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SIP Call-Info Parameters for Rich Call Data
draft-ietf-sipcore-callinfo-rcd-04

Document Type Active Internet-Draft (sipcore WG)
Authors Chris Wendt , Jon Peterson
Last updated 2022-03-07
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draft-ietf-sipcore-callinfo-rcd-04
Network Working Group                                           C. Wendt
Internet-Draft                                                Somos Inc.
Intended status: Standards Track                             J. Peterson
Expires: 8 September 2022                                   Neustar Inc.
                                                            7 March 2022

              SIP Call-Info Parameters for Rich Call Data
                   draft-ietf-sipcore-callinfo-rcd-04

Abstract

   This document describes a SIP Call-Info header field usage defined to
   include rich data associated with the identity of the calling party
   that can be rendered to a called party for providing more useful
   information about the caller or the specific reason for the call.
   This includes extended comprehensive information about the caller
   such as what a jCard object can represent for describing the calling
   party or other call specific information such as describing the
   reason or intent of the call.  The elements defined for this purpose
   are intended to be extensible to accommodate related information
   about calls that helps people decide whether to pick up the phone and
   additionally, with the use of jCard and other elements, to be
   compatible with the STIR/PASSporT Rich Call Data framework.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
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   Drafts is at https://datatracker.ietf.org/drafts/current/.

   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."

   This Internet-Draft will expire on 8 September 2022.

Copyright Notice

   Copyright (c) 2022 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

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   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents (https://trustee.ietf.org/
   license-info) in effect on the date of publication of this document.
   Please review these documents carefully, as they describe your rights
   and restrictions with respect to this document.  Code Components
   extracted from this document must include Revised BSD License text as
   described in Section 4.e of the Trust Legal Provisions and are
   provided without warranty as described in the Revised BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   4
   3.  Overview  . . . . . . . . . . . . . . . . . . . . . . . . . .   4
   4.  "jcard" Call-Info Token . . . . . . . . . . . . . . . . . . .   5
   5.  "call-reason" Call-Info Parameter . . . . . . . . . . . . . .   6
   6.  "jmin" Call-Info Token  . . . . . . . . . . . . . . . . . . .   7
   7.  Usage of jCard and property specific usage  . . . . . . . . .   9
     7.1.  Usage of URIs in jCard  . . . . . . . . . . . . . . . . .   9
     7.2.  Usage of multimedia data in jCard . . . . . . . . . . . .   9
     7.3.  Cardinality . . . . . . . . . . . . . . . . . . . . . . .  10
     7.4.  Identification properties . . . . . . . . . . . . . . . .  11
       7.4.1.  "fn" property . . . . . . . . . . . . . . . . . . . .  11
       7.4.2.  "n" property  . . . . . . . . . . . . . . . . . . . .  11
       7.4.3.  "nickname" property . . . . . . . . . . . . . . . . .  12
       7.4.4.  "photo" property  . . . . . . . . . . . . . . . . . .  12
     7.5.  Delivery Addressing Properties  . . . . . . . . . . . . .  12
       7.5.1.  "adr" property  . . . . . . . . . . . . . . . . . . .  12
     7.6.  Communications Properties . . . . . . . . . . . . . . . .  13
       7.6.1.  "tel" property  . . . . . . . . . . . . . . . . . . .  13
       7.6.2.  "email" property  . . . . . . . . . . . . . . . . . .  14
       7.6.3.  "lang" property . . . . . . . . . . . . . . . . . . .  14
     7.7.  Geographical Properties . . . . . . . . . . . . . . . . .  14
       7.7.1.  "tz" property . . . . . . . . . . . . . . . . . . . .  14
       7.7.2.  "geo" property  . . . . . . . . . . . . . . . . . . .  15
     7.8.  Organizational Properties . . . . . . . . . . . . . . . .  15
       7.8.1.  "title" property  . . . . . . . . . . . . . . . . . .  15
       7.8.2.  "role" property . . . . . . . . . . . . . . . . . . .  15
       7.8.3.  "logo" property . . . . . . . . . . . . . . . . . . .  16
       7.8.4.  "org" property  . . . . . . . . . . . . . . . . . . .  16
     7.9.  Explanatory Properties  . . . . . . . . . . . . . . . . .  16
       7.9.1.  "categories" property . . . . . . . . . . . . . . . .  16
       7.9.2.  "note" property . . . . . . . . . . . . . . . . . . .  17
       7.9.3.  "sound" property  . . . . . . . . . . . . . . . . . .  17
       7.9.4.  "uid" property  . . . . . . . . . . . . . . . . . . .  17
       7.9.5.  "url" property  . . . . . . . . . . . . . . . . . . .  18
       7.9.6.  "version" property  . . . . . . . . . . . . . . . . .  18
   8.  Extension of jCard  . . . . . . . . . . . . . . . . . . . . .  18

