IETF 79 Proceedings

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vCard and CardDAV (vcarddav) (WG)

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In addition to this official charter maintained by the IETF Secretariat, there is additional information about this working group on the Web at:
Additional VCARDDAV Web Page

Additional information is available at tools.ietf.org/wg/vcarddav

Chair(s):

Applications Area Director(s):

Applications Area Advisor:

Meeting Slides

Internet-Drafts:

Request for Comments:

Charter (as of 2010-03-25)

A personal address book (PAB) contains a read/write copy of attributes
describing a user's interpersonal contacts. This is distinct from a
directory which contains a primarily read-only copy of users within an
organization. While these two data objects share a large number of
common attributes, their use and access patterns are fundamentally
different. The IETF has a standards-track data format (vCard) which
has been successfully used to interchange both personal-address-book
and user directory entry data objects. However, due to the lack of a
standard access control model for LDAP, the lack of a standard LDAP
schema and DIT-model for vCard PAB objects, and the different access
patterns for PAB data (as opposed to directory data), the use
of LDAP as an access protocol for PABs has had mixed results in
practice. Moreover, the vCard format has been extended by many parties
and the current specification is ambiguous for some objects.

If the deployed protocols related to interpersonal communication are
viewed as a component-based system, there are a number of points in
the system that would benefit from a standards track access protocol
for personal address book data.
This includes:

* Mail User Agents use PAB data to assist outgoing email addressing
and may use vCard attachments to transport PAB data between users.
* Calendar User Agents use PAB data to invite attendees to events
* Instant Messaging User Agents can provide additional information
about a user's buddies if they can be associated with a user's PAB
entry.
* A server-side Sieve engine with the spamtest/virustest extension
would benefit from access to a user's PAB to provide per-user white
list capabilities.
* Various deployed challenge-response mechanisms for email present in
Mail Transfer Agents, such as TMDA, would be improved by a PAB-based
white list.
* Mobile device synchronization software might be simplified by a
single cross-platform PAB access protocol.
* A voice conference or IP telephony system could access a user's PAB
to provide name-based or nickname-based dialing.


This WG will produce the following outputs:

(1) A revision of the vCard specification (RFC2426) at proposed
standard status. This revision shall include other vCard standardized
extensions (RFC 2739, 4770) and extensions assisting synchronization
technologies (for example, a per-entry UUID or per-attribute sequence
number). Other extensions shall be considered either in the base
specification or in additional documents.

(2) An address book access protocol leveraging the vCard data format.
The Internet-draft draft-daboo-carddav will be the starting point.
The WG is explicitly cautioned to keep the base specification feature
set small with an adequate extension mechanism, as failure to do so
was a problem for previous PAB efforts (ACAP). The WG will consider
arguments of the form "feature X must be in the base feature set
because ..." with great skepticism.

These documents will consider security implications carefully. The WG
will consider developing a mechanism that provides the ability to
check if an email address (or im address, etc) is in the user's PAB
without providing unrestricted access to all of the user's PAB data.
The WG should also consider developing a mechanism that allows the
user to grant this limited permission to a third-party service (such
as a server-based Sieve engine) for white-list purposes.

Once the primary outputs are complete, the WG will consider the
following secondary outputs:

(3) An XML schema which is semantically identical to vCard in all ways
and can be mechanically translated to and from vCard format without
loss of data. While vCard has deployed successfully and will remain
the preferred interchange format, a standard XML schema which
preserves vCard semantics might make vCard data more accessible to XML-
centric technologies such as AJAX and XSLT. Such a standard format
would be preferable to multiple proprietary XML schemas,
particularly if vCard semantics were lost by some of them and a lossy
gateway problem resulted.

(4) Identifying useful deployed vCard vendor extensions and creating
standards track versions of those extensions.

(5) Cooperate with the Sieve WG to produce a Sieve extension for
address book Sieve tests.

(6) LDAP mapping to the new vCard format without loss of data.

Goals and Milestones:

Mar 2008  Address book access protocol draft
Mar 2008  vCard new revision draft
Jun 2008  submit to IESG both drafts
Jun 2008  XML schema
Jun 2008  LDAP schema
Sep 2008  vcard extensions
Dec 2008  submit to IESG remaining drafts