Network Working Group Frank Dawson/Lotus Internet Draft Steve Mansour/Netscape <draft-ietf-calsch-imip-02.txt> Steve Silverberg/Microsoft Expires six months after October 24, 1997 iCalendar Message-Based Interoperability Protocol (iMIP) Status of this Memo This document is an Internet-Draft. 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. Internet-Drafts may be updated, replaced, or made obsolete by other documents at any time. It is not appropriate to use Internet- Drafts as reference material or to cite them other than as a "working draft" or "work in progress". To learn the current status of any Internet-Draft, please check the 1id-abstracts.txt listing contained in the Internet-Drafts Shadow Directories on ds.internic.net (US East Coast), nic.nordu.net (Europe), ftp.isi.edu (US West Coast), or munnari.oz.au (Pacific Rim). Distribution of this document is unlimited. Abstract This document specifies a binding from the iCalendar Transport- independent Interoperability Protocol [ITIP] to Internet email-based transports. Calendaring entries defined by the iCalendar Object Model [ICAL] are composed using constructs from [RFC-822], [RFC-2045], [RFC-2046], [RFC-2047], [RFC-2048] and [RFC-2049]. This document is based on the calendaring and scheduling model defined by [ICMS]. This document is based on discussions within the Internet Engineering Task Force (IETF) Calendaring and Scheduling (CALSCH) working group. More information about the IETF CALSCH working group activities can be found on the IMC website at http://www.imc.org, the IETF website at http://www.ietf.org/html.charters/calsch-charter.html. Refer to the references within this document for further information on how to access these various documents. Distribution of this document is unlimited. Comments and suggestions for improvement should be sent to the authors. Dawson/Mansour/Silverberg 1 Expires May 1998 Internet DraftiCalendar Message-based Interoperability Protocol (iMIP) October 24, 1997 1 Introduction This binding document provides the transport specific information necessary convey iCalendar Transport-independent Interoperability Protocol [ITIP] over MIME as defined in [RFC-822] and [RFC-2045]. 1.1 Related Memos Implementors will need to be familar with several other memos that, along with this memo, form a framework for Internet calendaring and scheduling standards. This document - specifies an Internet email binding for [ITIP]. [ICMS] - specifies a common terminology and abstract; [ICAL] - specifies a core specification of objects, data types, properties and property parameters; [ITIP] - specifies an interoperability protocol for scheduling between different implementations; [IRIP] - specifies an Internet real time protocol binding for [ITIP]. This memo does not attempt to repeat the specification of concepts or definitions from these other memos. Where possible, references are made to the memo that provides for the specification of these concepts or definitions. 1.2 Formatting Conventions The mechanisms defined in this memo are defined in propose. In order to refer to elements of the calendaring and scheduling model, core object or interoperability protocol defined in [ICMS], [ICAL] and [ITIP] some formatting conventions have been used. Calendaring and scheduling roles defined by [ICMS] are referred to in quoted-strings of text with the first character of each word in upper case. For example, "Organizer" refers to a role of a "Calendar User" within the scheduling protocol defined by [ITIP] Calendar components defined by [ICAL] are referred to with capitalized, quoted-strings of text. All calendar components start with the letter "V". For example, "VEVENT" refers to the event calendar component, "VTODO" refers to the to-do calendar component and "VJOURNAL" refers to the daily journal calendar component. Scheduling methods defined by [ITIP] are referred to with capitalized, quoted-strings of text. For example, "REQUEST" refers to the method for requesting a scheduling calendar component be created or modified, "REPLY" refers to the method a recipient of a request uses to update