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   9.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  19
   10. IANA Considerations . . . . . . . . . . . . . . . . . . . . .  19
     10.1.  SIP Call-Info Header Field Purpose Token Request . . . .  19
     10.2.  SIP Call-Info Header Field Purpose Token Request . . . .  19
   11. Security Considerations . . . . . . . . . . . . . . . . . . .  19
   12. Normative References  . . . . . . . . . . . . . . . . . . . .  19
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  21

1.  Introduction

   Traditional telephone network signaling protocols have long supported
   delivering a 'calling name' from the originating side, though in
   practice, the terminating side is often left to derive a name from
   the calling party number by consulting a local address book or an
   external database.  SIP similarly can carry a 'display-name' in the
   From header field value from the originating to terminating side,
   though it is an unsecured field that is not commonly trusted and
   often replaced or ignored.  The same is often true of information in
   the Call-Info header fields.

   To allow calling parties to initiate, and called parties to receive,
   a more comprehensive, deterministic, and extensible rich call data
   for incoming calls, we describe new tokens for the SIP [RFC3261]
   Call-Info header field and a corresponding "purpose" parameter.  We
   also define a new parameter of Call-Info designed for carrying a
   "reason" value.  For this document, depending on the policies of the
   communications system, calling parties could either be the end user
   device or an originating service provider, and called parties could
   also similarly be an end user device or the terminating service
   provider acting on behalf of the recipient of the call.

   Used on its own, this specification assumes that the called party
   user agent can trust the SIP network or the SIP provider to deliver
   the correct rich call data (RCD) information.  This may not always be
   the case and thus, the entity inserting the Call-Info header field
   and the UAS relying on it SHOULD be part of the same trust domain
   [RFC3324].  Alternatively, and likely the recommended approach, the
   entity inserting the Call-Info header field should also sign the
   caller information via STIR mechanisms [RFC8224] and specifically
   through the [I-D.ietf-stir-passport-rcd].  This STIR signature would
   likely be provided by the caller itself or the originating service
   provider using an authoritative signature to authenticate the
   information is from the originator and hasn't been tampered with in
   transmission.

   [RFC7852] provides a means of carrying additional data about callers
   for the purposes of emergency services (especially its Section 4.4
   "Owner/Subscriber" information).  This specification provides an

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   overlapping functionality for non-emergency cases.  Rather than
   overloading its "EmergencyCallData" Call-Info "purpose" parameter
   value, this document defines a separate "purpose" parameter for the
   more generic delivery of information via jCard [RFC7095].  This
   document borrows from [RFC7852] the capability to carry a data
   structure as a body, through the use of the "cid" URI scheme
   [RFC2392].

2.  Terminology

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL" in this document are to be interpreted as described in BCP
   14 [RFC2119] [RFC8174] when, and only when, they appear in all
   capitals, as shown here.

3.  Overview

   The Call-Info header field, defined in [RFC3261] Section 20.9,
   defines a purpose parameter currently with "info", "icon", and "card"
   tokens.  This document defines two new purpose values and one new
   generic parameter for Call-Info.

   The first purpose value defined is "jcard" and is used to associate
   rich call data related to the identity of the calling party in the
   form of a jCard [RFC7095].  While there is a "card" token that is
   already defined with similar purpose, there are two primary reasons
   for the definition and usage of jCard and the use of JSON over the
   XML based vCard [RFC2426].  First, JSON has become the default and is
   generally the widely accepted optimally supported format for
   transmission, parsing, and manipulation of data on IP networks.
   Second, jCard has also been defined in [I-D.ietf-stir-passport-rcd]
   and has been adopted by PASSporT [RFC8225] because of the usage of
   JSON Web Tokens (JWT) [RFC7519].

   A generic parameter for "call-reason" is to be used to provide a
   string or other object that is used to convey the intent or reason
   the caller is calling to help the called party understand better the
   context of the call and why they may want to answer the call.

   The second purpose value defined is "jmin" and is intended to be a
   minimal call-info URI specifically for purposes where call-info does
   not point to any structured information via URI, but is used to carry
   parameters either defined in this document or future documents.

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4.  "jcard" Call-Info Token

   The use of the new Call-Info Token "jcard" is for the purpose of
   supporting RCD associated with the identity of a calling party in a
   SIP call [RFC3261] Section 20.9.  The format of a Call-Info header
   field when using the "jcard" is as follows.

   The Call-Info header field is defined to include a URI, where here
   the resource pointed to by the URI is a jCard JSON object [RFC7095].
   The MIME media type set for the JSON text MUST be set as application/
   json with a default encoding of UTF-8 [RFC4627].  A jCard also MAY be
   carried in the body of the SIP request bearing this Call-Info via the
   "cid" URI scheme [RFC2392].  Alternatively, the URI MUST define the
   use HTTPS or a transport that can validate the integrity of the
   source of the resource as well as the transport channel through which
   the resource is retrieved.

