SIP Call-Info Parameters for Labeling Calls
draft-ietf-sipcore-callinfo-spam-04

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SIPCORE                                                   H. Schulzrinne
Internet-Draft                                       Columbia University
Intended status: Standards Track                         August 29, 2019
Expires: March 1, 2020

              SIP Call-Info Parameters for Labeling Calls
                  draft-ietf-sipcore-callinfo-spam-04

Abstract

   Called parties often wish to decide whether to accept, reject or
   redirect calls based on the likely nature of the call.  For example,
   they may want to reject unwanted telemarketing or fraudulent calls,
   but accept emergency alerts from numbers not in their address book.
   This document describes SIP Call-Info parameters and a feature tag
   that allow originating, intermediate and terminating SIP entities to
   label calls as to their type, confidence and references to additional
   information.

Status of This Memo

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   This Internet-Draft will expire on March 1, 2020.

Copyright Notice

   Copyright (c) 2019 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
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   (https://trustee.ietf.org/license-info) in effect on the date of
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   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must

Schulzrinne               Expires March 1, 2020                 [Page 1]
Internet-Draft               Call-Info Spam                  August 2019

   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Normative Language  . . . . . . . . . . . . . . . . . . . . .   3
   3.  Overview of Operation . . . . . . . . . . . . . . . . . . . .   4
   4.  Parameters  . . . . . . . . . . . . . . . . . . . . . . . . .   4
   5.  Call Types  . . . . . . . . . . . . . . . . . . . . . . . . .   5
   6.  Examples  . . . . . . . . . . . . . . . . . . . . . . . . . .   7
     6.1.  REGISTER Response . . . . . . . . . . . . . . . . . . . .   7
     6.2.  INVITE Request  . . . . . . . . . . . . . . . . . . . . .   7
   7.  ABNF  . . . . . . . . . . . . . . . . . . . . . . . . . . . .   7
   8.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   8
     8.1.  SIP Call-Info Header Field Parameters . . . . . . . . . .   8
     8.2.  SIP Global Feature-Capability Indicator . . . . . . . . .   8
     8.3.  SIP Call-Info Type Parameter  . . . . . . . . . . . . . .   8
   9.  Security Considerations . . . . . . . . . . . . . . . . . . .   9
   10. Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   9
   11. References  . . . . . . . . . . . . . . . . . . . . . . . . .  10
     11.1.  Normative References . . . . . . . . . . . . . . . . . .  10
     11.2.  Informative References . . . . . . . . . . . . . . . . .  11
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .  11

1.  Introduction

   In many countries, an increasing number of calls are unwanted
   [RFC5039], as they might be fraudulent, telemarketing or the
   receiving party does not want to be disturbed by, say, surveys or
   solicitation by charities.  Currently, called parties have to rely
   exclusively on the caller's number or, if provided, caller name, but
   unwanted callers may not provide their true name or may use a name
   that misleads, e.g., "Cardholder Services".  On the other hand, many
   calls from unknown numbers may be important to the called party,
   whether this is an emergency alert from their emergency management
   office or a reminder about a doctor's appointment.  Since many
   subscribers now reject all calls from unknown numbers, such calls may
   also inadvertently be left unanswered.  Users may also install
   smartphone apps that can benefit from additional information in
   making decisions as to whether to ring, reject or redirect a call to
   voicemail.

   To allow called parties to make more informed decisions on how to
   handle incoming calls from unknown callers, we describe a new set of
   parameters for the SIP [RFC3261] Call-Info header field for labeling