://www.ietf.org/rfc/rfc2446.txt, November 1998. This is the current version of iTIP used in examples in this memo. [XML] "Extensible Markup Language (XML)", Worldwide Web Consortium, http://www.w3.org/TR/1998/REC-xml-19980210, February 1998. [XML] "Extensible Markup Language (XML)", Worldwide Web Consortium, http://www.w3.org/TR/1998/REC-xml-19980210, February 1998. Author's Address Doug Royer IntelliCal LLC 267 Kentlands Blvd., #3041 Gaithersburg, MD 20878 US Phone: (208)881-0380 Email: Doug@Royer.com Royer Expires April 25, 2006 [Page 22] Internet-Draft xCal-Basic-RSS October 2005 Intellectual Property Statement The IETF takes no position regarding the validity or scope of any Intellectual Property Rights or other rights that might be claimed to pertain to the implementation or use of the technology described in this document or the extent to which any license under such rights might or might not be available; nor does it represent that it has made any independent effort to identify any such rights. Information on the procedures with respect to rights in RFC documents can be found in BCP 78 and BCP 79. Copies of IPR disclosures made to the IETF Secretariat and any assurances of licenses to be made available, or the result of an attempt made to obtain a general license or permission for the use of such proprietary rights by implementers or users of this specification can be obtained from the IETF on-line IPR repository at http://www.ietf.org/ipr. The IETF invites any interested party to bring to its attention any copyrights, patents or patent applications, or other proprietary rights that may cover technology that may be required to implement this standard. Please address the information to the IETF at ietf-ipr@ietf.org. Disclaimer of Validity This document and the information contained herein are provided on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Copyright Statement Copyright (C) The Internet Society (2005). This document is subject to the rights, licenses and restrictions contained in BCP 78, and except as set forth therein, the authors retain all their rights. Acknowledgment Funding for the RFC Editor function is currently provided by the Internet Society. Royer Expires April 25, 2006 [Page 23]