   An example of a Call-Info header field is:

   Call-Info: <https://example.com/qbranch.json>;purpose=jcard

   An example contents of a URL linked jCard JSON file is shown as
   follows:

   ["vcard",
     [
       ["version",{},"text","4.0"],
       ["fn",{},"text","Q Branch"],
       ["org",{},"text","MI6;Q Branch Spy Gadgets"],
       ["photo",{},"uri","https://example.com/photos/q-256x256.png"],
       ["logo",{},"uri","https://example.com/logos/mi6-256x256.jpg"],
       ["logo",{},"uri","https://example.com/logos/mi6-64x64.jpg"]
     ]
   ]

   An example SIP INVITE using the "cid" URI scheme is as follows.

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   INVITE sip:alice@example.com SIP/2.0
   Via: SIP/2.0/TLS pc33.atlanta.example.com;branch=z9hG4bKnashds8
   To: Alice <sip:alice@example.com>
   From: Bob <sip:12155551000@example.com;user=phone>;tag=1928301774>
   Call-ID: a84b4c76e66710
   Call-Info: <cid:12155551000@example.com>;purpose=jcard;call-reason= \
     "Rendezvous for Little Nellie"
   CSeq: 314159 INVITE
   Max-Forwards: 70
   Date: Fri, 25 Sep 2015 19:12:25 GMT
   Contact: <sip:12155551000@gateway.example.com>
   Content-Type: multipart/mixed; boundary=boundary1
   Content-Length: ...

   --boundary1

   Content-Type: application/sdp

   v=0
   o=UserA 2890844526 2890844526 IN IP4 pc33.atlanta.example.com
   s=Session SDP
   c=IN IP4 pc33.atlanta.example.com
   t=0 0
   m=audio 49172 RTP/AVP 0
   a=rtpmap:0 PCMU/8000

   --boundary1

   Content-Type: application/vcard+json
   Content-ID: <12155551000@example.com>

   ["vcard",[["version",{},"text","4.0"],["fn",{},"text","Q Branch"],
   ["org",{},"text","MI6;Q Branch Spy Gadgets"],["photo",{},"uri","ht
   tps://example.com/photos/quartermaster-256x256.png"],["logo",{},"u
   ri","https://example.com/logos/mi6-256x256.jpg"],["logo",{},"uri",
   "https://example.com/logos/mi6-64x64.jpg"]]]

5.  "call-reason" Call-Info Parameter

   This specification also defines a parameter of the Call-Info header
   called "call-reason".  The "call-reason" parameter is intended to
   convey a short textual message suitable for display to an end user
   during call alerting.  As a general guideline, this message SHOULD be
   no longer than 64 characters; displays that support this
   specification may be forced to truncate messages that cannot fit onto
   a screen.  This message conveys the caller's intention in contacting
   the callee.  It is an optional parameter, and the sender of a SIP
   request cannot guarantee that its display will be supported by the

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   terminating endpoint.  The manner in which this reason is set by the
   caller is outside the scope of this specification.

   One alternative approach would be to use the baseline [RFC3261]
   Subject header field value to convey the reason for the call.
   Because the Subject header has seen little historical use in SIP
   implementations, however, and its specification describes its
   potential use in filtering, it seems more prudent to define a new
   means of carrying a call reason indication.

   An example of a Call-Info header field value with the "call-reason"
   parameter follows:

   Call-Info: <https://example.com/jbond.json>;purpose=jcard;
     call-reason="For your ears only"

   Refer to the next section that extends call-reason and, in
   particular, discusses reasoning for the use of "call-reason"
   parameter versus considering "jinfo" with an included "call-reason"
   key value.

6.  "jmin" Call-Info Token

   This specification defines a token for the Call-Info header field
   called "jmin".  The "jmin" call-info URI is intended to address the
   need for scenarios where there it is not needed to use the URI value
   of call-info but only necessary to use defined call-info parameters,
   one example being the "call-reason" parameter defined in this
   document.  The URI referenced value by "jmin" is defined as a minimal
   JSON formatted object that MUST be the specific value "{}".  The JSON
   object "{}" is a valid JSON object per [RFC8259] but specifically
   contains no keys or values.  The MIME media type for this minimal
   JSON object text MUST be set as application/json with a default
   encoding of UTF-8 [RFC4627].  The "jmin" minimal JSON object string
   MAY be carried in the body of the SIP request bearing this Call-Info
   via the "cid" URI scheme [RFC2392].  Alternatively, the URI MUST
   define the use HTTPS or a transport that can validate the integrity
   of the source of the resource as well as the transport channel
   through which the resource is retrieved.

   We define this minimal JSON object for the express purpose of being a
   valid URI that will not break implementations that are not
   implementing this specification that reference the URI per procedures
   defined in [RFC3261] Section 20.9.  However, for implementations that
   do support this specification, because the value referenced by the
   URI MUST be "{}", as an optimization, implementations of this
   specification MAY consider it a shortcut to not reference the URI and
   trust that the value referenced will always be "{}".