their status with the "Organizer" of the calendar component. Dawson/Mansour/Silverberg 2 Expires May 1998 Internet DraftiCalendar Message-based Interoperability Protocol (iMIP) October 24, 1997 Properties defined by [ICAL] are referred to with capitalized, quoted-strings of text, followed by the word "property". For example, "ATTENDEE" property refers to the iCalendar property used to convey the calendar address of a calendar user. Property parameters defined by [ICAL] are referred to with lower case, quoted-strings of text, followed by the word "parameter". For example, "VALUE" parameter refers to the iCalendar property parameter used to override the default data type for a property value. 1.3 Terminology The email terms used in this memo are defined in [RFC-822] and [RFC- 2045]. The calendaring and scheduling terms used in this memo are defined in [ICMS], [ICAL] and [ITIP] 2 MIME Message Format Binding This section defines the message binding to the MIME electronic mail transport. The sections below refer to the "originator" and the "respondent" of an iMIP message. Typically, the originator is the owner or oganizer of an event. The respondent is an attendee of the event. In a well-organized email message the Reply-To header contains the email address of the originator or respondent of an event. However, this cannot be guaranteed as Mail User Agents (MUA) are not required to enforce iMIP semantics. 2.1 MIME Media Type A MIME entity containing content information formatted according to this design document will be referenced as a "text/calendar" content type. It is assumed that this content type will be transported through a MIME electronic mail transport. 2.2 Security This section addresses several aspects of security including Authentication, Authorization and Confidentiality. Authentication and confidentiality can be achieved using RFC 1847 which specifies the Security Multiparts for MIME. This framework defines new content types and subtypes of multipart: signed and encrypted. Each contains two body parts: one for the protected data and another for the control information necessary to remove the protection. 2.2.1 Authorization Per the [ICSM], only the organizer has authorization to modify or cancel calendar entries they organize. That is, spoof@xyz.com should not be able to modify or cancel a meeting that was organized by Dawson/Mansour/Silverberg 3 Expires May 1998 Internet DraftiCalendar Message-based Interoperability Protocol (iMIP) October 24, 1997 a@xyz.com. Furthermore, only the respondent has the authorization to indicate their status to the organizer. That is, spoof@xyz.com should not be able to tell the organizer that b@xyz.com declines a meeting invitation. Hence, iMIP implementations must verify the authenticity of the sender of an iCalendar object before taking any action. This could be done by utilizing a Multipart/signed implementation of either PGP/MIME or S/MIME. 2.2.2 Authentication Authentication can be performed using an implementation of RFC 1847 Multipart/signed that supports public/private key certificates. However, since most MUAs provide for the forwarding of messages, the organizer of an event and the sender of the message may be different. Therefore authentication may not be possible. 2.2.3 Confidentiality To ensure confidentiality using iMIP implementations should utilize RFC 1847 compliant encryption. The protocol does not restrict a CUA from forwarding Requests or Responses to other users or agents. 2.3 RFC 822 Addresses The calendar address specified within the "ATTENDEE" property in an iCalendar object MUST be a fully qualified, RFC 822 address specification for the corresponding "Owner", "Organizer" or "Attendee" of the "VEVENT" or "VTODO". The address MUST be the RFC 822 address for the calendaring and scheduling mailbox for the attendee. For purposes of authentication and authorization the RFC 822 "Sender" and "Reply-to" value MUST be the same as the address value for the "Organizer". Because [ITIP] does not preclude "Attendees" from forwarding "VEVENTS" or "VTODOS" to others, the RFC-822 "Sender" value may not