Subject: RE: iRIP and CAP

From: [email-masked]
Date: Tue, 1 Aug 2000 16:21:29 -0400

Ok. That's what I needed to hear.  I had only heard a couple of "Keep" the 
draft - and more "let it go away."  One group says that most if not all 
the iRIP functionality is in CAP - therefore we don't need iRIP.  The 
pieces that are not there should be in a "short doc" and John Stracke has 
volunteered to work on such a document.  I can not speak for him - but 
watch for something soon.

However, I have no particular interest either way. I have no problem 
resubmitting the draft if there is a strong concensus to do so.  No 
problem at all.  We just need to make sure we have editors assigned - 
resubmitting means new draft number, etc.
___________________
Patricia Egen Consulting
www.egenconsulting.com
423-875-2652

[email-masked]
08/01/00 03:51 PM

        To:     [email-masked]
        cc:     [email-masked]
        Subject:        RE: iRIP and CAP

I think we should renew iRIP as well.  I agree, we may want to include 
iRIP
functionality in CAP

[email-masked] on 07/18/2000 12:34:20 PM

 

 To:      [email-masked], [email-masked] 
 
 cc:      (bcc: Cengiz Satir/ON Technology) 

 Subject: RE: iRIP and CAP 

I think we should renew iRIP. At a minumum, it contains
good information should we want to include iRIP style
functionality in CAP.

-----Original Message-----
From: John Stracke [mailto:[email-masked]]
Sent: Tuesday, July 18, 2000 12:05 PM
To: [email-masked]
Subject: Re: iRIP and CAP

[email-masked] wrote:

> So it sounds like 1 vote to let iRIP expire.  Or did I misread
> your meaning?

Mmm...I would actually prefer to see iRIP exist; I think
real-time iTIP has value.  But, if we can't do iRIP, then we
should do the subset.

Hmm.  OK, so Bruce and I want to finish iRIP.  I'm willing to
work on it; Bruce, are you? Does anybody have any objections to
seeing iRIP completed and standardized?

--
/==============================================================\
|John Stracke    | http://www.ecal.com |My opinions are my own.|
|Chief Scientist |=============================================|
|eCal Corp.      |Solipsists have all the fun.                 |
[email-masked]|                                             |
\==============================================================/

---

From: John Stracke <[email-masked]>
Date: Wed, 02 Aug 2000 09:21:11 -0400

[email-masked] wrote:

> Ok. That's what I needed to hear.  I had only heard a couple of
> "Keep" the draft - and more "let it go away."  One group says
> that most if not all the iRIP functionality is in CAP -
> therefore we don't need iRIP.  The pieces that are not there
> should be in a "short doc" and John Stracke has volunteered to
> work on such a document.  I can not speak for him - but watch
> for something soon.

OK, so here's the story: CAP already contains iTIP
functionality.  All commands and responses are embedded in
iCalendars; while there are some CAP-specific commands (e.g.,
QUERY), the full set of iTIP is also available.  The problem,
though, is that, for interdomain scheduling, you don't
necessarily want to expose your CAP server--it would be like
having to expose your IMAP server in order to accept SMTP
traffic.  (Sure, some people do expose their IMAP or POP servers,
so their users can get in--but they have the choice; and they
have the ability to apply different security rules.) An iRIP
server would be more limited; it would only accept iTIP.  So what
I did was to write up a profile for CAP, a subset which supports
only iTIP functionality.  This way, we don't have to maintain two
full-sized protocols; moreover, a site can smoothly transition
their public server between full CAP and iTIP only.

I didn't call the subset iRIP, because of the possibility for
confusion.  Instead, I called it CRISP: CAP Real-time iTIP-based
Scheduling Profile.

As it turned out, the profile was fairly easy; about all I had to
do was specify the capability set that makes a CAP server a CRISP
server.  (I also had to define a new capability value of NONE for
a couple of mandatory features; but the CAP editors have said
they don't object to adding those to the CAP spec, if the WG
agrees.) The I-D is attached.  The version number is -xx because
I can't submit it for publication until after the meeting, so we
might have to change it before the the -00 version.

--
/=================================================================\
|John Stracke    | http://www.ecal.com |My opinions are my own.   |
|Chief Scientist |================================================|
|eCal Corp.      |No matter how tempting the prospect of unlimited|
[email-masked]|power, I will not consume any energy field      |
|                |bigger than my head.                            |
\=================================================================/

Internet Engineering Task Force                     J. Stracke
INTERNET DRAFT                                            eCal
draft-stracke-calsch-crisp-xx.txt                  August 2000
                                        Expires: February 2001

           CAP Realtime iTIP-based Scheduling Profile (CRISP)

1.  Status of this Memo

   This document is an Internet-Draft and is in full conformance with
   all provisions of Section 10 of RFC2026.