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   An example of a Call-Info header field using "jmin" purpose and call-
   reason parameter is:

   Call-Info: <https://example.com/min.json>;purpose=jmin;
     call-reason="For your ears only"

   The resource referenced by the URL for the above example would be a
   file containing:

   {}

   An example SIP INVITE using the "cid" URI scheme equivalent to the
   above example is as follows.

   INVITE sip:alice@example.com SIP/2.0
   Via: SIP/2.0/TLS pc33.atlanta.example.com;branch=z9hG4bKnashds8
   To: Alice <sip:alice@example.com>
   From: Bob <sip:12155551000@example.com;user=phone>;tag=1928301774>
   Call-ID: a84b4c76e66710
   Call-Info: <cid:12155551000@example.com>;purpose=jmin;call-reason=
     "For your ears only"
   CSeq: 314159 INVITE
   Max-Forwards: 70
   Date: Fri, 25 Sep 2015 19:12:25 GMT
   Contact: <sip:12155551000@gateway.example.com>
   Content-Type: multipart/mixed; boundary=boundary1
   Content-Length: ...

   --boundary1

   Content-Type: application/sdp

   v=0
   o=UserA 2890844526 2890844526 IN IP4 pc33.atlanta.example.com
   s=Session SDP
   c=IN IP4 pc33.atlanta.example.com
   t=0 0
   m=audio 49172 RTP/AVP 0
   a=rtpmap:0 PCMU/8000

   --boundary1

   Content-Type: application/json
   Content-ID: <12155551000@example.com>

   {}

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7.  Usage of jCard and property specific usage

   Beyond the definition of the specific properties or JSON arrays
   associated with each property.  This specification defines a few
   rules above and beyond [RFC7095] specific to the use of jCard for
   Call-Info and Rich Call Data making sure there is a minimum level of
   supported properties that every implementation of this specification
   should adhere to.  This includes support for interpreting the value
   of this property and the ability to render in some appropriate form
   the display capabilities of common telephone devices, as well as
   apps, and also includes requirements specific to either textual
   displays and graphics capable displays.

7.1.  Usage of URIs in jCard

   When one or more URIs are used in a jCard, it is important to note
   that any URI referenced data, with the exception of the top-level
   usage of "jcl" as a URI to the jCard itself (unless updated by any
   future extensions of this specification) MUST NOT contain any URI
   references.  In other words, the jCard can have URI references as
   defined in the jCard specification and this document, but the content
   referenced by those URIs MUST NOT have any URIs, and therefore MUST
   be enforced by the client to not follow those URI references or not
   render that content to the user if any URI are present in that
   specific URI linked content.  The purpose of this is to control the
   security and more specifically align with the content integrity
   mechanism defined in [I-D.ietf-stir-passport-rcd].  It is the belief
   of the authors that there isn't a scenario that deeper URI references
   would be required or even supported by the current set of properties
   for the typical use of jCard properties, but because jCard is
   extensible, this rule is set to restrict further extension without
   the proper consideration of security and integrity properties of both
   Call-Info usage as well as the Rich Call Data and STIR signing of the
   data [I-D.ietf-stir-passport-rcd], [RFC8224].

7.2.  Usage of multimedia data in jCard

   There are a few cases where jCards incorporate URIs or directly
   include via Base64 encoding of digital images and sounds.  We specify
   a few recommended conventions to facilitate more consistent support
   of the successful rendering of these images.

   For images, such as for the photo and logo properties, the default
   image formats SHOULD be png or jpg.  These files are mostly commonly
   used to support 24-bit RGB images which should consequently be the
   default.  There are some older telephone devices that may only
   support bmp type of images with lower bit-range (e.g. 16-bit or 8-bit
   or 1-bit), also with potentially only grayscale or 1-bit black and

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   white color displays.  These exceptions are should considered
   optional to support or even recommended not to support and at least
   at the time of writing this document are becoming increasingly rare
   (i.e. typically displays on devices are either color or color-aware
   graphical displays that support png or jpg formats or exclusively
   textual displays).

   In addition, vector images are increasingly popular in their use for
   icons and the need for scalable images without having to send
   multiple resolutions.  SVG format and [W3C SVG 1.2 Tiny or higher]
   specifically appropriate for this specification has gained wide
   support as of the writing of this document, as a common format for
   vector images and should be supported as an additional default format
   for devices that support this specification.

   For the cases where image files are referenced by URIs as file
   resources, this document defines a character string that SHOULD be
   concatenated on to the end of a file name, before the file extension
   that signals the height and width of the image to the end device for
   the convenience of determining the appropriate resolution to retrieve
   without the need to retrieve all the image files.  It is also
   recommended that images are square ratio formatted with equal height
   and width and with a power of two value for the number of pixels
   (e.g. 32x32, 128x128, 512x512).  The format of the string should be
   "filename-HxW" where filename represents the unique string
   representing the file and H represents the height in pixels and W
   represents the width in pixels.