equal that of the organizer. In these cases, authentication cannot be verified. Additionally, the "Organizer" cannot be inferred by the RFC-822 "Sender" or "Reply-to" values. Instead, it MUST be derived by opening the proper text/calendar MIME body part. 2.4 Content Type A MIME body part containing content information that conforms to this design document MUST have a Content-Type value of "text/calendar". The content type header field MUST also include the type parameter "method". The parameter value MUST be one of the message types defined by this method. The value MUST also be the same as the value of the METHOD calendar property within the iCalendar object. This means that if a MIME message containing multiple iCalendar objects with different method values, then they must be further encapsulated Dawson/Mansour/Silverberg 4 Expires May 1998 Internet DraftiCalendar Message-based Interoperability Protocol (iMIP) October 24, 1997 with a "multipart/mixed" MIME entity. This will allow each of the iCalendar objects to be encapsulated within their own "text/calendar" MIME entity. A CHARSET parameter MUST be present when the "text/calendar" is used. RFC-2046 discusses the selection of an appropriate CHARSET value. The optional Content-Type COMPONENT parameter defines the iCalendar component type contained within the iCalendar object. The following is an example of this header field with a value that indicates an event message. Content-Type:text/calendar; method=request; charset=UTF-8; component=vevent The "text/calendar" content type allows for the scheduling message type to be included in a MIME message with other content information (i.e., multipart/mixed) or included in a MIME message with a clear- text, human-readable form of the scheduling message (i.e., multipart/alternative). In order to permit the information in the scheduling message to be understood by MIME user agents (UA) that do not support the text/calendar content type, scheduling messages should be sent with an alternative, human-readable form of the information. 2.5 Content-Transfer-Encoding Note that the default character set for iCalendar objects is UTF-8. A transfer encoding SHOULD be used for iCalendar objects containing any characters that are not part of the US-ASCII character set. Content-Transfer-Encoding:quoted-printable 3 Security Considerations [ITIP] details the security threats that applications must address when implementing ITIP. Two spoofing threats are identified: Spoofing the "Organizer", and Spoofing an "Attendee". To address these threats, the originator of an iCalendar object must be authenticated by a recipient. Once authenticated, a determination can be made as to whether or not the originator is authorized to perform the requested operation. Applications requiring protection from this type of threat SHOULD provide a mechanism based on Security Multiparts for MIME [RFC1847] to authenticate the originator of the iCalendar object. The steps are described below: 1. The iCalendar object must be signed by the "Organizer" sending an update or the "Attendee" sending a reply. 2. Using the RFC1847-compliant security mechanism, determine who signed the iCalendar object. This is the "signer". Note that the Dawson/Mansour/Silverberg 5 Expires May 1998 Internet DraftiCalendar Message-based Interoperability Protocol (iMIP) October 24, 1997 signer is not necessarily the person sending an e-mail message. An e-mail message can be forwarded. 3. Correlate the "signer" to an "ATTENDEE" property in the iCalendar object. If the signer cannot be correlated to an "ATTENDEE" property, ignore the message. 4. Determine whether or not the "ATTENDEE" is authorized to perform the operation. ITIP states: (a) the "Organizer" is the only person authorized to make changes to an existing "VEVENT", "VTODO", "VJOURNAL" calendar component and redistribute the updates to the "Attendees" (b) an "Attendee" of a "VEVENT", "VTODO", "VJOURNAL" calendar component is the only person authorized to update any parameter associated with their "ATTENDEE" property and send it to the "Organizer" If these conditions are not met, ignore the message. 