   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 docu-
   ments 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 document and related documents are discussed on the calsch mail-
   ing list.

2.  Copyright Notice

   Copyright (C) The Internet Society (2000).  All Rights Reserved.

3.  Abstract

   This document sets forth a restricted profile of [CAP], one which
   supports no operations beyond the scheduling functionality of [iTIP].
   The motivation is to permit use of CAP's real-time iTIP functionality
   without exposing the calendar access functionality (which may require
   stricter security controls than iTIP).

Stracke                                                         [Page 1]

CRISP                                                           May 2000

4.  Introduction

   [iTIP] defines a scheduling protocol based on exchanging specially
   formatted [iCalendar] messages.  iTIP is defined to be independent of
   transport protocol.  At present, there is one standard binding of
   iTIP to a transport protocol, [iMIP], which carries iTIP messages in
   email.  This is a useful base level capability (email can reach vir-
   tually any user on the Net), but can involve considerable latencies.
   A real-time binding for iTIP would be useful; it would permit appli-
   cation developers to give users better feedback on the progress of
   the iTIP operations.

   Since CAP includes full iTIP functionality, one option would be to
   permit full access to CAP; to schedule an event with a remote user,
   one would then make a CAP connection to their CS.  The problem is
   that such a connection may be considered a security risk in some
   organizations; even though the CS has ACLs to prevent the client from
   performing non-iTIP operations, it would be better if client simply
   could not attempt such operations.  (It's as if mail administrators
   were told that an SMTP server outside the firewall had to include
   IMAP functionality as well.)  Thus, this document defines a profile
   of CAP, a subset which does not support non-iTIP operations.

5.  Profile Definition

   A CRISP server is a CAP server with the following capabilities:

      * ITIPVERSION=1.0
      * CAPVERSION=1.0
      * CAR=NONE
      * QUERYLEVEL=NONE

   In addition, various AUTH capabilities are expected.  Other capabili-
   ties which apply to iTIP operations may be specified; e.g., MAXDATE
   and MAXICALOBJECTSIZE.

   Note that NONE is not a legal value for CAR or QUERYLEVEL in the cur-
   rent draft of CAP.  This will have to be resolved.

   A CRISP server MUST NOT accept any iCalendar component which is not a
   valid iTIP component.

6.  Firewall Application

   Clearly, it would be undesirable for an organization with a CAP
   server to have a CRISP server implemented completely separately, but

Stracke                                                         [Page 2]

CRISP                                                           May 2000

   having access to the same database.  Such duplication would increase
   development costs, maintenance costs, and security exposure.  On the
   other hand, it would be possible to build a CRISP server which han-
   dles all operations by proxying them to the CAP server.  Such a proxy
   could be placed in the "no-man's-land" common in firewalls; the fire-
   wall would permit CAP connections from the outside to the proxy, and
   from the proxy to the internal CAP server.  The proxy would review
   all incoming iCalendar components and validate that they were legiti-
   mate iTIP operations; no non-iTIP components would be forwarded to
   the CAP server.  Similarly, if necessary, the proxy might censor the
   iTIP replies coming from the CAP server.

7.  Security Considerations

   The protocol defined in this document is a subset of [CAP], and
   accordingly inherits all of CAP's security analysis.  However, new
   analysis does need to be done for the subset, especially since the
   whole point of the subset is to address security concerns.

8.  Author's Address:

   John Stracke
   Chief Scientist
   eCal Corp.
   Email: [email-masked]

9.  References

   [iTIP] Silverberg, Mansour, Dawson, Hopson, "iCalendar Transport-
   Independent Interoperability Protocol (iTIP)", RFC 2446, November
   1998

   [iMIP] Dawson, Mansour, Silverberg, "iCalendar Message-Based Interop-
   erability Protocol (iMIP)", RFC 2445, November 1998

   [CAP] Mansour, Dawson, Royer, Taler, Hill, "Calendar Access Protocol
   (CAP)", draft-ietf-calsch-cap-03.txt, July 2000.  Work in progress.

   [iCAL] Dawson, Stenerson, "Internet Calendaring and Scheduling Core
   Object Specification (iCalendar)", RFC 2445, November 1998

Stracke                                                         [Page 3]