   Because this is a complex and often debated topic that has evolved
   over the many years of advances in image coding and display
   technologies, we likely suggest relying on either future
   specifications or industry forum specifications that might correspond
   to supporting particular classes of devices to further define how
   URIs can reference appropriate image formats and files.

   For audio files, the recommendation is to provide mp3, m4a, or wav
   files, although the usage of sound is not well defined in this
   specification as, for example, a special ring tone for a particular
   caller, and future documents should consider both usage and potential
   security risks of playing sounds that are not specifically authorized
   by a device user.

7.3.  Cardinality

   Property cardinalities are indicated, for convenience, using the
   following notation and follow the guidance of jCard [RFC7095] and
   vCard [RFC6350], which is based on ABNF (see [RFC5234], Section 3.6):

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     +-------------+--------------------------------------------------+
     | Cardinality | Meaning                                          |
     +-------------+--------------------------------------------------+
     |      1      | Exactly one instance per jCard MUST be present.  |
     |      *1     | Exactly one instance per jCard MAY be present.   |
     |      1*     | One or more instances per jCard MUST be present. |
     |      *      | One or more instances per jCard MAY be present.  |
     +-------------+--------------------------------------------------+

7.4.  Identification properties

   These types are used to capture information associated with the
   identification and naming of the entity associated with the jCard.
   They are initially defined in [RFC6350], but the following list of
   properties included and repeated in this Section is a subset of the
   properties defined for jCard with properties selected for this
   document that have relevance to telephone and messaging applications.
   jCard is an extensible object and therefore, there may also be future
   specifications that extend the set of properties that may be relevant
   to the set of communications applications that utilize this
   specification.

7.4.1.  "fn" property

   The "fn" property has the intent of providing a formatted text
   corresponding to the name of the object the jCard represents.
   Reference [RFC6350] Section 6.2.1.

   Value type: A single text value.

   Cardinality: 1*

   Example:
   ["fn", {}, "text", "Mr. John Q. Public\, Esq."]

7.4.2.  "n" property

   The "n" property has the intent of providing the components of the
   name of the object the jCard represents.  Reference [RFC6350]
   Section 6.2.2.

   Value type: A single structured text value.  Each component can have
   multiple values.

   Cardinality: *1

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   Example:
   ["n", {}, "text", "Public;John;Quinlan;Mr.;Esq."]
   ["n", {}, "text", "Stevenson;John;Philip,Paul;Dr.;Jr.,M.D.,A.C.P."]

7.4.3.  "nickname" property

   The "nickname" property has the intent of providing the text
   corresponding to the nickname of the object the jCard represents.
   Reference [RFC6350] Section 6.2.3.

   Value type: One or more text values separated by a COMMA character
   (U+002C).

   Cardinality: *

   Example:
   ["nickname", {}, "text", "Robbie"]
   ["nickname", {}, "text", "Jim,Jimmie"]
   ["nickname", {}, "text", "TYPE=work:Boss"]

7.4.4.  "photo" property

   The "photo" property has the intent of supplying an image or
   photograph information that annotates some aspect of the object the
   jCard represents.  Reference [RFC6350] Section 6.2.4.

   In addition to the definition of jCard, and to promote
   interoperability and proper formatting and rendering of images, the
   photo SHOULD correspond to a square image size of the sizes 128x128,
   256x256, 512x512, or 1024x1024 pixels.

   Value type: A single URI.

   Cardinality: *

   Example:
   ["photo", {}, "uri", "http://www.example.com/jqpublic-256x256.png"]

7.5.  Delivery Addressing Properties

   These properties are concerned with information related to the
   delivery addressing or label for the jCard object.

7.5.1.  "adr" property

   The "adr" property has the intent of providing the delivery address
   of the object the jCard represents.  Reference [RFC6350]
   Section 6.3.1.

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   Value type: A single structured text value, separated by the
   SEMICOLON character (U+003B).

   Cardinality: *

   Example:
   ["adr", {"type":"work"}, "text",
     ["", "", "3100 Massachusetts Avenue NW", "Washington", "DC",
     "20008", "USA"]

7.6.  Communications Properties

   These properties describe information about how to communicate with
   the object the jCard represents.

7.6.1.  "tel" property

   The "tel" property has the intent of providing the telephone number
   for telephony communication of the object the jCard represents.
   Reference [RFC6350] Section 6.4.1.

   Relative to the SIP From header field value this information may
   provide alternate telephone number or other related telephone numbers
   for other uses.