5. If all the above conditions are met, the message can be processed. 4 Examples 4.1 Single Component With An ATTACH Property This minimal message shows a how a an iCalendar object references an attachment. The attachment is accessible by anyone via its URL. From: sman@netscape.com To: stevesil@microsoft.com Subject: Phone Conference Mime-Version: 1.0 Content-Type:text/calendar; method=REQUEST; charset=US-ASCII Content-Transfer-Encoding: 7bit BEGIN:VCALENDAR PRODID:-//ACME/DesktopCalendar//EN METHOD:REQUEST VERSION:2.0 BEGIN:VEVENT ATTENDEE;ROLE=OWNER;STATUS=ACCEPTED:sman@netscape.com ATTENDEE;RSVP=YES;EXPECT=REQUEST:stevesil@microsoft.com DTSTAMP:19970611T190000Z DTSTART:19970701T100000-0700 DTEND:19970701T103000-0700 SUMMARY:Phone Conference DESCRIPTION:Please review the attached document. UID:www.acme.com-873970198738777 ATTACH:ftp\://ftp.bar.com/pub/docs/foo.doc SEQUENCE:0 STATUS:CONFIRMED Dawson/Mansour/Silverberg 6 Expires May 1998 Internet DraftiCalendar Message-based Interoperability Protocol (iMIP) October 24, 1997 END:VEVENT END:VCALENDAR 4.2 Single Component With An ATTACH Property and Inline Attachment This example shows how a message containing an iCalendar object references an attached document. The reference is made using a Content-id (CID). Thus, the iCalendar object and the document are packaged in a multipart/related encapsulation. From: foo1@bar.net To: foo2@bar.net Subject: Phone Conference Mime-Version: 1.0 Content-Type: multipart/related; boundary="boundary-example-1"; type=text/calendar --boundary-example-1 Content-Type:text/calendar; method=REQUEST; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Content-Disposition: attachment; filename="event.vcs" BEGIN:VCALENDAR PRODID:-//ACME/DesktopCalendar//EN METHOD:REQUEST VERSION:2.0 BEGIN:VEVENT ATTENDEE;ROLE=OWNER;STATUS=ACCEPTED:foo1@bar.net ATTENDEE;RSVP=YES;EXPECT=REQUEST; TYPE=INDIVIDUAL:foo2@bar.net DTSTAMP:19970611T190000Z DTSTART:19970701T100000-0700 DTEND:19970701T103000-0700 SUMMARY:Phone Conference UID:www.acme.com-873970198738777 ATTACH:cid\:123456789@example.com SEQUENCE:0 STATUS:CONFIRMED END:VEVENT END:VCALENDAR --boundary-example-1 Content-Type: application/msword; name="FieldReport.doc" Content-Transfer-Encoding: base64 Content-Disposition: inline; filename="FieldReport.doc" Content-ID: <123456789@example.com> 0M8R4KGxGuEAAAAAAAAAAAAAAAAAAAAAPgADAP7/CQAGAAAAAAAAAAABAAAARAAAAAAA AAAAEAAAQAAAAAEAAAD+////AAAAAEUAAAD/////////////////////////////////e tc... Dawson/Mansour/Silverberg 7 Expires May 1998 Internet DraftiCalendar Message-based Interoperability Protocol (iMIP) October 24, 1997 --boundary-example-1-- 4.3 Multiple Similar Components Multiple iCalendar components can be included in the iCalendar object when the METHOD is the same for each component. From: foo1@bar.net To: foo2@bar.net Subject: Phone Conference Mime-Version: 1.0 Content-Type:text/calendar; method=REQUEST; charset=US-ASCII Content-Transfer-Encoding: quoted-printable Content-Disposition: attachment; filename="event.vcs" BEGIN:VCALENDAR PRODID:-//ACME/DesktopCalendar//EN METHOD:REQUEST VERSION:2.0 BEGIN:VEVENT ATTENDEE;ROLE=OWNER;STATUS=ACCEPTED:foo1@bar.net ATTENDEE;RSVP=YES;EXPECT=REQUEST;TYPE=INDIVIDUAL:foo2@bar.net DTSTAMP:19970611T190000Z DTSTART:19970701T100000-0700 DTEND:19970701T103000-0700 SUMMARY:Phone Conference DESCRIPTION:Discuss the contents of the attached document UID:www.acme.com-873970198738777 SEQUENCE:0 STATUS:CONFIRMED END:VEVENT BEGIN:VEVENT ATTENDEE;ROLE=OWNER;STATUS=ACCEPTED:foo1@bar.net ATTENDEE;RSVP=YES;EXPECT=REQUEST;TYPE=INDIVIDUAL:foo2@bar.net DTSTAMP:19970611T190000Z DTSTART:19970801T100000-0700 DTEND:19970801T103000-0700 SUMMARY:Follow-up Phone Conference DESCRIPTION:Discuss the contents of the attached document UID:www.acme.com-873970198738777 SEQUENCE:0 STATUS:CONFIRMED END:VEVENT END:VCALENDAR 4.4 Multiple Mixed Components Different component types must be encapsulated in separate iCalendar objects. From: foo1@bar.net To: foo2@bar.net Dawson/Mansour/Silverberg 8 Expires May 1998 Internet DraftiCalendar Message-based Interoperability