Subject: Re: Fwd: I-D ACTION:draft-stracke-calsch-crisp-00.txt

From: [email-masked]
Date: Tue, 15 Aug 2000 15:35:39 -0400

2 Quick questions come to mind after reading this preliminary draft:

1: Is a CRISP server intended to be an iTIP->CAP bridge ONLY or is it 
intended to be iTIP<->CAP (ie: a bidirectional transcoder)?? 

2: Is CRISP an attempt to try to make a realtime ONLY iTIP bridge to CAP 
or is there any intenet/expectation to do iMIP bridging? 

Bruce
===========================================================================
Bruce Kahn                                INet: [email-masked]
Iris Associates                          Phone: 978.392.5335
Westford, MA, USA 01886                    FAX: and nothing but the FAX...
Standard disclaimers apply, even where prohibited by law...

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From: Doug Royer <[email-masked]>
Date: Tue, 15 Aug 2000 13:03:07 -0700

> or is there any intenet/expectation to do iMIP bridging?

CRISP is a CAP server that is limited to iTIP functionality.
It is in response to several peoples desire to keep iRIP alive.
So a client expecting to talk to a CRISP server could also
talk to a CAP server and everything would work.

-Doug

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From: John Stracke <[email-masked]>
Date: Fri, 18 Aug 2000 12:13:06 -0400

(Sorry; I was on vacation most of this week.)

[email-masked] wrote:

> 1: Is a CRISP server intended to be an iTIP->CAP bridge ONLY or
> is it intended to be iTIP<->CAP (ie: a bidirectional
> transcoder)??
>
> 2: Is CRISP an attempt to try to make a realtime ONLY iTIP
> bridge to CAP or is there any intenet/expectation to do iMIP
> bridging?

CRISP is a subset of CAP (hence the term "Profile").  It could be
used to create a bridge (as in the proxy case in section 6); or
you could build a CAP server that lives in a DMZ and is
CRISP-only when it gets a connection from the outside world; or
(if you don't have CAP at all) you could build a server that just
does CRISP.

The notion of a CRISP implementation being a sidecar slapped on
to the side of CAP to provide iTIP services is interesting, but
probably can't really hold up in practice, since it relies too
much on CAP's non-iTIP services (e.g., authentication).

I'll see about clarifying the text.

--
/===============================================================\
|John Stracke    | http://www.ecal.com |My opinions are my own. |
|Chief Scientist |==============================================|
|eCal Corp.      |"Fate just isn't what it used to be." --Hobbes|
[email-masked]|                                              |
\===============================================================/

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From: John Stracke <[email-masked]>
Date: Fri, 18 Aug 2000 12:32:03 -0400

> > bridge to CAP or is there any intenet/expectation to do iMIP

Forgot to answer this part.  My expectation is that iMIP is done via
a separate system.  First of all, in order to have iMIP feed
automatically into the user's calendar, you need to be able to get
at the user's incoming email.  POP and IMAP are not adequate for
this purpose, because the user might read and delete the message
before you get to it.  This means that the iMIP receiver has to be
integrated into the email server by some nonstandard process, which
in turn means that it might not be able to run anywhere near the CAP
server.  In addition, such an iMIP implementation has to be very
careful about what it does with the iTIP messages it gets, since
they aren't authenticated (unless you're using S/MIME or something).

Personally, I believe that a more reasonable approach to iMIP is to
give the user a way to take incoming iTIP attachments and submit
them to the CS by hand (via CAP, probably [CRISP would suffice]).
Then you don't have to worry about tapping their email, and the
CS can ignore questions of authentication and just trust that the
user has some reason to believe that the message is legitimate.

--
/================================================================\
|John Stracke    | http://www.ecal.com |My opinions are my own.  |
|Chief Scientist |===============================================|
|eCal Corp.      |We want forty million helicopters and a dollar!|
[email-masked]|--"Dinosaurs"                                  |
\================================================================/