   It is important to note that any of the potential instances of the
   "tel" property should not be considered part of the authentication or
   verification part of STIR [RFC8224] or required to match the "orig"
   claim in the PASSporT [RFC8225].  These telephone numbers should be
   considered for contact, fax, or other purposes aligned with the
   general usage of jCard and vCard, although consideration of confusing
   the caller with different contact telephone number information versus
   the actual verified telephone number should be made from a general
   policy point of view.

   Value type: By default, it is a single free-form text value (for
   backward compatibility with vCard 3), but it SHOULD be reset to a URI
   value.  It is expected that the URI scheme will be "tel", as
   specified in [RFC3966], but other schemes MAY be used.

   Cardinality: *

   Example:
   ["tel", { "type": ["voice", "text", "cell"], "pref": "1" }, "uri",
     "tel:+1-202-555-1000"]
   ["tel", { "type": ["fax"] }, "uri", "tel:+1-202-555-1001"]

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7.6.2.  "email" property

   The "email" property has the intent of providing the electronic mail
   address for communication of the object the jCard represents.
   Reference [RFC6350] Section 6.4.2.

   Value type: A single text value.

   Cardinality: *

   Example:
   ["email", {"type":"work"}, "text", "jqpublic@xyz.example.com"]
   ["email", {"pref":"1"}, "text", "jane_doe@example.com"]

7.6.3.  "lang" property

   The "lang" property has the intent of providing the language(s) that
   may be used for contacting of the object the jCard represents.
   Reference [RFC6350] Section 6.4.4.

   Value type: A single language-tag value.

   Cardinality: *

   Example:
   ["lang", {"type":"work", "pref":"1"}, "language-tag", "en"]
   ["lang", {"type":"work", "pref":"2"}, "language-tag", "fr"]
   ["lang", {"type":"home"}, "language-tag", "fr"]

7.7.  Geographical Properties

   These properties are concerned with information associated with
   geographical positions or regions associated with the object the
   jCard represents.

7.7.1.  "tz" property

   The "tz" property has the intent of providing the time zone of the
   object the jCard represents.  Reference [RFC6350] Section 6.5.1.

   Note: the up-to-date reference for where time-zone names are
   maintained is, at the authoring of this document, at this web
   address, https://www.iana.org/time-zones.

   Value type: The default is a single text value.  It can also be reset
   to a single URI or utc-offset value.

   Cardinality: *

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   Example:
   ["tz", {}, "text", "Raleigh/North America"]

7.7.2.  "geo" property

   The "geo" property has the intent of providing the global positioning
   of the object the jCard represents.  Reference [RFC6350]
   Section 6.5.2.

   Value type: A single URI.

   Cardinality: *

   Example:
   ["geo", {}, "uri", "geo:37.386013,-122.082932"]

7.8.  Organizational Properties

   These properties are concerned with information associated with
   characteristics of the organization or organizational units of the
   object that the jCard represents.

7.8.1.  "title" property

   The "title" property has the intent of providing the position or job
   of the object the jCard represents.  Reference [RFC6350]
   Section 6.6.1.

   Value type: A single text value.

   Cardinality: *

   Example:
   ["title", {}, "text", "Research Scientist"]

7.8.2.  "role" property

   The "role" property has the intent of providing the position or job
   of the object the jCard represents.  Reference [RFC6350]
   Section 6.6.2.

   Value type: A single text value.

   Cardinality: *

   Example:
   ["role", {}, "text", "Project Leader"]

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7.8.3.  "logo" property

   The "logo" property has the intent of specifying a graphic image of a
   logo associated with the object the jCard represents.  Reference
   [RFC6350] Section 6.6.3.

   Value type: A single URI.

   Cardinality: *

   Example:
   ["logo", {}, "uri", "http://www.example.com/abccorp-512x512.jpg"]

   ["logo", {}, "uri", "data:image/jpeg;base64,MIICajCCAdOgAwIBAgIC
         AQEEBQAwdzELMAkGA1UEBhMCVVMxLDAqBgNVBAoTI05ldHNjYXBlIENvbW11bm
         ljYXRpb25zIENvcnBvcmF0aW9uMRwwGgYDVQQLExNJbmZvcm1hdGlvbiBTeXN0
         <...the remainder of base64-encoded data...>"]

7.8.4.  "org" property

   The "org" property has the intent of specifying the organizational
   name and units of the object the jCard represents.  Reference
   [RFC6350] Section 6.6.2.

   Value type: A single structured text value consisting of components
   separated by the SEMICOLON character (U+003B).

   Cardinality: *

   Example:
   ["org", {}, "text", "ABC\, Inc.;North American Division;Marketing"]

7.9.  Explanatory Properties

   These properties are concerned with additional explanations, such as
   that related to informational notes or revisions specific to the
   jCard.

7.9.1.  "categories" property

   The "categories" property has the intent of specifying application
   category information about the object the jCard represents.
   Reference [RFC6350] Section 6.7.1.

   Value type: One or more text values separated by a COMMA character
   (U+002C).