Protocol (iMIP) October 24, 1997 Subject: Phone Conference Mime-Version: 1.0 Content-Type:multipart/mixed;boundary="--FEE3790DC7E35189CA67CE2C" This is a multi-part message in MIME format. ----FEE3790DC7E35189CA67CE2C Content-Type:text/calendar; method=REQUEST; charset=US-ASCII Content-Transfer-Encoding: quoted-printable Content-Disposition: attachment; filename="event.vcs" BEGIN:VCALENDAR PRODID:-//ACME/DesktopCalendar//EN METHOD:REQUEST VERSION:2.0 BEGIN:VEVENT ATTENDEE;ROLE=OWNER;STATUS=ACCEPTED:foo1@bar.net ATTENDEE;RSVP=YES;EXPECT=REQUEST;TYPE=INDIVIDUAL:foo2@bar.net DTSTAMP:19970611T190000Z DTSTART:19970701T100000-0700 DTEND:19970701T103000-0700 SUMMARY:Phone Conference DESCRIPTION:Discuss the contents of the attached document UID:www.acme.com-873970198738777 SEQUENCE:0 STATUS:CONFIRMED END:VEVENT END:VCALENDAR ----FEE3790DC7E35189CA67CE2C Content-Type:text/calendar; method=REQUEST; charset=US-ASCII Content-Transfer-Encoding:8bit Content-Disposition: attachment; filename="event.vcs" BEGIN:VCALENDAR PRODID:-//ACME/DesktopCalendar//EN METHOD:REQUEST VERSION:2.0 BEGIN:VTODO DUE:19970701T090000-0700 SUMMARY:Phone Conference DESCRIPTION:Discuss the contents of the attached document UID:www.acme.com-td-873970198738777 SEQUENCE:0 STATUS:CONFIRMED END:VEVENT END:VCALENDAR ----FEE3790DC7E35189CA67CE2C 4.5 Detailed Components With An ATTACH Property This example shows the format of a message containing a group meeting between three individuals. The multipart/related encapsulation is Dawson/Mansour/Silverberg 9 Expires May 1998 Internet DraftiCalendar Message-based Interoperability Protocol (iMIP) October 24, 1997 used because the iCalendar object contains an ATTACH property that uses a CID to reference the attachment. From: Steve Mansour <sman@netscape.com> MIME-Version: 1.0 To: Steve Silverberg <stevesil@exchange.microsoft.com>, Frank Dawson <fdawson@earthlink.net> Subject: REQUEST - Phone Conference Content-Type:multipart/mixed;boundary="--FEE3790DC7E35189CA67CE2C" This is a multi-part message in MIME format. ----FEE3790DC7E35189CA67CE2C Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Event REQUEST Decription: Lets discuss the attached document Begin: July 1, 1997 10:00 PDT End: July 1, 1997 10:30 PDT ----FEE3790DC7E35189CA67CE2C Content-Type: multipart/related; boundary="boundary-example-2"; type=text/calendar --boundary-example-2 Content-Type:text/calendar; method=REQUEST; charset=US-ASCII; Component=vevent Content-Transfer-Encoding: quoted-printable Content-Disposition: attachment; filename="event.vcs" BEGIN:VCALENDAR PRODID:-//ACME/DesktopCalendar//EN PROFILE:REQUEST PROFILE-VERSION:1.0 VERSION:2.0 BEGIN:VEVENT ATTENDEE;ROLE=OWNER;STATUS=ACCEPTED:foo1@bar.net ATTENDEE;RSVP=YES;EXPECT=REQUEST;TYPE=INDIVIDUAL:foo2@bar.net DTSTAMP:19970611T190000Z DTSTART:19970701T100000-0700 DTEND:19970701T103000-0700 SUMMARY:Lets discuss the attached document UID:www.acme.com-873970198738777 ATTACH:cid:www.acme.com-12345aaa SEQUENCE:0 STATUS:CONFIRMED END:VEVENT END:VCALENDAR --boundary-example-2 Content-Type: application/msword; name="FieldReport.doc" Content-Transfer-Encoding: base64 Dawson/Mansour/Silverberg 10 Expires May 1998 Internet DraftiCalendar Message-based Interoperability Protocol (iMIP) October 24, 1997 Content-Disposition: inline; filename="FieldReport.doc" Content-ID: <www.acme.com-12345aaa> 0M8R4KGxGuEAAAAAAAAAAAAAAAAAAAAAPgADAP7/CQAGAAAAAAAAAAABAAAARAAAAAAA AAAAEAAAQAAAAAEAAAD+////AAAAAEUAAAD/////////////////////////////////e tc... --boundary-example-2-- ----FEE3790DC7E35189CA67CE2C-- 5 Bibliography [CHST] Character Sets, ftp://ftp.isi.edu/in- notes/iana/assignments/character-sets [ICAL] "Internet Calendaring and Scheduling Core Object Specification - iCalendar", Internet-Draft, July 1997, ftp://ftp.ietf.org/internet- drafts/draft-ietf-calsch-ical-02.txt. [ICMS] "Internet Calendaring Model Specification", Internet-Draft, July 1997, ftp://ftp.ietf.org/internet-drafts/draft-ietf-calsch-mod- 00.txt. [ITIP] "iCalendar Transport-Independent Interoperability Protocol (iTIP) : Scheduling Events, Busy Time, To-dos and Journal Entries ", Internet-Draft, October 