   Cardinality: *

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   Example:
   ["categories", {}, "text", "TRAVEL AGENT"]

   ["categories", {}, "text", "INTERNET,IETF,INDUSTRY"]

7.9.2.  "note" property

   The "note" property has the intent of specifying supplemental
   information or a comment about the object the jCard represents.
   Reference [RFC6350] Section 6.7.2.

   Value type: A single text value.

   Cardinality: *

   Example:
   ["note", {}, "text", "This fax number is operational 0800 to 1715
                EST\, Mon-Fri."]

7.9.3.  "sound" property

   The "sound" property has the intent of specifying a digital sound
   content information that annotates some aspect of the object the
   jCard represents.  This property is often used to specify the proper
   pronunciation of the name property value of the jCard.  Reference
   [RFC6350] Section 6.7.5.

   Value type: A single URI.

   Cardinality: *

   Example:
   ["sound", {}, "uri", "http://www.example.com/pub/logos/abccorp.mp3"]

   ["sound", {}, "uri", "data:audio/basic;base64,MIICajCCAdOgAwIBAgICBE
         AQEEBQAwdzELMAkGA1UEBhMCVVMxLDAqBgNVBAoTI05ldHNjYXBlIENvbW11bm
         ljYXRpb25zIENvcnBvcmF0aW9uMRwwGgYDVQQLExNJbmZvcm1hdGlvbiBTeXN0
         <...the remainder of base64-encoded data...>"]

7.9.4.  "uid" property

   The "uid" property has the intent of specifying a globally unique
   identifier corresponding to the object the jCard represents.
   Reference [RFC6350] Section 6.7.6.

   Value type: A single URI value.  It MAY also be reset to free-form
   text.

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   Cardinality: *1

   Example:
   ["uid", {}, "uri", "urn:uuid:f81d4fae-7dec-11d0-a765-00a0c91e6bf6"]

7.9.5.  "url" property

   The "url" property has the intent of specifying a uniform resource
   locator associated with the object the jCard represents.  Reference
   [RFC6350] Section 6.7.8.

   There is potential security and privacy implications of providing
   URLs with telephone calls.  The end client receiving a jCard with a
   URL property MUST only display the URL and not automatically follow
   the URL or provide automatic preview of the URL, and generally
   provide good practices in making it clear to the user it is their
   choice to follow the URL in a browser context consistent with all of
   the common browser security and privacy practices available on most
   consumer OS environments.

   Value type: A single uri value.

   Cardinality: *

   Example:
   ["url", {}, "uri", "https://example.org/french-rest/chezchic.html"]

7.9.6.  "version" property

   The "version" property MUST be included and is intended to specify
   the version of the vCard specification used to format this vCard.
   Reference [RFC6350] Section 6.7.9.

   Value type: A single text value.

   Cardinality: 1

   Example:
   ["version", {}, "text", "4.0"]

8.  Extension of jCard

   Part of the intent of the usage of jCard is that it has its own
   extensibility properties where new properties can be defined to relay
   newly defined information related to a caller.  This capability is
   inherently supported as part of standard extensibility.  However,
   usage of those new properties should be published and registered
   following [RFC7095] Section 3.6 or new specifications.

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9.  Acknowledgements

   We would like to thank David Hancock, Alec Fenichel and other members
   of the SIPCORE and STIR working group for helpful suggestions and
   comments for the creation of this draft.

10.  IANA Considerations

10.1.  SIP Call-Info Header Field Purpose Token Request

   [this RFC] defines the "jcard" token for use as a new token in the
   Call-Info header in the "Header Field Parameters and Parameter
   Values" registry defined by [RFC3968].

     +--------------+----------------+-------------------+------------+
     | Header Field | Parameter Name | Predefined Values | Reference  |
     +--------------+----------------+-------------------+------------+
     | Call-Info    | jcard          | No                | [this RFC] |
     +--------------+----------------+-------------------+------------+

10.2.  SIP Call-Info Header Field Purpose Token Request

   [this RFC] defines the "call-reason" generic parameter for use as a
   new parameter in the Call-Info header in the "Header Field Parameters
   and Parameter Values" registry defined by [RFC3968].  The parameter's
   token is "call-reason" and it takes the value of a quoted string.

11.  Security Considerations

   Revealing information such as the name, location, and affiliation of
   a person necessarily entails certain privacy risks.  SIP and Call-
   Info has no particular confidentiality requirement, as the
   information sent in SIP is in the clear anyway.  Transport-level
   security can be used to hide information from eavesdroppers, and the
   same confidentiality mechanisms would protect any Call-Info or jCard
   information carried or referred to in SIP.