1997, http://www.imc.org/draft-ietf-calsch- itip-01.txt. [ID-UTF8] "UTF-8, a transformation format of Unicode and ISO 10646", Internet-Draft, July,1996, ftp://ftp.ietf.org/internet-drafts/draft- yergeau-utf8-01.txt. [RFC-822] Crocker, D., "Standard for the Format of ARPA Internet Text Messages", STD 11, RFC 822, August 1982. [RFC-1847]. J. Galvin, S. Murphy, S. Crocker & N. Freed, "Security Multiparts for MIME: Multipart/Signed and Multipart/Encrypted", RFC 1847, October 1995. [RFC-2112] Levinson, E., "The MIME Multipart/Related Content-type," RFC 2112, March 1997. [RFC-2015] M. Elkins, "MIME Security with Pretty Good Privacy (PGP)," RFC 2015, October 1996. [RFC-2045] Freed, N., Borenstein, N., " Multipurpose Internet Mail Extensions (MIME) - Part One: Format of Internet Message Bodies", RFC 2045, November 1996. [RFC-2046] Freed, N., Borenstein, N., " Multipurpose Internet Mail Extensions (MIME) - Part Two: Media Types", RFC 2046, November 1996. Dawson/Mansour/Silverberg 11 Expires May 1998 Internet DraftiCalendar Message-based Interoperability Protocol (iMIP) October 24, 1997 [RFC-2047] Moore, K., "Multipurpose Internet Mail Extensions (MIME) - Part Three: Message Header Extensions for Non-ASCII Text", RFC 2047, November 1996. [RFC-2048] Freed, N., J. Klensin, J. Postel, "Multipurpose Internet Mail Extensions (MIME) - Part Four: Registration Procedures", RFC 2048, January 1997. 6 Author's Address The following address information is provided in a vCard v2.1, Electronic Business Card, format. BEGIN:VCARD FN:Frank Dawson ORG:Lotus Development Corporation ADR;WORK;POSTAL;PARCEL:;;6544 Battleford Drive;Raleigh;NC;27613- 3502;USA TEL;WORK;MSG:+1-919-676-9515 TEL;WORK;FAX:+1-919-676-9564 EMAIL;INTERNET:fdawson@earthlink.net URL:http://home.earthlink.net/~fdawson END:VCARD BEGIN:VCARD FN:Steve Mansour ORG:Netscape Communications Corporation ADR;WORK;POSTAL;PARCEL:;;501 East Middlefield Road;Mountain View;CA;94043;USA TEL;WORK;MSG:+1-415-937-2378 TEL;WORK;FAX:+1-415-428-4059 EMAIL;INTERNET:sman@netscape.com END:VCARD BEGIN:VCARD FN:Steve Silverberg ORG:Microsoft Corporation ADR;WORK;POSTAL;PARCEL:;;One Microsoft Way; Redmond;WA;98052-6399;USA TEL;WORK;MSG:+1-206-936-9277 TEL;WORK;FAX:+1-206-936-8019 EMAIL;INTERNET:stevesil@Exchange.Microsoft.com END:VCARD The iCalendar Object is a result of the work of the Internet Engineering Task Force Calendaring and scheduling Working Group. The chairman of that working group is: BEGIN:VCARD FN:Anik Ganguly ORG:OnTime, Inc. ADR;WORK;POSTAL;PARCEL:10 Floor;;21700 Northwestern Highway;Southfield;MI;48075;USA Dawson/Mansour/Silverberg 12 Expires May 1998 Internet DraftiCalendar Message-based Interoperability Protocol (iMIP) October 24, 1997 TEL;WORK;MSG:+1-810-559-5955 TEL;WORK;FAX:+1-810-559-5034 EMAIL;INTERNET:anik@ontime.com END:VCARD 7 Full Copyright Statement "Copyright (C) The Internet Society (date). All Rights Reserved. This document and translations of it MAY be copied and furnished to others, and derivative works that comment on or otherwise explain it or assist in its implmentation MAY be prepared, copied, published and distributed, in whole or in part, without restriction of any kind, provided that the above copyright notice and this paragraph are included on all such copies and derivative works. However, this document itself MAY NOT be modified in any way, such as by removing the copyright notice or references to the Internet Society or other Internet organizations, except as needed for the purpose of developing Internet standards in which case the procedures for copyrights defined in the Internet Standards process MUST be followed, or as required to translate it into languages other than English. The limited permissions granted above are perpetual and will not be revoked by the Internet Society or its successors or assigns. This document and the information contained herein is provided on an "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIMS 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. Dawson/Mansour/Silverberg 13 Expires May 1998
Datatracker
draft-ietf-calsch-imip-02
Internet-Draft