   The security framework of signing and providing integrity to this
   data should be followed [I-D.ietf-stir-passport-rcd], with the idea
   that the use of constraints and other certificate based associations
   should be considered.  This includes considerations around
   information about the calling party being generally constant vs per
   call data being more temporal.  This also includes the relationship
   that certificates with constraints presents to how they relate to
   each other and how that information is managed, protected, and
   associated with the correct call corresponding to a calling party.

12.  Normative References

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   [I-D.ietf-stir-passport-rcd]
              Wendt, C. and J. Peterson, "PASSporT Extension for Rich
              Call Data", Work in Progress, Internet-Draft, draft-ietf-
              stir-passport-rcd-14, 25 October 2021,
              <https://www.ietf.org/archive/id/draft-ietf-stir-passport-
              rcd-14.txt>.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/info/rfc2119>.

   [RFC2392]  Levinson, E., "Content-ID and Message-ID Uniform Resource
              Locators", RFC 2392, DOI 10.17487/RFC2392, August 1998,
              <https://www.rfc-editor.org/info/rfc2392>.

   [RFC2426]  Dawson, F. and T. Howes, "vCard MIME Directory Profile",
              RFC 2426, DOI 10.17487/RFC2426, September 1998,
              <https://www.rfc-editor.org/info/rfc2426>.

   [RFC3261]  Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston,
              A., Peterson, J., Sparks, R., Handley, M., and E.
              Schooler, "SIP: Session Initiation Protocol", RFC 3261,
              DOI 10.17487/RFC3261, June 2002,
              <https://www.rfc-editor.org/info/rfc3261>.

   [RFC3324]  Watson, M., "Short Term Requirements for Network Asserted
              Identity", RFC 3324, DOI 10.17487/RFC3324, November 2002,
              <https://www.rfc-editor.org/info/rfc3324>.

   [RFC3966]  Schulzrinne, H., "The tel URI for Telephone Numbers",
              RFC 3966, DOI 10.17487/RFC3966, December 2004,
              <https://www.rfc-editor.org/info/rfc3966>.

   [RFC3968]  Camarillo, G., "The Internet Assigned Number Authority
              (IANA) Header Field Parameter Registry for the Session
              Initiation Protocol (SIP)", BCP 98, RFC 3968,
              DOI 10.17487/RFC3968, December 2004,
              <https://www.rfc-editor.org/info/rfc3968>.

   [RFC4627]  Crockford, D., "The application/json Media Type for
              JavaScript Object Notation (JSON)", RFC 4627,
              DOI 10.17487/RFC4627, July 2006,
              <https://www.rfc-editor.org/info/rfc4627>.

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   [RFC5234]  Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax
              Specifications: ABNF", STD 68, RFC 5234,
              DOI 10.17487/RFC5234, January 2008,
              <https://www.rfc-editor.org/info/rfc5234>.

   [RFC6350]  Perreault, S., "vCard Format Specification", RFC 6350,
              DOI 10.17487/RFC6350, August 2011,
              <https://www.rfc-editor.org/info/rfc6350>.

   [RFC7095]  Kewisch, P., "jCard: The JSON Format for vCard", RFC 7095,
              DOI 10.17487/RFC7095, January 2014,
              <https://www.rfc-editor.org/info/rfc7095>.

   [RFC7519]  Jones, M., Bradley, J., and N. Sakimura, "JSON Web Token
              (JWT)", RFC 7519, DOI 10.17487/RFC7519, May 2015,
              <https://www.rfc-editor.org/info/rfc7519>.

   [RFC7852]  Gellens, R., Rosen, B., Tschofenig, H., Marshall, R., and
              J. Winterbottom, "Additional Data Related to an Emergency
              Call", RFC 7852, DOI 10.17487/RFC7852, July 2016,
              <https://www.rfc-editor.org/info/rfc7852>.

   [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
              2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
              May 2017, <https://www.rfc-editor.org/info/rfc8174>.

   [RFC8224]  Peterson, J., Jennings, C., Rescorla, E., and C. Wendt,
              "Authenticated Identity Management in the Session
              Initiation Protocol (SIP)", RFC 8224,
              DOI 10.17487/RFC8224, February 2018,
              <https://www.rfc-editor.org/info/rfc8224>.

   [RFC8225]  Wendt, C. and J. Peterson, "PASSporT: Personal Assertion
              Token", RFC 8225, DOI 10.17487/RFC8225, February 2018,
              <https://www.rfc-editor.org/info/rfc8225>.

   [RFC8259]  Bray, T., Ed., "The JavaScript Object Notation (JSON) Data
              Interchange Format", STD 90, RFC 8259,
              DOI 10.17487/RFC8259, December 2017,
              <https://www.rfc-editor.org/info/rfc8259>.

Authors' Addresses

   Chris Wendt
   Somos Inc.
   United States of America
   Email: chris-ietf@chriswendt.net

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   Jon Peterson
   Neustar Inc.
   1800 Sutter St Suite 570
   Concord, CA  94520,
   United States of America
   Email: jon.peterson@neustar.biz

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